1
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Oboh MA, Asmorom N, Falade C, Ojurongbe O, Thomas BN. High genetic and haplotype diversity in vaccine candidate Pfceltos but not Pfrh5 among malaria-infected children in Ibadan, Nigeria. PeerJ 2023; 11:e16519. [PMID: 38099304 PMCID: PMC10720411 DOI: 10.7717/peerj.16519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 11/03/2023] [Indexed: 12/17/2023] Open
Abstract
Malaria remains a global public health challenge. The disease has a great impact in sub-Saharan Africa among children under five years of age and pregnant women. Malaria control programs targeting the parasite and mosquitoes vectors with combinational therapy and insecticide-treated bednets are becoming obsolete due to the phenomenon of resistance, which is a challenge for reducing morbidity and mortality. Malaria vaccines would be effective alternative to the problem of parasite and insecticide resistance, but focal reports of polymorphisms in malaria candidate antigens have made it difficult to design an effective malaria vaccine. Therefore, studies geared towards elucidating the polymorphic pattern and how genes targeted for vaccine design evolve are imperative. We have carried out molecular and genetic analysis of two genes encoding vaccine candidates-the Plasmodium falciparum cell traversal ookinetes and sporozoites (Pfceltos) and P. falciparum reticulocyte binding protein 5 (Pfrh5) in parasite isolates from malaria-infected children in Ibadan, Nigeria to evaluate their genetic diversity, relatedness and pattern of molecular evolution. Pfceltos and Pfrh5 genes were amplified from P. falciparum positive samples. Amplified fragments were purified and sequenced using the chain termination method. Post-sequence edit of fragments and application of various population genetic analyses was done. We observed a higher number of segregating sites and haplotypes in the Pfceltos than in Pfrh5 gene, the former also presenting higher haplotype (0.942) and nucleotide diversity (θ = 0.01219 and π = 0.01148). In contrast, a lower haplotype (0.426) and nucleotide diversity (θ = 0.00125; π = 0.00095) was observed in the Pfrh5 gene. Neutrality tests do not show deviation from neutral expectations for Pfceltos, with the circulation of multiple low frequency haplotypes (Tajima's D = -0.21637; Fu and Li's D = -0.08164; Fu and Li's F = -0.14051). Strong linkage disequilibrium was observed between variable sites, in each of the genes studied. We postulate that the high diversity and circulation of multiple haplotypes has the potential of making a Pfceltos-subunit vaccine ineffective, while the low genetic diversity of Pfrh5 gene substantiates its evolutionary conservation and potential as a malaria vaccine candidate.
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Affiliation(s)
- Mary Aigbiremo Oboh
- Biomedical Sciences, Rochester Institute of Technology, Rochester, NY, United States of America
| | - Naemy Asmorom
- Biomedical Sciences, Rochester Institute of Technology, Rochester, NY, United States of America
| | - Catherine Falade
- Pharmacology and Therapeutics, University of Ibadan, Ibadan, Oyo, Nigeria
| | - Olusola Ojurongbe
- Medical Microbiology and Parasitology, Ladoke Akintola University of Technology, Ogbomosho, Osun, Nigeria
- Centre for Emerging and Re-emerging Infectious Diseases, Ladoke Akintola University of Technology, Ogbomosho, Oyo, Nigeria
| | - Bolaji N. Thomas
- Biomedical Sciences, Rochester Institute of Technology, Rochester, NY, United States of America
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2
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Baina MT, Djontu JC, Lissom A, Doulamo NVA, Umuhoza DM, Ntabi JDM, Vouvoungui CJ, Boumpoutou RK, Mayela J, Diafouka-Kietela S, Nguimbi E, Ntoumi F. Plasmodium falciparum msp-1 and msp-2 genetic diversity and multiplicity of infection in isolates from Congolese patients in the Republic of Congo. Parasitol Res 2023; 122:2433-2443. [PMID: 37624380 DOI: 10.1007/s00436-023-07951-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 08/18/2023] [Indexed: 08/26/2023]
Abstract
With limited up to date data from the Republic of Congo, the aim of this study was to investigate allelic polymorphism of merozoite surface protein-1 (msp-1) and merozoite surface protein-2 (msp-2). This will help assess the genetic diversity and multiplicity of Plasmodium falciparum infection (MOI), from uncomplicated malaria individuals living in Brazzaville. Between March and October 2021, a cross-sectional study was carried out at a health center in Madibou District located in the south of Brazzaville. Plasmodium infection was diagnosed in human blood by microscopy and the block 2 of P. falciparum msp-1 and block 3 of msp-2 genes were genotyped by nested PCR. Overall, 57 genotypes with fragment sizes ranging from 110 to 410 bp were recorded for msp-1, among which 25, 21, and 11 genotypes identified for K1, MAD20, and RO33 allelic families respectively. RO33 (34.3%) and MAD20 (34.3%) allelic families were more frequent compared to K1 (31.4%) although the difference was not statistically significant. Also, 47 msp-2 genotypes were identified, including 26 FC27 genotypes type, and 21 genotypes belonging to the 3D7 allelic family. FC27 was more frequent (52.3%) compared to 3D7 (47.7%). The prevalence of the polyclonal infection was 90.0% while the MOI was 2.90 ± 1.0. The MOI and polyclonal infection were not significantly associated with the parasitaemia and anaemia. This study reveals a high genetic diversity and the trend of increasing MOI of P. falciparum isolates from the south of Brazzaville, compared to the reports from the same setting before the COVID-19 pandemic.
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Affiliation(s)
- Marcel Tapsou Baina
- Fondation Congolaise pour la Recherche Médicale, Brazzaville, Republic of Congo
- Faculté des Sciences et Techniques, Université Marien Ngouabi, Brazzaville, Republic of Congo
| | - Jean Claude Djontu
- Fondation Congolaise pour la Recherche Médicale, Brazzaville, Republic of Congo.
| | - Abel Lissom
- Fondation Congolaise pour la Recherche Médicale, Brazzaville, Republic of Congo
- Department of Zoology, Faculty of Science, University of Bamenda, Bamenda, Cameroon
| | - Naura Veil Assioro Doulamo
- Fondation Congolaise pour la Recherche Médicale, Brazzaville, Republic of Congo
- Faculté des Sciences et Techniques, Université Marien Ngouabi, Brazzaville, Republic of Congo
| | - Dieu Merci Umuhoza
- Fondation Congolaise pour la Recherche Médicale, Brazzaville, Republic of Congo
- Faculté des Sciences et Techniques, Université Marien Ngouabi, Brazzaville, Republic of Congo
| | - Jacque Dollon Mbama Ntabi
- Fondation Congolaise pour la Recherche Médicale, Brazzaville, Republic of Congo
- Faculté des Sciences et Techniques, Université Marien Ngouabi, Brazzaville, Republic of Congo
| | - Christevy Jeanney Vouvoungui
- Fondation Congolaise pour la Recherche Médicale, Brazzaville, Republic of Congo
- Faculté des Sciences et Techniques, Université Marien Ngouabi, Brazzaville, Republic of Congo
| | | | - Jolivet Mayela
- Fondation Congolaise pour la Recherche Médicale, Brazzaville, Republic of Congo
| | | | - Etienne Nguimbi
- Fondation Congolaise pour la Recherche Médicale, Brazzaville, Republic of Congo
- Faculté des Sciences et Techniques, Université Marien Ngouabi, Brazzaville, Republic of Congo
| | - Francine Ntoumi
- Fondation Congolaise pour la Recherche Médicale, Brazzaville, Republic of Congo.
- Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany.
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3
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Yanik S, Venkatesh V, Parker ML, Ramaswamy R, Diouf A, Sarkar D, Miura K, Long CA, Boulanger MJ, Srinivasan P. Structure guided mimicry of an essential P. falciparum receptor-ligand complex enhances cross neutralizing antibodies. Nat Commun 2023; 14:5879. [PMID: 37735574 PMCID: PMC10514071 DOI: 10.1038/s41467-023-41636-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 09/13/2023] [Indexed: 09/23/2023] Open
Abstract
Invasion of human erythrocytes by Plasmodium falciparum (Pf) merozoites relies on the interaction between two parasite proteins: apical membrane antigen 1 (AMA1) and rhoptry neck protein 2 (RON2). While antibodies to AMA1 provide limited protection against Pf in non-human primate malaria models, clinical trials using recombinant AMA1 alone (apoAMA1) yielded no protection due to insufficient functional antibodies. Immunization with AMA1 bound to RON2L, a 49-amino acid peptide from its ligand RON2, has shown superior protection by increasing the proportion of neutralizing antibodies. However, this approach relies on the formation of a complex in solution between the two vaccine components. To advance vaccine development, here we engineered chimeric antigens by replacing the AMA1 DII loop, displaced upon ligand binding, with RON2L. Structural analysis confirmed that the fusion chimera (Fusion-FD12) closely mimics the binary AMA1-RON2L complex. Immunization studies in female rats demonstrated that Fusion-FD12 immune sera, but not purified IgG, neutralized vaccine-type parasites more efficiently compared to apoAMA1, despite lower overall anti-AMA1 titers. Interestingly, Fusion-FD12 immunization enhanced antibodies targeting conserved epitopes on AMA1, leading to increased neutralization of non-vaccine type parasites. Identifying these cross-neutralizing antibody epitopes holds promise for developing an effective, strain-transcending malaria vaccine.
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Affiliation(s)
- Sean Yanik
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, MD, 21205, USA
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Varsha Venkatesh
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, MD, 21205, USA
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Michelle L Parker
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 3P6, Canada
| | - Raghavendran Ramaswamy
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 3P6, Canada
| | - Ababacar Diouf
- Laboratory of Malaria and Vector Research, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20852, USA
| | - Deepti Sarkar
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, MD, 21205, USA
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20852, USA
| | - Carole A Long
- Laboratory of Malaria and Vector Research, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20852, USA
| | - Martin J Boulanger
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 3P6, Canada
| | - Prakash Srinivasan
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, MD, 21205, USA.
- The Johns Hopkins Malaria Research Institute, Baltimore, MD, 21205, USA.
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4
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Patel PN, Dickey TH, Diouf A, Salinas ND, McAleese H, Ouahes T, Long CA, Miura K, Lambert LE, Tolia NH. Structure-based design of a strain transcending AMA1-RON2L malaria vaccine. Nat Commun 2023; 14:5345. [PMID: 37660103 PMCID: PMC10475129 DOI: 10.1038/s41467-023-40878-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 08/14/2023] [Indexed: 09/04/2023] Open
Abstract
Apical membrane antigen 1 (AMA1) is a key malaria vaccine candidate and target of neutralizing antibodies. AMA1 binds to a loop in rhoptry neck protein 2 (RON2L) to form the moving junction during parasite invasion of host cells, and this complex is conserved among apicomplexan parasites. AMA1-RON2L complex immunization achieves higher growth inhibitory activity than AMA1 alone and protects mice against Plasmodium yoelii challenge. Here, three single-component AMA1-RON2L immunogens were designed that retain the structure of the two-component AMA1-RON2L complex: one structure-based design (SBD1) and two insertion fusions. All immunogens elicited high antibody titers with potent growth inhibitory activity, yet these antibodies did not block RON2L binding to AMA1. The SBD1 immunogen induced significantly more potent strain-transcending neutralizing antibody responses against diverse strains of Plasmodium falciparum than AMA1 or AMA1-RON2L complex vaccination. This indicates that SBD1 directs neutralizing antibody responses to strain-transcending epitopes in AMA1 that are independent of RON2L binding. This work underscores the importance of neutralization mechanisms that are distinct from RON2 blockade. The stable single-component SBD1 immunogen elicits potent strain-transcending protection that may drive the development of next-generation vaccines for improved malaria and apicomplexan parasite control.
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Affiliation(s)
- Palak N Patel
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Thayne H Dickey
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Ababacar Diouf
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Nichole D Salinas
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Holly McAleese
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Tarik Ouahes
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Carole A Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Lynn E Lambert
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Niraj H Tolia
- Host-Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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5
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Markwalter CF, Petersen JEV, Zeno EE, Sumner KM, Freedman E, Mangeni JN, Abel L, Obala AA, Prudhomme-O’Meara W, Taylor SM. Symptomatic malaria enhances protection from reinfection with homologous Plasmodium falciparum parasites. PLoS Pathog 2023; 19:e1011442. [PMID: 37307293 PMCID: PMC10289385 DOI: 10.1371/journal.ppat.1011442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 06/23/2023] [Accepted: 05/24/2023] [Indexed: 06/14/2023] Open
Abstract
A signature remains elusive of naturally-acquired immunity against Plasmodium falciparum. We identified P. falciparum in a 14-month cohort of 239 people in Kenya, genotyped at immunogenic parasite targets expressed in the pre-erythrocytic (circumsporozoite protein, CSP) and blood (apical membrane antigen 1, AMA-1) stages, and classified into epitope type based on variants in the DV10, Th2R, and Th3R epitopes in CSP and the c1L region of AMA-1. Compared to asymptomatic index infections, symptomatic malaria was associated with reduced reinfection by parasites bearing homologous CSP-Th2R (adjusted hazard ratio [aHR]:0.63; 95% CI:0.45-0.89; p = 0.008) CSP-Th3R (aHR:0.71; 95% CI:0.52-0.97; p = 0.033), and AMA-1 c1L (aHR:0.63; 95% CI:0.43-0.94; p = 0.022) epitope types. The association of symptomatic malaria with reduced hazard of homologous reinfection was strongest for rare epitope types. Symptomatic malaria provides more durable protection against reinfection with parasites bearing homologous epitope types. The phenotype represents a legible molecular epidemiologic signature of naturally-acquired immunity by which to identify new antigen targets.
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Affiliation(s)
- Christine F. Markwalter
- Duke Global Health Institute, Duke University, Durham, North Carolina, United States of America
| | - Jens E. V. Petersen
- Division of Infectious Diseases, School of Medicine, Duke University, Durham, North Carolina, United States of America
| | - Erica E. Zeno
- Division of Infectious Diseases, School of Medicine, Duke University, Durham, North Carolina, United States of America
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Kelsey M. Sumner
- Division of Infectious Diseases, School of Medicine, Duke University, Durham, North Carolina, United States of America
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Elizabeth Freedman
- Division of Infectious Diseases, School of Medicine, Duke University, Durham, North Carolina, United States of America
| | - Judith N. Mangeni
- School of Public Health, College of Health Sciences, Moi University, Eldoret, Kenya
| | - Lucy Abel
- Academic Model Providing Access to Healthcare, Moi Teaching and Referral Hospital, Eldoret, Kenya
| | - Andrew A. Obala
- School of Medicine, College of Health Sciences, Moi University, Eldoret, Kenya
| | - Wendy Prudhomme-O’Meara
- Duke Global Health Institute, Duke University, Durham, North Carolina, United States of America
- Division of Infectious Diseases, School of Medicine, Duke University, Durham, North Carolina, United States of America
- School of Public Health, College of Health Sciences, Moi University, Eldoret, Kenya
| | - Steve M. Taylor
- Duke Global Health Institute, Duke University, Durham, North Carolina, United States of America
- Division of Infectious Diseases, School of Medicine, Duke University, Durham, North Carolina, United States of America
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, United States of America
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6
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Srinivasan P, Yanik S, Venkatesh V, Parker M, Diouf A, Sarkar D, Miura K, Long C, Boulanger M. Structure guided mimicry of an essential P. falciparum receptor-ligand complex enhances cross neutralizing antibodies. RESEARCH SQUARE 2023:rs.3.rs-2733434. [PMID: 37131813 PMCID: PMC10153359 DOI: 10.21203/rs.3.rs-2733434/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Invasion of human red blood cells (RBCs) by Plasmodium falciparum (Pf) merozoites relies on the interaction between two parasite proteins, apical membrane antigen 1 (AMA1) and rhoptry neck protein 2 (RON2) 1,2 . Antibodies to AMA1 confer limited protection against P. falciparum in non-human primate malaria models 3,4 . However, clinical trials with recombinant AMA1 alone (apoAMA1) saw no protection, likely due to inadequate levels of functional antibodies 5-8 . Notably, immunization with AMA1 in its ligand bound conformation using RON2L, a 49 amino acid peptide from RON2, confers superior protection against P. falciparum malaria by enhancing the proportion of neutralizing antibodies 9,10 . A limitation of this approach, however, is that it requires the two vaccine components to form a complex in solution. To facilitate vaccine development, we engineered chimeric antigens by strategically replacing the AMA1 DII loop that is displaced upon ligand binding with RON2L. Structural characterization of the fusion chimera, Fusion-F D12 to 1.55 Å resolution showed that it closely mimics the binary receptor-ligand complex. Immunization studies showed that Fusion-F D12 immune sera neutralized parasites more efficiently than apoAMA1 immune sera despite having an overall lower anti-AMA1 titer, suggesting improvement in antibody quality. Furthermore, immunization with Fusion-F D12 enhanced antibodies targeting conserved epitopes on AMA1 resulting in greater neutralization of non-vaccine type parasites. Identifying epitopes of such cross-neutralizing antibodies will help in the development of an effective, strain-transcending malaria vaccine. Our fusion protein design is a robust vaccine platform that can be enhanced by incorporating polymorphisms in AMA1 to effectively neutralize all P. falciparum parasites.
