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Tiwari R, Checkley L, Ferdig MT, Vennerstrom JL, Miller MJ. Synthesis and antimalarial activity of amide and ester conjugates of siderophores and ozonides. Biometals 2023; 36:315-320. [PMID: 35229216 PMCID: PMC9433463 DOI: 10.1007/s10534-022-00375-8] [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: 10/04/2021] [Accepted: 02/14/2022] [Indexed: 11/25/2022]
Abstract
Despite advances in chemotherapeutic interventions for the treatment of malaria, there is a continuing need for the development of new antimalarial agents. Previous studies indicated that co-administration of chloroquine with antioxidants such as the iron chelator deferoxamine (DFO) prevented the development of persistent cognitive damage in surrogate models of cerebral malaria. The work described herein reports the syntheses and antimalarial activities of covalent conjugates of both natural (siderophores) and artificial iron chelators, namely DFO, ferricrocin and ICL-670, with antimalarial 1,2,4-trioxolanes (ozonides). All of the synthesized conjugates had potent antimalarial activities against the in vitro cultures of drug resistant and drug sensitive strains of Plasmodium falciparum. The work described herein provides the basis for future development of covalent combination of iron chelators and antimalarial chemotherapeutic agents for the treatment of cerebral malaria.
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Affiliation(s)
- Rohit Tiwari
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Lisa Checkley
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Michael T Ferdig
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Jonathan L Vennerstrom
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Marvin J Miller
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA.
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2
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Ochwedo KO, Ariri FO, Otambo WO, Magomere EO, Debrah I, Onyango SA, Orondo PW, Atieli HE, Ogolla SO, Otieno ACA, Mukabana WR, Githeko AK, Lee MC, Yan G, Zhong D, Kazura JW. Rare Alleles and Signatures of Selection on the Immunodominant Domains of Pfs230 and Pfs48/45 in Malaria Parasites From Western Kenya. Front Genet 2022; 13:867906. [PMID: 35656326 PMCID: PMC9152164 DOI: 10.3389/fgene.2022.867906] [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: 02/01/2022] [Accepted: 04/25/2022] [Indexed: 01/27/2023] Open
Abstract
Background: Malaria elimination and eradication efforts can be advanced by including transmission-blocking or reducing vaccines (TBVs) alongside existing interventions. Key transmission-blocking vaccine candidates, such as Pfs230 domain one and Pfs48/45 domain 3, should be genetically stable to avoid developing ineffective vaccines due to antigenic polymorphisms. We evaluated genetic polymorphism and temporal stability of Pfs230 domain one and Pfs48/45 domain three in Plasmodium falciparum parasites from western Kenya. Methods: Dry blood spots on filter paper were collected from febrile malaria patients reporting to community health facilities in endemic areas of Homa Bay and Kisumu Counties and an epidemic-prone area of Kisii County in 2018 and 2019. Plasmodium speciation was performed using eluted DNA and real-time PCR. Amplification of the target domains of the two Pfs genes was performed on P. falciparum positive samples. We sequenced Pfs230 domain one on 156 clinical isolates and Pfs48/45 domain three on 118 clinical isolates to infer the levels of genetic variability, signatures of selection, genetic diversity indices and perform other evolutionary analyses. Results: Pfs230 domain one had low nucleotide diversity (π = 0.15 × 10-2) with slight variation per study site. Six polymorphic sites with nonsynonymous mutations and eight haplotypes were discovered. I539T was a novel variant, whereas G605S was nearing fixation. Pfs48/45 domain three had a low π (0.063 × 10-2), high conservation index, and three segregating sites, resulting in nonsynonymous mutation and four haplotypes. Some loci of Pfs230 D1 were in positive or negative linkage disequilibrium, had negative or positive selection signatures, and others (1813, 1955) and (1813, 1983) had a history of recombination. Mutated loci pairs in Pfs48/45 domain three had negative linkage disequilibrium, and some had negative and positive Tajima's D values with no history of recombination events. Conclusion: The two transmission blocking vaccine candidates have low nucleotide diversity, a small number of zone-specific variants, high nucleotide conservation index, and high frequency of rare alleles. With the near fixation a polymorphic site and the proximity of mutated codons to antibody binding epitopes, it will be necessary to continue monitoring sequence modifications of these domains when designing TBVs that include Pfs230 and Pfs48/45 antigens.
