1
|
Fernandes GM, Rodrigues-Mattos GH, Torres LM, Guedes KS, Fontes CJF, Ntumngia FB, Adams JH, Brito CFA, Kano FS, de Sousa TN, Carvalho LH. Natural genetic diversity of the DBL domain of a novel member of the Plasmodium vivax erythrocyte binding-like proteins (EBP2) in the Amazon rainforest. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2024; 123:105628. [PMID: 38936525 DOI: 10.1016/j.meegid.2024.105628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 06/20/2024] [Accepted: 06/23/2024] [Indexed: 06/29/2024]
Abstract
In malaria parasites, the erythrocyte binding-like proteins (EBL) are a family of invasion proteins that are attractive vaccine targets. In the case of Plasmodium vivax, the widespread malaria parasite, blood-stage vaccines have been largely focused on a single EBL candidate, the Duffy binding-like domain (DBL) of the Duffy binding protein (DBPII), due to its well-characterized role in the reticulocyte invasion. A novel P. vivax EBL family member, the Erythrocyte binding protein (EBP2, also named EBP or DBP2), binds preferentially to reticulocytes and may mediate an alternative P. vivax invasion pathway. To gain insight into the natural genetic diversity of the DBL domain of EBP2 (region II; EBP2-II), we analyzed ebp2-II gene sequences of 71 P. vivax isolates collected in different endemic settings of the Brazilian Amazon rainforest, where P. vivax is the predominant malaria-associated species. Although most of the substitutions in the ebp2-II gene were non-synonymous and suggested positive selection, the results showed that the DBL domain of the EBP2 was much less polymorphic than that of DBPII. The predominant EBP2 haplotype in the Amazon region corresponded to the C127 reference sequence first described in Cambodia (25% C127-like haplotype). An overview of ebp2-II gene sequences available at GenBank (n = 352) from seven countries (Cambodia, Madagascar, Myanmar, PNG, South Korea, Thailand, Vietnam) confirmed the C127-like haplotype as highly prevalent worldwide. Two out of 43 haplotypes (5 to 20 inferred per country) showed a global frequency of 60%. The results presented here open new avenues of research pursuit while suggesting that a vaccine based on the DBL domain of EBP2 should target a few haplotypes for broad coverage.
Collapse
Affiliation(s)
- Gabriela M Fernandes
- Biologia Molecular e Imunologia da Malária, Instituto René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil; Universidade Federal de Minas Gerais (UFMG), Departamento de Parasitologia, Belo Horizonte, Brazil
| | - Guilherme H Rodrigues-Mattos
- Biologia Molecular e Imunologia da Malária, Instituto René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
| | - Letícia M Torres
- Faculdade Ciências Médicas de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Karla S Guedes
- Julio Muller School Hospital, Faculdade de Medicina, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso, Brazil
| | - Cor J F Fontes
- Julio Muller School Hospital, Faculdade de Medicina, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso, Brazil
| | - Francis B Ntumngia
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, United States of America
| | - John H Adams
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, United States of America
| | - Cristiana F A Brito
- Biologia Molecular e Imunologia da Malária, Instituto René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
| | - Flora S Kano
- Biologia Molecular e Imunologia da Malária, Instituto René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
| | - Taís N de Sousa
- Biologia Molecular e Imunologia da Malária, Instituto René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil; Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden.
| | - Luzia H Carvalho
- Biologia Molecular e Imunologia da Malária, Instituto René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil.
| |
Collapse
|
2
|
Dickey TH, McAleese H, Salinas ND, Lambert LE, Tolia NH. Structure-based design of a Plasmodium vivax Duffy-binding protein immunogen focuses the antibody response to functional epitopes. Protein Sci 2024; 33:e5095. [PMID: 38988315 PMCID: PMC11237555 DOI: 10.1002/pro.5095] [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: 02/07/2024] [Revised: 06/13/2024] [Accepted: 06/15/2024] [Indexed: 07/12/2024]
Abstract
The Duffy-binding protein (DBP) is a promising antigen for a malaria vaccine that would protect against clinical symptoms caused by Plasmodium vivax infection. Region II of DBP (DBP-II) contains the receptor-binding domain that engages host red blood cells, but DBP-II vaccines elicit many non-neutralizing antibodies that bind distal to the receptor-binding surface. Here, we engineered a truncated DBP-II immunogen that focuses the immune response to the receptor-binding surface. This immunogen contains the receptor-binding subdomain S1S2 and lacks the immunodominant subdomain S3. Structure-based computational design of S1S2 identified combinatorial amino acid changes that stabilized the isolated S1S2 without perturbing neutralizing epitopes. This immunogen elicited DBP-II-specific antibodies in immunized mice that were significantly enriched for blocking activity compared to the native DBP-II antigen. This generalizable design process successfully stabilized an integral core fragment of a protein and focused the immune response to desired epitopes to create a promising new antigen for malaria vaccine development.
Collapse
MESH Headings
- Protozoan Proteins/immunology
- Protozoan Proteins/chemistry
- Protozoan Proteins/genetics
- Antigens, Protozoan/immunology
- Antigens, Protozoan/chemistry
- Antigens, Protozoan/genetics
- Plasmodium vivax/immunology
- Animals
- Malaria Vaccines/immunology
- Malaria Vaccines/chemistry
- Epitopes/immunology
- Epitopes/chemistry
- Mice
- Antibodies, Protozoan/immunology
- Receptors, Cell Surface/immunology
- Receptors, Cell Surface/chemistry
- Receptors, Cell Surface/genetics
- Models, Molecular
- Malaria, Vivax/immunology
- Malaria, Vivax/prevention & control
- Mice, Inbred BALB C
Collapse
Affiliation(s)
- Thayne H. Dickey
- Host‐Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious DiseasesNational Institutes of Health (NIH)BethesdaMarylandUSA
| | - Holly McAleese
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious DiseasesNational Institutes of Health (NIH)BethesdaMarylandUSA
| | - Nichole D. Salinas
- Host‐Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious DiseasesNational Institutes of Health (NIH)BethesdaMarylandUSA
| | - Lynn E. Lambert
- Vaccine Development Unit, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious DiseasesNational Institutes of Health (NIH)BethesdaMarylandUSA
| | - Niraj H. Tolia
- Host‐Pathogen Interactions and Structural Vaccinology Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious DiseasesNational Institutes of Health (NIH)BethesdaMarylandUSA
| |
Collapse
|
3
|
Abebe A, Dieng CC, Dugassa S, Abera D, Shenkutie TT, Assefa A, Menard D, Lo E, Golassa L. Genetic differentiation of Plasmodium vivax duffy binding protein in Ethiopia and comparison with other geographical isolates. Malar J 2024; 23:55. [PMID: 38395885 PMCID: PMC10885561 DOI: 10.1186/s12936-024-04887-1] [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: 12/18/2023] [Accepted: 02/21/2024] [Indexed: 02/25/2024] Open
Abstract
BACKGROUND Plasmodium vivax Duffy binding protein (PvDBP) is a merozoite surface protein located in the micronemes of P. vivax. The invasion of human reticulocytes by P. vivax merozoites depends on the parasite DBP binding domain engaging Duffy Antigen Receptor for Chemokine (DARC) on these red blood cells (RBCs). PvDBPII shows high genetic diversity which is a major challenge to its use in the development of a vaccine against vivax malaria. METHODS A cross-sectional study was conducted from February 2021 to September 2022 in five study sites across Ethiopia. A total of 58 blood samples confirmed positive for P. vivax by polymerase chain reaction (PCR) were included in the study to determine PvDBPII genetic diversity. PvDBPII were amplified using primers designed from reference sequence of P. vivax Sal I strain. Assembling of sequences was done using Geneious Prime version 2023.2.1. Alignment and phylogenetic tree constructions using MEGA version 10.1.1. Nucleotide diversity and haplotype diversity were analysed using DnaSP version 6.12.03, and haplotype network was generated with PopART version 1.7. RESULTS The mean age of the participants was 25 years, 5 (8.6%) participants were Duffy negatives. From the 58 PvDBPII sequences, seven haplotypes based on nucleotide differences at 8 positions were identified. Nucleotide diversity and haplotype diversity were 0.00267 ± 0.00023 and 0.731 ± 0.036, respectively. Among the five study sites, the highest numbers of haplotypes were identified in Arbaminch with six different haplotypes while only two haplotypes were identified in Gambella. The phylogenetic tree based on PvDBPII revealed that parasites of different study sites shared similar genetic clusters with few exceptions. Globally, a total of 39 haplotypes were identified from 223 PvDBPII sequences representing different geographical isolates obtained from NCBI archive. The nucleotide and haplotype diversity were 0.00373 and 0.845 ± 0.015, respectively. The haplotype prevalence ranged from 0.45% to 27.3%. Two haplotypes were shared among isolates from all geographical areas of the globe. CONCLUSIONS PvDBPII of the Ethiopian P. vivax isolates showed low nucleotide but high haplotype diversity, this pattern of genetic variability suggests that the population may have undergone a recent expansion. Among the Ethiopian P. vivax isolates, almost half of the sequences were identical to the Sal-I reference sequence. However, there were unique haplotypes observed in the Ethiopian isolates, which does not share with isolates from other geographical areas. There were two haplotypes that were common among populations across the globe. Categorizing population haplotype frequency can help to determine common haplotypes for designing an effective blood-stage vaccine which will have a significant role for the control and elimination of P. vivax.
Collapse
Affiliation(s)
- Abnet Abebe
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, P.O. Box 24756, Addis Ababa, Ethiopia.