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Affiliation(s)
| | | | | | | | | | | | | | - Carole Long
- Laboratory of Malaria and Vector Resarch, NIAID/NIH
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7
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Markwalter CF, Petersen JEV, Zeno EE, Sumner KM, Freedman E, Mangeni JN, Abel L, Obala AA, Prudhomme-O’Meara W, Taylor SM. Symptomatic malaria enhances protection from reinfection with homologous Plasmodium falciparum parasites. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.01.04.23284198. [PMID: 36711685 PMCID: PMC9882554 DOI: 10.1101/2023.01.04.23284198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A signature remains elusive of naturally-acquired immunity against Plasmodium falciparum . We identified P. falciparum in a 14-month cohort of 239 people in Kenya, genotyped at immunogenic parasite targets expressed in the pre-erythrocytic (circumsporozoite protein, CSP) and blood (apical membrane antigen 1, AMA-1) stages, and classified into epitope type based on variants in the DV10, Th2R, and Th3R epitopes in CSP and the c1L region of AMA-1. Compared to asymptomatic index infections, symptomatic malaria was associated with a reduced reinfection by parasites bearing homologous CSP-Th2R (adjusted hazard ratio [aHR]:0.63; 95% CI:0.45-0.89; p=0.008) CSP-Th3R (aHR:0.71; 95% CI:0.52-0.97; p=0.033), and AMA-1 c1L (aHR:0.63; 95% CI:0.43-0.94; p=0.022) epitope types. The association of symptomatic malaria with reduced risk of homologous reinfection was strongest for rare epitope types. Symptomatic malaria more effectively promotes functional immune responses. The phenotype represents a legible molecular epidemiologic signature of naturally-acquired immunity by which to identify new antigen targets.
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Affiliation(s)
| | - Jens E. V. Petersen
- Division of Infectious Diseases, School of Medicine, Duke University, Durham NC USA
| | - Erica E. Zeno
- Division of Infectious Diseases, School of Medicine, Duke University, Durham NC USA,Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill NC USA
| | - Kelsey M. Sumner
- Division of Infectious Diseases, School of Medicine, Duke University, Durham NC USA,Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill NC USA
| | - Elizabeth Freedman
- Division of Infectious Diseases, School of Medicine, Duke University, Durham NC USA
| | - Judith N. Mangeni
- School of Public Health, College of Health Sciences, Moi University, Eldoret, Kenya
| | - Lucy Abel
- Academic Model Providing Access to Healthcare, Moi Teaching and Referral Hospital, Eldoret Kenya
| | - Andrew A. Obala
- School of Medicine, College of Health Sciences, Moi University, Eldoret Kenya
| | - Wendy Prudhomme-O’Meara
- Duke Global Health Institute, Duke University, Durham NC USA,Division of Infectious Diseases, School of Medicine, Duke University, Durham NC USA,School of Public Health, College of Health Sciences, Moi University, Eldoret, Kenya
| | - Steve M. Taylor
- Duke Global Health Institute, Duke University, Durham NC USA,Division of Infectious Diseases, School of Medicine, Duke University, Durham NC USA,Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill NC USA,Corresponding author: Steve M Taylor ,
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8
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Malaria Vaccines. Infect Dis (Lond) 2023. [DOI: 10.1007/978-1-0716-2463-0_536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
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9
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Plasmodium falciparum Merozoite Surface Proteins Polymorphisms and Treatment Outcomes among Patients with Uncomplicated Malaria in Mwanza, Tanzania. J Trop Med 2022; 2022:5089143. [DOI: 10.1155/2022/5089143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 09/26/2022] [Accepted: 10/20/2022] [Indexed: 11/25/2022] Open
Abstract
Background. The severity of malaria infection depends on the host, parasite and environmental factors. Merozoite surface protein (msp) diversity determines transmission dynamics, P. falciparum immunity evasion, and pathogenesis or virulence. There is limited updated information on P. falciparum msp polymorphisms and their impact on artemether-lumefantrine treatment outcomes in Tanzania. Therefore, this study is aimed at examining msp genetic diversity and multiplicity of infection (MOI) among P. falciparum malaria patients. The influence of MOI on peripheral parasite clearance and adequate clinical and parasitological response (ACPR) was also assessed. Methods. Parasite DNA was extracted from dried blood spots according to the manufacture’s protocol. Primary and nested PCR were performed. The PCR products for both the block 2 region of msp1 and the block 3 regions of msp2 genes and their specific allelic families were visualized on a 2.5% agarose gel. Results. The majority of the isolates, 58/102 (58.8%) for msp1 and 69/115 (60.1%) for msp2, harboured more than one parasite genotypes. For the msp1 gene, K1 was the predominant allele observed (75.64%), whereas RO33 occurred at the lowest frequency (43.6%). For the msp2 gene, the 3D7 allele was observed at a higher frequency (81.7%) than the FC27 allele (76.9%). The MOIs were 2.44 for msp1 and 2.27 for msp2 (
). A significant correlation between age and multiplicity of infection (MOI) for msp1 or MOI for msp2 was not established in this study (rho = 0.074,
and rho = −0.129,
, respectively). Similarly, there was no positive correlation between parasite density at day 1 and MOI for both msp1 (rho = 0.113,
) and msp2 (rho = 0.043,
). The association between MOI and ACPR was not observed for either msp1 or mps2 (
and 0.296, respectively). Conclusions. This study reports high polyclonal infections, MOI and allelic frequencies for both msp1 and msp2. There was a lack of correlation between MOI and ACPR. However, a borderline significant correlation was observed between day 2 parasitaemia and MOI.
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Oboh MA, Isaac C, Schroeter MN, Morenikeji OB, Amambua-Ngwa A, Meremikwu MM, Thomas BN. Population genetic analysis of Plasmodium falciparum cell-traversal protein for ookinetes and sporozoite among malaria patients from southern Nigeria. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2022; 105:105369. [PMID: 36182066 DOI: 10.1016/j.meegid.2022.105369] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 09/12/2022] [Accepted: 09/20/2022] [Indexed: 11/27/2022]
Abstract
Plasmodium falciparum immune escape mechanisms affect antigens being prioritized for vaccine design. As a result of the multiple surface antigens the parasite exhibits at different life cycle stages, designing a vaccine that would efficiently boost the immune system in clearing infections has been challenging. The P. falciparum cell-traversal protein for ookinetes and sporozoite (Pfceltos) is instrumental for ookinete traversal of the mosquito midgut and sporozoites invasion of the human liver cells. Pfceltos elicits both humoral and cellular immune response but has been reported with multiple single nucleotide polymorphisms in global isolates. A cross-sectional survey, conducted in southern Nigeria, between January-March 2021 recruited 283 individuals. Of this, 166 demonstrated P. falciparum infections (86 from Cross River and 80 from Edo), 48 (55.8%) while only 36 (45%) were amplified for Pfceltos gene from both sites respectively. Fifty amplified samples were sequenced and analysed for their diversity, polymorphisms and population structure of the gene. The number of segregating sites in Edo State was higher (34) than that of Cross River State. Though nucleotide diversity was higher for Edo compared to Cross River State (θw = 0.02505; π = 0.03993 versus θw = 0.00930; π = 0.01033 respectively), the reverse was the case for haplotype diversity (0.757 versus 0.890 for Edo and Cross River respectively). Of the twelve haplotypes observed from both states, only two (KASLPVEK and NAFLSFEK) were shared, with haplotype prevalence higher in Edo (16% and 36%) than Cross River (8% and 4%). The Tajima's D test was positive for both states, with Fst value showing a strong genetic differentiation (Fst = 0.25599), indicating the occurrence of balancing selection favoring haplotype circulation at a low frequency. The shared haplotypes, low Hst and Fst values presents a challenge to predict the extent of gene flow. High LD values present a grim public health consequence should a Pfceltos-conjugated vaccine be considered for prophylaxis in Nigeria.
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Affiliation(s)
- Mary A Oboh
- Department of Biomedical Sciences, Rochester Institute of Technology, Rochester, NY, United States of America.
| | - Clement Isaac
- Department of Zoology, Faculty of Life Sciences, Ambrose Ali University, Ekpoma, Nigeria
| | - Marissa N Schroeter
- Department of Biomedical Sciences, Rochester Institute of Technology, Rochester, NY, United States of America
| | - Olanrewaju B Morenikeji
- Division of Biological and Health Sciences, University of Pittsburgh, Bradford, PA 16701, United States of America
| | - Alfred Amambua-Ngwa
- Medical Research Council Unit, The Gambia, at the London School of Hygiene and Tropical Medicine, Fajara, the Gambia
| | - Martin M Meremikwu
- University of Calabar Teaching Hospital, Calabar, Cross River State, Nigeria
| | - Bolaji N Thomas
- Department of Biomedical Sciences, Rochester Institute of Technology, Rochester, NY, United States of America.
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Ullah I, Afridi SG, Israr M, Khan H, Shams S, Zaib K, Le HG, Kang JM, Na BK, Khan A. Population genetic analyses inferred a limited genetic diversity across the pvama-1 DI domain among Plasmodium vivax isolates from Khyber Pakhtunkhwa regions of Pakistan. BMC Infect Dis 2022; 22:807. [PMID: 36310166 PMCID: PMC9620592 DOI: 10.1186/s12879-022-07798-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 10/11/2022] [Indexed: 11/24/2022] Open
Abstract
Background Plasmodium vivax apical membrane antigen-1 (pvama-1) is an important vaccine candidate against Malaria. The genetic composition assessment of pvama-1 from wide-range geography is vital to plan the antigen based vaccine designing against Malaria. Methods The blood samples were collected from 84 P. vivax positive malaria patients from different districts of Khyber Pakhtunkhwa (KP) province of Pakistan. The highly polymorphic and immunogenic domain-I (DI) region of pvama-1 was PCR amplified and DNA sequenced. The QC based sequences raw data filtration was done using DNASTAR package. The downstream population genetic analyses were performed using MEGA4, DnaSP, Arlequin v3.5 and Network.5 resources. Results The analyses unveiled total 57 haplotypes of pvama-1 (DI) in KP samples with majorly prevalent H-14 and H-5 haplotypes. Pairwise comparative population genetics analyses identified limited to moderate genetic distinctions among the samples collected from different districts of KP, Pakistan. In context of worldwide available data, the KP samples depicted major genetic differentiation against the Korean samples with Fst = 0.40915 (P-value = 0.0001), while least distinction was observed against Indian and Iranian samples. The statistically significant negative values of Fu and Li’s D* and F* tests indicate the evidence of population expansion and directional positive selection signature. The slow LD decay across the nucleotide distance in KP isolates indicates low nucleotide diversity. In context of reference pvama-1 sequence, the KP samples were identified to have 09 novel non-synonymous single nucleotide polymorphisms (nsSNPs), including several trimorphic and tetramorphic substitutions. Few of these nsSNPs are mapped within the B-cell predicted epitopic motifs of the pvama-1, and possibly modulate the immune response mechanism. Conclusion Low genetic differentiation was observed across the pvama-1 DI among the P. vivax isolates acquired from widespread regions of KP province of Pakistan. The information may implicate in future vaccine designing strategies based on antigenic features of pvama-1. Supplementary Information The online version contains supplementary material available at 10.1186/s12879-022-07798-1.
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12
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Zhao X, Hu Y, Zhao Y, Wang L, Wu Z, Soe MT, Kyaw MP, Cui L, Zhu X, Cao Y. Genetic diversity in the transmission-blocking vaccine candidate Plasmodium vivax gametocyte protein Pvs230 from the China-Myanmar border area and central Myanmar. Parasit Vectors 2022; 15:371. [PMID: 36253843 PMCID: PMC9574792 DOI: 10.1186/s13071-022-05523-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 09/27/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Sexual stage surface antigens are potential targets of transmission-blocking vaccines (TBVs). The gametocyte and gamete surface antigen P230, a leading TBV candidate, is critical for red blood cell binding during exflagellation and subsequent oocyst development. Here, the genetic diversity of Pvs230 was studied in Plasmodium vivax parasite isolates from the China-Myanmar border (CMB) and central Myanmar. METHODS Plasmodium vivax isolates were collected in clinics from malaria-endemic areas of the CMB (143 samples) and Myanmar (23 samples). The interspecies variable part (IVP, nucleotides 1-807) and interspecies conserved part (ICP, 808-2862) of Pvs230 were amplified by PCR and sequenced. Molecular evolution studies were conducted to evaluate the genetic diversity, signature of selection, population differentiation, haplotype network, and population structure of the study parasite populations and publicly available Pvs230 sequences from six global P. vivax populations. RESULTS Limited genetic diversity was observed for the CMB (π = 0.002) and Myanmar (π = 0.001) isolates. Most amino acid substitutions were located in the IVP and cysteine-rich domain of Pvs230. Evidence of positive selection was observed for IVP and purifying selection for ICP. Codon-based tests identified specific codons under natural selection in both IVP and ICP. The fixation index (FST) showed low genetic differentiation between East and Southeast Asian populations, with FST ranging from 0.018 to 0.119. The highest FST value (FST = 0.503) was detected between the Turkey and Papua New Guinea populations. A total of 92 haplotypes were identified in global isolates, with the major haplotypes 2 and 9 being the most abundant and circulating in East and Southeast Asia populations. Several detected non-synonymous substitutions were mapped in the predicted structure and B-cell epitopes of Pvs230. CONCLUSIONS We detected low levels of genetic diversity of Pvs230 in global P. vivax populations. Geographically specific haplotypes were identified for Pvs230. Some mutations are located within a potential B-cell epitope region and need to be considered in future TBV designs.
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Affiliation(s)
- Xin Zhao
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110122, Liaoning, People's Republic of China
| | - Yubing Hu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110122, Liaoning, People's Republic of China.,Central Laboratory of the First Affiliated Hospital of China Medical University, Shenyang, China
| | - Yan Zhao
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110122, Liaoning, People's Republic of China
| | - Lin Wang
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110122, Liaoning, People's Republic of China
| | - Zifang Wu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110122, Liaoning, People's Republic of China
| | - Myat Thu Soe
- Myanmar Health Network Organization, Yangon, Myanmar
| | | | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Suite 304, Tampa, FL, 33612, USA
| | - Xiaotong Zhu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110122, Liaoning, People's Republic of China.
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110122, Liaoning, People's Republic of China.
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13
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Thiam LG, Mangou K, Ba A, Mbengue A, Bei AK. Leveraging genome editing to functionally evaluate Plasmodium diversity. Trends Parasitol 2022; 38:558-571. [PMID: 35469746 DOI: 10.1016/j.pt.2022.03.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/20/2022] [Accepted: 03/21/2022] [Indexed: 12/13/2022]
Abstract
The ambitious goal of malaria elimination requires an in-depth understanding of the parasite's biology to counter the growing threat of antimalarial resistance and immune evasion. Timely assessment of the functional impact of antigenic diversity in the early stages of vaccine development will be critical for achieving the goal of malaria control, elimination, and ultimately eradication. Recent advances in targeted genome editing enabled the functional validation of resistance-associated markers in Plasmodium falciparum, the deadliest malaria-causing pathogen and strain-specific immune neutralization. This review explores recent advances made in leveraging genome editing to aid the functional evaluation of Plasmodium diversity and highlights how these techniques can assist in prioritizing both therapeutic and vaccine candidates.
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Affiliation(s)
- Laty Gaye Thiam
- G4 - Malaria Experimental Genetic Approaches & Vaccines, Pôle Immunophysiopathologie et Maladies Infectieuses, Institut Pasteur de Dakar, Dakar, Senegal
| | - Khadidiatou Mangou
- G4 - Malaria Experimental Genetic Approaches & Vaccines, Pôle Immunophysiopathologie et Maladies Infectieuses, Institut Pasteur de Dakar, Dakar, Senegal
| | - Aboubacar Ba
- G4 - Malaria Experimental Genetic Approaches & Vaccines, Pôle Immunophysiopathologie et Maladies Infectieuses, Institut Pasteur de Dakar, Dakar, Senegal
| | - Alassane Mbengue
- G4 - Malaria Experimental Genetic Approaches & Vaccines, Pôle Immunophysiopathologie et Maladies Infectieuses, Institut Pasteur de Dakar, Dakar, Senegal
| | - Amy K Bei
- G4 - Malaria Experimental Genetic Approaches & Vaccines, Pôle Immunophysiopathologie et Maladies Infectieuses, Institut Pasteur de Dakar, Dakar, Senegal; Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA.
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14
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Molina-Franky J, Patarroyo ME, Kalkum M, Patarroyo MA. The Cellular and Molecular Interaction Between Erythrocytes and Plasmodium falciparum Merozoites. Front Cell Infect Microbiol 2022; 12:816574. [PMID: 35433504 PMCID: PMC9008539 DOI: 10.3389/fcimb.2022.816574] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 02/21/2022] [Indexed: 11/13/2022] Open
Abstract
Plasmodium falciparum is the most lethal human malaria parasite, partly due to its genetic variability and ability to use multiple invasion routes via its binding to host cell surface receptors. The parasite extensively modifies infected red blood cell architecture to promote its survival which leads to increased cell membrane rigidity, adhesiveness and permeability. Merozoites are initially released from infected hepatocytes and efficiently enter red blood cells in a well-orchestrated process that involves specific interactions between parasite ligands and erythrocyte receptors; symptoms of the disease occur during the life-cycle’s blood stage due to capillary blockage and massive erythrocyte lysis. Several studies have focused on elucidating molecular merozoite/erythrocyte interactions and host cell modifications; however, further in-depth analysis is required for understanding the parasite’s biology and thus provide the fundamental tools for developing prophylactic or therapeutic alternatives to mitigate or eliminate Plasmodium falciparum-related malaria. This review focuses on the cellular and molecular events during Plasmodium falciparum merozoite invasion of red blood cells and the alterations that occur in an erythrocyte once it has become infected.