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Affiliation(s)
- Kevin O. Ochwedo
- Department of Biology, Faculty of Science and Technology, University of Nairobi, Nairobi, Kenya,Sub-Saharan Africa International Centre for Excellence in Malaria Research, Homa Bay, Kenya
| | - Fredrick O. Ariri
- Sub-Saharan Africa International Centre for Excellence in Malaria Research, Homa Bay, Kenya,Department of Zoology, School of Physical and Biological Sciences, Maseno University, Kisumu, Kenya
| | - Wilfred O. Otambo
- Sub-Saharan Africa International Centre for Excellence in Malaria Research, Homa Bay, Kenya,Department of Zoology, School of Physical and Biological Sciences, Maseno University, Kisumu, Kenya
| | - Edwin O. Magomere
- Sub-Saharan Africa International Centre for Excellence in Malaria Research, Homa Bay, Kenya,Department of Biochemistry, Egerton University, Nakuru, Kenya
| | - Isaiah Debrah
- Sub-Saharan Africa International Centre for Excellence in Malaria Research, Homa Bay, Kenya,West Africa Centre for Cell Biology of Infectious Pathogen, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, Ghana
| | - Shirley A. Onyango
- Sub-Saharan Africa International Centre for Excellence in Malaria Research, Homa Bay, Kenya,School of Zoological Sciences, Kenyatta University, Nairobi, Kenya
| | - Pauline W. Orondo
- Sub-Saharan Africa International Centre for Excellence in Malaria Research, Homa Bay, Kenya
| | - Harrysone E. Atieli
- Sub-Saharan Africa International Centre for Excellence in Malaria Research, Homa Bay, Kenya
| | - Sidney O. Ogolla
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Antony C. A. Otieno
- Department of Biology, Faculty of Science and Technology, University of Nairobi, Nairobi, Kenya
| | - Wolfgang R. Mukabana
- Department of Biology, Faculty of Science and Technology, University of Nairobi, Nairobi, Kenya,Sub-Saharan Africa International Centre for Excellence in Malaria Research, Homa Bay, Kenya
| | - Andrew K. Githeko
- Sub-Saharan Africa International Centre for Excellence in Malaria Research, Homa Bay, Kenya,Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Ming-Chieh Lee
- Program in Public Health, College of Health Sciences, University of California, Irvine, Irvine, CA, United States
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California, Irvine, Irvine, CA, United States
| | - Daibin Zhong
- Program in Public Health, College of Health Sciences, University of California, Irvine, Irvine, CA, United States,*Correspondence: Daibin Zhong,
| | - James W. Kazura
- Centre for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, United States
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3
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Moser KA, Drábek EF, Dwivedi A, Stucke EM, Crabtree J, Dara A, Shah Z, Adams M, Li T, Rodrigues PT, Koren S, Phillippy AM, Munro JB, Ouattara A, Sparklin BC, Dunning Hotopp JC, Lyke KE, Sadzewicz L, Tallon LJ, Spring MD, Jongsakul K, Lon C, Saunders DL, Ferreira MU, Nyunt MM, Laufer MK, Travassos MA, Sauerwein RW, Takala-Harrison S, Fraser CM, Sim BKL, Hoffman SL, Plowe CV, Silva JC. Strains used in whole organism Plasmodium falciparum vaccine trials differ in genome structure, sequence, and immunogenic potential. Genome Med 2020; 12:6. [PMID: 31915075 PMCID: PMC6950926 DOI: 10.1186/s13073-019-0708-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 12/19/2019] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Plasmodium falciparum (Pf) whole-organism sporozoite vaccines have been shown to provide significant protection against controlled human malaria infection (CHMI) in clinical trials. Initial CHMI studies showed significantly higher durable protection against homologous than heterologous strains, suggesting the presence of strain-specific vaccine-induced protection. However, interpretation of these results and understanding of their relevance to vaccine efficacy have been hampered by the lack of knowledge on genetic differences between vaccine and CHMI strains, and how these strains are related to parasites in malaria endemic regions. METHODS Whole genome sequencing using long-read (Pacific Biosciences) and short-read (Illumina) sequencing platforms was conducted to generate de novo genome assemblies for the vaccine strain, NF54, and for strains used in heterologous CHMI (7G8 from Brazil, NF166.C8 from Guinea, and NF135.C10 from Cambodia). The assemblies were used to characterize sequences in each strain relative to the reference 3D7 (a clone of NF54) genome. Strains were compared to each other and to a collection of clinical isolates (sequenced as part of this study or from public repositories) from South America, sub-Saharan Africa, and Southeast Asia. RESULTS While few variants were detected between 3D7 and NF54, we identified tens of thousands of variants between NF54 and the three heterologous strains. These variants include SNPs, indels, and small structural variants that fall in regulatory and immunologically important regions, including transcription factors (such as PfAP2-L and PfAP2-G) and pre-erythrocytic antigens that may be key for sporozoite vaccine-induced protection. Additionally, these variants directly contributed to diversity in immunologically important regions of the genomes as detected through in silico CD8+ T cell epitope predictions. Of all heterologous strains, NF135.C10 had the highest number of unique predicted epitope sequences when compared to NF54. Comparison to global clinical isolates revealed that these four strains are representative of their geographic origin despite long-term culture adaptation; of note, NF135.C10 is from an admixed population, and not part of recently formed subpopulations resistant to artemisinin-based therapies present in the Greater Mekong Sub-region. CONCLUSIONS These results will assist in the interpretation of vaccine efficacy of whole-organism vaccines against homologous and heterologous CHMI.