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia.
| | - Cheikh Cambel Dieng
- Department of Microbiology and Immunology, College of Medicine, Drexel University, Philadelphia, USA
| | - Sisay Dugassa
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, P.O. Box 24756, Addis Ababa, Ethiopia
| | - Deriba Abera
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, P.O. Box 24756, Addis Ababa, Ethiopia
| | - Tassew T Shenkutie
- Department of Microbiology and Immunology, College of Medicine, Drexel University, Philadelphia, USA
| | - Ashenafi Assefa
- Institute of Infectious Disease and Global Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Didier Menard
- Malaria Genetics and Resistance Unit, INSERM U1201, Institut Pasteur, Université Paris Cité, 75015, Paris, France
- Dynamics of Host-Pathogen Interactions, Université de Strasbourg, Institute of Parasitology and Tropical Diseases, 67000, Strasbourg, France
| | - Eugenia Lo
- Department of Microbiology and Immunology, College of Medicine, Drexel University, Philadelphia, USA
| | - Lemu Golassa
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, P.O. Box 24756, Addis Ababa, Ethiopia.
| |
Collapse
|
4
|
Lee SK, Nguyen TK, Mohring F, Han JH, Firdaus ER, Na SH, Park WS, Moon RW, Han ET. Merozoite surface protein 1 paralog is involved in the human erythrocyte invasion of a zoonotic malaria, Plasmodium knowlesi. Front Cell Infect Microbiol 2023; 13:1314533. [PMID: 38111629 PMCID: PMC10726050 DOI: 10.3389/fcimb.2023.1314533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 11/15/2023] [Indexed: 12/20/2023] Open
Abstract
The zoonotic malaria parasite Plasmodium knowlesi is an important public health concern in Southeast Asia. Invasion of host erythrocytes is essential for parasite growth, and thus, understanding the repertoire of parasite proteins that enable this process is vital for identifying vaccine candidates and how some species are able to cause zoonotic infection. Merozoite surface protein 1 (MSP1) is found in all malaria parasite species and is perhaps the most well-studied as a potential vaccine candidate. While MSP1 is encoded by a single gene in P. falciparum, all other human infective species (P. vivax, P. knowlesi, P. ovale, and P. malariae) additionally encode a divergent paralogue known as MSP1P, and little is known about its role or potential functional redundancy with MSP1. We, therefore, studied the function of P. knowlesi merozoite surface protein 1 paralog (PkMSP1P), using both recombinant protein and CRISPR-Cas9 genome editing. The recombinant 19-kDa C-terminus of PkMSP1P (PkMSP1P-19) was shown to bind specifically to human reticulocytes. However, immunoblotting data suggested that PkMSP1P-19-induced antibodies can recognize PkMSP1-19 and vice versa, confounding our ability to separate the properties of these two proteins. Targeted disruption of the pkmsp1p gene profoundly impacts parasite growth, demonstrating for the first time that PkMSP1P is important in in vitro growth of P. knowlesi and likely plays a distinct role from PkMSP1. Importantly, the MSP1P KO also enabled functional characterization of the PkMSP1P-19 antibodies, revealing clear immune cross-reactivity between the two paralogues, highlighting the vital importance of genetic studies in contextualizing recombinant protein studies.
Collapse
Affiliation(s)
- Seong-Kyun Lee
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
| | - Tuyet Kha Nguyen
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
| | - Franziska Mohring
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Jin-Hee Han
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
| | - Egy Rahman Firdaus
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
| | - Sung-Hun Na
- Department of Obstetrics and Gynecology, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
| | - Won-Sun Park
- Department of Physiology, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
| | - Robert W. Moon
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Eun-Taek Han
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
| |
Collapse
|
5
|
Dickey TH, Tolia NH. Designing an effective malaria vaccine targeting Plasmodium vivax Duffy-binding protein. Trends Parasitol 2023; 39:850-858. [PMID: 37481347 PMCID: PMC11099547 DOI: 10.1016/j.pt.2023.06.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 06/26/2023] [Accepted: 06/26/2023] [Indexed: 07/24/2023]
Abstract
Malaria caused by the Plasmodium vivax parasite is a major global health burden. Immunity against blood-stage infection reduces parasitemia and disease severity. Duffy-binding protein (DBP) is the primary parasite protein responsible for the invasion of red blood cells and it is a leading subunit vaccine candidate. An effective vaccine, however, is still lacking despite decades of interest in DBP as a vaccine candidate. This review discusses the reasons for targeting DBP, the challenges associated with developing a vaccine, and modern structural vaccinology methods that could be used to create an effective DBP vaccine. Next-generation DBP vaccines have the potential to elicit a broadly protective immune response and provide durable and potent protection from P. vivax malaria.
Collapse
Affiliation(s)
- Thayne H Dickey
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20894, USA
| | - Niraj H Tolia
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20894, USA.
| |
Collapse
|
6
|
Hart MN, Mohring F, DonVito SM, Thomas JA, Muller-Sienerth N, Wright GJ, Knuepfer E, Saibil HR, Moon RW. Sequential roles for red blood cell binding proteins enable phased commitment to invasion for malaria parasites. Nat Commun 2023; 14:4619. [PMID: 37528099 PMCID: PMC10393984 DOI: 10.1038/s41467-023-40357-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 07/20/2023] [Indexed: 08/03/2023] Open
Abstract
Invasion of red blood cells (RBCs) by Plasmodium merozoites is critical to their continued survival within the host. Two major protein families, the Duffy binding-like proteins (DBPs/EBAs) and the reticulocyte binding like proteins (RBLs/RHs) have been studied extensively in P. falciparum and are hypothesized to have overlapping, but critical roles just prior to host cell entry. The zoonotic malaria parasite, P. knowlesi, has larger invasive merozoites and contains a smaller, less redundant, DBP and RBL repertoire than P. falciparum. One DBP (DBPα) and one RBL, normocyte binding protein Xa (NBPXa) are essential for invasion of human RBCs. Taking advantage of the unique biological features of P. knowlesi and iterative CRISPR-Cas9 genome editing, we determine the precise order of key invasion milestones and demonstrate distinct roles for each family. These distinct roles support a mechanism for phased commitment to invasion and can be targeted synergistically with invasion inhibitory antibodies.
Collapse
Affiliation(s)
- Melissa N Hart
- Department of Infection Biology, Faculty of Infectious and Tropical Disease, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hawkshead Lane, Hatfield, AL9 7TA, UK
| | - Franziska Mohring
- Department of Infection Biology, Faculty of Infectious and Tropical Disease, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Sophia M DonVito
- Department of Infection Biology, Faculty of Infectious and Tropical Disease, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - James A Thomas
- Department of Infection Biology, Faculty of Infectious and Tropical Disease, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | | | - Gavin J Wright
- Wellcome Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
- Department of Biology, Hull York Medical School, York Biomedical Research Institute, University of York, Wentworth Way, York, YO10 5DD, UK
| | - Ellen Knuepfer
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hawkshead Lane, Hatfield, AL9 7TA, UK
- Malaria Parasitology Laboratory, Francis Crick Institute, London, NW1 1AT, UK
| | - Helen R Saibil
- ISMB, Biological Sciences, Birkbeck, University of London, Malet St, London, WC1E 7HX, UK
| | - Robert W Moon
- Department of Infection Biology, Faculty of Infectious and Tropical Disease, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK.
| |
Collapse
|
7
|
Moskovitz R, Pholcharee T, DonVito SM, Guloglu B, Lowe E, Mohring F, Moon RW, Higgins MK. Structural basis for DARC binding in reticulocyte invasion by Plasmodium vivax. Nat Commun 2023; 14:3637. [PMID: 37336887 DOI: 10.1038/s41467-023-39357-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 06/06/2023] [Indexed: 06/21/2023] Open
Abstract
The symptoms of malaria occur during the blood stage of infection, when the parasite replicates within human red blood cells. The human malaria parasite, Plasmodium vivax, selectively invades reticulocytes in a process which requires an interaction between the ectodomain of the human DARC receptor and the Plasmodium vivax Duffy-binding protein, PvDBP. Previous studies have revealed that a small helical peptide from DARC binds to region II of PvDBP (PvDBP-RII). However, it is also known that sulphation of tyrosine residues on DARC affects its binding to PvDBP and these residues were not observed in previous structures. We therefore present the structure of PvDBP-RII bound to sulphated DARC peptide, showing that a sulphate on tyrosine 41 binds to a charged pocket on PvDBP-RII. We use molecular dynamics simulations, affinity measurements and growth-inhibition experiments in parasites to confirm the importance of this interaction. We also reveal the epitope for vaccine-elicited growth-inhibitory antibody DB1. This provides a complete understanding of the binding of PvDBP-RII to DARC and will guide the design of vaccines and therapeutics to target this essential interaction.