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Affiliation(s)
- Jessica Molina-Franky
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia
- Department of Immunology and Theranostics, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute of the City of Hope, Duarte, CA, United States
- PhD Programme in Biotechnology, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Manuel Elkin Patarroyo
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia
- Health Sciences Division, Universidad Santo Tomás, Bogotá, Colombia
- Faculty of Medicine, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Markus Kalkum
- Department of Immunology and Theranostics, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute of the City of Hope, Duarte, CA, United States
- *Correspondence: Markus Kalkum, ; Manuel Alfonso Patarroyo,
| | - Manuel Alfonso Patarroyo
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia
- Health Sciences Division, Universidad Santo Tomás, Bogotá, Colombia
- Faculty of Medicine, Universidad Nacional de Colombia, Bogotá, Colombia
- *Correspondence: Markus Kalkum, ; Manuel Alfonso Patarroyo,
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15
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Lagnika HO, Moussiliou A, Agonhossou R, Sovegnon P, Djihinto OY, Medjigbodo AA, Djossou L, Amoah LE, Ogouyemi-Hounto A, Djogbenou LS. Plasmodium falciparum msp1 and msp2 genetic diversity in parasites isolated from symptomatic and asymptomatic malaria subjects in the South of Benin. Parasitol Res 2022; 121:167-175. [PMID: 34993632 DOI: 10.1007/s00436-021-07399-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 11/29/2021] [Indexed: 10/19/2022]
Abstract
Symptomatic and asymptomatic malaria patients are considered as the reservoirs of human Plasmodium. In the present study, we have evaluated the Plasmodium falciparum merozoite surface protein-1 (Pfmsp1) and protein-2 (Pfmsp2) genetic diversity among the symptomatic and asymptomatic malaria infection from health facilities in Cotonou, Benin Republic. A cross-sectional study recruited 158 individuals, including 77 from the asymptomatic and 81 from the symptomatic groups. The parasites were genotyped using Nested Polymerase Chain Reaction. Samples identified as Plasmodium falciparum were genotyped for their genetic diversity. No significant difference was observed in the overall multiplicity of infection (MOI) between the asymptomatic and symptomatic groups. In the symptomatic group, the overall frequency of K1, MAD20, and RO33 allelic family was more predominant (98.5%) followed by 3D7 (87.3%) and FC27 (83.1%). However, in asymptomatic group, the K1 alleles were the most prevalent (100%) followed by FC27 (89.9%), 3D7 (76.8%), MAD20 (60.5%), and RO33 (35.5%). The frequency of multiple allelic types (K1+MAD20+RO33) at the Pfmsp1 loci in the symptomatic infections was significantly higher when compared to that of the asymptomatic ones (97% vs. 34%, p < 0.05), whereas no difference was observed in the frequency of multiple allelic types (3D7 and FC27) at the Pfmsp2 loci between the two groups. The high presence of msp1 multiple infections in the symptomatic group compared to asymptomatic ones suggests an association between the genetic diversity and the onset of malaria symptoms. These data can provide valuable information in the development of a vaccine that could reduce the symptomatic disease.
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Affiliation(s)
- Hamirath Odée Lagnika
- Tropical Infectious Diseases Research Centre, University of Abomey-Calavi, 01BP 526, Cotonou, Benin
- Laboratory of Infectious Vector-Borne Diseases, Regional Institute of Public Health/University of Abomey-Calavi, BP 384, Ouidah, Benin
| | - Azizath Moussiliou
- Laboratory of Infectious Vector-Borne Diseases, Regional Institute of Public Health/University of Abomey-Calavi, BP 384, Ouidah, Benin
| | - Romuald Agonhossou
- Tropical Infectious Diseases Research Centre, University of Abomey-Calavi, 01BP 526, Cotonou, Benin
- Laboratory of Infectious Vector-Borne Diseases, Regional Institute of Public Health/University of Abomey-Calavi, BP 384, Ouidah, Benin
| | - Pierre Sovegnon
- Tropical Infectious Diseases Research Centre, University of Abomey-Calavi, 01BP 526, Cotonou, Benin
- Laboratory of Infectious Vector-Borne Diseases, Regional Institute of Public Health/University of Abomey-Calavi, BP 384, Ouidah, Benin
| | - Oswald Yédjinnavênan Djihinto
- Tropical Infectious Diseases Research Centre, University of Abomey-Calavi, 01BP 526, Cotonou, Benin
- Laboratory of Infectious Vector-Borne Diseases, Regional Institute of Public Health/University of Abomey-Calavi, BP 384, Ouidah, Benin
| | - Adandé Assogba Medjigbodo
- Tropical Infectious Diseases Research Centre, University of Abomey-Calavi, 01BP 526, Cotonou, Benin
- Laboratory of Infectious Vector-Borne Diseases, Regional Institute of Public Health/University of Abomey-Calavi, BP 384, Ouidah, Benin
| | - Laurette Djossou
- Tropical Infectious Diseases Research Centre, University of Abomey-Calavi, 01BP 526, Cotonou, Benin
- Laboratory of Infectious Vector-Borne Diseases, Regional Institute of Public Health/University of Abomey-Calavi, BP 384, Ouidah, Benin
| | - Linda Eva Amoah
- Immunology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | | | - Luc Salako Djogbenou
- Tropical Infectious Diseases Research Centre, University of Abomey-Calavi, 01BP 526, Cotonou, Benin.
- Laboratory of Infectious Vector-Borne Diseases, Regional Institute of Public Health/University of Abomey-Calavi, BP 384, Ouidah, Benin.
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16
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Usman-Yamman H, Omalu C J I, Abubakar A, Abolarinwa S O, Eke S S, Otuu CA. Genetic diversity of plasmodium falciparum isolates in Minna, North Central Nigeria inferred by PCR genotyping of Merozoite surface protein 1 and 2. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2021; 96:105143. [PMID: 34800712 DOI: 10.1016/j.meegid.2021.105143] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 11/01/2021] [Accepted: 11/13/2021] [Indexed: 10/19/2022]
Abstract
North Central Nigeria is one region in Nigeria with a significant incidence of malaria caused majorly by Plasmodium falciparum. This study utilizes the msp1 and msp2 genes of P. falciparum to examine its diversity and multiplicity of infection (MOI). Blood samples were collected from 247 children across selected healthcare facilities in Minna, from infants and children aged 6 months to 17 years. Of the total collection, 143 (58%) of the children were infected with P. falciparum with parasite density ≥ 1000 μl, and from which fifty (50) samples was randomly selected and presented for PCR for the characterization of msp1 and msp2 gene using nested-PCR method. Overall, 57 msp1 genotypes, including K1, MAD20 and RO33 were identified, ranging from (250-1000 bp), (100-500 bp) and (400-500 bp), respectively. In addition, 54 different msp2 genotypes of FC27 and 3D7 alleles ranging from (100-900 bp) and (100-800 bp), respectively were selected. A monoclonal infection of 39% and a polyclonal infection of 61% was recorded, however, a particularity about this study is the polyclonal nature of RO33. Determination of gene diversity revealed MAD20 as the predominant allele for msp1 with a mean MOI of 1.35 and FC27 for msp2 with 1.72 MOI. The overall MOI recorded for the study was 1.60. There was, however, no statistical significance difference between MOI and age of the child (P > 0.05). Meanwhile, findings from this study revealed P. falciparum populations were not genetically diverse with Heterozygosity (He) index of 0.0636. However, a significant level gene diversity within the antigenic markers of msp1 and msp2 was observed with He index of 0.714 and 0.830, respectively. This study has demonstrated the potential of gene diversity and MOI of P. falciparum, as important markers for assessing differences in malaria transmission intensity. Continuous malaria genetic surveillance is therefore recommended as a fundamental tool for monitoring changes in gene types and for intervention programs' effectiveness.
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Affiliation(s)
- Hadijah Usman-Yamman
- Department of Animal Biology, Federal University of Technology, Minna, Niger State, Nigeria.
| | - Innocent Omalu C J
- Department of Animal Biology, Federal University of Technology, Minna, Niger State, Nigeria.
| | - Abdulkadir Abubakar
- Department of Biochemistry, Federal University of Technology, Minna, Niger State, Nigeria.
| | - Abolarinwa S O
- Department of Animal Biology, Federal University of Technology, Minna, Niger State, Nigeria.
| | - Samuel Eke S
- Department of Biology, Air Force Institute of Technology, Kaduna, Nigeria.
| | - Chidiebere A Otuu
- Parasitology and Public Health Research Unit, Department of Zoology and Environmental Biology, University of Nigeria, Nsukka, Nigeria.
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Analysis of Genetic Diversity in Indian Isolates of Rhipicephalus microplus Based on Bm86 Gene Sequence. Vaccines (Basel) 2021; 9:vaccines9030194. [PMID: 33652549 PMCID: PMC7996562 DOI: 10.3390/vaccines9030194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 01/21/2021] [Accepted: 01/26/2021] [Indexed: 11/16/2022] Open
Abstract
The control of cattle tick, Rhipicephalus microplus, is focused on repeated use of acaricides. However, due to growing acaricide resistance and residues problem, immunization of animals along with limited use of effective acaricides is considered a suitable option for the control of tick infestations. To date, more than fifty vaccine candidates have been identified and tested worldwide, but two vaccines were developed using the extensively studied candidate, Bm86. The main reason for limited vaccine commercialization in other countries is genetic diversity in the Bm86 gene leading to considerable variation in vaccine efficacy. India, with 193.46 million cattle population distributed in 28 states and 9 union territories, is suffering from multiple tick infestation dominated by R. microplus. As R. microplus has developed multi-acaricide resistance, an efficacious vaccine may provide a sustainable intervention for tick control. Preliminary experiments revealed that the presently available commercial vaccine based on the BM86 gene is not efficacious against Indian strain. In concert with the principle of reverse vaccinology, genetic polymorphism of the Bm86 gene within Indian isolates of R. microplus was studied. A 578 bp conserved nucleotide sequences of Bm86 from 65 R. microplus isolates collected from 9 Indian states was sequenced and revealed 95.6-99.8% and 93.2-99.5% identity in nucleotides and amino acids sequences, respectively. The identities of nucleotides and deduced amino acids were 94.7-99.8% and 91.8-99.5%, respectively, between full-length sequence (orf) of the Bm86 gene of IVRI-I strain and published sequences of vaccine strains. Six nucleotides deletion were observed in Indian Bm86 sequences. Four B-cell epitopes (D519-K554, H563-Q587, C598-T606, T609-K623), which are present in the conserved region of the IVRI-I Bm86 sequence, were selected. The results confirm that the use of available commercial Bm86 vaccines is not a suitable option against Indian isolates of R. microplus. A country-specific multi-epitope Bm86 vaccine consisting of four specific B-cell epitopes along with candidate molecules, subolesin and tropomyosin in chimeric/co-immunization format may provide a sustainable option for implementation in an integrated tick management system.
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Abamecha A, El-Abid H, Yilma D, Addisu W, Ibenthal A, Bayih AG, Noedl H, Yewhalaw D, Moumni M, Abdissa A. Genetic diversity and genotype multiplicity of Plasmodium falciparum infection in patients with uncomplicated malaria in Chewaka district, Ethiopia. Malar J 2020; 19:203. [PMID: 32513191 PMCID: PMC7281928 DOI: 10.1186/s12936-020-03278-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 05/29/2020] [Indexed: 12/03/2022] Open
Abstract
Background Genetic diversity in Plasmodium falciparum poses a major threat to malaria control and elimination interventions. Characterization of the genetic diversity of P. falciparum strains can be used to assess intensity of parasite transmission and identify potential deficiencies in malaria control programmes, which provides vital information to evaluating malaria elimination efforts. This study investigated the P. falciparum genetic diversity and genotype multiplicity of infection in parasite isolates from cases with uncomplicated P. falciparum malaria in Southwest Ethiopia. Methods A total of 80 P. falciparum microscopy and qPCR positive blood samples were collected from study participants aged 6 months to 60 years, who visited the health facilities during study evaluating the efficacy of artemether-lumefantrine from September–December, 2017. Polymorphic regions of the msp-1 and msp-2 were genotyped by nested polymerase chain reactions (nPCR) followed by gel electrophoresis for fragment analysis. Results Of 80 qPCR-positive samples analysed for polymorphisms on msp-1 and msp-2 genes, the efficiency of msp-1 and msp-2 gene amplification reactions with family-specific primers were 95% and 98.8%, respectively. Allelic variation of 90% (72/80) for msp-1 and 86.2% (69/80) for msp-2 were observed. K1 was the predominant msp-1 allelic family detected in 20.8% (15/72) of the samples followed by MAD20 and RO33. Within msp-2, allelic family FC27 showed a higher frequency (26.1%) compared to IC/3D7 (15.9%). Ten different alleles were observed in msp-1 with 6 alleles for K1, 3 alleles for MAD20 and 1 allele for RO33. In msp-2, 19 individual alleles were detected with 10 alleles for FC27 and 9 alleles for 3D7. Eighty percent (80%) of isolates had multiple genotypes and the overall mean multiplicity of infection was 3.2 (95% CI 2.87–3.46). The heterozygosity indices were 0.43 and 0.85 for msp-1 and msp-2, respectively. There was no significant association between multiplicity of infection and age or parasite density. Conclusions The study revealed high levels of genetic diversity and mixed-strain infections of P. falciparum populations in Chewaka district, Ethiopia, suggesting that both endemicity level and malaria transmission remain high and that strengthened control efforts are needed in Ethiopia.
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Affiliation(s)
- Abdulhakim Abamecha
- School of Medical Laboratory Science, Faculty of Health Sciences, Institute of Health, Jimma University, Jimma, Ethiopia. .,Department of Biomedical, College of Public Health and Medical Science, Mettu University, Mettu, Ethiopia. .,Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia.
| | - Hassan El-Abid
- Laboratory of Cellular Genomics and Molecular Techniques for Investigation, Faculty of Sciences, Moulay Ismail University, Meknès, Morocco
| | - Daniel Yilma
- Department of Internal Medicine, Institute of Health, Jimma University, Jimma, Ethiopia
| | - Wondimagegn Addisu
- School of Medical Laboratory Science, Faculty of Health Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
| | - Achim Ibenthal
- Faculty of Science and Art, HAWK University, Gottingen, Germany
| | | | - Harald Noedl
- Malaria Research Initiative Bandarban (MARIB), Vienna, Austria
| | - Delenasaw Yewhalaw
- School of Medical Laboratory Science, Faculty of Health Sciences, Institute of Health, Jimma University, Jimma, Ethiopia.,Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - Mohieddine Moumni
- Laboratory of Cellular Genomics and Molecular Techniques for Investigation, Faculty of Sciences, Moulay Ismail University, Meknès, Morocco
| | - Alemseged Abdissa
- School of Medical Laboratory Science, Faculty of Health Sciences, Institute of Health, Jimma University, Jimma, Ethiopia.,Armauer Hansen Research Institute, Addis Ababa, Ethiopia
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Zhang CL, Zhou HN, Liu Q, Yang YM. Genetic polymorphism of merozoite surface proteins 1 and 2 of Plasmodium falciparum in the China-Myanmar border region. Malar J 2019; 18:367. [PMID: 31744492 PMCID: PMC6862846 DOI: 10.1186/s12936-019-3003-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 11/11/2019] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Malaria is a major public health problem in the China-Myanmar border region. The genetic structure of malaria parasite may affect its transmission model and control strategies. The present study was to analyse genetic diversity of Plasmodium falciparum by merozoite surface proteins 1 and 2 (MSP1 and MSP2) and to determine the multiplicity of infection in clinical isolates in the China-Myanmar border region. METHODS Venous blood samples (172) and filter paper blood spots (70) of P. falciparum isolates were collected from the patients of the China-Myanmar border region from 2006 to 2011. The genomic DNA was extracted, and the msp1 and msp2 genes were genotyped by nested PCR using allele-specific primers for P. falciparum. RESULTS A total of 215 P. falciparum clinical isolates were genotyped at the msp1 (201) and msp2 (204), respectively. For the msp1 gene, MAD20 family was dominant (53.49%), followed by the K1 family (44.65%), and the RO33 family (12.56%). For the msp2 gene, the most frequent allele was the FC27 family (80.93%), followed by the 3D7 family (75.81%). The total multiplicity of infection (MOI) of msp1 and msp2 was 1.76 and 2.21, with a prevalence of 64.19% and 72.09%, respectively. A significant positive correlation between the MOI and parasite density was found in the msp1 gene of P. falciparum. Sequence analysis revealed 38 different alleles of msp1 (14 K1, 23 MAD20, and 1 RO33) and 52 different alleles of msp2 (37 3D7 and 15 FC27). CONCLUSION The present study showed the genetic polymorphisms with diverse allele types of msp1 and msp2 as well as the high MOI of P. falciparum clinical isolates in the China-Myanmar border region.
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Affiliation(s)
- Cang-Lin Zhang
- Yunnan Provincial Key Laboratory of Vector-borne Diseases Control and Research, Yunnan Provincial Center of Malaria Research, Yunnan Institute of Parasitic Diseases, Pu'er, 665000, Yunnan, China
| | - Hong-Ning Zhou
- Yunnan Provincial Key Laboratory of Vector-borne Diseases Control and Research, Yunnan Provincial Center of Malaria Research, Yunnan Institute of Parasitic Diseases, Pu'er, 665000, Yunnan, China
| | - Quan Liu
- School of Life Sciences and Engineering, Foshan University, Foshan, 528225, Guangdong, China.
- Key Laboratory of Organ Regeneration & Transplantation of the Ministry of Education, The First Hospital of Jilin University, Changchun, 130021, China.
| | - Ya-Ming Yang
- Yunnan Provincial Key Laboratory of Vector-borne Diseases Control and Research, Yunnan Provincial Center of Malaria Research, Yunnan Institute of Parasitic Diseases, Pu'er, 665000, Yunnan, China.