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Affiliation(s)
- Kara A. Moser
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201 USA
- Present address: Institute for Global Health and Infectious Diseases, University of North Carolina Chapel Hill, Chapel Hill, USA
| | - Elliott F. Drábek
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Ankit Dwivedi
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Emily M. Stucke
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Jonathan Crabtree
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Antoine Dara
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Zalak Shah
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Matthew Adams
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Tao Li
- Sanaria, Inc., Rockville, MD 20850 USA
| | - Priscila T. Rodrigues
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Sergey Koren
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, Bethesda, MD 20892 USA
| | - Adam M. Phillippy
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, Bethesda, MD 20892 USA
| | - James B. Munro
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Amed Ouattara
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Benjamin C. Sparklin
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Julie C. Dunning Hotopp
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Kirsten E. Lyke
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Lisa Sadzewicz
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Luke J. Tallon
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Michele D. Spring
- Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Krisada Jongsakul
- Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Chanthap Lon
- Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - David L. Saunders
- Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
- Present address: Warfighter Expeditionary Medicine and Treatment, US Army Medical Material Development Activity, Frederick, USA
| | - Marcelo U. Ferreira
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Myaing M. Nyunt
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD 21201 USA
- Present address: Duke Global Health Institute, Duke University, Durham, NC 27708 USA
| | - Miriam K. Laufer
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Mark A. Travassos
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Robert W. Sauerwein
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Shannon Takala-Harrison
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Claire M. Fraser
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | | | | | - Christopher V. Plowe
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD 21201 USA
- Present address: Duke Global Health Institute, Duke University, Durham, NC 27708 USA
| | - Joana C. Silva
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201 USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201 USA
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Ndiaye T, Sy M, Gaye A, Ndiaye D. Genetic polymorphism of Merozoite Surface Protein 1 (msp1) and 2 (msp2) genes and multiplicity of Plasmodium falciparum infection across various endemic areas in Senegal. Afr Health Sci 2019; 19:2446-2456. [PMID: 32127816 PMCID: PMC7040301 DOI: 10.4314/ahs.v19i3.19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION Despite a significant decline in Senegal, malaria remains a burden in various parts of the country. Assessment of multiplicity of Plasmodium falciparum infection and genetic diversity of parasites population could help in monitoring of malaria control. OBJECTIVE To assess genetic diversity and multiplicity of infection in P. falciparum isolates from three areas in Senegal with different malaria transmissions. METHODS 136 blood samples were collected from patients with uncomplicated P. falciparum malaria in Pikine, Kedougou and Thies. Polymorphic loci of msp1 and 2 (Merozoite surface protein-1 and 2) genes were amplified by nested PCR. RESULTS For msp1gene, K1 allelic family was predominant with frequency of 71%. Concerning msp2 gene, IC3D7 allelic family was the most represented with frequency of 83%. Multiclonal isolates found were 36% and 31% for msp1et msp2 genes respectively. The MOI found in all areas was 2.56 and was statistically different between areas (P=0.024). Low to intermediate genetic diversity were found with heterozygosity range (He=0,394-0,637) and low genetic differentiation (Fst msp1= 0.011; Fst msp2=0.017) were observed between P. falciparum population within the country. CONCLUSION Low to moderate genetic diversity of P.falciparum strains and MOI disparities were found in Senegal.