Collapse
Affiliation(s)
- Re'em Moskovitz
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Tossapol Pholcharee
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Sophia M DonVito
- London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Bora Guloglu
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Edward Lowe
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Franziska Mohring
- London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Robert W Moon
- London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Matthew K Higgins
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
| |
Collapse
|
8
|
Park JH, Kim MH, Sutanto E, Na SW, Kim MJ, Yeom JS, Nyunt MH, Abbas Elfaki MM, Abdel Hamid MM, Cha SH, Alemu SG, Sriprawat K, Anstey NM, Grigg MJ, Barber BE, William T, Gao Q, Liu Y, Pearson RD, Price RN, Nosten F, Yoon SI, No JH, Han ET, Auburn S, Russell B, Han JH. Geographical distribution and genetic diversity of Plasmodium vivax reticulocyte binding protein 1a correlates with patient antigenicity. PLoS Negl Trop Dis 2022; 16:e0010492. [PMID: 35737709 PMCID: PMC9258880 DOI: 10.1371/journal.pntd.0010492] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 07/06/2022] [Accepted: 05/12/2022] [Indexed: 01/12/2023] Open
Abstract
Plasmodium vivax is the most widespread cause of human malaria. Recent reports of drug resistant vivax malaria and the challenge of eradicating the dormant liver forms increase the importance of vaccine development against this relapsing disease. P. vivax reticulocyte binding protein 1a (PvRBP1a) is a potential vaccine candidate, which is involved in red cell tropism, a crucial step in the merozoite invasion of host reticulocytes. As part of the initial evaluation of the PvRBP1a vaccine candidate, we investigated its genetic diversity and antigenicity using geographically diverse clinical isolates. We analysed pvrbp1a genetic polymorphisms using 202 vivax clinical isolates from six countries. Pvrbp1a was separated into six regions based on specific domain features, sequence conserved/polymorphic regions, and the reticulocyte binding like (RBL) domains. In the fragmented gene sequence analysis, PvRBP1a region II (RII) and RIII (head and tail structure homolog, 152-625 aa.) showed extensive polymorphism caused by random point mutations. The haplotype network of these polymorphic regions was classified into three clusters that converged to independent populations. Antigenicity screening was performed using recombinant proteins PvRBP1a-N (157-560 aa.) and PvRBP1a-C (606-962 aa.), which contained head and tail structure region and sequence conserved region, respectively. Sensitivity against PvRBP1a-N (46.7%) was higher than PvRBP1a-C (17.8%). PvRBP1a-N was reported as a reticulocyte binding domain and this study identified a linear epitope with moderate antigenicity, thus an attractive domain for merozoite invasion-blocking vaccine development. However, our study highlights that a global PvRBP1a-based vaccine design needs to overcome several difficulties due to three distinct genotypes and low antigenicity levels.
Collapse
Affiliation(s)
- Ji-Hoon Park
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Republic of Korea
| | - Min-Hee Kim
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Republic of Korea
| | - Edwin Sutanto
- Eijkman Institute for Molecular Biology, Jakarta, Indonesia
| | - Seok-Won Na
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Republic of Korea
| | - Min-Jae Kim
- Department of Infectious Diseases, Asan Medical Center, Seoul, Republic of Korea
| | - Joon Sup Yeom
- Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea
| | | | - Mohammed Mohieldien Abbas Elfaki
- Department of Parasitology and Medical Entomology, Institute of Endemic Diseases, University of Khartoum, Khartoum, Sudan
- Department of Microbiology and Parasitology, Faculty of Medicine, Jazan University, Jizan, Saudi Arabia
| | - Muzamil Mahdi Abdel Hamid
- Department of Parasitology and Medical Entomology, Institute of Endemic Diseases, University of Khartoum, Khartoum, Sudan
| | - Seok Ho Cha
- Department of Parasitology and Tropical Medicine, Inha University School of Medicine, Incheon, Republic of Korea
| | - Sisay Getachew Alemu
- College of Natural Sciences, Addis Ababa University, Addis Ababa, Ethiopia
- Armauer Hansen Research Institute, Jimma Road, Addis Ababa, Ethiopia
- Bioreliance, Rockville, Maryland, United States of America
| | - Kanlaya Sriprawat
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Tak, Thailand
| | - Nicholas M. Anstey
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Australia
| | - Matthew J. Grigg
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Australia
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Sabah, Malaysia
| | - Bridget E. Barber
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Australia
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Sabah, Malaysia
| | - Timothy William
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Sabah, Malaysia
- Clinical Research Centre, Queen Elizabeth Hospital, Sabah, Malaysia
- Gleneagles Hospital, Sabah, Malaysia
| | - Qi Gao
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, China
| | - Yaobao Liu
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, China
- School of Public Health, Nanjing Medical University, Nanjing, China
| | | | - Ric N. Price
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Australia
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine Research Building, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Francois Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Tak, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine Research Building, University of Oxford, Oxford, United Kingdom
| | - Sung-Il Yoon
- Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon, Republic of Korea
| | - Joo Hwan No
- Host-Parasite Research Laboratory, Institut Pasteur Korea, Seongnam, Republic of Korea
| | - Eun-Taek Han
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Republic of Korea
| | - Sarah Auburn
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Australia
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine Research Building, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Bruce Russell
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Jin-Hee Han
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Republic of Korea
- * E-mail:
| |
Collapse
|
9
|
White M, Chitnis CE. Potential role of vaccines in elimination of Plasmodium vivax. Parasitol Int 2022; 90:102592. [PMID: 35489701 DOI: 10.1016/j.parint.2022.102592] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 04/25/2022] [Indexed: 10/18/2022]
Abstract
The unique biology of Plasmodium vivax, with its ability to form latent hypnozoites in the liver stage and the early appearance of gametocytes during blood stage infection, makes it difficult to target for elimination with standard malaria control tools. Here, we use modelling studies to demonstrate that vaccines that target different stages of P. vivax could greatly assist efforts to eliminate P. vivax. Combination of vaccines that target different P. vivax life cycle stages may be required to achieve high efficacy. Our simulations demonstrate that repeated rounds of mass vaccination with multi-stage vaccines can help achieve pre-elimination levels of P. vivax in both low and high transmission settings. We review the status of global efforts to develop vaccines for P. vivax malaria. We describe the status of the leading P. vivax vaccine candidates and share some thoughts on the prospects for availability of an effective vaccine for P. vivax malaria.
Collapse
Affiliation(s)
- Michael White
- Infectious Disease Epidemiology and Analytics G5 Unit, Department of Global Health, Institut Pasteur, Université de Paris, Paris, France
| | - Chetan E Chitnis
- Malaria Parasite Biology and Vaccines Unit, Department of Parasites and Insect Vectors, Institut Pasteur, Université de Paris, Paris, France.
| |
Collapse
|
10
|
Kumari V, Prasad KM, Kalia I, Sindhu G, Dixit R, Rawat DS, Singh OP, Singh AP, Pandey KC. Dissecting The role of Plasmodium metacaspase-2 in malaria gametogenesis and sporogony. Emerg Microbes Infect 2022; 11:938-955. [PMID: 35264080 PMCID: PMC8973346 DOI: 10.1080/22221751.2022.2052357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The family of apicomplexan specific proteins contains caspases–like proteins called “metacaspases”. These enzymes are present in the malaria parasite but absent in human; therefore, these can be explored as potential drug targets. We deleted the MCA-2 gene from Plasmodium berghei genome using a gene knockout strategy to decipher its precise function. This study has identified that MCA-2 plays an important role in parasite transmission since it is critical for the formation of gametocytes and for maintaining an appropriate number of infectious sporozoites required for sporogony. It is noticeable that a significant reduction in gametocyte, oocysts, ookinete and sporozoites load along with a delay in hepatocytes invasion were observed in the MCA-2 knockout parasite. Furthermore, a study found the two MCA-2 inhibitory molecules known as C-532 and C-533, which remarkably inhibited the MCA-2 activity, abolished the in vitro parasite growth, and also impaired the transmission cycle of P. falciparum and P. berghei in An. stephensi. Our findings indicate that the deletion of MCA-2 hampers the Plasmodium development during erythrocytic and exo-erythrocytic stages, and its inhibition by C-532 and C-533 critically affects the malaria transmission biology.
Collapse
Affiliation(s)
- Vandana Kumari
- ICMR-National Institute of Malaria Research, New Delhi, India
| | | | | | | | - Rajnikant Dixit
- ICMR-National Institute of Malaria Research, New Delhi, India
| | - Diwan S Rawat
- Depatment of Chemistry, University of Delhi, New Delhi, India
| | - O P Singh
- ICMR-National Institute of Malaria Research, New Delhi, India
| | - Agam P Singh
- National Institute of Immunology, New Delhi, India
| | - Kailash C Pandey
- ICMR-National Institute of Malaria Research, New Delhi, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad Uttar Pradesh, UP, India
| |
Collapse
|
11
|
Voinson M, Nunn CL, Goldberg A. Primate malarias as a model for cross-species parasite transmission. eLife 2022; 11:e69628. [PMID: 35086643 PMCID: PMC8798051 DOI: 10.7554/elife.69628] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 01/14/2022] [Indexed: 12/16/2022] Open
Abstract
Parasites regularly switch into new host species, representing a disease burden and conservation risk to the hosts. The distribution of these parasites also gives insight into characteristics of ecological networks and genetic mechanisms of host-parasite interactions. Some parasites are shared across many species, whereas others tend to be restricted to hosts from a single species. Understanding the mechanisms producing this distribution of host specificity can enable more effective interventions and potentially identify genetic targets for vaccines or therapies. As ecological connections between human and local animal populations increase, the risk to human and wildlife health from novel parasites also increases. Which of these parasites will fizzle out and which have the potential to become widespread in humans? We consider the case of primate malarias, caused by Plasmodium parasites, to investigate the interacting ecological and evolutionary mechanisms that put human and nonhuman primates at risk for infection. Plasmodium host switching from nonhuman primates to humans led to ancient introductions of the most common malaria-causing agents in humans today, and new parasite switching is a growing threat, especially in Asia and South America. Based on a wild host-Plasmodium occurrence database, we highlight geographic areas of concern and potential areas to target further sampling. We also discuss methodological developments that will facilitate clinical and field-based interventions to improve human and wildlife health based on this eco-evolutionary perspective.