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20
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Wang YN, Lin M, Liang XY, Chen JT, Xie DD, Wang YL, Ehapo CS, Eyi UM, Huang HY, Wu JL, Xu DY, Chen ZM, Cao YL, Chen HB. Natural selection and genetic diversity of domain I of Plasmodium falciparum apical membrane antigen-1 on Bioko Island. Malar J 2019; 18:317. [PMID: 31533747 PMCID: PMC6751645 DOI: 10.1186/s12936-019-2948-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 09/06/2019] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Plasmodium falciparum apical membrane antigen-1 (PfAMA-1) is a promising candidate antigen for a blood-stage malaria vaccine. However, antigenic variation and diversity of PfAMA-1 are still major problems to design a universal malaria vaccine based on this antigen, especially against domain I (DI). Detail understanding of the PfAMA-1 gene polymorphism can provide useful information on this potential vaccine component. Here, general characteristics of genetic structure and the effect of natural selection of DIs among Bioko P. falciparum isolates were analysed. METHODS 214 blood samples were collected from Bioko Island patients with P. falciparum malaria between 2011 and 2017. A fragment spanning DI of PfAMA-1 was amplified by nested polymerase chain reaction and sequenced. Polymorphic characteristics and the effect of natural selection were analysed using MEGA 5.0, DnaSP 6.0 and Popart programs. Genetic diversity in 576 global PfAMA-1 DIs were also analysed. Protein function prediction of new amino acid mutation sites was performed using PolyPhen-2 program. RESULTS 131 different haplotypes of PfAMA-1 were identified in 214 Bioko Island P. falciparum isolates. Most amino acid changes identified on Bioko Island were found in C1L. 32 amino acid changes identified in PfAMA-1 sequences from Bioko Island were found in predicted RBC-binding sites, B cell epitopes or IUR regions. Overall patterns of amino acid changes of Bioko PfAMA-1 DIs were similar to those in global PfAMA-1 isolates. Differential amino acid substitution frequencies were observed for samples from different geographical regions. Eight new amino acid changes of Bioko island isolates were also identified and their three-dimensional protein structural consequences were predicted. Evidence for natural selection and recombination event were observed in global isolates. CONCLUSIONS Patterns of nucleotide diversity and amino acid polymorphisms of Bioko Island isolates were similar to those of global PfAMA-1 DIs. Balancing natural selection across DIs might play a major role in generating genetic diversity in global isolates. Most amino acid changes in DIs occurred in predicted B-cell epitopes. Novel sites mapped on a three dimensional structure of PfAMA-1 showed that these regions were located at the corner. These results may provide significant value in the design of a malaria vaccine based on this antigen.
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Affiliation(s)
- Ya-Nan Wang
- Department of Histology and Embryology, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Min Lin
- School of Food Engineering and Biotechnology, Hanshan Normal University, Chaozhou, Guangdong, People's Republic of China
| | - Xue-Yan Liang
- Department of Histology and Embryology, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
- School of Food Engineering and Biotechnology, Hanshan Normal University, Chaozhou, Guangdong, People's Republic of China
| | - Jiang-Tao Chen
- Laboratory Medical Centre, Huizhou Municipal Central Hospital, Huizhou, Guangdong, People's Republic of China
- The Chinese Medical Aid Team to the Republic of Equatorial Guinea, Guangzhou, Guangdong, People's Republic of China
| | - Dong-De Xie
- Laboratory Medical Centre, Huizhou Municipal Central Hospital, Huizhou, Guangdong, People's Republic of China
| | - Yu-Ling Wang
- Laboratory Medical Centre, Huizhou Municipal Central Hospital, Huizhou, Guangdong, People's Republic of China
| | - Carlos Salas Ehapo
- Department of Medical Laboratory, Malabo Regional Hospital, Malabo, Equatorial Guinea
| | - Urbano Monsuy Eyi
- Department of Medical Laboratory, Malabo Regional Hospital, Malabo, Equatorial Guinea
| | - Hui-Ying Huang
- Department of Histology and Embryology, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
- School of Food Engineering and Biotechnology, Hanshan Normal University, Chaozhou, Guangdong, People's Republic of China
| | - Jing-Li Wu
- 2014 Clinical Medicine Programme, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Dan-Yan Xu
- 2014 Clinical Medicine Programme, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Zhi-Mao Chen
- 2014 Clinical Medicine Programme, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Yi-Long Cao
- 2014 Clinical Medicine Programme, Shantou University Medical College, Shantou, Guangdong, People's Republic of China
| | - Hai-Bin Chen
- Department of Histology and Embryology, Shantou University Medical College, Shantou, Guangdong, People's Republic of China.
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21
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Younis S, Faber BW, Kocken CHM, Remarque EJ. Identification of adjuvants for clinical trials performed with Plasmodium falciparum AMA1 in rabbits. BMC Immunol 2019; 20:25. [PMID: 31362695 PMCID: PMC6664700 DOI: 10.1186/s12865-019-0307-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 07/18/2019] [Indexed: 11/20/2022] Open
Abstract
Background In this study, seven adjuvants were compared for use with Plasmodium falciparum DiCo-Apical Membrane Antigen 1 (Pf-DiCo-AMA1), with the aim to identify an ideal adjuvant which yields high antibody titres and potentially broadens the responses in clinical trials. The following adjuvant formulations were evaluated: SE, SE-GLA, Liposomes, Liposomes-GLA, CoVaccine HT™, ImSaVac-P and ImSaVac-P o/w. The study was performed in rabbits, which were immunized with FVO-AMA1 in combination with one of the seven adjuvants. Antibody levels (humoral responses) and functional activity of the antibodies induced against malaria vaccine candidate AMA1 were evaluated. Thus, in this study the ideal adjuvant is expected to induce high functional antibody levels, a long-lived response, and a broad cross-strain activity. Results AMA1 formulated in all adjuvants was immunogenic. However, the magnitude of the immune responses differed between the seven adjuvants. The highest IgG levels were observed for the CoVaccine HT™ group, this was statistically significant for all four AMA1 variants versus all other adjuvant groups. No differences were observed in the breadth of the humoral response, i.e., increased recognition of AMA1 variants. Also, Growth Inhibition Activity (GIA) for both Plasmodium falciparum strains (FCR3 – homologous to FVO AMA1 protein and NF54 – heterologous to FVO AMA1 protein) were significantly higher in the CoVaccine HT™ group as compared to the other adjuvant groups. Conclusions In brief, all seven vaccine – adjuvant formulations were immunogenic. The magnitude of the immune responses differed between the seven adjuvants. No statistically significant differences were observed in the breadth of the humoral response, nor in longevity of the response. Nevertheless, AMA1 formulated in CoVaccine HT™ appeared as the best adjuvant for use in clinical trials. Electronic supplementary material The online version of this article (10.1186/s12865-019-0307-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sumera Younis
- Biomedical Primate Research Centre, Department of Parasitology, Rijswijk, The Netherlands
| | - Bart W Faber
- Biomedical Primate Research Centre, Department of Parasitology, Rijswijk, The Netherlands
| | - Clemens H M Kocken
- Biomedical Primate Research Centre, Department of Parasitology, Rijswijk, The Netherlands
| | - Edmond J Remarque
- Biomedical Primate Research Centre, Department of Parasitology, Rijswijk, The Netherlands.
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22
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Lê HG, Kang JM, Jun H, Lee J, Thái TL, Myint MK, Aye KS, Sohn WM, Shin HJ, Kim TS, Na BK. Changing pattern of the genetic diversities of Plasmodium falciparum merozoite surface protein-1 and merozoite surface protein-2 in Myanmar isolates. Malar J 2019; 18:241. [PMID: 31311565 PMCID: PMC6636015 DOI: 10.1186/s12936-019-2879-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 07/09/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Plasmodium falciparum merozoite surface protein-1 (PfMSP-1) and -2 (PfMSP-2) are major blood-stage vaccine candidate antigens. Understanding the genetic diversity of the genes, pfmsp-1 and pfmsp-2, is important for recognizing the genetic structure of P. falciparum, and the development of an effective vaccine based on the antigens. In this study, the genetic diversities of pfmsp-1 and pfmsp-2 in the Myanmar P. falciparum were analysed. METHODS The pfmsp-1 block 2 and pfmsp-2 block 3 regions were amplified by polymerase chain reaction from blood samples collected from Myanmar patients who were infected with P. falciparum in 2013-2015. The amplified gene fragments were cloned into a T&A vector, and sequenced. Sequence analysis of Myanmar pfmsp-1 block 2 and pfmsp-2 block 3 was performed to identify the genetic diversity of the regions. The temporal genetic changes of both pfmsp-1 and pfmsp-2 in the Myanmar P. falciparum population, as well as the polymorphic diversity in the publicly available global pfmsp-1 and pfmsp-2, were also comparatively analysed. RESULTS High levels of genetic diversity of pfmsp-1 and pfmsp-2 were observed in the Myanmar P. falciparum isolates. Twenty-eight different alleles of pfmsp-1 (8 for K1 type, 14 for MAD20 type, and 6 for RO33 type) and 59 distinct alleles of pfmsp-2 (18 for FC27, and 41 for 3D7 type) were identified in the Myanmar P. falciparum population in amino acid level. Comparative analyses of the genetic diversity of the Myanmar pfmsp-1 and pfmsp-2 alleles in the recent (2013-2015) and past (2004-2006) Myanmar P. falciparum populations indicated the dynamic genetic expansion of the pfmsp-1 and pfmsp-2 in recent years, suggesting that a high level of genetic differentiation and recombination of the two genes may be maintained. Population genetic structure analysis of the global pfmsp-1 and pfmsp-2 also suggested that a high level of genetic diversity of the two genes was found in the global P. falciparum population. CONCLUSION Despite the recent remarkable decline of malaria cases, the Myanmar P. falciparum population still remains of sufficient size to allow the generation and maintenance of genetic diversity. The high level of genetic diversity of pfmsp-1 and pfmsp-2 in the global P. falciparum population emphasizes the necessity for continuous monitoring of the genetic diversity of the genes for better understanding of the genetic make-up and evolutionary aspect of the genes in the global P. falciparum population.
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Affiliation(s)
- Hương Giang Lê
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea.,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea
| | - Jung-Mi Kang
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea.,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea
| | - Hojong Jun
- Department of Tropical Medicine, and Inha Research Institute for Medical Sciences, Inha University College of Medicine, Incheon, 22212, Republic of Korea
| | - Jinyoung Lee
- Department of Tropical Medicine, and Inha Research Institute for Medical Sciences, Inha University College of Medicine, Incheon, 22212, Republic of Korea
| | - Thị Lam Thái
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea.,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea
| | - Moe Kyaw Myint
- Department of Medical Research Pyin Oo Lwin Branch, Pyin Oo Lwin, Myanmar
| | - Khin Saw Aye
- Department of Medical Research Pyin Oo Lwin Branch, Pyin Oo Lwin, Myanmar
| | - Woon-Mok Sohn
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea
| | - Ho-Joon Shin
- Department of Microbiology, Ajou University School of Medicine, Suwon, 16499, Republic of Korea
| | - Tong-Soo Kim
- Department of Tropical Medicine, and Inha Research Institute for Medical Sciences, Inha University College of Medicine, Incheon, 22212, Republic of Korea
| | - Byoung-Kuk Na
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju, 52727, Republic of Korea. .,BK21Plus Team for Anti-aging Biotechnology and Industry, Department of Convergence Medical Science, Gyeongsang National University, Jinju, 52727, Republic of Korea.
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23
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Identification of Antimalarial Compounds That Require CLAG3 for Their Uptake by Plasmodium falciparum-Infected Erythrocytes. Antimicrob Agents Chemother 2019; 63:AAC.00052-19. [PMID: 30782998 DOI: 10.1128/aac.00052-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 02/01/2019] [Indexed: 01/15/2023] Open
Abstract
During the intraerythrocytic asexual cycle malaria parasites acquire nutrients and other solutes through a broad selectivity channel localized at the membrane of the infected erythrocyte termed the plasmodial surface anion channel (PSAC). The protein product of the Plasmodium falciparum clonally variant clag3.1 and clag3.2 genes determines PSAC activity. Switches in the expression of clag3 genes, which are regulated by epigenetic mechanisms, are associated with changes in PSAC-dependent permeability that can result in resistance to compounds toxic for the parasite, such as blasticidin S. Here, we investigated whether other antimalarial drugs require CLAG3 to reach their intracellular target and consequently are prone to parasite resistance by epigenetic mechanisms. We found that the bis-thiazolium salts T3 (also known as albitiazolium) and T16 require the product of clag3 genes to enter infected erythrocytes. P. falciparum populations can develop resistance to these compounds via the selection of parasites with dramatically reduced expression of both genes. However, other compounds previously demonstrated or predicted to enter infected erythrocytes through transport pathways absent from noninfected erythrocytes, such as fosmidomycin, doxycycline, azithromycin, lumefantrine, or pentamidine, do not require expression of clag3 genes for their antimalarial activity. This suggests that they use alternative CLAG3-independent routes to access parasites. Our results demonstrate that P. falciparum can develop resistance to diverse antimalarial compounds by epigenetic changes in the expression of clag3 genes. This is of concern for drug development efforts because drug resistance by epigenetic mechanisms can arise quickly, even during the course of a single infection.
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24
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Reverse immunodynamics: a new method for identifying targets of protective immunity. Sci Rep 2019; 9:2164. [PMID: 30770839 PMCID: PMC6377634 DOI: 10.1038/s41598-018-37288-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 11/20/2018] [Indexed: 12/21/2022] Open
Abstract
Despite a dramatic increase in our ability to catalogue variation among pathogen genomes, we have made far fewer advances in using this information to identify targets of protective immunity. Epidemiological models predict that strong immune selection can cause antigenic variants to structure into genetically discordant sets of antigenic types (e.g. serotypes). A corollary of this theory is that targets of immunity may be identified by searching for non-overlapping associations of amino acids among co-circulating antigenic variants. We propose a novel population genetics methodology that combines such predictions with phylogenetic analyses to identify genetic loci (epitopes) under strong immune selection. We apply this concept to the AMA-1 protein of the malaria parasite Plasmodium falciparum and find evidence of epitopes among certain regions of low variability which could render them ideal vaccine candidates. The proposed method can be applied to a myriad of multi-strain pathogens for which vast amounts of genetic data has been collected in recent years.
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25
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Fatoba AJ, Adeleke MA. Diagnosis and control of chicken coccidiosis: a recent update. J Parasit Dis 2018; 42:483-493. [PMID: 30538344 PMCID: PMC6261147 DOI: 10.1007/s12639-018-1048-1] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Accepted: 10/24/2018] [Indexed: 11/25/2022] Open
Abstract
Coccidiosis is a deadly disease that hampers chicken's productivity and welfare. Thus, the disease is a major menace to the global poultry industry. Coccidiosis which is caused by the apicomplexan parasite of the genus Eimeria has seven known species which affect the different parts of the intestinal tract of chickens. The disease which occurs by ingestion of sporulated oocyst has been associated with poor poultry management system. Mixed infection among the species of this parasite contributes to both pathogenicity and misdiagnosis of the disease. A progress in identification and diagnosis approach which cuts across pathological, morphological and molecular has been reported for this parasite. Control measures which include anticoccidial drugs, vaccines and natural products have dominated literature for this disease. However, the emergence of genetic and antigenic diversity with implication on resistance to anticoccidials among different strains of Eimeria parasite has generated concerns on the effectiveness of the current anticoccidial vaccines. A new look on the control strategy therefore becomes imperative. This study reviews the current trends on the identification and control of chicken coccidiosis with focus on (1) Avian coccidiosis (2) Epidemiology of chicken coccidiosis (3) Eimeria parasite and distribution in poultry (4) Diagnosis of Eimeria parasite (5) Control measures of coccidiosis (6) Threats posed by genetic and antigenic diversity of Eimeria parasite on coccidiosis control. Genomic study on diversity of Eimeria parasite becomes imperative for effective vaccine design against coccidiosis.
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Affiliation(s)
- Abiodun Joseph Fatoba
- Discipline of Genetics, School of Life Sciences, College of Agriculture, Engineering and Science, University of KwaZulu-Natal, Westville, P/Bag X54001, Durban, 4000 South Africa
| | - Matthew Adekunle Adeleke
- Discipline of Genetics, School of Life Sciences, College of Agriculture, Engineering and Science, University of KwaZulu-Natal, Westville, P/Bag X54001, Durban, 4000 South Africa
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26
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Nasr A, Saleh AM, Eltoum M, Abushouk A, Hamza A, Aljada A, El-Toum ME, Abu-Zeid YA, Allam G, ElGhazali G. Antibody responses to P. falciparum Apical Membrane Antigen 1(AMA-1) in relation to haemoglobin S (HbS), HbC, G6PD and ABO blood groups among Fulani and Masaleit living in Western Sudan. Acta Trop 2018; 182:115-123. [PMID: 29486174 DOI: 10.1016/j.actatropica.2018.02.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 02/12/2018] [Accepted: 02/23/2018] [Indexed: 01/02/2023]
Abstract
Fulani and Masaleit are two sympatric ethnic groups in western Sudan who are characterised by marked differences in susceptibility to Plasmodium falciparum malaria. It has been demonstrated that Glucose-6-phosphate dehydrogenase (G6PD) deficiency and Sickle cell trait HbAS carriers are protected from the most severe forms of malaria. This study aimed to investigate a set of specific IgG subclasses against P. falciparum Apical Membrane Antigen 1 (AMA-1 3D7), haemoglobin variants and (G6PD) in association with malaria susceptibility among Fulani ethnic group compared to sympatric ethnic group living in Western Sudan. A total of 124 children aged 5-9 years from each tribe living in an area of hyper-endemic P. falciparum unstable malaria transmission were recruited and genotyped for the haemoglobin (Hb) genes, (G6PD) and (ABO) blood groups. Furthermore, the level of plasma IgG antibody subclasses against P. falciparum antigen (AMA-1) were measured using enzyme linked immunosorbent assays (ELISA). Higher levels of anti-malarial IgG1, IgG2 and IgG3 but not IgG4 antibody were found in Fulani when compared to Masaleit. Individuals carrying the HbCC phenotype were significantly associated with higher levels of IgG1 and IgG2. Furthermore, individuals having the HbAS phenotype were associated with higher levels of specific IgG2 and IgG4 antibodies. In addition, patients with G6PD A/A genotype were associated with higher levels of specific IgG2 antibody compared with those carrying the A/G and G/G genotypes. The results indicate that the Fulani ethnic group show lower frequency of HbAS, HbSS and HbAC compared to the Masaleit ethnic group. The inter-ethnic analysis shows no statistically significant difference in G6PD genotypes (P value = 0.791). However, the intra-ethnic analysis indicates that both ethnic groups have less A/A genotypes and (A) allele frequency of G6PD compared to G/G genotypes, while the HbSA genotype was associated with higher levels of IgG2 (AMA-1) and IgG4 antibodies. In addition, patients carrying the G6PD A/A genotype were associated with higher levels of specific IgG2 antibody compared with those carrying the A/G and G/G genotypes. The present results revealed that the Fulani ethnic group has statistically significantly lower frequency of abnormal haemoglobin resistant to malaria infection compared to the Masaleit ethnic group.