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Affiliation(s)
- Tolla Ndiaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Mouhamad Sy
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Amy Gaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Daouda Ndiaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, USA
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Paul NH, Vengesai A, Mduluza T, Chipeta J, Midzi N, Bansal GP, Kumar N. Prevalence of Plasmodium falciparum transmission reducing immunity among primary school children in a malaria moderate transmission region in Zimbabwe. Acta Trop 2016; 163:103-8. [PMID: 27491342 DOI: 10.1016/j.actatropica.2016.07.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 07/25/2016] [Accepted: 07/29/2016] [Indexed: 12/25/2022]
Abstract
Malaria continues to cause alarming morbidity and mortality in more than 100 countries worldwide. Antigens in the various life cycle stages of malaria parasites are presented to the immune system during natural infection and it is widely recognized that after repeated malaria exposure, adults develop partially protective immunity. Specific antigens of natural immunity represent among the most important targets for the development of malaria vaccines. Immunity against the transmission stages of the malaria parasite represents an important approach to reduce malaria transmission and is believed to become an important tool for gradual elimination of malaria. Development of immunity against Plasmodium falciparum sexual stages was evaluated in primary school children aged 6-16 years in Makoni district of Zimbabwe, an area of low to modest malaria transmission. Malaria infection was screened by microscopy, rapid diagnostic tests and finally using nested PCR. Plasma samples were tested for antibodies against recombinant Pfs48/45 and Pfs47 by ELISA. Corresponding serum samples were used to test for P. falciparum transmission reducing activity in Anopheles stephensi and An. gambiae mosquitoes using the membrane feeding assay. The prevalence of malaria diagnosed by rapid diagnostic test kit (Paracheck)™ was 1.7%. However, of the randomly tested blood samples, 66% were positive by nested PCR. ELISA revealed prevalence (64% positivity at 1:500 dilution, in randomly selected 66 plasma samples) of antibodies against recombinant Pfs48/45 (mean A 405nm=0.53, CI=0.46-0.60) and Pfs47 (mean A405nm=0.91, CI=0.80-1.02); antigens specific to the sexual stages. The mosquito membrane feeding assay demonstrated measurable transmission reducing ability of the samples that were positive for Pfs48/45 antibodies by ELISA. Interestingly, 3 plasma samples revealed enhancement of infectivity of P. falciparum in An. stephensi mosquitoes. These studies revealed the presence of antibodies with transmission reducing immunity in school age children from a moderate transmission area of malaria, and provide further support to exploit target antigens such as Pfs48/45 for further development of a malaria transmission blocking vaccine.
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Affiliation(s)
- Noah H Paul
- Scientific and Industrial Research and Development Centre, Food and Biomedical Technology Institute, 1574 Alpes Rd., P O Box 6640, Hatcliffe, Harare, Zimbabwe; University of Zimbabwe, Biochemistry Department, P O Box MP 167, Mount Pleasant, Harare, Zimbabwe
| | - Arthur Vengesai
- University of Zimbabwe, Biochemistry Department, P O Box MP 167, Mount Pleasant, Harare, Zimbabwe
| | - Takafira Mduluza
- University of Zimbabwe, Biochemistry Department, P O Box MP 167, Mount Pleasant, Harare, Zimbabwe; School of Laboratory Medicine & Medical Sciences, College of Health Sciences, University of KwaZulu Natal, Durban, South Africa
| | - James Chipeta
- University of Zambia School of Medicine and University Teaching Hospital, Department of Paediatrics and Child Health, P.O. Box 50110, Lusaka, Zambia
| | - Nicholas Midzi
- University of Zimbabwe, College of Health Sciences Department of Community Medicine, P O Box MP 167, Mount Pleasant, Harare, Zimbabwe
| | - Geetha P Bansal
- Department of Tropical Medicine, School of Public Health and Tropical Medicine, and Vector Borne Infectious Diseases Research Center, Tulane University, New Orleans, LA 70112, USA
| | - Nirbhay Kumar
- Department of Tropical Medicine, School of Public Health and Tropical Medicine, and Vector Borne Infectious Diseases Research Center, Tulane University, New Orleans, LA 70112, USA.
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Teirlinck AC, Roestenberg M, van de Vegte-Bolmer M, Scholzen A, Heinrichs MJL, Siebelink-Stoter R, Graumans W, van Gemert GJ, Teelen K, Vos MW, Nganou-Makamdop K, Borrmann S, Rozier YPA, Erkens MAA, Luty AJF, Hermsen CC, Sim BKL, van Lieshout L, Hoffman SL, Visser LG, Sauerwein RW. NF135.C10: a new Plasmodium falciparum clone for controlled human malaria infections. J Infect Dis 2012. [PMID: 23186785 PMCID: PMC3549599 DOI: 10.1093/infdis/jis725] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
UNLABELLED We established a new field clone of Plasmodium falciparum for use in controlled human malaria infections and vaccine studies to complement the current small portfolio of P. falciparum strains, primarily based on NF54. The Cambodian clone NF135.C10 consistently produced gametocytes and generated substantial numbers of sporozoites in Anopheles mosquitoes and diverged from NF54 parasites by genetic markers. In a controlled human malaria infection trial, 3 of 5 volunteers challenged by mosquitoes infected with NF135.C10 and 4 of 5 challenged with NF54 developed parasitemia as detected with microscopy. The 2 strains induced similar clinical signs and symptoms as well as cellular immunological responses. CLINICAL TRIALS REGISTRATION NCT01002833.