Collapse
Affiliation(s)
- Marina Voinson
- Department of Evolutionary Anthropology, Duke UniversityDurhamUnited States
| | - Charles L Nunn
- Department of Evolutionary Anthropology, Duke UniversityDurhamUnited States
- Duke Global Health, Duke UniversityDurhamUnited States
| | - Amy Goldberg
- Department of Evolutionary Anthropology, Duke UniversityDurhamUnited States
| |
Collapse
|
12
|
Ndegwa DN, Kundu P, Hostetler JB, Marin-Menendez A, Sanderson T, Mwikali K, Verzier LH, Coyle R, Adjalley S, Rayner JC. Using Plasmodium knowlesi as a model for screening Plasmodium vivax blood-stage malaria vaccine targets reveals new candidates. PLoS Pathog 2021; 17:e1008864. [PMID: 34197567 PMCID: PMC8279373 DOI: 10.1371/journal.ppat.1008864] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 07/14/2021] [Accepted: 06/01/2021] [Indexed: 11/18/2022] Open
Abstract
Plasmodium vivax is responsible for the majority of malaria cases outside Africa. Unlike P. falciparum, the P. vivax life-cycle includes a dormant liver stage, the hypnozoite, which can cause infection in the absence of mosquito transmission. An effective vaccine against P. vivax blood stages would limit symptoms and pathology from such recurrent infections, and therefore could play a critical role in the control of this species. Vaccine development in P. vivax, however, lags considerably behind P. falciparum, which has many identified targets with several having transitioned to Phase II testing. By contrast only one P. vivax blood-stage vaccine candidate based on the Duffy Binding Protein (PvDBP), has reached Phase Ia, in large part because the lack of a continuous in vitro culture system for P. vivax limits systematic screening of new candidates. We used the close phylogenetic relationship between P. vivax and P. knowlesi, for which an in vitro culture system in human erythrocytes exists, to test the scalability of systematic reverse vaccinology to identify and prioritise P. vivax blood-stage targets. A panel of P. vivax proteins predicted to function in erythrocyte invasion were expressed as full-length recombinant ectodomains in a mammalian expression system. Eight of these antigens were used to generate polyclonal antibodies, which were screened for their ability to recognize orthologous proteins in P. knowlesi. These antibodies were then tested for inhibition of growth and invasion of both wild type P. knowlesi and chimeric P. knowlesi lines modified using CRISPR/Cas9 to exchange P. knowlesi genes with their P. vivax orthologues. Candidates that induced antibodies that inhibited invasion to a similar level as PvDBP were identified, confirming the utility of P. knowlesi as a model for P. vivax vaccine development and prioritizing antigens for further follow up.
Collapse
Affiliation(s)
- Duncan N. Ndegwa
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
- Department of Biological Sciences, University of Embu, Embu, Kenya
| | - Prasun Kundu
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge, United Kingdom
| | - Jessica B. Hostetler
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | | | - Theo Sanderson
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Kioko Mwikali
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Lisa H. Verzier
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Rachael Coyle
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Sophie Adjalley
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Julian C. Rayner
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge Biomedical Campus, Hills Road, Cambridge, United Kingdom
| |
Collapse
|
13
|
De SL, Ntumngia FB, Nicholas J, Adams JH. Progress towards the development of a P. vivax vaccine. Expert Rev Vaccines 2021; 20:97-112. [PMID: 33481638 PMCID: PMC7994195 DOI: 10.1080/14760584.2021.1880898] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 01/21/2021] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Plasmodium vivax causes significant public health problems in endemic regions. A vaccine to prevent disease is critical, considering the rapid spread of drug-resistant parasite strains, and the development of hypnozoites in the liver with potential for relapse. A minimally effective vaccine should prevent disease and transmission while an ideal vaccine provides sterile immunity. AREAS COVERED Despite decades of research, the complex life cycle, technical challenges and a lack of funding have hampered progress of P. vivax vaccine development. Here, we review the progress of potential P. vivax vaccine candidates from different stages of the parasite life cycle. We also highlight the challenges and important strategies for rational vaccine design. These factors can significantly increase immune effector mechanisms and improve the protective efficacy of these candidates in clinical trials to generate sustained protection over longer periods of time. EXPERT OPINION A vaccine that presents functionally-conserved epitopes from multiple antigens from various stages of the parasite life cycle is key to induce broadly neutralizing strain-transcending protective immunity to effectively disrupt parasite development and transmission.
Collapse
Affiliation(s)
- Sai Lata De
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Tampa – 33612, FL
| | - Francis B. Ntumngia
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Tampa – 33612, FL
| | - Justin Nicholas
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Tampa – 33612, FL
| | - John H. Adams
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Tampa – 33612, FL
| |
Collapse
|
14
|
Kepple D, Pestana K, Tomida J, Abebe A, Golassa L, Lo E. Alternative Invasion Mechanisms and Host Immune Response to Plasmodium vivax Malaria: Trends and Future Directions. Microorganisms 2020; 9:E15. [PMID: 33374596 PMCID: PMC7822457 DOI: 10.3390/microorganisms9010015] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/19/2020] [Accepted: 12/21/2020] [Indexed: 11/21/2022] Open
Abstract
Plasmodium vivax malaria is a neglected tropical disease, despite being more geographically widespread than any other form of malaria. The documentation of P. vivax infections in different parts of Africa where Duffy-negative individuals are predominant suggested that there are alternative pathways for P. vivax to invade human erythrocytes. Duffy-negative individuals may be just as fit as Duffy-positive individuals and are no longer resistant to P.vivax malaria. In this review, we describe the complexity of P. vivax malaria, characterize pathogenesis and candidate invasion genes of P. vivax, and host immune responses to P. vivax infections. We provide a comprehensive review on parasite ligands in several Plasmodium species that further justify candidate genes in P. vivax. We also summarize previous genomic and transcriptomic studies related to the identification of ligand and receptor proteins in P. vivax erythrocyte invasion. Finally, we identify topics that remain unclear and propose future studies that will greatly contribute to our knowledge of P. vivax.
Collapse
Affiliation(s)
- Daniel Kepple
- Biological Sciences, University of North Carolina, Charlotte, NC 28223, USA; (K.P.); (J.T.)
| | - Kareen Pestana
- Biological Sciences, University of North Carolina, Charlotte, NC 28223, USA; (K.P.); (J.T.)
| | - Junya Tomida
- Biological Sciences, University of North Carolina, Charlotte, NC 28223, USA; (K.P.); (J.T.)
| | - Abnet Abebe
- Ethiopian Public Health Institute, Addis Ababa 1000, Ethiopia;
| | - Lemu Golassa
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa 1000, Ethiopia;
| | - Eugenia Lo
- Biological Sciences, University of North Carolina, Charlotte, NC 28223, USA; (K.P.); (J.T.)
| |
Collapse
|
15
|
Ntumngia FB, Thomson-Luque R, Galusic S, Frato G, Frischmann S, Peabody DS, Chackerian B, Ferreira MU, King CL, Adams JH. Identification and Immunological Characterization of the Ligand Domain of Plasmodium vivax Reticulocyte Binding Protein 1a. J Infect Dis 2019; 218:1110-1118. [PMID: 29741629 DOI: 10.1093/infdis/jiy273] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 05/04/2018] [Indexed: 02/02/2023] Open
Abstract
Background Erythrocyte invasion by malaria parasites is essential for blood-stage development. Consequently, parasite proteins critically involved in erythrocyte invasion, such as the Plasmodium vivax reticulocyte binding proteins (RBPs) that mediate preferential invasion of reticulocytes, are considered potential vaccine targets. Thus, targeting the RBPs could prevent blood-stage infection and disease. The RBPs are large, and little is known about their functional domains and whether individuals naturally exposed to P. vivax acquire binding-inhibitory antibodies to these critical binding regions. This study aims to functionally and immunologically characterize Plasmodium vivax RBP1a. Methods Recombinant proteins of overlapping fragments of RBP1a were used to determine binding specificity to erythrocytes and immunogenicity in laboratory animals. The naturally acquired antibody response to these proteins was evaluated using serum samples from individuals in regions of endemicity. Results The N-terminal extracellular region, RBP1157-650 (RBP1:F8), was determined to bind both reticulocytes and normocytes, with a preference for immature reticulocytes. Antibodies elicited against rRBP1:F8 blocked binding between RBP1:F8 and erythrocytes. Naturally acquired anti-RBP1 binding-inhibitory antibodies were detected in serum specimens from P. vivax-exposed individuals from Papua New Guinea and Brazil. Conclusion Recombinant RBP1:F8 binds human erythrocytes, elicits artificially induced functional blocking antibodies, and is a target of naturally acquired binding-inhibitory antibodies.
Collapse
Affiliation(s)
- Francis B Ntumngia
- Center for Global Health and Infectious Diseases Research, University of South Florida, Tampa, FL
| | - Richard Thomson-Luque
- Center for Global Health and Infectious Diseases Research, University of South Florida, Tampa, FL
| | - Sandra Galusic
- Center for Global Health and Infectious Diseases Research, University of South Florida, Tampa, FL
| | - Gabriel Frato
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH
| | - Sarah Frischmann
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH
| | - David S Peabody
- Department of Molecular Genetics and Microbiology, University of New Mexico School of Medicine, Albuquerque, NM
| | - Bryce Chackerian
- Department of Molecular Genetics and Microbiology, University of New Mexico School of Medicine, Albuquerque, NM
| | - Marcelo U Ferreira
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Brazil
| | - Christopher L King
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH
| | - John H Adams
- Center for Global Health and Infectious Diseases Research, University of South Florida, Tampa, FL
| |
Collapse
|
16
|
Mohring F, Hart MN, Rawlinson TA, Henrici R, Charleston JA, Diez Benavente E, Patel A, Hall J, Almond N, Campino S, Clark TG, Sutherland CJ, Baker DA, Draper SJ, Moon RW. Rapid and iterative genome editing in the malaria parasite Plasmodium knowlesi provides new tools for P. vivax research. eLife 2019; 8:45829. [PMID: 31205002 PMCID: PMC6579517 DOI: 10.7554/elife.45829] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 05/28/2019] [Indexed: 12/14/2022] Open
Abstract
Tackling relapsing Plasmodium vivax and zoonotic Plasmodium knowlesi infections is critical to reducing malaria incidence and mortality worldwide. Understanding the biology of these important and related parasites was previously constrained by the lack of robust molecular and genetic approaches. Here, we establish CRISPR-Cas9 genome editing in a culture-adapted P. knowlesi strain and define parameters for optimal homology-driven repair. We establish a scalable protocol for the production of repair templates by PCR and demonstrate the flexibility of the system by tagging proteins with distinct cellular localisations. Using iterative rounds of genome-editing we generate a transgenic line expressing P. vivax Duffy binding protein (PvDBP), a lead vaccine candidate. We demonstrate that PvDBP plays no role in reticulocyte restriction but can alter the macaque/human host cell tropism of P. knowlesi. Critically, antibodies raised against the P. vivax antigen potently inhibit proliferation of this strain, providing an invaluable tool to support vaccine development.