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27
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Huang B, Tuo F, Liang Y, Wu W, Wu G, Huang S, Zhong Q, Su XZ, Zhang H, Li M, Bacar A, Abdallah KS, Mliva AMSA, Wang Q, Yang Z, Zheng S, Xu Q, Song J, Deng C. Temporal changes in genetic diversity of msp-1, msp-2, and msp-3 in Plasmodium falciparum isolates from Grande Comore Island after introduction of ACT. Malar J 2018; 17:83. [PMID: 29458365 PMCID: PMC5819244 DOI: 10.1186/s12936-018-2227-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 02/08/2018] [Indexed: 11/26/2022] Open
Abstract
Background Malaria is still one of the serious public health problems in Grande Comore Island, although the number of annual cases has been greatly reduced in recent years. A better understanding of malaria parasite population diversity and transmission dynamics is critical for assessing the effectiveness of malaria control measures. The objective of this study is to investigate temporal changes in genetic diversity of Plasmodium falciparum populations and multiplicity of infection (MOI) in Grande Comore 10 years after introduction of ACT. Methods A total of 232 P. falciparum clinical isolates were collected from the Grande Comore Island during two sampling periods (118 for 2006‒2007 group, and 114 for 2013‒2016 group). Parasite isolates were characterized for genetic diversity and complexity of infection by genotyping polymorphic regions in merozoite surface protein gene 1 (msp-1), msp-2, and msp-3 using nested PCR and DNA sequencing. Results Three msp-1 alleles (K1, MAD20, and RO33), two msp-2 alleles (FC27 and 3D7), and two msp-3 alleles (K1 and 3D7) were detected in parasites of both sampling periods. The RO33 allele of msp-1 (84.8%), 3D7 allele of msp-2 (90.8%), and K1 allele of msp-3 (66.7%) were the predominant allelic types in isolates from 2006–2007 group. In contrast, the RO33 allele of msp-1 (63.4%), FC27 allele of msp-2 (91.1%), and 3D7 allele of msp-3 (53.5%) were the most prevalent among isolates from the 2013–2016 group. Compared with the 2006‒2007 group, polyclonal infection rates of msp-1 (from 76.7 to 29.1%, P < 0.01) and msp-2 (from 62.4 to 28.3%, P < 0.01) allelic types were significantly decreased in those from 2013‒2016 group. Similarly, the MOIs for both msp-1 and msp-2 were higher in P. falciparum isolates in the 2006–2007 group than those in 2013–2016 group (MOI = 3.11 vs 1.63 for msp-1; MOI = 2.75 vs 1.35 for msp-2). DNA sequencing analyses also revealed reduced numbers of distinct sequence variants in the three genes from 2006‒2007 to 2013‒2016: msp-1, from 32 to 23 (about 28% decline); msp-2 from 29 to 21 (about 28% decline), and msp-3 from 11 to 3 (about 72% decline). Conclusions The present data showed dramatic reduction in genetic diversity and MOI among Grande Comore P. falciparum populations over the course of the study, suggesting a trend of decreasing malaria transmission intensity and genetic diversity in Grande Comore Island. These data provide valuable information for surveillance of P. falciparum infection and for assessing the appropriateness of the current malarial control strategies in the endemic area.
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Affiliation(s)
- Bo Huang
- Institute of Tropical Medicine, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China.,Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510445, Guangdong, People's Republic of China
| | - Fei Tuo
- Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510445, Guangdong, People's Republic of China
| | - Yuan Liang
- Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510445, Guangdong, People's Republic of China
| | - Wanting Wu
- Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510445, Guangdong, People's Republic of China
| | - Guangchao Wu
- Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510445, Guangdong, People's Republic of China
| | - Shiguang Huang
- School of Stomatology, Jinan University, Guangzhou, 510632, Guangdong, People's Republic of China
| | - Qirun Zhong
- Artepharm, Co., Ltd, Guangzhou, 510405, Guangdong, People's Republic of China
| | - Xin-Zhuan Su
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Hongying Zhang
- Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510445, Guangdong, People's Republic of China
| | - Mingqiang Li
- Artepharm, Co., Ltd, Guangzhou, 510405, Guangdong, People's Republic of China
| | - Affane Bacar
- National Malaria Control Programme, BP 500, Moroni, Comoros
| | | | | | - Qi Wang
- Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510445, Guangdong, People's Republic of China
| | - Zhaoli Yang
- Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510445, Guangdong, People's Republic of China
| | - Shaoqin Zheng
- Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510445, Guangdong, People's Republic of China
| | - Qin Xu
- Institute of Tropical Medicine, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China
| | - Jianping Song
- Institute of Tropical Medicine, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China. .,Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510445, Guangdong, People's Republic of China.
| | - Changsheng Deng
- Institute of Tropical Medicine, Guangzhou University of Chinese Medicine, Guangzhou, 510006, Guangdong, People's Republic of China. .,Science and Technology Park, Guangzhou University of Chinese Medicine, Guangzhou, 510445, Guangdong, People's Republic of China.
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Pirahmadi S, Zakeri S, Mehrizi AA, Djadid ND. Analysis of genetic diversity and population structure of gene encoding cell-traversal protein for ookinetes and sporozoites (CelTOS) vaccine candidate antigen in global Plasmodium falciparum populations. INFECTION GENETICS AND EVOLUTION 2018; 59:113-125. [PMID: 29391203 DOI: 10.1016/j.meegid.2018.01.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 11/24/2017] [Accepted: 01/25/2018] [Indexed: 10/18/2022]
Abstract
Plasmodium falciparum cell-traversal protein for ookinetes and sporozoites (PfCelTOS) has been reported as one of the most attractive malaria vaccine candidate antigens. To design a broadly effective malaria vaccine based on this antigen, it is crucial to have adequate information on genetic diversity in global PfCelTOS. Therefore, the extent of sequence diversity at the full-length of the pfceltos was assessed among both natural P. falciparum isolates collected from Iran (n = 93) and from available global pfceltos sequence data retrieved from PlasmoDB database (n = 159). Also, recombination, natural selection, the degree of genetic differentiation as well as the predicted immunodominant regions in PfCelTOS were analyzed. In total, 40 SNPs (including 1 synonymous and 39 non-synonymous) were detected in 34 positions, as compared to 3D7 sequence, which led to 66 distinct haplotypes with different frequencies. Among those haplotypes, 34 (51.5%, excluded from further analysis) were singleton haplotype and mostly detected among Senegalese parasite isolates. PfCelt-1 was found as predominant haplotype (32.6% total frequency) that was only detected in Iranian P. falciparum isolates. Nucleotide diversity was low in French Guiana (0.00236 ± 0.00203) and Iranian (0.00259 ± 0.00048) P. falciparum isolates in comparison with African populations. Evidence for positive selection by host immunity and intragenic recombination were detected that are two key factors responsible for gene evolution and genetic diversity of pfceltos gene. The results of Fst analysis and haplotype network revealed that PfCelTOS antigen displayed evident genetic structure between geographical parasite populations. In conclusion, the present analysis demonstrates that there is a limited antigenic diversity and geographic variation in global PfCelTOS, and this finding may be associated with the critical function of this antigen in cell traversal of the parasite in sporozoite and ookinete. Besides, most of the predicted B- and T-cell epitopes were located in the conserved region of the gene, but most of the amino acid replacements were located at the C-terminal region of PfCelTOS. The obtained results in this investigation could provide knowledge for better design of PfCelTOS-based malaria vaccine.
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Affiliation(s)
- Sakineh Pirahmadi
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran, Pasteur Avenue, P.O. Box 1316943551, Tehran, Iran
| | - Sedigheh Zakeri
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran, Pasteur Avenue, P.O. Box 1316943551, Tehran, Iran.
| | - Akram Abouie Mehrizi
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran, Pasteur Avenue, P.O. Box 1316943551, Tehran, Iran
| | - Navid Dinparast Djadid
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran, Pasteur Avenue, P.O. Box 1316943551, Tehran, Iran
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29
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Nedaei F, Noormohammadi Z, Naddaf SR, Mohammadi S, Esmaeili Rastaghi AR. Analysis of Plasmodium vivax Apical Membrane Antigen-1 (PvAMA-1) Haplotypes among Iranian Isolates. INTERNATIONAL JOURNAL OF MOLECULAR AND CELLULAR MEDICINE 2017; 6:222-234. [PMID: 29988191 PMCID: PMC6004292 DOI: 10.22088/bums.6.4.222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 11/11/2017] [Indexed: 11/18/2022]
Abstract
Plasmodium vivax apical membrane antigen-1(PvAMA-1) is a surface protein with polymorphic sites. This study was aimed to analyze the polymorphic amino acid residues at PvAMA-1 in different infected age groups. 92 blood samples were collected from the south and southeast of Iran. The DNA coding for the domain I (DI), DII, and partial DIII of this antigen was amplified by Nested-PCR, and sequenced. Nucleotide mutations were found in 49 sites and based on the amino acid sequence, 30 variable sites were detected. Age distribution of malaria cases showed that the majority of the patients were between 10 to 30 years old. The scattering plot haplotypes by age showed an increasing incidence rate with age during childhood, whereas, incidence was the lowest in patients under five years old. Comparison of the polymorphic sites of PvAMA-1 in Iranian isolates with those found in other geographic regions of the world indicated nine common variable positions. In addition, a significant dependence was found between some particular substitutions and age categories. Dependence between particular substitutions and age groups suggests that certain residues in AMA-1 are responsible for clinical attacks in different ages, likely as a result of host immune pressure. The crystal structure of the PvAMA-1 showed that the amino acid substitutions that changed the protein charge were exclusively located in loops and turns where, the interactions with antibodies could occur. These data provide the necessary information for an AMA-1 based malaria vaccine design to be effective across all ages.
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Affiliation(s)
- Fatemeh Nedaei
- Department of Parasitology, Pasteur Institute of Iran, Tehran, Iran
| | - Zahra Noormohammadi
- Department of Biology , College of Basic Science Islamic Azad University, Science and Research Branch, Tehran, Iran
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30
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Ntumngia FB, Pires CV, Barnes SJ, George MT, Thomson-Luque R, Kano FS, Alves JRS, Urusova D, Pereira DB, Tolia NH, King CL, Carvalho LH, Adams JH. An engineered vaccine of the Plasmodium vivax Duffy binding protein enhances induction of broadly neutralizing antibodies. Sci Rep 2017; 7:13779. [PMID: 29062081 PMCID: PMC5653783 DOI: 10.1038/s41598-017-13891-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 10/02/2017] [Indexed: 12/31/2022] Open
Abstract
Plasmodium vivax invasion into human reticulocytes is a complex process. The Duffy binding protein (DBP) dimerization with its cognate receptor is vital for junction formation in the invasion process. Due to its functional importance, DBP is considered a prime vaccine candidate, but variation in B-cell epitopes at the dimer interface of DBP leads to induction of strain-limited immunity. We believe that the polymorphic residues tend to divert immune responses away from functionally conserved epitopes important for receptor binding or DBP dimerization. As a proof of concept, we engineered the vaccine DEKnull to ablate the dominant Bc epitope to partially overcome strain-specific immune antibody responses. Additional surface engineering on the next generation immunogen, DEKnull-2, provides an immunogenicity breakthrough to conserved protective epitopes. DEKnull-2 elicits a stronger broadly neutralizing response and reactivity with long-term persistent antibody responses of acquired natural immunity. By using novel engineered DBP immunogens, we validate that the prime targets of protective immunity are conformational epitopes at the dimer interface. These successful results indicate a potential approach that can be used generally to improve efficacy of other malaria vaccine candidates.
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Affiliation(s)
- Francis B Ntumngia
- Center for Global Health and Infectious Diseases Research, Department of Global Health, College of Public Health, University of South Florida, Tampa, 33612, USA
| | - Camilla V Pires
- Centro de Pesquisas René Rachou/FIOCRUZ, Belo Horizonte, 30190, Brazil
| | - Samantha J Barnes
- Center for Global Health and Infectious Diseases Research, Department of Global Health, College of Public Health, University of South Florida, Tampa, 33612, USA
| | - Miriam T George
- Center for Global Health and Infectious Diseases Research, Department of Global Health, College of Public Health, University of South Florida, Tampa, 33612, USA
| | - Richard Thomson-Luque
- Center for Global Health and Infectious Diseases Research, Department of Global Health, College of Public Health, University of South Florida, Tampa, 33612, USA
| | - Flora S Kano
- Centro de Pesquisas René Rachou/FIOCRUZ, Belo Horizonte, 30190, Brazil
| | - Jessica R S Alves
- Centro de Pesquisas René Rachou/FIOCRUZ, Belo Horizonte, 30190, Brazil
| | - Darya Urusova
- Departments of Molecular Microbiology & Microbial Pathogenesis, and Biochemistry & Molecular Biophysics, Washington University School of Medicine, Saint Louis, 63130, USA
| | - Dhelio B Pereira
- Centro de Pesquisa em Medicina Tropical de Rondonia-CEPEM, Porto Velho, 76812-245, Brazil
| | - Niraj H Tolia
- Departments of Molecular Microbiology & Microbial Pathogenesis, and Biochemistry & Molecular Biophysics, Washington University School of Medicine, Saint Louis, 63130, USA
| | - Christopher L King
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, 44106, USA
| | - Luzia H Carvalho
- Centro de Pesquisas René Rachou/FIOCRUZ, Belo Horizonte, 30190, Brazil
| | - John H Adams
- Center for Global Health and Infectious Diseases Research, Department of Global Health, College of Public Health, University of South Florida, Tampa, 33612, USA.
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31
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Arévalo-Pinzón G, Bermúdez M, Hernández D, Curtidor H, Patarroyo MA. Plasmodium vivax ligand-receptor interaction: PvAMA-1 domain I contains the minimal regions for specific interaction with CD71+ reticulocytes. Sci Rep 2017; 7:9616. [PMID: 28855657 PMCID: PMC5577344 DOI: 10.1038/s41598-017-10025-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 08/02/2017] [Indexed: 12/18/2022] Open
Abstract
The malarial parasite’s invasion is complex, active and coordinated, involving many low and high affinity interactions with receptors on target cell membrane. Proteomics analysis has described around 40 proteins in P. vivax which could be involved in reticulocyte invasion; few have been studied with the aim of elucidating how many of them establish specific interactions with their respective host cells. Given the importance of knowing which of the parasite’s protein regions are functionally important for invasion, minimum regions mediating specific interaction between Plasmodium vivax apical membrane antigen 1 (PvAMA-1) and its host cell were here elucidated. The region covering PvAMA-1 domains I and II (PvAMA-DI-II) specifically bound to the CD71+ red blood cell subpopulation. A 20 residue-long region (81EVENAKYRIPAGRCPVFGKG100) located in domain I was capable of inhibiting PvAMA-DI-II recombinant protein binding to young reticulocytes (CD71+CD45−) and rosette formation. This conserved peptide specifically interacted with high affinity with reticulocytes (CD71+) through a neuraminidase- and chymotrypsin-treatment sensitive receptor. Such results showed that, despite AMA-1 having universal functions during late Plasmodium invasion stages, PvAMA-1 had reticulocyte-preferring binding regions, suggesting that P. vivax target cell selection is not just restricted to initial interactions but maintained throughout the erythrocyte invasion cycle, having important implications for designing a specific anti-P. vivax vaccine.
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Affiliation(s)
- Gabriela Arévalo-Pinzón
- Fundación Instituto de Inmunología de Colombia (FIDIC), Carrera 50 # 26-20, Bogotá, Colombia.,PhD Program in Biomedical and Biological Sciences, Universidad del Rosario, Carrera 24 #, 63C-69, Bogotá, Colombia
| | - Maritza Bermúdez
- Fundación Instituto de Inmunología de Colombia (FIDIC), Carrera 50 # 26-20, Bogotá, Colombia.,MSc Program in Biological Sciences, Pontificia Universidad Javeriana, Carrera 7 # 40-62, Bogotá, Colombia
| | - Diana Hernández
- Fundación Instituto de Inmunología de Colombia (FIDIC), Carrera 50 # 26-20, Bogotá, Colombia
| | - Hernando Curtidor
- Fundación Instituto de Inmunología de Colombia (FIDIC), Carrera 50 # 26-20, Bogotá, Colombia.,School of Medicine and Health Sciences, Universidad del Rosario, Carrera 24 #, 63C-69, Bogotá, Colombia
| | - Manuel Alfonso Patarroyo
- Fundación Instituto de Inmunología de Colombia (FIDIC), Carrera 50 # 26-20, Bogotá, Colombia. .,School of Medicine and Health Sciences, Universidad del Rosario, Carrera 24 #, 63C-69, Bogotá, Colombia.
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32
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Rittipornlertrak A, Nambooppha B, Simking P, Punyapornwithaya V, Tiwananthagorn S, Jittapalapong S, Chung YT, Sthitmatee N. Low levels of genetic diversity associated with evidence of negative selection on the Babesia bovis apical membrane antigen 1 from parasite populations in Thailand. INFECTION GENETICS AND EVOLUTION 2017; 54:447-454. [PMID: 28807856 DOI: 10.1016/j.meegid.2017.08.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 08/08/2017] [Accepted: 08/10/2017] [Indexed: 10/19/2022]
Abstract
Babesia bovis, a parasite infecting cattle and buffalo, continues to spread throughout the developing world. The babesial vaccine was developed to be a sustainable alternative treatment to control the parasite. However, genetic diversity is a major obstacle for designing and developing a safe and effective vaccine. The apical membrane antigen 1 (AMA-1) is considered to be a potential vaccine candidate antigen among immunogenic genes of B. bovis. To gain a more comprehensive understanding of B. bovis AMA-1 (BbAMA-1), three B. bovis DNA samples were randomly selected to characterize in order to explore genetic diversity and natural selection and to predict the antigen epitopes. The sequence analysis revealed that BbAMA-1 has a low level of polymorphism and is highly conserved (95.46-99.94%) among Thai and global isolates. The majority of the polymorphic sites were observed in domains I and III. Conversely, domain II contained no polymorphic sites. We report the first evidence of strong negative or purifying selection across the full length of the gene, especially in domain I, by demonstrating a significant excess of the average number of synonymous (dS) over the non-synonymous (dN) substitutions. Finally, we also predict the linear and conformational B-cell epitope. The predicted B-cell epitopes appeared to be involved with the amino acid changes. Collectively, the results suggest that the conserved BbAMA-1 may be used to detect regional differences in the B. bovis parasite. Importantly, the limitation of BbAMA-1 diversity under strong negative selection indicates strong functional constraints on this gene. Thus, the gene could be a valuable target vaccine candidate antigen.