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Affiliation(s)
- Anne C Teirlinck
- Department of Medical Microbiology, Radboud University Nijmegen Medical Center, the Netherlands
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Bousema T, Drakeley C. Epidemiology and infectivity of Plasmodium falciparum and Plasmodium vivax gametocytes in relation to malaria control and elimination. Clin Microbiol Rev 2011; 24:377-410. [PMID: 21482730 PMCID: PMC3122489 DOI: 10.1128/cmr.00051-10] [Citation(s) in RCA: 508] [Impact Index Per Article: 39.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Malaria remains a major cause of morbidity and mortality in the tropics, with Plasmodium falciparum responsible for the majority of the disease burden and P. vivax being the geographically most widely distributed cause of malaria. Gametocytes are the sexual-stage parasites that infect Anopheles mosquitoes and mediate the onward transmission of the disease. Gametocytes are poorly studied despite this crucial role, but with a recent resurgence of interest in malaria elimination, the study of gametocytes is in vogue. This review highlights the current state of knowledge with regard to the development and longevity of P. falciparum and P. vivax gametocytes in the human host and the factors influencing their distribution within endemic populations. The evidence for immune responses, antimalarial drugs, and drug resistance influencing infectiousness to mosquitoes is reviewed. We discuss how the application of molecular techniques has led to the identification of submicroscopic gametocyte carriage and to a reassessment of the human infectious reservoir. These components are drawn together to show how control measures that aim to reduce malaria transmission, such as mass drug administration and a transmission-blocking vaccine, might better be deployed.
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Affiliation(s)
- Teun Bousema
- Department of Immunology & Infection, London School of Hygiene and Tropical Medicine, London W1CE 7HT, United Kingdom
| | - Chris Drakeley
- Department of Immunology & Infection, London School of Hygiene and Tropical Medicine, London W1CE 7HT, United Kingdom
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8
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Malaria gametocytogenesis. Mol Biochem Parasitol 2010; 172:57-65. [PMID: 20381542 PMCID: PMC2880792 DOI: 10.1016/j.molbiopara.2010.03.019] [Citation(s) in RCA: 159] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2010] [Revised: 03/29/2010] [Accepted: 03/30/2010] [Indexed: 02/07/2023]
Abstract
Male and female gametocytes are the components of the malaria parasite life cycle which are taken up from an infected host bloodstream by mosquitoes and thus mediate disease transmission. These gamete precursors are morphologically and functionally quite distinct from their asexual blood stage counterparts and this is reflected in their distinct patterns of gene expression, cellular development and metabolism. Recent transcriptome, proteome and reverse genetic studies have added valuable information to that obtained from traditional studies. However, we still have no answer to the fundamental question regarding sexual development: 'what triggers gametocytogenesis'? In the current climate of eradication/elimination, tackling transmission by killing gametocytes has an important place on the agenda because most antimalarial drugs, whilst killing asexual blood stage parasites, have no effect on the transmissible stages.
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Coutinho-Abreu IV, Ramalho-Ortigao M. Transmission blocking vaccines to control insect-borne diseases: a review. Mem Inst Oswaldo Cruz 2010; 105:1-12. [PMID: 20209323 DOI: 10.1590/s0074-02762010000100001] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Accepted: 12/17/2009] [Indexed: 11/22/2022] Open
Abstract
Insect-borne diseases are responsible for severe mortality and morbidity worldwide. As control of insect vector populations relies primarily on the use of insecticides, the emergence of insecticide resistance as well to unintended consequences of insecticide use pose significant challenges to their continued application. Novel approaches to reduce pathogen transmission by disease vectors are been attempted, including transmission-blocking vaccines (TBVs) thought to be a feasible strategy to reduce pathogen burden in endemic areas. TBVs aim at preventing the transmission of pathogens from infected to uninfected vertebrate host by targeting molecule(s) expressed on the surface of pathogens during their developmental phase within the insect vector or by targeting molecules expressed by the vectors. For pathogen-based molecules, the majority of the TBV candidates selected as well as most of the data available regarding the effectiveness of this approach come from studies using malaria parasites. However, TBV candidates also have been identified from midgut tissues of mosquitoes and sand flies. In spite of the successes achieved in the potential application of TBVs against insect-borne diseases, many significant barriers remain. In this review, many of the TBV strategies against insect-borne pathogens and their respective ramification with regards to the immune response of the vertebrate host are discussed.