Collapse
Affiliation(s)
- Franziska Mohring
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Melissa Natalie Hart
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | | | - Ryan Henrici
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - James A Charleston
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Ernest Diez Benavente
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Avnish Patel
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Joanna Hall
- Division of Infectious Disease Diagnostics, National Institute for Biological Standards and Control, Health Protection Agency, Hertfordshire, United Kingdom
| | - Neil Almond
- Division of Infectious Disease Diagnostics, National Institute for Biological Standards and Control, Health Protection Agency, Hertfordshire, United Kingdom
| | - Susana Campino
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Taane G Clark
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Colin J Sutherland
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - David A Baker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Simon J Draper
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Robert William Moon
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| |
Collapse
|
17
|
Structural basis for inhibition of Plasmodium vivax invasion by a broadly neutralizing vaccine-induced human antibody. Nat Microbiol 2019; 4:1497-1507. [PMID: 31133755 PMCID: PMC6711757 DOI: 10.1038/s41564-019-0462-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 04/16/2019] [Indexed: 12/21/2022]
Abstract
The most widespread form of malaria is caused by Plasmodium vivax. To replicate, this parasite must invade immature red blood cells, through a process which requires interaction of the Plasmodium vivax Duffy binding protein, PvDBP with its human receptor, the Duffy antigen receptor for chemokines, DARC. Naturally acquired antibodies that inhibit this interaction associate with clinical immunity, suggesting PvDBP as a leading candidate for inclusion in a vaccine to prevent malaria due to Plasmodium vivax. Here, we isolated a panel of monoclonal antibodies from human volunteers immunised in a clinical vaccine trial of PvDBP. We screened their ability to prevent PvDBP from binding to DARC, and their capacity to block red blood cell invasion by a transgenic Plasmodium knowlesi parasite genetically modified to express PvDBP and to prevent reticulocyte invasion by multiple clinical isolates of Plasmodium vivax. This identified a broadly neutralising human monoclonal antibody which inhibited invasion of all tested strains of Plasmodium vivax. Finally, we determined the structure of a complex of this antibody bound to PvDBP, indicating the molecular basis for inhibition. These findings will guide future vaccine design strategies and open up possibilities for testing the prophylactic use of such an antibody.
Collapse
|
18
|
Kassegne K, Abe EM, Cui YB, Chen SB, Xu B, Deng WP, Shen HM, Wang Y, Chen JH, Zhou XN. Contribution of Plasmodium immunomics: potential impact for serological testing and surveillance of malaria. Expert Rev Proteomics 2018; 16:117-129. [PMID: 30513025 DOI: 10.1080/14789450.2019.1554441] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Introduction: Plasmodium vivax (Pv) and P. knowlesi account together for a considerable share of the global burden of malaria, along with P. falciparum (Pf). However, inaccurate diagnosis and undetectable asymptomatic/submicroscopic malaria infections remain very challenging. Blood-stage antigens involved in either invasion of red blood cells or sequestration/cytoadherence of parasitized erythrocytes have been immunomics-characterized, and are vital for the detection of malaria incidence. Areas covered: We review the recent advances in Plasmodium immunomics to discuss serological markers with potential for specific and sensitive diagnosis of malaria. Insights on alternative use of immunomics to assess malaria prevalence are also highlighted. Finally, we provide practical applications of serological markers as diagnostics, with an emphasis on dot immunogold filtration assay which holds promise for malaria diagnosis and epidemiological surveys. Expert commentary: The approach largely contributes to Pf and Pv research in identifying promising non-orthologous antigens able to detect malaria incidence and to differentiate between past and recent infections. However, further studies to profiling naturally acquired immune responses are expected in order to help discover/validate serological markers of no cross-seroreactivity and guide control interventions. More so, the application of immunomics to knowlesi infections would help validate the recently identified antigens and contribute to the discovery of additional biomarkers of exposure, immunity, or both.
Collapse
Affiliation(s)
- Kokouvi Kassegne
- a National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Key Laboratory of Parasite and Vector Biology of the Chinese Ministry of Health , National Centre for International Research on Tropical Diseases, WHO Collaborating Center for Tropical Diseases, Shanghai, People's Republic of China
| | - Eniola Michael Abe
- a National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Key Laboratory of Parasite and Vector Biology of the Chinese Ministry of Health , National Centre for International Research on Tropical Diseases, WHO Collaborating Center for Tropical Diseases, Shanghai, People's Republic of China
| | - Yan-Bing Cui
- a National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Key Laboratory of Parasite and Vector Biology of the Chinese Ministry of Health , National Centre for International Research on Tropical Diseases, WHO Collaborating Center for Tropical Diseases, Shanghai, People's Republic of China
| | - Shen-Bo Chen
- a National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Key Laboratory of Parasite and Vector Biology of the Chinese Ministry of Health , National Centre for International Research on Tropical Diseases, WHO Collaborating Center for Tropical Diseases, Shanghai, People's Republic of China
| | - Bin Xu
- a National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Key Laboratory of Parasite and Vector Biology of the Chinese Ministry of Health , National Centre for International Research on Tropical Diseases, WHO Collaborating Center for Tropical Diseases, Shanghai, People's Republic of China
| | - Wang-Ping Deng
- a National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Key Laboratory of Parasite and Vector Biology of the Chinese Ministry of Health , National Centre for International Research on Tropical Diseases, WHO Collaborating Center for Tropical Diseases, Shanghai, People's Republic of China
| | - Hai-Mo Shen
- a National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Key Laboratory of Parasite and Vector Biology of the Chinese Ministry of Health , National Centre for International Research on Tropical Diseases, WHO Collaborating Center for Tropical Diseases, Shanghai, People's Republic of China
| | - Yue Wang
- b Institute of Parasitic Diseases , Zhejiang Academy of Medical Sciences , Hangzhou , People's Republic of China
| | - Jun-Hu Chen
- a National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Key Laboratory of Parasite and Vector Biology of the Chinese Ministry of Health , National Centre for International Research on Tropical Diseases, WHO Collaborating Center for Tropical Diseases, Shanghai, People's Republic of China
| | - Xiao-Nong Zhou
- a National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Key Laboratory of Parasite and Vector Biology of the Chinese Ministry of Health , National Centre for International Research on Tropical Diseases, WHO Collaborating Center for Tropical Diseases, Shanghai, People's Republic of China
| |
Collapse
|
19
|
Fong MY, Cheong FW, Lau YL. Erythrocyte-binding assays reveal higher binding of Plasmodium knowlesi Duffy binding protein to human Fy a+/b+ erythrocytes than to Fy a+/b- erythrocytes. Parasit Vectors 2018; 11:527. [PMID: 30257710 PMCID: PMC6158824 DOI: 10.1186/s13071-018-3118-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 09/18/2018] [Indexed: 01/05/2023] Open
Abstract
Background The merozoite of the zoonotic Plasmodium knowlesi invades human erythrocytes via the binding of its Duffy binding protein (PkDBPαII) to the Duffy antigen on the eythrocytes. The Duffy antigen has two immunologically distinct forms, Fya and Fyb. In this study, the erythrocyte-binding assay was used to quantitatively determine and compare the binding level of PkDBPαII to Fya+/b+ and Fya+/b- human erythrocytes. Results In the erythrocyte-binding assay, binding level was determined by scoring the number of rosettes that were formed by erythrocytes surrounding transfected mammalian COS-7 cells which expressed PkDBPαII. The assay result revealed a significant difference in the binding level. The number of rosettes scored for Fya+/b+ was 1.64-fold higher than that of Fya+/b- (155.50 ± 34.32 and 94.75 ± 23.16 rosettes, respectively; t(6) = -2.935, P = 0.026). Conclusions The erythrocyte-binding assay provided a simple approach to quantitatively determine the binding level of PkDBPαII to the erythrocyte Duffy antigen. Using this assay, PkDBPαII was found to display higher binding to Fya+/b+ erythrocytes than to Fya+/b- erythrocytes.