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Affiliation(s)
| | | | - Pacharathon Simking
- Faculty of Agricultural Technology, Rajamangala University of Technology Thanyaburi, Pathumthani 12110, Thailand
| | | | | | | | - Yang-Tsung Chung
- Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, Taichung 402, Taiwan
| | - Nattawooti Sthitmatee
- Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand; Excellent Center in Veterinary Bioscience, Chiang Mai University, Chiang Mai 50100, Thailand.
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33
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Kundu K, Garg R, Kumar S, Mandal M, Tomley FM, Blake DP, Banerjee PS. Humoral and cytokine response elicited during immunisation with recombinant Immune Mapped protein-1 (EtIMP-1) and oocysts of Eimeria tenella. Vet Parasitol 2017; 244:44-53. [PMID: 28917316 DOI: 10.1016/j.vetpar.2017.07.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 07/16/2017] [Accepted: 07/22/2017] [Indexed: 11/19/2022]
Abstract
Eimeria tenella, the causative agent of caecal coccidiosis, is a pathogenic gut dwelling protozoan which can cause severe morbidity and mortality in farmed chickens. Immune mapped protein-1 (IMP-1) has been identified as an anticoccidial vaccine candidate; in the present study allelic polymorphism was assessed across the IMP-1 coding sequence in E. tenella isolates from four countries and compared with the UK reference Houghton strain. Nucleotide diversity was low, limited to expansion/contraction of a CAG triplet repeat and five substitutions, three of which were non-synonymous. The EtIMP-1 coding sequence from a cloned Indian E. tenella isolate was expressed in E. coli and purified as a His-tagged thioredoxin fusion protein. An in-vivo vaccination and challenge trial was conducted to test the vaccine potential of recombinant EtIMP-1 (rEtIMP-1) and to compare post-vaccination immune responses of chickens to those stimulated by live oocyst infection. Following challenge, parasite replication measured using quantitative PCR was significantly reduced in chickens that had been vaccinated with rEtIMP-1 (rIC group; 67% reduction compared to UC or unimmunised controls; 79% reduction compared to rTC group or recombinant thioredoxin mock-immunised controls, p<0.05), or the birds vaccinated by infection with oocysts (OC group, 90% compared to unimmunised controls). Chickens vaccinated with oocysts (OC) had significantly higher levels of interferon gamma in their serum post-challenge, compared to rEtIMP-1 vaccinated birds (rIC). Conversely rEtIMP-1 (rIC) vaccinated birds had significantly higher antigen specific serum IgY responses, correlating with higher serum IL-4 (both p<0.05).
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Affiliation(s)
- Krishnendu Kundu
- Division of Parasitology, Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, PIN-243122, India
| | - Rajat Garg
- Division of Parasitology, Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, PIN-243122, India
| | - Saroj Kumar
- Division of Parasitology, Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, PIN-243122, India
| | - Mrityunjay Mandal
- Division of Parasitology, Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, PIN-243122, India
| | - Fiona M Tomley
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL97TA, UK
| | - Damer P Blake
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL97TA, UK
| | - Partha Sarathi Banerjee
- Division of Parasitology, Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, PIN-243122, India.
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34
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Taniguchi T, Md Mannoor K, Nonaka D, Toma H, Li C, Narita M, Vanisaveth V, Kano S, Takahashi M, Watanabe H. A Unique Subset of γδ T Cells Expands and Produces IL-10 in Patients with Naturally Acquired Immunity against Falciparum Malaria. Front Microbiol 2017; 8:1288. [PMID: 28769886 PMCID: PMC5515829 DOI: 10.3389/fmicb.2017.01288] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 06/27/2017] [Indexed: 01/03/2023] Open
Abstract
Although expansions in γδ T cell populations are known to occur in the peripheral blood of patients infected with Plasmodium falciparum, the role of these cells in people with naturally acquired immunity against P. falciparum who live in malaria-endemic areas is poorly understood. We used a cross-sectional survey to investigate the role of peripheral blood γδ T cells in people living in Lao People's Democratic Republic, a malaria-endemic area. We found that the proportion of non-Vγ9 γδ T cells was higher in non-hospitalized uncomplicated falciparum malaria patients (UMPs) from this region. Notably, we found that the non-Vγ9 γδ T cells in the peripheral blood of UMPs and negative controls from this region had the potential to expand and produce IL-10 and interferon-γ when cultured in the presence of IL-2 and/or crude P. falciparum antigens for 10 days. Furthermore, these cells were associated with plasma interleukin 10 (IL-10), which was elevated in UMPs. This is the first report demonstrating that, in UMPs living in a malaria-endemic area, a γδ T cell subset, the non-Vγ9 γδT cells, expands and produces IL-10. These results contribute to understanding of the mechanisms of naturally acquired immunity against P. falciparum.
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Affiliation(s)
- Tomoyo Taniguchi
- Department of Parasitology, Graduate School of Medicine, Gunma UniversityMaebashi, Japan
- Center for Medical Education, Graduate School of Medicine, Gunma UniversityMaebashi, Japan
- Immunobiology Group, Center of Molecular Biosciences, Tropical Biosphere Research Center, University of the RyukyusNishihara, Japan
| | - Kaiissar Md Mannoor
- Department of Pathology, University of Maryland School of Medicine, BaltimoreMD, United States
| | - Daisuke Nonaka
- Department of Parasitology and Immunopathoetiology, Graduate School of Medicine, University of the RyukyusNishihara, Japan
| | - Hiromu Toma
- Department of Parasitology and Immunopathoetiology, Graduate School of Medicine, University of the RyukyusNishihara, Japan
| | - Changchun Li
- Department of Health Sciences, Trans-disciplinary Research Organization for Subtropics and Island Studies, University of the RyukyusNishihara, Japan
| | - Miwako Narita
- Laboratory of Hematology and Oncology, Graduate School of Health Sciences, Niigata UniversityNiigata, Japan
| | | | - Shigeyuki Kano
- Research Institute, National Center for Global Health and MedicineTokyo, Japan
| | - Masuhiro Takahashi
- Laboratory of Hematology and Oncology, Graduate School of Health Sciences, Niigata UniversityNiigata, Japan
| | - Hisami Watanabe
- Immunobiology Group, Center of Molecular Biosciences, Tropical Biosphere Research Center, University of the RyukyusNishihara, Japan
- Infectious Diseases Research Center of Niigata University in Myanmar, Institute of Medicine and Dentistry, Niigata UniversityNiigata, Japan
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35
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Bei AK, Ahouidi AD, Dvorin JD, Miura K, Diouf A, Ndiaye D, Premji Z, Diakite M, Mboup S, Long CA, Duraisingh MT. Functional Analysis Reveals Geographical Variation in Inhibitory Immune Responses Against a Polymorphic Malaria Antigen. J Infect Dis 2017; 216:267-275. [PMID: 28605544 PMCID: PMC5853457 DOI: 10.1093/infdis/jix280] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Accepted: 06/08/2017] [Indexed: 12/28/2022] Open
Abstract
Background Plasmodium falciparum reticulocyte-binding protein homologue 2b (PfRh2b) is an invasion ligand that is a potential blood-stage vaccine candidate antigen; however, a naturally occurring deletion within an immunogenic domain is present at high frequencies in Africa and has been associated with alternative invasion pathway usage. Standardized tools that provide antigenic specificity in in vitro assays are needed to functionally assess the neutralizing potential of humoral responses against malaria vaccine candidate antigens. Methods Transgenic parasite lines were generated to express the PfRh2b deletion. Total immunoglobulin G (IgG) from individuals residing in malaria-endemic regions in Tanzania, Senegal, and Mali were used in growth inhibition assays with transgenic parasite lines. Results While the PfRh2b deletion transgenic line showed no change in invasion pathway utilization compared to the wild-type in the absence of specific antibodies, it outgrew wild-type controls in competitive growth experiments. Inhibition differences with total IgG were observed in the different endemic sites, ranging from allele-specific inhibition to allele-independent inhibitory immune responses. Conclusions The PfRh2b deletion may allow the parasite to escape neutralizing antibody responses in some regions. This difference in geographical inhibition was revealed using transgenic methodologies, which provide valuable tools for functionally assessing neutralizing antibodies against vaccine-candidate antigens in regions with varying malaria endemicity.
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Affiliation(s)
- Amy K Bei
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts
- Laboratory of Bacteriology and Virology, Le Dantec Hospital, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, Dakar, Senegal
- Laboratory of Parasitology and Mycology, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, Dakar, Senegal
| | - Ambroise D Ahouidi
- Laboratory of Bacteriology and Virology, Le Dantec Hospital, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, Dakar, Senegal
| | - Jeffrey D Dvorin
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts
- Division of Infectious Diseases, Boston Children's Hospital and Harvard Medical School, Massachusetts
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Ababacar Diouf
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Daouda Ndiaye
- Laboratory of Parasitology and Mycology, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, Dakar, Senegal
| | - Zul Premji
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar-es-Salaam, Tanzania
- Department of Pathology, Aga Khan University Hospital, Nairobi, Kenya
| | - Mahamadou Diakite
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Odontostomatology, University of Science, Techniques and Technologies of Bamako, Mali
| | - Souleymane Mboup
- Laboratory of Bacteriology and Virology, Le Dantec Hospital, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, Dakar, Senegal
- Institut de Recherche en Santé, de Surveillance Epidemiologique et de Formations, Dakar, Senegal
| | - Carole A Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Manoj T Duraisingh
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts
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36
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Spiegel H, Boes A, Fendel R, Reimann A, Schillberg S, Fischer R. Immunization with the Malaria Diversity-Covering Blood-Stage Vaccine Candidate Plasmodium falciparum Apical Membrane Antigen 1 DiCo in Complex with Its Natural Ligand PfRon2 Does Not Improve the In Vitro Efficacy. Front Immunol 2017; 8:743. [PMID: 28702028 PMCID: PMC5484772 DOI: 10.3389/fimmu.2017.00743] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 06/12/2017] [Indexed: 01/05/2023] Open
Abstract
The blood-stage malaria vaccine candidate Plasmodium falciparum apical membrane antigen 1 (PfAMA1) can induce strong parasite growth-inhibitory antibody responses in animals but has not achieved the anticipated efficacy in clinical trials. Possible explanations in humans are the insufficient potency of the elicited antibody responses, as well as the high degree of sequence polymorphisms found in the field. Several strategies have been developed to improve the cross-strain coverage of PfAMA1-based vaccines, whereas innovative concepts to increase the potency of PfAMA1-specific IgG responses have received little attention even though this may be an essential requirement for protective efficacy. A previous study has demonstrated that immunization with a complex of PyAMA1 and PyRON2, a ligand with an essential functional role in erythrocyte invasion, leads to protection from lethal Plasmodium yoelli challenge in an animal model and suggested to extend this strategy toward improved strain coverage by using multiple PfAMA1 alleles in combination with PfRon2L. As an alternative approach along this line, we decided to use PfRon2L in combination with three PfAMA1 diversity covering variants (DiCo) to investigate the potential of this complex to induce more potent parasite growth inhibitory immune response in combination with better cross-strain-specific efficacy. Within the limits of the study design, the ability of the PfAMA1 DiCo-Mix to induce cross-strain-specific antibodies was not affected in all immunization groups, but the DiCo-PfRon2L complexes did not improve the potency of PfAMA1-specific IgG responses.
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Affiliation(s)
- Holger Spiegel
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Alexander Boes
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Rolf Fendel
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Andreas Reimann
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
| | - Stefan Schillberg
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany.,Institute for Phytopathology and Applied Zoology, Justus-Liebig University Giessen, Giessen, Germany
| | - Rainer Fischer
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany.,RWTH Aachen University, Institute for Molecular Biotechnology, Aachen, Germany.,Indiana Biosciences Research Institute (IBRI), Indianapolis, IN, United States
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37
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Srinivasan P, Baldeviano GC, Miura K, Diouf A, Ventocilla JA, Leiva KP, Lugo-Roman L, Lucas C, Orr-Gonzalez S, Zhu D, Villasante E, Soisson L, Narum DL, Pierce SK, Long CA, Diggs C, Duffy PE, Lescano AG, Miller LH. A malaria vaccine protects Aotus monkeys against virulent Plasmodium falciparum infection. NPJ Vaccines 2017; 2. [PMID: 28804644 PMCID: PMC5551459 DOI: 10.1038/s41541-017-0015-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The Plasmodium falciparum protein, apical membrane antigen 1 forms a complex with another parasite protein, rhoptry neck protein 2, to initiate junction formation with the erythrocyte and is essential for merozoite invasion during the blood stage of infection. Consequently, apical membrane antigen 1 has been a target of vaccine development but vaccination with apical membrane antigen 1 alone in controlled human malaria infections failed to protect and showed limited efficacy in field trials. Here we show that vaccination with AMA1–RON2L complex in Freund’s adjuvant protects Aotus monkeys against a virulent Plasmodium falciparum infection. Vaccination with AMA1 alone gave only partial protection, delaying infection in one of eight animals. However, the AMA1–RON2L complex vaccine completely protected four of eight monkeys and substantially delayed infection (>25 days) in three of the other four animals. Interestingly, antibodies from monkeys vaccinated with the AMA1–RON2L complex had significantly higher neutralizing activity than antibodies from monkeys vaccinated with AMA1 alone. Importantly, we show that antibodies from animals vaccinated with the complex have significantly higher neutralization activity against non-vaccine type parasites. We suggest that vaccination with the AMA1–RON2L complex induces functional antibodies that better recognize AMA1 as it appears complexed with RON2 during merozoite invasion. These data justify progression of this next generation AMA1 vaccine towards human trials. A vaccine targeting a protein complex that allows malaria-causing parasite to enter red blood cells has been produced. Malaria caused by the parasite Plasmodium falciparum is an oft-deadly infectious disease without an effective vaccine. A team of researchers at the National Institutes of Health led by Prakash Srinivasan, currently at the Johns Hopkins Malaria Research Institute, United States, demonstrated the efficacy of a vaccine candidate that works by priming a host’s immune system to a parasitic protein complex required to form a junction with red blood cells, allowing entry and proliferation of the pathogen. The group’s vaccine conferred more effective protection in monkeys than prior candidates that targeted only one component of the parasitic protein complex. This research warrants a closer look into how this candidate, and others targeting the protein complex, can be used to prevent malaria in humans.
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Affiliation(s)
- Prakash Srinivasan
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | | | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Ababacar Diouf
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | | | - Karina P Leiva
- US Naval Medical Research Unit No. 6 (NAMRU-6), Callao, Peru
| | - Luis Lugo-Roman
- US Naval Medical Research Unit No. 6 (NAMRU-6), Callao, Peru
| | - Carmen Lucas
- US Naval Medical Research Unit No. 6 (NAMRU-6), Callao, Peru
| | - Sachy Orr-Gonzalez
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Daming Zhu
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Eileen Villasante
- US Military Malaria Vaccine Program, Naval Medical Research Center, Silver Spring, MD, USA
| | - Lorraine Soisson
- Malaria Vaccine Development Program, U.S. Agency for International Development, Washington, DC, USA
| | - David L Narum
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Susan K Pierce
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Carole A Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Carter Diggs
- Malaria Vaccine Development Program, U.S. Agency for International Development, Washington, DC, USA
| | - Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | | | - Louis H Miller
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
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Bitencourt Chaves L, Perce-da-Silva DDS, Rodrigues-da-Silva RN, Martins da Silva JH, Cassiano GC, Machado RLD, Pratt-Riccio LR, Banic DM, Lima-Junior JDC. Plasmodium vivax Cell Traversal Protein for Ookinetes and Sporozoites (PvCelTOS) gene sequence and potential epitopes are highly conserved among isolates from different regions of Brazilian Amazon. PLoS Negl Trop Dis 2017; 11:e0005344. [PMID: 28158176 PMCID: PMC5310920 DOI: 10.1371/journal.pntd.0005344] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 02/15/2017] [Accepted: 01/21/2017] [Indexed: 01/07/2023] Open
Abstract
The Plasmodium vivax Cell-traversal protein for ookinetes and sporozoites (PvCelTOS) plays an important role in the traversal of host cells. Although essential to PvCelTOS progress as a vaccine candidate, its genetic diversity remains uncharted. Therefore, we investigated the PvCelTOS genetic polymorphism in 119 field isolates from five different regions of Brazilian Amazon (Manaus, Novo Repartimento, Porto Velho, Plácido de Castro and Oiapoque). Moreover, we also evaluated the potential impact of non-synonymous mutations found in the predicted structure and epitopes of PvCelTOS. The field isolates showed high similarity (99.3% of bp) with the reference Sal-1 strain, presenting only four Single-Nucleotide Polymorphisms (SNP) at positions 24A, 28A, 109A and 352C. The frequency of synonymous C109A (82%) was higher than all others (p<0.0001). However, the non-synonymous G28A and G352C were observed in 9.2% and 11.7% isolates. The great majority of the isolates (79.8%) revealed complete amino acid sequence homology with Sal-1, 10.9% presented complete homology with Brazil I and two undescribed PvCelTOS sequences were observed in 9.2% field isolates. Concerning the prediction analysis, the N-terminal substitution (Gly10Ser) was predicted to be within a B-cell epitope (PvCelTOS Accession Nos. AB194053.1) and exposed at the protein surface, while the Val118Leu substitution was not a predicted epitope. Therefore, our data suggest that although G28A SNP might interfere in potential B-cell epitopes at PvCelTOS N-terminal region the gene sequence is highly conserved among the isolates from different geographic regions, which is an important feature to be taken into account when evaluating its potential as a vaccine candidate. Cell-traversal protein for ookinetes and sporozoites (CelTOS) presents a pivotal role in the cell traversal of host cells in mosquito and vertebrate hosts. For this reason, it has been considered a potential novel alternative for a vaccine against malaria caused by P. falciparum. However, little is known about its orthologous P. vivax CelTOS. Although the genetic diversity of this protein could be a limiting factor for acquisition of immunity and present implications for an effective vaccine development, it has never been explored. Thus, considering that the epidemiology of malaria in Brazil presents variable transmission rates and the knowledge on the genetic polymorphism of PvCelTOS remains unknown, we aimed to identify the pvceltos gene in isolates from five different regions of the Brazilian Amazon and to study the potential impacts of the genetic diversity of PvCelTOS in protein structures and predicted epitopes. Our findings indicate that PvCelTOS is an extremely conserved protein, presenting only four SNPs in the entire sequences of field isolates from Brazilian Amazon. The two non-synonymous mutations found in our field isolates presented no significant effect on the protein structure and a very low impact on potential T and B-cell epitopes indicated by our epitope prediction. Collectively, our data suggest that the small need to avoid the immune recognition by the human host and its importance on the parasite’s survival and transmission reflects a very conservative profile of pvceltos gene in field samples from Brazil and other endemic areas worldwide.