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Affiliation(s)
- Iliano V Coutinho-Abreu
- Biology of Disease Vectors Laboratory, Department of Entomology, Kansas State University, Manhattan, KS 66506, USA
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Population genetic analysis of large sequence polymorphisms in Plasmodium falciparum blood-stage antigens. INFECTION GENETICS AND EVOLUTION 2009; 10:200-6. [PMID: 19931645 DOI: 10.1016/j.meegid.2009.11.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Revised: 11/06/2009] [Accepted: 11/11/2009] [Indexed: 11/24/2022]
Abstract
Plasmodium falciparum, the causative agent of human malaria, invades host erythrocytes using several proteins on the surface of the invasive merozoite, which have been proposed as potential vaccine candidates. Members of the multi-gene PfRh family are surface antigens that have been shown to play a central role in directing merozoites to alternative erythrocyte receptors for invasion. Recently, we identified a large structural polymorphism, a 0.58Kb deletion, in the C-terminal region of the PfRh2b gene, present at a high frequency in parasite populations from Senegal. We hypothesize that this region is a target of humoral immunity. Here, by analyzing 371 P. falciparum isolates we show that this major allele is present at varying frequencies in different populations within Senegal, Africa, and throughout the world. For allelic dimorphisms in the asexual stage antigens, Msp-2 and EBA-175, we find minimal geographic differentiation among parasite populations from Senegal and other African localities, suggesting extensive gene flow among these populations and/or immune-mediated frequency-dependent balancing selection. In contrast, we observe a higher level of inter-population divergence (as measured by F(st)) for the PfRh2b deletion, similar to that observed for SNPs from the sexual stage Pfs45/48 loci, which is postulated to be under directional selection. We confirm that the region containing the PfRh2b polymorphism is a target of humoral immune responses by demonstrating antibody reactivity of endemic sera. Our analysis of inter-population divergence suggests that in contrast to the large allelic dimorphisms in EBA-175 and Msp-2, the presence or absence of the large PfRh2b deletion may not elicit frequency-dependent immune selection, but may be under positive immune selection, having important implications for the development of these proteins as vaccine candidates.
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Paganotti GM, Palladino C, Modiano D, Sirima BS, Råberg L, Diarra A, Konaté A, Coluzzi M, Walliker D, Babiker HA. Genetic complexity and gametocyte production of Plasmodium falciparum in Fulani and Mossi communities in Burkina Faso. Parasitology 2006; 132:607-14. [PMID: 16420718 DOI: 10.1017/s0031182005009601] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2005] [Revised: 09/12/2005] [Accepted: 10/28/2005] [Indexed: 11/07/2022]
Abstract
We have examined Plasmodium falciparum gametocyte prevalence, density and their genetic complexity among children of 2 sympatric ethnic groups (Mossi and Fulani) in villages in Burkina Faso. The 2 groups are known to have distinct differences in their susceptibility and immune responses to malaria. We used RT-PCR and sequence-specific probes to detect and type RNA of the gametocyte-specific protein Pfs48/45. There were no differences in detection rates of asexual forms and gametocytes among the 2 groups, using PCR and RT-PCR, respectively. However, there were significant differences in densities of asexual forms and gametocytes, which were both higher among Mossi than Fulani. Both asexual forms and gametocyte densities were influenced by age and ethnicity. Multiple-clone infections with more than 1 gametocyte genotype were equally prevalent among Fulani and Mossi. These differences can most probably be attributed to genetic differences in malaria susceptibility in the 2 ethnic groups.
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Affiliation(s)
- G M Paganotti
- Institute of Infection and Immunology Research, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, UK
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12
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Abstract
Immune responses that kill pathogens or reduce their reproductive rate are generally important in protecting hosts from infection and disease. Pathogens that escape the full impact of such responses will survive, and any heritable genetic basis of this evasion will be selected. Due to the memory component of vertebrate immune responses, pathogens with rare alleles of a target antigen can have an advantage over those with common alleles, leading to the maintenance of a polymorphism. At the genetic level, there ought to be detectable signatures of balancing selection in the genes encoding these antigens. Here, methods for identifying these selective signatures are reviewed. Their practical utility for identifying which antigens are targets of protective immune responses is discussed.
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Affiliation(s)
- D J Conway
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel St, London WC1E 7HT.
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Escalante AA, Grebert HM, Chaiyaroj SC, Riggione F, Biswas S, Nahlen BL, Lal AA. Polymorphism in the gene encoding the Pfs48/45 antigen of Plasmodium falciparum. XI. Asembo Bay Cohort Project. Mol Biochem Parasitol 2002; 119:17-22. [PMID: 11755182 DOI: 10.1016/s0166-6851(01)00386-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We have investigated the genetic diversity of the gene encoding the transmission-blocking vaccine antigen Pfs48/45 of Plasmodium falciparum parasites from western Kenya and compared it with parasite populations from Thailand, India, and Venezuela. We report 44 complete new sequences. Overall, the antigen is less polymorphic as compared with other pre-erythrocytic and blood stage antigens. Contrary to other P. falciparum antigens, the number of synonymous substitutions per synonymous site exceeds the number of non-synonymous substitutions per non-synonymous site. We have found that the Pfs48/45 gene of Kenyan parasites is more polymorphic than parasites from other geographic origins. Our analysis reveals that positive natural selection is involved in the maintenance of the observed polymorphism. No evidence of intragenic recombination was found. F(st) values reveal high levels of gene flow between India and Thailand, however, there are strong constraints in gene flow among Kenyan, Southeast Asian, and Venezuelan parasites. No alleles could be linked to a specific geographic region. The results of this study suggest that this gametocyte antigen, like other asexual blood stage antigens, is under selection pressure.