Collapse
Affiliation(s)
- Mun Yik Fong
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
| | | | - Yee Ling Lau
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| |
Collapse
|
20
|
Hoque MR, Elfaki MMA, Ahmed MA, Lee SK, Muh F, Ali Albsheer MM, Hamid MMA, Han ET. Diversity pattern of Duffy binding protein sequence among Duffy-negatives and Duffy-positives in Sudan. Malar J 2018; 17:297. [PMID: 30119671 PMCID: PMC6098642 DOI: 10.1186/s12936-018-2425-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 07/21/2018] [Indexed: 02/08/2023] Open
Abstract
Background Vivax malaria is a leading public health concern worldwide. Due to the high prevalence of Duffy-negative blood group population, Plasmodium vivax in Africa historically is less attributable and remains a neglected disease. The interaction between Duffy binding protein and its cognate receptor, Duffy antigen receptor for chemokine plays a key role in the invasion of red blood cells and serves as a novel vaccine candidate against P. vivax. However, the polymorphic nature of P. vivax Duffy binding protein (DBP), particularly N-terminal cysteine-rich region (PvDBPII), represents a major obstacle for the successful design of a DBP-based vaccine to enable global protection. In this study, the level of pvdbpII sequence variations, Duffy blood group genotypes, number of haplotypes circulating, and the natural selection at pvdbpII in Sudan isolates were analysed and the implication in terms of DBP-based vaccine design was discussed. Methods Forty-two P. vivax-infected blood samples were collected from patients from different areas of Sudan during 2014–2016. For Duffy blood group genotyping, the fragment that indicates GATA-1 transcription factor binding site of the FY gene (− 33T > C) was amplified by PCR and sequenced by direct sequencing. The region II flanking pvdbpII was PCR amplified and sequenced by direct sequencing. The genetic diversity and natural selection of pvdbpII were done using DnaSP ver 5.0 and MEGA ver 5.0 programs. Based on predominant, non-synonymous, single nucleotide polymorphisms (SNPs), prevalence of Sudanese haplotypes was assessed in global isolates. Results Twenty SNPs (14 non-synonymous and 6 synonymous) were identified in pvdbpII among the 42 Sudan P. vivax isolates. Sequence analysis revealed that 11 different PvDBP haplotypes exist in Sudan P. vivax isolates and the region has evolved under positive selection. Among the identified PvDBP haplotypes five PvDBP haplotypes were shared among Duffy-negative as well as Duffy-positive individuals. The high selective pressure was mainly found on the known B cell epitopes (H3) of pvdbpII. Comparison of Sudanese haplotypes, based on 10 predominant non-synonymous SNPs with 10 malaria-endemic countries, demonstrated that Sudanese haplotypes were prevalent in most endemic countries. Conclusion This is the first pvdbp genetic diversity study from an African country. Sudanese isolates display high haplotype diversity and the gene is under selective pressure. Haplotype analysis indicated that Sudanese haplotypes are a representative sample of the global population. However, studies with a large number of samples are needed. These findings would be valuable for the development of PvDBP-based malaria vaccine. Electronic supplementary material The online version of this article (10.1186/s12936-018-2425-z) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Mohammad Rafiul Hoque
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
| | - Mohammed Mohieldien Abbas Elfaki
- Department of Parasitology and Medical Entomology, Institute of Endemic Diseases, University of Khartoum, Qassr Street, Khartoum, Sudan.,Department of Microbiology and Parasitology, Faculty of Medicine, Jazan University, Jizan, Saudi Arabia
| | - Md Atique Ahmed
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
| | - Seong-Kyun Lee
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
| | - Fauzi Muh
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
| | - Musab M Ali Albsheer
- Department of Parasitology and Medical Entomology, Institute of Endemic Diseases, University of Khartoum, Qassr Street, Khartoum, Sudan
| | - Muzamil Mahdi Abdel Hamid
- Department of Parasitology and Medical Entomology, Institute of Endemic Diseases, University of Khartoum, Qassr Street, Khartoum, Sudan.
| | - Eun-Taek Han
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea.
| |
Collapse
|
21
|
Kegawa Y, Asada M, Ishizaki T, Yahata K, Kaneko O. Critical role of Erythrocyte Binding-Like protein of the rodent malaria parasite Plasmodium yoelii to establish an irreversible connection with the erythrocyte during invasion. Parasitol Int 2018; 67:706-714. [PMID: 30025976 DOI: 10.1016/j.parint.2018.07.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 07/13/2018] [Accepted: 07/14/2018] [Indexed: 01/14/2023]
Abstract
Plasmodium malaria parasites multiply within erythrocytes and possess a repertoire of proteins whose function is to recognize and invade these vertebrate host cells. One such protein involved in erythrocyte invasion is the micronemal protein, Erythrocyte Binding-Like (EBL), which has been studied as a potential target of vaccine development in Plasmodium vivax (PvDBP) and Plasmodium falciparum (EBA-175). In the rodent malaria parasite model Plasmodium yoelii, specific substitutions in the EBL regions responsible for intracellular trafficking (17XL parasite line) or receptor recognition (17X1.1pp. parasite line), paradoxically increase invasion ability and virulence rather than abolish EBL function. Attempts to disrupt the ebl gene locus in the 17XL and 17XNL lines were unsuccessful, suggesting EBL essentiality. To understand the mechanisms behind these potentially conflicting outcomes, we generated 17XL-based transfectants in which ebl expression is suppressed with anhydrotetracycline (ATc) and investigated merozoite behavior during erythrocyte invasion. In the absence of ATc, EBL was secreted to the merozoite surface, whereas following ATc administration parasitemia was negligible in vivo. Merozoites lacking EBL were unable to invade erythrocytes in vitro, indicating that EBL has a critical role for erythrocyte invasion. Quantitative time-lapse imaging revealed that with ATc administration a significant number of merozoites were detached from the erythrocyte after the erythrocyte deformation event and no echinocytosis was observed, indicating that EBL is required for merozoites to establish an irreversible connection with erythrocytes during invasion.
Collapse
Affiliation(s)
- Yuto Kegawa
- Program for Nurturing Global Leaders in Tropical and Emerging Communicable Diseases, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan.
| | - Masahito Asada
- Program for Nurturing Global Leaders in Tropical and Emerging Communicable Diseases, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan.
| | - Takahiro Ishizaki
- Program for Nurturing Global Leaders in Tropical and Emerging Communicable Diseases, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan.
| | - Kazuhide Yahata
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan.
| | - Osamu Kaneko
- Program for Nurturing Global Leaders in Tropical and Emerging Communicable Diseases, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan.
| |
Collapse
|
22
|
Lyth O, Vizcay-Barrena G, Wright KE, Haase S, Mohring F, Najer A, Henshall IG, Ashdown GW, Bannister LH, Drew DR, Beeson JG, Fleck RA, Moon RW, Wilson DW, Baum J. Cellular dissection of malaria parasite invasion of human erythrocytes using viable Plasmodium knowlesi merozoites. Sci Rep 2018; 8:10165. [PMID: 29976932 PMCID: PMC6033891 DOI: 10.1038/s41598-018-28457-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 06/22/2018] [Indexed: 12/21/2022] Open
Abstract
Plasmodium knowlesi, a zoonotic parasite causing severe-to-lethal malaria disease in humans, has only recently been adapted to continuous culture with human red blood cells (RBCs). In comparison with the most virulent human malaria, Plasmodium falciparum, there are, however, few cellular tools available to study its biology, in particular direct investigation of RBC invasion by blood-stage P. knowlesi merozoites. This leaves our current understanding of biological differences across pathogenic Plasmodium spp. incomplete. Here, we report a robust method for isolating viable and invasive P. knowlesi merozoites to high purity and yield. Using this approach, we present detailed comparative dissection of merozoite invasion (using a variety of microscopy platforms) and direct assessment of kinetic differences between knowlesi and falciparum merozoites. We go on to assess the inhibitory potential of molecules targeting discrete steps of invasion in either species via a quantitative invasion inhibition assay, identifying a class of polysulfonate polymer able to efficiently inhibit invasion in both, providing a foundation for pan-Plasmodium merozoite inhibitor development. Given the close evolutionary relationship between P. knowlesi and P. vivax, the second leading cause of malaria-related morbidity, this study paves the way for inter-specific dissection of invasion by all three major pathogenic malaria species.
Collapse
Affiliation(s)
- Oliver Lyth
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London, UK
| | - Gema Vizcay-Barrena
- Centre for Ultrastructural Imaging, Guy's Campus, King's College London, London, UK
| | - Katherine E Wright
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London, UK
| | - Silvia Haase
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London, UK
| | - Franziska Mohring
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK
| | - Adrian Najer
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London, UK
| | - Isabelle G Henshall
- Research Centre for Infectious Diseases, School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - George W Ashdown
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London, UK
| | - Lawrence H Bannister
- Centre for Ultrastructural Imaging, Guy's Campus, King's College London, London, UK
| | - Damien R Drew
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, Australia.,Central Clinical School, Monash University, Victoria, Australia
| | - James G Beeson
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, Australia.,Central Clinical School, Monash University, Victoria, Australia
| | - Roland A Fleck
- Centre for Ultrastructural Imaging, Guy's Campus, King's College London, London, UK
| | - Robert W Moon
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK
| | - Danny W Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, The University of Adelaide, Adelaide, Australia. .,Burnet Institute, 85 Commercial Road, Melbourne, Victoria, Australia.
| | - Jake Baum
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London, UK.
| |
Collapse
|
23
|
Lim C, Dankwa S, Paul AS, Duraisingh MT. Host Cell Tropism and Adaptation of Blood-Stage Malaria Parasites: Challenges for Malaria Elimination. Cold Spring Harb Perspect Med 2017; 7:a025494. [PMID: 28213436 PMCID: PMC5666624 DOI: 10.1101/cshperspect.a025494] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Plasmodium falciparum and Plasmodium vivax account for most of the mortality and morbidity associated with malaria in humans. Research and control efforts have focused on infections caused by P. falciparum and P. vivax, but have neglected other malaria parasite species that infect humans. Additionally, many related malaria parasite species infect nonhuman primates (NHPs), and have the potential for transmission to humans. For malaria elimination, the varied and specific challenges of all of these Plasmodium species will need to be considered. Recent advances in molecular genetics and genomics have increased our knowledge of the prevalence and existing diversity of the human and NHP Plasmodium species. We are beginning to identify the extent of the reservoirs of each parasite species in humans and NHPs, revealing their origins as well as potential for adaptation in humans. Here, we focus on the red blood cell stage of human infection and the host cell tropism of each human Plasmodium species. Determinants of tropism are unique among malaria parasite species, presenting a complex challenge for malaria elimination.