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Affiliation(s)
- Lana Bitencourt Chaves
- Laboratory of Immunoparasitology, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Rio de Janeiro, Brazil
| | | | | | | | - Gustavo Capatti Cassiano
- Laboratory of Tropical Diseases - Prof. Luiz Jacintho da Silva, Department of Genetics, Evolution and Bioagents, University of Campinas, Campinas, São Paulo, Brazil
| | | | - Lilian Rose Pratt-Riccio
- Laboratory of Malaria Research, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Dalma Maria Banic
- Laboratory of Clinical Immunology, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Josué da Costa Lima-Junior
- Laboratory of Immunoparasitology, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Rio de Janeiro, Brazil
- * E-mail:
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Devine SM, MacRaild CA, Norton RS, Scammells PJ. Antimalarial drug discovery targeting apical membrane antigen 1. MEDCHEMCOMM 2017; 8:13-20. [PMID: 30108688 PMCID: PMC6072474 DOI: 10.1039/c6md00495d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 10/27/2016] [Indexed: 01/06/2023]
Abstract
Malaria continues to frustrate humanity's attempts to eradicate this deadly disease. Although gains have been made over the last 15 years, drug resistance to malaria continues to be a major concern. The lack of new antimalarials with novel mechanisms of action continues to challenge the scientific community to find innovative targets to combat this persistent disease. One such target, apical membrane antigen 1 (AMA1), is an essential protein that helps the parasite invade host erythrocytes. Recently, a number of efforts have focused on the druggability of this target, aiming to block the interactions of AMA1 that mediate invasion of host cells. This review covers recent progress in drug discovery targeting this crucial protein-protein interaction in malaria.
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Affiliation(s)
- Shane M Devine
- Medicinal Chemistry , Monash Institute of Pharmaceutical Sciences , Monash University , Parkville , VIC 3052 , Australia . ;
| | - Christopher A MacRaild
- Medicinal Chemistry , Monash Institute of Pharmaceutical Sciences , Monash University , Parkville , VIC 3052 , Australia . ;
| | - Raymond S Norton
- Medicinal Chemistry , Monash Institute of Pharmaceutical Sciences , Monash University , Parkville , VIC 3052 , Australia . ;
| | - Peter J Scammells
- Medicinal Chemistry , Monash Institute of Pharmaceutical Sciences , Monash University , Parkville , VIC 3052 , Australia . ;
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40
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Pegg E, Doyle K, Clark EL, Jatau ID, Tomley FM, Blake DP. Application of a new PCR-RFLP panel suggests a restricted population structure for Eimeria tenella in UK and Irish chickens. Vet Parasitol 2016; 229:60-67. [PMID: 27809980 PMCID: PMC5108357 DOI: 10.1016/j.vetpar.2016.09.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 09/18/2016] [Accepted: 09/24/2016] [Indexed: 12/03/2022]
Abstract
Eimeria tenella populations differ in genetic diversity between regions. PCR-RFLP provides a robust tool to assess genetic diversity for Eimeria tenella. Cost-effective genotyping can support expansion of population genetics for Eimeria.
Eimeria species cause coccidiosis, most notably in chickens where the global cost exceeds US$3 billion every year. Understanding variation in Eimeria population structure and genetic diversity contributes valuable information that can be used to minimise the impact of drug resistance and develop new, cost-effective anticoccidial vaccines. Little knowledge is currently available on the epidemiology of Eimeria species and strains in different regions, or under different chicken production systems. Recently, 244 Eimeria tenella isolates collected from countries in Africa and Asia were genotyped using a Sequenom single nucleotide polymorphism (SNP) tool, revealing significant variation in haplotype diversity and population structure, with a marked North/South regional divide. To expand studies on genetic polymorphism to larger numbers of E. tenella populations in other geographic regions a cheaper and more accessible technique, such as polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), is desirable. We have converted a subset of SNP markers for use as PCR-RFLPs and re-analysed the original 244 isolates with the PCR-RFLPs to assess their utility. In addition, application of the PCR-RFLP to E. tenella samples collected from UK and Irish broiler chickens revealed a tightly restricted haplotype diversity. Just two of the PCR-RFLPs accounted for all of the polymorphism detected in the UK and Irish parasite populations, but analysis of the full dataset revealed different informative markers in different regions, supporting validity of the PCR-RFLP panel. The tools described here provide an accessible and cost-effective method that can be used to enhance understanding of E. tenella genetic diversity and population structure.
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Affiliation(s)
- Elaine Pegg
- Pathology and Pathogen Biology, Royal Veterinary College, Hawkshead Lane, North Mymms, AL9 7TA, UK
| | - Kate Doyle
- Pathology and Pathogen Biology, Royal Veterinary College, Hawkshead Lane, North Mymms, AL9 7TA, UK
| | - Emily L Clark
- Pathology and Pathogen Biology, Royal Veterinary College, Hawkshead Lane, North Mymms, AL9 7TA, UK
| | - Isa D Jatau
- Department of Parasitology and Entomology, Faculty of Veterinary Medicine, Ahmadu Bello University, Zaria, Nigeria
| | - Fiona M Tomley
- Pathology and Pathogen Biology, Royal Veterinary College, Hawkshead Lane, North Mymms, AL9 7TA, UK
| | - Damer P Blake
- Pathology and Pathogen Biology, Royal Veterinary College, Hawkshead Lane, North Mymms, AL9 7TA, UK.
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41
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Drew DR, Wilson DW, Elliott SR, Cross N, Terheggen U, Hodder AN, Siba PM, Chelimo K, Dent AE, Kazura JW, Mueller I, Beeson JG. A novel approach to identifying patterns of human invasion-inhibitory antibodies guides the design of malaria vaccines incorporating polymorphic antigens. BMC Med 2016; 14:144. [PMID: 27658419 PMCID: PMC5034621 DOI: 10.1186/s12916-016-0691-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 09/08/2016] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The polymorphic nature of many malaria vaccine candidates presents major challenges to achieving highly efficacious vaccines. Presently, there is very little knowledge on the prevalence and patterns of functional immune responses to polymorphic vaccine candidates in populations to guide vaccine design. A leading polymorphic vaccine candidate against blood-stage Plasmodium falciparum is apical membrane antigen 1 (AMA1), which is essential for erythrocyte invasion. The importance of AMA1 as a target of acquired human inhibitory antibodies, their allele specificity and prevalence in populations is unknown, but crucial for vaccine design. METHODS P. falciparum lines expressing different AMA1 alleles were genetically engineered and used to quantify functional antibodies from two malaria-exposed populations of adults and children. The acquisition of AMA1 antibodies was also detected using enzyme-linked immunosorbent assay (ELISA) and competition ELISA (using different AMA1 alleles) from the same populations. RESULTS We found that AMA1 was a major target of naturally acquired invasion-inhibitory antibodies that were highly prevalent in malaria-endemic populations and showed a high degree of allele specificity. Significantly, the prevalence of inhibitory antibodies to different alleles varied substantially within populations and between geographic locations. Inhibitory antibodies to three specific alleles were highly prevalent (FVO and W2mef in Papua New Guinea; FVO and XIE in Kenya), identifying them for potential vaccine inclusion. Measurement of antibodies by standard or competition ELISA was not strongly predictive of allele-specific inhibitory antibodies. The patterns of allele-specific functional antibody responses detected with our novel assays may indicate that acquired immunity is elicited towards serotypes that are prevalent in each geographic location. CONCLUSIONS These findings provide new insights into the nature and acquisition of functional immunity to a polymorphic vaccine candidate and strategies to quantify functional immunity in populations to guide rational vaccine design.
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Affiliation(s)
- Damien R Drew
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia
| | - Danny W Wilson
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia.,Research Centre for Infectious Diseases, School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, Australia
| | - Salenna R Elliott
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia
| | - Nadia Cross
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia
| | - Ulrich Terheggen
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia.,Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Parkville, Victoria, Australia
| | - Anthony N Hodder
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Peter M Siba
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | | | - Arlene E Dent
- Case Western Reserve University, Cleveland, Ohio, USA
| | | | - Ivo Mueller
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - James G Beeson
- The Burnet Institute of Medical Research and Public Health, 85 Commercial Road, Melbourne, Victoria, 3004, Australia. .,Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Parkville, Victoria, Australia. .,Department of Microbiology, Monash University, Clayton, Victoria, Australia.
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42
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Clark EL, Tomley FM, Blake DP. Are Eimeria Genetically Diverse, and Does It Matter? Trends Parasitol 2016; 33:231-241. [PMID: 27593338 DOI: 10.1016/j.pt.2016.08.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 08/05/2016] [Accepted: 08/09/2016] [Indexed: 10/21/2022]
Abstract
Eimeria pose a risk to all livestock species as a cause of coccidiosis, reducing productivity and compromising animal welfare. Pressure to reduce drug use in the food chain makes the development of cost-effective vaccines against Eimeria essential. For novel vaccines to be successful, understanding genetic and antigenic diversity in field populations is key. Eimeria species that infect chickens are most significant, with Eimeria tenella among the best studied and most economically important. Genome-wide single nucleotide polymorphism (SNP)-based haplotyping has been used to determine population structure, genotype distribution, and potential for cross-fertilization between E. tenella strains. Here, we discuss recent developments in our understanding of diversity for Eimeria in relation to its specialized life cycle, distribution across the globe, and the challenges posed to vaccine development.
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Affiliation(s)
- Emily L Clark
- Department of Pathology and Pathogen Biology, Royal Veterinary College, North Mymms, Hertfordshire, UK; Current address: The Roslin Institute, The University of Edinburgh, Easter Bush, Midlothian, UK
| | - Fiona M Tomley
- Department of Pathology and Pathogen Biology, Royal Veterinary College, North Mymms, Hertfordshire, UK
| | - Damer P Blake
- Department of Pathology and Pathogen Biology, Royal Veterinary College, North Mymms, Hertfordshire, UK.
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43
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Ochola-Oyier LI, Okombo J, Wagatua N, Ochieng J, Tetteh KK, Fegan G, Bejon P, Marsh K. Comparison of allele frequencies of Plasmodium falciparum merozoite antigens in malaria infections sampled in different years in a Kenyan population. Malar J 2016; 15:261. [PMID: 27154310 PMCID: PMC4858837 DOI: 10.1186/s12936-016-1304-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 04/20/2016] [Indexed: 11/24/2022] Open
Abstract
Background Plasmodium falciparum merozoite antigens elicit antibody responses in malaria-endemic populations, some of which are clinically protective, which is one of the reasons why merozoite antigens are the focus of malaria vaccine development efforts. Polymorphisms in several merozoite antigen-encoding genes are thought to arise as a result of selection by the human immune system. Methods The allele frequency distribution of 15 merozoite antigens over a two-year period, 2007 and 2008, was examined in parasites obtained from children with uncomplicated malaria. In the same population, allele frequency changes pre- and post-anti-malarial treatment were also examined. Any gene which showed a significant shift in allele frequencies was also assessed longitudinally in asymptomatic and complicated malaria infections. Results Fluctuating allele frequencies were identified in codons 147 and 148 of reticulocyte-binding homologue (Rh) 5, with a shift from HD to YH haplotypes over the two-year period in uncomplicated malaria infections. However, in both the asymptomatic and complicated malaria infections YH was the dominant and stable haplotype over the two-year and ten-year periods, respectively. A logistic regression analysis of all three malaria infection populations between 2007 and 2009 revealed, that the chance of being infected with the HD haplotype decreased with time from 2007 to 2009 and increased in the uncomplicated and asymptomatic infections. Conclusion Rh5 codons 147 and 148 showed heterogeneity at both an individual and population level and may be under some degree of immune selection. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1304-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - John Okombo
- KEMRI-Wellcome Trust Collaborative Programme, P.O. Box 230, Kilifi, 80108, Kenya
| | - Njoroge Wagatua
- KEMRI-Wellcome Trust Collaborative Programme, P.O. Box 230, Kilifi, 80108, Kenya
| | - Jacob Ochieng
- KEMRI-Wellcome Trust Collaborative Programme, P.O. Box 230, Kilifi, 80108, Kenya
| | - Kevin K Tetteh
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Greg Fegan
- KEMRI-Wellcome Trust Collaborative Programme, P.O. Box 230, Kilifi, 80108, Kenya
| | - Philip Bejon
- KEMRI-Wellcome Trust Collaborative Programme, P.O. Box 230, Kilifi, 80108, Kenya
| | - Kevin Marsh
- KEMRI-Wellcome Trust Collaborative Programme, P.O. Box 230, Kilifi, 80108, Kenya
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44
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Kateera F, Nsobya SL, Tukwasibwe S, Mens PF, Hakizimana E, Grobusch MP, Mutesa L, Kumar N, van Vugt M. Malaria case clinical profiles and Plasmodium falciparum parasite genetic diversity: a cross sectional survey at two sites of different malaria transmission intensities in Rwanda. Malar J 2016; 15:237. [PMID: 27113354 PMCID: PMC4845397 DOI: 10.1186/s12936-016-1287-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 04/13/2016] [Indexed: 11/10/2022] Open
Abstract
Background Malaria remains a public health challenge in sub-Saharan Africa with Plasmodiumfalciparum being the principal cause of malaria disease morbidity and mortality. Plasmodium falciparum virulence is attributed, in part, to its population-level genetic diversity—a characteristic that has yet to be studied in Rwanda. Characterizing P. falciparum molecular epidemiology in an area is needed for a better understand of malaria transmission and to inform choice of malaria control strategies. Methods In this health-facility based survey, malaria case clinical profiles and parasite densities as well as parasite genetic diversity were compared among P.falciparum-infected patients identified at two sites of different malaria transmission intensities in Rwanda. Data on demographics and clinical features and finger-prick blood samples for microscopy and parasite genotyping were collected. Nested PCR was used to genotype msp-2 alleles of FC27 and 3D7. Results Patients’ variables of age group, sex, fever (both by patient report and by measured tympanic temperatures), parasite density, and bed net use were found differentially distributed between the higher endemic (Ruhuha) and lower endemic (Mubuga) sites. Overall multiplicity of P.falciparum infection (MOI) was 1.73 but with mean MOI found to vary significantly between 2.13 at Ruhuha and 1.29 at Mubuga (p < 0.0001). At Ruhuha, expected heterozygosity (EH) for FC27 and 3D7 alleles were 0.62 and 0.49, respectively, whilst at Mubuga, EH for FC27 and 3D7 were 0.26 and 0.28, respectively. Conclusions In this study, a higher geometrical mean parasite counts, more polyclonal infections, higher MOI, and higher allelic frequency were observed at the higher malaria-endemic (Ruhuha) compared to the lower malaria-endemic (Mubuga) area. These differences in malaria risk and MOI should be considered when choosing setting-specific malaria control strategies, assessing p. falciparum associated parameters such as drug resistance, immunity and impact of used interventions, and in proper interpretation of malaria vaccine studies.