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Affiliation(s)
- Ananias A Escalante
- Instituto Venezolano de Investigaciones Científicas, Apartado 21827, 1020-A, Caracas, Venezuela.
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Awadalla P, Walliker D, Babiker H, Mackinnon M. The question of Plasmodium falciparum population structure. Trends Parasitol 2001; 17:351-3. [PMID: 11685887 DOI: 10.1016/s1471-4922(01)02034-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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15
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Conway DJ, Fanello C, Lloyd JM, Al-Joubori BM, Baloch AH, Somanath SD, Roper C, Oduola AM, Mulder B, Povoa MM, Singh B, Thomas AW. Origin of Plasmodium falciparum malaria is traced by mitochondrial DNA. Mol Biochem Parasitol 2000; 111:163-71. [PMID: 11087926 DOI: 10.1016/s0166-6851(00)00313-3] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The origin and geographical spread of Plasmodium falciparum is here determined by analysis of mitochondrial DNA sequence polymorphism and divergence from its most closely related species P. reichenowi (a rare parasite of chimpanzees). The complete 6 kb mitochondrial genome was sequenced from the single known isolate of P. reichenowi and from four different cultured isolates of P. falciparum, and aligned with the two previously derived P. falciparum sequences. The extremely low synonymous nucleotide polymorphism in P. falciparum (pi=0.0004) contrasts with the divergence at such sites between the two species (kappa=0.1201), and supports a hypothesis that P. falciparum has recently emerged from a single ancestral population. To survey the geographical distribution of mitochondrial haplotypes in P. falciparum, 104 isolates from several endemic areas were typed for each of the identified single nucleotide polymorphisms. The haplotypes show a radiation out of Africa, with unique types in Southeast Asia and South America being related to African types by single nucleotide changes. This indicates that P. falciparum originated in Africa and colonised Southeast Asia and South America separately.
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Affiliation(s)
- D J Conway
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel St, London WC1E 7HT, UK.
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16
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Silva NS, Silveira LA, Machado RL, Póvoa MM, Ferreira MU. Temporal and spatial distribution of the variants of merozoite surface protein-1 (MSP-1) in Plasmodium falciparum populations in Brazil. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2000; 94:675-88. [PMID: 11144809 DOI: 10.1080/00034983.2000.11813591] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The polymorphic, merozoite surface protein-1 (MSP-1) of Plasmodium falciparum, an antigen of the parasite's asexual blood-stages, is a major malaria-vaccine candidate. Nucleotide sequences of each variable domain or block of this antigen may be grouped into one of three possible allelic types (K1, MAD20 and RO33), and 24 major types of the msp-1 gene may be defined, as unique combinations of allelic types in these variable blocks. Isolates collected from the Brazilian Amazon, over a period of 14 years, have now been investigated, by PCR-based typing of the msp-1 gene. Thirteen of the 24 possible gene-types were identified, and 336 P. falciparum clones were fully typed among 239 isolates. Most parasites (87%) belonged to one of the seven most frequent gene-types. Marked temporal variation in the distribution of msp-1 variants was found when comparing parasites sampled in the same sites at intervals of at least 5 years. Spatial variations were also found when comparing parasites from both neighbouring and distant sites within the Amazon Basin. The between-population variance in the frequencies of msp-1 allelic types found in Brazil, as estimated by Wright's FST statistic, is of similar magnitude to that found in previous world-wide comparisons. The potential implications of these findings for the development of an MSP-1-based, multivalent malaria vaccine are discussed.