Collapse
Affiliation(s)
- Caeul Lim
- Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115
| | - Selasi Dankwa
- Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115
| | - Aditya S Paul
- Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115
| | | |
Collapse
|
24
|
Onkoba N, Mumo RM, Ochanda H, Omwandho C, Ozwara HS, Egwang TG. Safety, immunogenicity, and cross-species protection of a plasmid DNA encoding Plasmodium falciparum SERA5 polypeptide, microbial epitopes and chemokine genes in mice and olive baboons. J Biomed Res 2017; 31:321-332. [PMID: 28808204 PMCID: PMC5548993 DOI: 10.7555/jbr.31.20160025] [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: 03/16/2016] [Accepted: 12/29/2016] [Indexed: 11/03/2022] Open
Abstract
Incorporation of biomolecular epitopes to malarial antigens should be explored in the development of strain-transcending malarial vaccines. The present study sought to determine safety, immunogenicity and cross-species efficacy ofPlasmodium falciparum serine repeat antigen 5 polypeptide co-expressed with epitopes of Bacille-Calmette Guerin (BCG), tetanus toxoid (TT) and a chemokine gene. Olive baboons and BALB/c mice were randomly assigned into vaccine and control groups. The vaccine group animals were primed and boosted twice with pIRES plasmids encoding the SERA5+ BCG+ TT alone, or with either CCL5 or CCL20 and the control group with pIRES plasmid vector backbone. Mice and baboons were challenged withP. berghei ANKA and P. knowlesi H strain parasites, respectively. Safety was determined by observing for injection sites reactogenicities, hematology and clinical chemistry. Parasitaemia and survivorship profiles were used to determine cross-species efficacy, and T cell phenotypes, Th1-, Th2-type, T-regulatory immune responses and antibody responses were assessed to determine vaccine immunogenicity. The pSeBCGTT plasmid DNA vaccines were safe and induced Th1-, Th2-type, and T-regulatory responses vaccinated animals showed enhanced CD4+ (P<0.01), CD 8+ T cells (P<0.001) activation and IgG anti-SE36 antibodies responses (P<0.001) at week 4 and 8 post vaccination compared to the control group. Vaccinated mice had a 31.45-68.69% cumulative parasite load reduction and 60% suppression in baboons (P<0.05) and enhanced survivorship (P<0.001) with no clinical signs of malaria compared to the control group. The results showed that the vaccines were safe, immunogenic and conferred partial cross-species protection.
Collapse
Affiliation(s)
- Nyamongo Onkoba
- . Department of Tropical & Infectious Diseases, Institute of Primate Research, Nairobi P. O. Box 24481-00502, Kenya
- . School of Biological Sciences, University of Nairobi, Nairobi P. O. Box 30197-00100, Kenya
| | - Ruth M. Mumo
- . Department of Tropical & Infectious Diseases, Institute of Primate Research, Nairobi P. O. Box 24481-00502, Kenya
- . Department of Biochemistry, School of Medicine, University of Nairobi, Nairobi P. O. Box 30197-00100, Kenya
| | - Horace Ochanda
- . School of Biological Sciences, University of Nairobi, Nairobi P. O. Box 30197-00100, Kenya
| | - Charles Omwandho
- . Department of Biochemistry, School of Medicine, University of Nairobi, Nairobi P. O. Box 30197-00100, Kenya
- . Kirinyaga University College, Kerugoya P. O. Box 143-10300, Kenya
| | - Hastings S. Ozwara
- . Department of Tropical & Infectious Diseases, Institute of Primate Research, Nairobi P. O. Box 24481-00502, Kenya
| | | |
Collapse
|
25
|
Payne RO, Silk SE, Elias SC, Milne KH, Rawlinson TA, Llewellyn D, Shakri AR, Jin J, Labbé GM, Edwards NJ, Poulton ID, Roberts R, Farid R, Jørgensen T, Alanine DG, de Cassan SC, Higgins MK, Otto TD, McCarthy JS, de Jongh WA, Nicosia A, Moyle S, Hill AV, Berrie E, Chitnis CE, Lawrie AM, Draper SJ. Human vaccination against Plasmodium vivax Duffy-binding protein induces strain-transcending antibodies. JCI Insight 2017; 2:93683. [PMID: 28614791 PMCID: PMC5470884 DOI: 10.1172/jci.insight.93683] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 05/16/2017] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND. Plasmodium vivax is the most widespread human malaria geographically; however, no effective vaccine exists. Red blood cell invasion by the P. vivax merozoite depends on an interaction between the Duffy antigen receptor for chemokines (DARC) and region II of the parasite’s Duffy-binding protein (PvDBP_RII). Naturally acquired binding-inhibitory antibodies against this interaction associate with clinical immunity, but it is unknown whether these responses can be induced by human vaccination. METHODS. Safety and immunogenicity of replication-deficient chimpanzee adenovirus serotype 63 (ChAd63) and modified vaccinia virus Ankara (MVA) viral vectored vaccines targeting PvDBP_RII (Salvador I strain) were assessed in an open-label dose-escalation phase Ia study in 24 healthy UK adults. Vaccines were delivered by the intramuscular route in a ChAd63-MVA heterologous prime-boost regimen using an 8-week interval. RESULTS. Both vaccines were well tolerated and demonstrated a favorable safety profile in malaria-naive adults. PvDBP_RII–specific ex-vivo IFN-γ T cell, antibody-secreting cell, memory B cell, and serum IgG responses were observed after the MVA boost immunization. Vaccine-induced antibodies inhibited the binding of vaccine homologous and heterologous variants of recombinant PvDBP_RII to the DARC receptor, with median 50% binding-inhibition titers greater than 1:100. CONCLUSION. We have demonstrated for the first time to our knowledge that strain-transcending antibodies can be induced against the PvDBP_RII antigen by vaccination in humans. These vaccine candidates warrant further clinical evaluation of efficacy against the blood-stage P. vivax parasite. TRIAL REGISTRATION. Clinicaltrials.gov NCT01816113. FUNDING. Support was provided by the UK Medical Research Council, UK National Institute of Health Research Oxford Biomedical Research Centre, and the Wellcome Trust. A clinical trial of a candidate blood-stage Plasmodium vivax vaccine targeting the Duffy-binding protein demonstrates safety and immunogenicity in healthy adults and induces strain-transcending antibodies.
Collapse
Affiliation(s)
- Ruth O Payne
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Sarah E Silk
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Sean C Elias
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Kathryn H Milne
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | | | - David Llewellyn
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - A Rushdi Shakri
- International Center for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India
| | - Jing Jin
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | | | - Nick J Edwards
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Ian D Poulton
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Rachel Roberts
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Ryan Farid
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Thomas Jørgensen
- ExpreS2, ion Biotechnologies, SCION-DTU Science Park, Hørsholm, Denmark
| | | | | | - Matthew K Higgins
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Thomas D Otto
- Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - James S McCarthy
- QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia
| | - Willem A de Jongh
- ExpreS2, ion Biotechnologies, SCION-DTU Science Park, Hørsholm, Denmark
| | - Alfredo Nicosia
- ReiThera SRL (formerly Okairòs SRL), Viale Città d'Europa, Rome, Italy.,CEINGE, Naples, Italy.,Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Sarah Moyle
- Clinical Biomanufacturing Facility, University of Oxford, Oxford, United Kingdom
| | - Adrian Vs Hill
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Eleanor Berrie
- Clinical Biomanufacturing Facility, University of Oxford, Oxford, United Kingdom
| | - Chetan E Chitnis
- International Center for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India.,Institut Pasteur, Department of Parasites and Insect Vectors, Paris, France
| | - Alison M Lawrie
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Simon J Draper
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| |
Collapse
|
26
|
Abstract
The primate malaria Plasmodium knowlesi has a long-standing history as an experimental malaria model. Studies using this model parasite in combination with its various natural and experimental non-human primate hosts have led to important advances in vaccine development and in our understanding of malaria invasion, immunology and parasite-host interactions. The adaptation to long-term in vitro continuous blood stage culture in rhesus monkey, Macaca fascicularis and human red blood cells, as well as the development of various transfection methodologies has resulted in a highly versatile experimental malaria model, further increasing the potential of what was already a very powerful model. The growing evidence that P. knowlesi is an important human zoonosis in South-East Asia has added relevance to former and future studies of this parasite species.
Collapse
|
27
|
Cheng Y, Lu F, Wang B, Li J, Han JH, Ito D, Kong DH, Jiang L, Wu J, Ha KS, Takashima E, Sattabongkot J, Cao J, Nyunt MH, Kyaw MP, Desai SA, Miller LH, Tsuboi T, Han ET. Plasmodium vivax GPI-anchored micronemal antigen (PvGAMA) binds human erythrocytes independent of Duffy antigen status. Sci Rep 2016; 6:35581. [PMID: 27759110 PMCID: PMC5069673 DOI: 10.1038/srep35581] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 10/04/2016] [Indexed: 11/16/2022] Open
Abstract
Plasmodium vivax, a major agent of malaria in both temperate and tropical climates, has been thought to be unable to infect humans lacking the Duffy (Fy) blood group antigen because this receptor is critical for erythrocyte invasion. Recent surveys in various endemic regions, however, have reported P. vivax infections in Duffy-negative individuals, suggesting that the parasite may utilize alternative receptor-ligand pairs to complete the erythrocyte invasion. Here, we identified and characterized a novel parasite ligand, Plasmodium vivax GPI-anchored micronemal antigen (PvGAMA), that bound human erythrocytes regardless of Duffy antigen status. PvGAMA was localized at the microneme in the mature schizont-stage parasites. The antibodies against PvGAMA fragments inhibited PvGAMA binding to erythrocytes in a dose-dependent manner. The erythrocyte-specific binding activities of PvGAMA were significantly reduced by chymotrypsin treatment. Thus, PvGAMA may be an adhesion molecule for the invasion of Duffy-positive and -negative human erythrocytes.