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Affiliation(s)
- Fredrick Kateera
- Medical Research Centre Division, Rwanda Biomedical Centre, PO Box 7162, Kigali, Rwanda. .,Division of Internal Medicine, Department of Infectious Diseases, Centre of Tropical Medicine and Travel Medicine, Meibergdreef 9, 1100 DD, Amsterdam, The Netherlands.
| | - Sam L Nsobya
- Molecular Research Laboratory, Infectious Disease Research Collaboration, New Mulago Hospital Complex, PO Box 7051, Kampala, Uganda.,Department of Pathology, School Biomedical Science, College of Health Science, Makerere University, PO Box 7072, Kampala, Uganda
| | - Stephen Tukwasibwe
- Molecular Research Laboratory, Infectious Disease Research Collaboration, New Mulago Hospital Complex, PO Box 7051, Kampala, Uganda
| | - Petra F Mens
- Division of Internal Medicine, Department of Infectious Diseases, Centre of Tropical Medicine and Travel Medicine, Meibergdreef 9, 1100 DD, Amsterdam, The Netherlands.,Royal Tropical Institute/Koninklijk Instituutvoor de Tropen, KIT Biomedical Research, Meibergdreef 39, 1105 AZ, Amsterdam, The Netherlands
| | - Emmanuel Hakizimana
- Medical Research Centre Division, Rwanda Biomedical Centre, PO Box 7162, Kigali, Rwanda
| | - Martin P Grobusch
- Division of Internal Medicine, Department of Infectious Diseases, Centre of Tropical Medicine and Travel Medicine, Meibergdreef 9, 1100 DD, Amsterdam, The Netherlands
| | - Leon Mutesa
- School of Medicine, College of Medicine and Health Sciences, University of Rwanda, PO Box 3286, Kigali, Rwanda
| | - Nirbhay Kumar
- Department of Tropical Medicine, School of Public Health and Tropical Medicine, Vector-Borne Infectious Disease Research Centre, Tulane University, 333 S Liberty Street, Mail code 8317, New Orleans, LA, 70112, USA
| | - Michele van Vugt
- Division of Internal Medicine, Department of Infectious Diseases, Centre of Tropical Medicine and Travel Medicine, Meibergdreef 9, 1100 DD, Amsterdam, The Netherlands
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45
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Al-Qahtani AA, Abdel-Muhsin AMA, Dajem SMB, AlSheikh AAH, Bohol MFF, Al-Ahdal MN, Putaporntip C, Jongwutiwes S. Comparative sequence analysis of domain I of Plasmodium falciparum apical membrane antigen 1 from Saudi Arabia and worldwide isolates. INFECTION GENETICS AND EVOLUTION 2016; 39:381-388. [PMID: 26867816 DOI: 10.1016/j.meegid.2016.02.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 02/05/2016] [Accepted: 02/06/2016] [Indexed: 10/22/2022]
Abstract
The apical membrane antigen 1 of Plasmodium falciparum (PfAMA1) plays a crucial role in erythrocyte invasion and is a target of protective antibodies. Although domain I of PfAMA1 has been considered a promising vaccine component, extensive sequence diversity in this domain could compromise an effective vaccine design. To explore the extent of sequence diversity in domain I of PfAMA1, P. falciparum-infected blood samples from Saudi Arabia collected between 2007 and 2009 were analyzed and compared with those from worldwide parasite populations. Forty-six haplotypes and a novel codon change (M190V) were found among Saudi Arabian isolates. The haplotype diversity (0.948±0.004) and nucleotide diversity (0.0191±0.0008) were comparable to those from African hyperendemic countries. Positive selection in domain I of PfAMA1 among Saudi Arabian parasite population was observed because nonsynonymous nucleotide substitutions per nonsynonymous site (dN) significantly exceeded synonymous nucleotide substitutions per synonymous site (dS) and Tajima's D and its related statistics significantly deviated from neutrality in the positive direction. Despite a relatively low prevalence of malaria in Saudi Arabia, a minimum of 17 recombination events occurred in domain I. Genetic differentiation was significant between P. falciparum in Saudi Arabia and parasites from other geographic origins. Several shared or closely related haplotypes were found among parasites from different geographic areas, suggesting that vaccine derived from multiple shared epitopes could be effective across endemic countries.
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Affiliation(s)
- Ahmed A Al-Qahtani
- Department of Infection and Immunity, King Faisal Specialist Hospital & Research Center, Riyadh 11211, Saudi Arabia; Department of Microbiology and Immunology, Alfaisal University College of Medicine, Riyadh, Saudi Arabia.
| | - Abdel-Muhsin A Abdel-Muhsin
- Tropical Medicine Research Institute, National Centre for Research, Sudan; Department of Biology, Faculty of Science, University of Hail, Hail, Saudi Arabia
| | - Saad M Bin Dajem
- Department of Biology, Faculty of Science, King Khalid University, Abha, Saudi Arabia
| | - Adel Ali H AlSheikh
- National Center for Vector-Borne Diseases, Ministry of Health, Jazan, Saudi Arabia
| | - Marie Fe F Bohol
- Department of Infection and Immunity, King Faisal Specialist Hospital & Research Center, Riyadh 11211, Saudi Arabia
| | - Mohammed N Al-Ahdal
- Department of Infection and Immunity, King Faisal Specialist Hospital & Research Center, Riyadh 11211, Saudi Arabia; Department of Microbiology and Immunology, Alfaisal University College of Medicine, Riyadh, Saudi Arabia
| | - Chaturong Putaporntip
- Molecular Biology of Malaria and Opportunistic Parasites Research Unit, Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
| | - Somchai Jongwutiwes
- Molecular Biology of Malaria and Opportunistic Parasites Research Unit, Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.
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Zhu X, Zhao Z, Feng Y, Li P, Liu F, Liu J, Yang Z, Yan G, Fan Q, Cao Y, Cui L. Genetic diversity of the Plasmodium falciparum apical membrane antigen I gene in parasite population from the China-Myanmar border area. INFECTION GENETICS AND EVOLUTION 2016; 39:155-162. [PMID: 26825252 DOI: 10.1016/j.meegid.2016.01.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 01/20/2016] [Accepted: 01/23/2016] [Indexed: 11/28/2022]
Abstract
To investigate the genetic diversity of the Plasmodium falciparum apical membrane antigen 1 (PfAMA1) gene in Southeast Asia, we determined PfAMA1 sequences from 135 field isolates collected from the China-Myanmar border area and compared them with 956 publically available PfAMA1 sequences from seven global P. falciparum populations. This analysis revealed high genetic diversity of PfAMA1 in global P. falciparum populations with a total of 229 haplotypes identified. The genetic diversity of PfAMA1 gene from the China-Myanmar border is not evenly distributed in the different domains of this gene. Sequence diversity in PfAMA1 from the China-Myanmar border is lower than that observed in Thai, African and Oceanian populations, but higher than that in the South American population. This appeared to correlate well with the levels of endemicity of different malaria-endemic regions, where hyperendemic regions favor genetic cross of the parasite isolates and generation of higher genetic diversity. Neutrality tests show significant departure from neutrality in the entire ectodomain and Domain I of PfAMA1 in the China-Myanmar border parasite population. We found evidence supporting a substantial continent-wise genetic structure among P. falciparum populations, with the highest genetic differentiation detected between the China-Myanmar border and the South American populations. Whereas no alleles were unique to a specific region, there were considerable geographical differences in major alleles and their frequencies, highlighting further necessity to include more PfAMA1 alleles in vaccine designs.
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Affiliation(s)
- Xiaotong Zhu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning 110122, China
| | - Zhenjun Zhao
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Yonghui Feng
- Department of Laboratory Medicine, The First Hospital of China Medical University, Shenyang, Liaoning 110001, China
| | - Peipei Li
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Fei Liu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning 110122, China
| | - Jun Liu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning 110122, China
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, China
| | - Guiyun Yan
- Program in Public Health, University of California, Irvine, CA, USA
| | - Qi Fan
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning 110122, China.
| | - Liwang Cui
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, Liaoning 110122, China; Department of Entomology, The Pennsylvania State University, University Park, PA 16802, USA.
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Immune protection-inducing protein structures (IMPIPS) against malaria: the weapons needed for beating Odysseus. Vaccine 2015; 33:7525-37. [DOI: 10.1016/j.vaccine.2015.09.109] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 08/04/2015] [Accepted: 09/28/2015] [Indexed: 11/19/2022]
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Guy AJ, Irani V, MacRaild CA, Anders RF, Norton RS, Beeson JG, Richards JS, Ramsland PA. Insights into the Immunological Properties of Intrinsically Disordered Malaria Proteins Using Proteome Scale Predictions. PLoS One 2015; 10:e0141729. [PMID: 26513658 PMCID: PMC4626106 DOI: 10.1371/journal.pone.0141729] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 10/12/2015] [Indexed: 12/31/2022] Open
Abstract
Malaria remains a significant global health burden. The development of an effective malaria vaccine remains as a major challenge with the potential to significantly reduce morbidity and mortality. While Plasmodium spp. have been shown to contain a large number of intrinsically disordered proteins (IDPs) or disordered protein regions, the relationship of protein structure to subcellular localisation and adaptive immune responses remains unclear. In this study, we employed several computational prediction algorithms to identify IDPs at the proteome level of six Plasmodium spp. and to investigate the potential impact of protein disorder on adaptive immunity against P. falciparum parasites. IDPs were shown to be particularly enriched within nuclear proteins, apical proteins, exported proteins and proteins localised to the parasitophorous vacuole. Furthermore, several leading vaccine candidates, and proteins with known roles in host-cell invasion, have extensive regions of disorder. Presentation of peptides by MHC molecules plays an important role in adaptive immune responses, and we show that IDP regions are predicted to contain relatively few MHC class I and II binding peptides owing to inherent differences in amino acid composition compared to structured domains. In contrast, linear B-cell epitopes were predicted to be enriched in IDPs. Tandem repeat regions and non-synonymous single nucleotide polymorphisms were found to be strongly associated with regions of disorder. In summary, immune responses against IDPs appear to have characteristics distinct from those against structured protein domains, with increased antibody recognition of linear epitopes but some constraints for MHC presentation and issues of polymorphisms. These findings have major implications for vaccine design, and understanding immunity to malaria.
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Affiliation(s)
- Andrew J. Guy
- Centre for Biomedical Research, Burnet Institute, Melbourne, Australia
- Department of Immunology, Monash University, Melbourne, Australia
| | - Vashti Irani
- Centre for Biomedical Research, Burnet Institute, Melbourne, Australia
- Department of Medicine, University of Melbourne, Melbourne, Australia
| | - Christopher A. MacRaild
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | - Robin F. Anders
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - Raymond S. Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | - James G. Beeson
- Centre for Biomedical Research, Burnet Institute, Melbourne, Australia
- Department of Medicine, University of Melbourne, Melbourne, Australia
- Department of Microbiology, Monash University, Melbourne, Australia
| | - Jack S. Richards
- Centre for Biomedical Research, Burnet Institute, Melbourne, Australia
- Department of Medicine, University of Melbourne, Melbourne, Australia
- Department of Microbiology, Monash University, Melbourne, Australia
- Victorian Infectious Diseases Service, Royal Melbourne Hospital, Melbourne, Australia
- * E-mail: (JSR); (PAR)
| | - Paul A. Ramsland
- Centre for Biomedical Research, Burnet Institute, Melbourne, Australia
- Department of Immunology, Monash University, Melbourne, Australia
- Department of Surgery Austin Health, University of Melbourne, Heidelberg, Australia
- School of Biomedical Sciences, CHIRI Biosciences, Faculty of Health Sciences, Curtin University, Perth, Australia
- * E-mail: (JSR); (PAR)
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Draper SJ, Angov E, Horii T, Miller LH, Srinivasan P, Theisen M, Biswas S. Recent advances in recombinant protein-based malaria vaccines. Vaccine 2015; 33:7433-43. [PMID: 26458807 PMCID: PMC4687528 DOI: 10.1016/j.vaccine.2015.09.093] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 09/05/2015] [Accepted: 09/28/2015] [Indexed: 01/03/2023]
Abstract
Protein-based vaccines remain the cornerstone approach for B cell and antibody induction against leading target malaria antigens. Advances in antigen selection, immunogen design and epitope-focusing are advancing the field. New heterologous expression platforms are enabling cGMP production of next-generation protein vaccines. Next-generation antigens, protein-based immunogens and virus-like particle (VLP) delivery platforms are in clinical development. Protein-based vaccines will form part of a highly effective multi-component/multi-stage/multi-antigen subunit formulation against malaria.
Plasmodium parasites are the causative agent of human malaria, and the development of a highly effective vaccine against infection, disease and transmission remains a key priority. It is widely established that multiple stages of the parasite's complex lifecycle within the human host and mosquito vector are susceptible to vaccine-induced antibodies. The mainstay approach to antibody induction by subunit vaccination has been the delivery of protein antigen formulated in adjuvant. Extensive efforts have been made in this endeavor with respect to malaria vaccine development, especially with regard to target antigen discovery, protein expression platforms, adjuvant testing, and development of soluble and virus-like particle (VLP) delivery platforms. The breadth of approaches to protein-based vaccines is continuing to expand as innovative new concepts in next-generation subunit design are explored, with the prospects for the development of a highly effective multi-component/multi-stage/multi-antigen formulation seeming ever more likely. This review will focus on recent progress in protein vaccine design, development and/or clinical testing for a number of leading malaria antigens from the sporozoite-, merozoite- and sexual-stages of the parasite's lifecycle–including PfCelTOS, PfMSP1, PfAMA1, PfRH5, PfSERA5, PfGLURP, PfMSP3, Pfs48/45 and Pfs25. Future prospects and challenges for the development, production, human delivery and assessment of protein-based malaria vaccines are discussed.
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Affiliation(s)
- Simon J Draper
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford OX3 7DQ, UK.
| | - Evelina Angov
- Walter Reed Army Institute of Research, U. S. Military Malaria Research Program, Malaria Vaccine Branch, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
| | - Toshihiro Horii
- Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 561-873, Japan
| | - Louis H Miller
- Malaria Cell Biology Section, Laboratory of Malaria and Vector Research, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Prakash Srinivasan
- Malaria Cell Biology Section, Laboratory of Malaria and Vector Research, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Michael Theisen
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark; Centre for Medical Parasitology at Department of International Health, Immunology, and Microbiology and Department of Infectious Diseases, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Sumi Biswas
- The Jenner Institute, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford OX3 7DQ, UK
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Mvé-Ondo B, Nkoghe D, Arnathau C, Rougeron V, Bisvigou U, Mouele LY, Boundenga L, Durand P, Elguero E, Lemmers S, Délicat-Loembet LM, Diamella-Moukodoum N, Paupy C, Renaud F, Prugnolle F, Ollomo B. Genetic diversity of Plasmodium falciparum isolates from Baka Pygmies and their Bantu neighbours in the north of Gabon. Malar J 2015; 14:395. [PMID: 26450086 PMCID: PMC4599724 DOI: 10.1186/s12936-015-0862-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Accepted: 08/23/2015] [Indexed: 11/25/2022] Open
Abstract
Background There have been many reports on the population genetic structure of Plasmodium falciparum from different endemic regions especially sub-Saharan Africa. However, few studies have been performed on neglected populations, such as the Pygmy populations. In this study, the population genetic structure of P. falciparum was investigated in the Baka Pygmies of Gabon and compared to that observed in neighboring villages composed mostly of Bantu farmers. Methods A total of 342 blood samples were collected from 170 Baka Pygmies and 172 Bantus in the north of Gabon (Woleu Ntem Province). Plasmodium infections were characterized by sequencing a portion of the parasite cytochrome b gene. Population genetic structure of P. falciparum in the different villages was analysed using microsatellite markers and genes coding for antigenic proteins (MSP1, MSP2, GLURP, and EBA-175). Results Overall, prevalence of P. falciparum was around 57 % and no significant difference of prevalence was observed between Pygmies and Bantus. No significant differences of population genetic structure of P. falciparum was found between Pygmy and Bantu people except for one antigen-coding gene, glurp, for which genetic data suggested the existence of a potentially disruptive selection acting on this gene in the two types of populations. The genetic structure of P. falciparum followed a pattern of isolation by distance at the scale of the study. Conclusion The prevalence and genetic diversity of P. falciparum observed in Baka demonstrates a significant transmission of the parasite in this population, and some exchanges of parasites with Bantu neighbours. Despite that, some antigen-coding genes seem to have had a particular evolutionary trajectory in certain Pygmy populations due to specific local human and/or mosquito characteristics. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0862-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bertrand Mvé-Ondo
- Centre International de Recherches Médicales de Franceville (CIRMF), BP 769, Franceville, Gabon. .,Ecole Doctorale Régionale d'Afrique Centrale en Infectiologie Tropicale, BP 876, Franceville, Gabon.
| | - Dieudonné Nkoghe
- Centre International de Recherches Médicales de Franceville (CIRMF), BP 769, Franceville, Gabon. .,Ministry of Health, BP 50, Libreville, Gabon.
| | - Céline Arnathau
- Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), UMR CNRS 5290/IRD 224, Université Montpellier, CHRU de Montpellier, 39 Avenue Charles Flahault, 34295, Montpellier, France.
| | - Virginie Rougeron
- Centre International de Recherches Médicales de Franceville (CIRMF), BP 769, Franceville, Gabon. .,Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), UMR CNRS 5290/IRD 224, Université Montpellier, CHRU de Montpellier, 39 Avenue Charles Flahault, 34295, Montpellier, France.
| | | | - Lauriane Yacka Mouele
- Centre International de Recherches Médicales de Franceville (CIRMF), BP 769, Franceville, Gabon. .,Fac de Médecine, UMR-BIOMED, BP 8507, Libreville, Gabon.
| | - Larson Boundenga
- Centre International de Recherches Médicales de Franceville (CIRMF), BP 769, Franceville, Gabon. .,Département de Biologie Animale, Faculté des Sciences et Techniques, Laboratoire d'Écologie et Biologie évolutive, Université Cheikh AntaDiop de Dakar, BP 5005, Dakar, Senegal.
| | - Patrick Durand
- Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), UMR CNRS 5290/IRD 224, Université Montpellier, CHRU de Montpellier, 39 Avenue Charles Flahault, 34295, Montpellier, France.
| | - Eric Elguero
- Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), UMR CNRS 5290/IRD 224, Université Montpellier, CHRU de Montpellier, 39 Avenue Charles Flahault, 34295, Montpellier, France.
| | - Simone Lemmers
- Department of Anthropology, Durham University, Dawson Building, South Road, Durham, DH1 3LE, England, UK.
| | | | - Nancy Diamella-Moukodoum
- Centre International de Recherches Médicales de Franceville (CIRMF), BP 769, Franceville, Gabon.
| | - Christophe Paupy
- Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), UMR CNRS 5290/IRD 224, Université Montpellier, CHRU de Montpellier, 39 Avenue Charles Flahault, 34295, Montpellier, France.
| | - François Renaud
- Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), UMR CNRS 5290/IRD 224, Université Montpellier, CHRU de Montpellier, 39 Avenue Charles Flahault, 34295, Montpellier, France.
| | - Franck Prugnolle
- Centre International de Recherches Médicales de Franceville (CIRMF), BP 769, Franceville, Gabon. .,Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), UMR CNRS 5290/IRD 224, Université Montpellier, CHRU de Montpellier, 39 Avenue Charles Flahault, 34295, Montpellier, France.
| | - Benjamin Ollomo
- Centre International de Recherches Médicales de Franceville (CIRMF), BP 769, Franceville, Gabon. .,Fac de Médecine, UMR-BIOMED, BP 8507, Libreville, Gabon.
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