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Affiliation(s)
- N S Silva
- Laboratório de Parasitologia Molecular, Departamento de Doenças Infecciosas e Parasitárias, Faculdade de Medicina e Enfermagem de São José do Rio Preto, São José do Rio Preto, SP, Brazil
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17
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Anderson TJ, Haubold B, Williams JT, Estrada-Franco JG, Richardson L, Mollinedo R, Bockarie M, Mokili J, Mharakurwa S, French N, Whitworth J, Velez ID, Brockman AH, Nosten F, Ferreira MU, Day KP. Microsatellite markers reveal a spectrum of population structures in the malaria parasite Plasmodium falciparum. Mol Biol Evol 2000; 17:1467-82. [PMID: 11018154 DOI: 10.1093/oxfordjournals.molbev.a026247] [Citation(s) in RCA: 587] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Multilocus genotyping of microbial pathogens has revealed a range of population structures, with some bacteria showing extensive recombination and others showing almost complete clonality. The population structure of the protozoan parasite Plasmodium falciparum has been harder to evaluate, since most studies have used a limited number of antigen-encoding loci that are known to be under strong selection. We describe length variation at 12 microsatellite loci in 465 infections collected from 9 locations worldwide. These data reveal dramatic differences in parasite population structure in different locations. Strong linkage disequilibrium (LD) was observed in six of nine populations. Significant LD occurred in all locations with prevalence <1% and in only two of five of the populations from regions with higher transmission intensities. Where present, LD results largely from the presence of identical multilocus genotypes within populations, suggesting high levels of self-fertilization in populations with low levels of transmission. We also observed dramatic variation in diversity and geographical differentiation in different regions. Mean heterozygosities in South American countries (0.3-0.4) were less than half those observed in African locations (0. 76-0.8), with intermediate heterozygosities in the Southeast Asia/Pacific samples (0.51-0.65). Furthermore, variation was distributed among locations in South America (F:(ST) = 0.364) and within locations in Africa (F:(ST) = 0.007). The intraspecific patterns of diversity and genetic differentiation observed in P. falciparum are strikingly similar to those seen in interspecific comparisons of plants and animals with differing levels of outcrossing, suggesting that similar processes may be involved. The differences observed may also reflect the recent colonization of non-African populations from an African source, and the relative influences of epidemiology and population history are difficult to disentangle. These data reveal a range of population structures within a single pathogen species and suggest intimate links between patterns of epidemiology and genetic structure in this organism.
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Affiliation(s)
- T J Anderson
- Wellcome Trust Centre for the Epidemiology of Infectious Disease, Department of Zoology, University of Oxford, Oxford, England.
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Duraisingh MT, Roper C, Walliker D, Warhurst DC. Increased sensitivity to the antimalarials mefloquine and artemisinin is conferred by mutations in the pfmdr1 gene of Plasmodium falciparum. Mol Microbiol 2000; 36:955-61. [PMID: 10844681 DOI: 10.1046/j.1365-2958.2000.01914.x] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The declining efficacy of chloroquine and pyrimethamine/sulphadoxine in the treatment of human malaria has led to the use of newer antimalarials such as mefloquine and artemisinin. Sequence polymorphisms in the pfmdr1 gene, the gene encoding the plasmodial homologue of mammalian multidrug resistance transporters, have previously been linked to resistance to chloroquine in some, but not all, studies. In this study, we have used a genetic cross between the strains HB3 and 3D7 to study inheritance of sensitivity to the structurally unrelated drugs mefloquine and artemisinin, and to several other antimalarials. We find a complete allelic association between the HB3-like pfmdr1 allele and increased sensitivity to these drugs in the progeny. Different pfmdr1 sequence polymorphisms in other unrelated lines were also associated with increased sensitivity to these drugs. Our results indicate that the pfmdr1 gene is an important determinant of susceptibility to antimalarials, which has major implications for the future development of resistance.
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Affiliation(s)
- M T Duraisingh
- London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
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Anderson TJ, Day KP. Geographical structure and sequence evolution as inferred from the Plasmodium falciparum S-antigen locus. Mol Biochem Parasitol 2000; 106:321-6. [PMID: 10699263 DOI: 10.1016/s0166-6851(99)00222-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- T J Anderson
- Wellcome Trust Centre for Epidemiology of Infectious Disease, Department of Zoology, Oxford University, Oxford, UK.
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Conway DJ. Natural selection on polymorphic malaria antigens and the search for a vaccine. ACTA ACUST UNITED AC 1997; 13:26-9. [PMID: 15275163 DOI: 10.1016/s0169-4758(96)10077-6] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Most protein antigens identified as malaria vaccine candidates are polymorphic in natural parasite populations. Current opinion is that a vaccine must be based on conserved regions of antigens, and if naturally acquired immune responses to these regions are only partially protective in humans, then the vaccine must create what is lacking in Nature. An alternative view is that a successful vaccine might need to be based on multiple allelic forms of an antigen. David Conway here shows that, far from being too pessimistic or impractical, this view offers positive ways to identify targets of protective immunity.
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Affiliation(s)
- D J Conway
- Department of Medical Parasitology, London School of Hygiene and Tropical Medicine, Keppel Street, London, UK.
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