Collapse
Affiliation(s)
- Yang Cheng
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do 200-701, Republic of Korea.,Department of Parasitology, Wuxi Medical School, Jiangnan University, Wuxi, Jiangsu 214122, China.,Laboratory of Malaria and Vector Research (LMVR), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Rockville, MD 20852, USA
| | - Feng Lu
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do 200-701, Republic of Korea.,Jiangsu Institute of Parasitic Diseases, Wuxi, Jiangsu, People's China
| | - Bo Wang
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do 200-701, Republic of Korea.,Department of Clinical Laboratory, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Jian Li
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do 200-701, Republic of Korea.,Department of Parasitology, College of Basic Medicine, Hubei University of Medicine, Shiyan, Hubei, China
| | - Jin-Hee Han
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do 200-701, Republic of Korea
| | - Daisuke Ito
- Laboratory of Malaria and Vector Research (LMVR), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Rockville, MD 20852, USA.,Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime 790-8577, Japan
| | - Deok-Hoon Kong
- Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do 200-701, Republic of Korea
| | - Lubin Jiang
- Key Laboratory of Molecular Virology and Immunology, Unit of Human Parasite Molecular and Cell Biology, Institut Pasteur of Shanghai, Shanghai 200031, China
| | - Jian Wu
- Laboratory of Malaria and Vector Research (LMVR), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Rockville, MD 20852, USA
| | - Kwon-Soo Ha
- Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do 200-701, Republic of Korea
| | - Eizo Takashima
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime 790-8577, Japan
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Jun Cao
- Jiangsu Institute of Parasitic Diseases, Wuxi, Jiangsu, People's China
| | - Myat Htut Nyunt
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do 200-701, Republic of Korea.,Department of Medical Research, Yangon, Myanmar
| | | | - Sanjay A Desai
- Laboratory of Malaria and Vector Research (LMVR), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Rockville, MD 20852, USA
| | - Louis H Miller
- Laboratory of Malaria and Vector Research (LMVR), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Rockville, MD 20852, USA
| | - Takafumi Tsuboi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime 790-8577, Japan
| | - Eun-Taek Han
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do 200-701, Republic of Korea
| |
Collapse
|
28
|
Yiangou L, Montandon R, Modrzynska K, Rosen B, Bushell W, Hale C, Billker O, Rayner JC, Pance A. A Stem Cell Strategy Identifies Glycophorin C as a Major Erythrocyte Receptor for the Rodent Malaria Parasite Plasmodium berghei. PLoS One 2016; 11:e0158238. [PMID: 27362409 PMCID: PMC4928779 DOI: 10.1371/journal.pone.0158238] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 06/12/2016] [Indexed: 12/26/2022] Open
Abstract
The clinical complications of malaria are caused by the parasite expansion in the blood. Invasion of erythrocytes is a complex process that depends on multiple receptor-ligand interactions. Identification of host receptors is paramount for fighting the disease as it could reveal new intervention targets, but the enucleated nature of erythrocytes makes genetic approaches impossible and many receptors remain unknown. Host-parasite interactions evolve rapidly and are therefore likely to be species-specific. As a results, understanding of invasion receptors outside the major human pathogen Plasmodium falciparum is very limited. Here we use mouse embryonic stem cells (mESCs) that can be genetically engineered and differentiated into erythrocytes to identify receptors for the rodent malaria parasite Plasmodium berghei. Two proteins previously implicated in human malaria infection: glycophorin C (GYPC) and Band-3 (Slc4a1) were deleted in mESCs to generate stable cell lines, which were differentiated towards erythropoiesis. In vitro infection assays revealed that while deletion of Band-3 has no effect, absence of GYPC results in a dramatic decrease in invasion, demonstrating the crucial role of this protein for P. berghei infection. This stem cell approach offers the possibility of targeting genes that may be essential and therefore difficult to disrupt in whole organisms and has the potential to be applied to a variety of parasites in diverse host cell types.
Collapse
Affiliation(s)
- Loukia Yiangou
- Malaria Programme, Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Ruddy Montandon
- Malaria Programme, Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | | | - Barry Rosen
- Mouse Developmental Genetics and ES Cells Mutagenesis, Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Wendy Bushell
- Cellular Genetics, Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Christine Hale
- Microbial Pathogenesis, Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Oliver Billker
- Malaria Programme, Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Julian C. Rayner
- Malaria Programme, Wellcome Trust Sanger Institute, Cambridge, United Kingdom
- * E-mail: (AP); (JCR)
| | - Alena Pance
- Malaria Programme, Wellcome Trust Sanger Institute, Cambridge, United Kingdom
- * E-mail: (AP); (JCR)
| |
Collapse
|
29
|
Normocyte-binding protein required for human erythrocyte invasion by the zoonotic malaria parasite Plasmodium knowlesi. Proc Natl Acad Sci U S A 2016; 113:7231-6. [PMID: 27303038 DOI: 10.1073/pnas.1522469113] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The dominant cause of malaria in Malaysia is now Plasmodium knowlesi, a zoonotic parasite of cynomolgus macaque monkeys found throughout South East Asia. Comparative genomic analysis of parasites adapted to in vitro growth in either cynomolgus or human RBCs identified a genomic deletion that includes the gene encoding normocyte-binding protein Xa (NBPXa) in parasites growing in cynomolgus RBCs but not in human RBCs. Experimental deletion of the NBPXa gene in parasites adapted to growth in human RBCs (which retain the ability to grow in cynomolgus RBCs) restricted them to cynomolgus RBCs, demonstrating that this gene is selectively required for parasite multiplication and growth in human RBCs. NBPXa-null parasites could bind to human RBCs, but invasion of these cells was severely impaired. Therefore, NBPXa is identified as a key mediator of P. knowlesi human infection and may be a target for vaccine development against this emerging pathogen.
Collapse
|
30
|
Dankwa S, Lim C, Bei AK, Jiang RHY, Abshire JR, Patel SD, Goldberg JM, Moreno Y, Kono M, Niles JC, Duraisingh MT. Ancient human sialic acid variant restricts an emerging zoonotic malaria parasite. Nat Commun 2016; 7:11187. [PMID: 27041489 PMCID: PMC4822025 DOI: 10.1038/ncomms11187] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 02/25/2016] [Indexed: 01/19/2023] Open
Abstract
Plasmodium knowlesi is a zoonotic parasite transmitted from macaques causing malaria in humans in Southeast Asia. Plasmodium parasites bind to red blood cell (RBC) surface receptors, many of which are sialylated. While macaques synthesize the sialic acid variant N-glycolylneuraminic acid (Neu5Gc), humans cannot because of a mutation in the enzyme CMAH that converts N-acetylneuraminic acid (Neu5Ac) to Neu5Gc. Here we reconstitute CMAH in human RBCs for the reintroduction of Neu5Gc, which results in enhancement of P. knowlesi invasion. We show that two P. knowlesi invasion ligands, PkDBPβ and PkDBPγ, bind specifically to Neu5Gc-containing receptors. A human-adapted P. knowlesi line invades human RBCs independently of Neu5Gc, with duplication of the sialic acid-independent invasion ligand, PkDBPα and loss of PkDBPγ. Our results suggest that absence of Neu5Gc on human RBCs limits P. knowlesi invasion, but that parasites may evolve to invade human RBCs through the use of sialic acid-independent pathways.
Collapse
Affiliation(s)
- Selasi Dankwa
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, USA
| | - Caeul Lim
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, USA
| | - Amy K Bei
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, USA
| | - Rays H Y Jiang
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, USA
| | - James R Abshire
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Saurabh D Patel
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, USA.,Division of Gastroenterology, Hepatology and Nutrition, Boston Children's Hospital, Boston, Massachusetts 02115, USA
| | - Jonathan M Goldberg
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, USA
| | - Yovany Moreno
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, USA
| | - Maya Kono
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, USA
| | - Jacquin C Niles
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Manoj T Duraisingh
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, USA
| |
Collapse
|
31
|
Deroost K, Pham TT, Opdenakker G, Van den Steen PE. The immunological balance between host and parasite in malaria. FEMS Microbiol Rev 2015; 40:208-57. [PMID: 26657789 DOI: 10.1093/femsre/fuv046] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2015] [Indexed: 12/16/2022] Open
Abstract
Coevolution of humans and malaria parasites has generated an intricate balance between the immune system of the host and virulence factors of the parasite, equilibrating maximal parasite transmission with limited host damage. Focusing on the blood stage of the disease, we discuss how the balance between anti-parasite immunity versus immunomodulatory and evasion mechanisms of the parasite may result in parasite clearance or chronic infection without major symptoms, whereas imbalances characterized by excessive parasite growth, exaggerated immune reactions or a combination of both cause severe pathology and death, which is detrimental for both parasite and host. A thorough understanding of the immunological balance of malaria and its relation to other physiological balances in the body is of crucial importance for developing effective interventions to reduce malaria-related morbidity and to diminish fatal outcomes due to severe complications. Therefore, we discuss in this review the detailed mechanisms of anti-malarial immunity, parasite virulence factors including immune evasion mechanisms and pathogenesis. Furthermore, we propose a comprehensive classification of malaria complications according to the different types of imbalances.
Collapse
Affiliation(s)
- Katrien Deroost
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium The Francis Crick Institute, Mill Hill Laboratory, London, NW71AA, UK
| | - Thao-Thy Pham
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
| | - Ghislain Opdenakker
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
| | - Philippe E Van den Steen
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
| |
Collapse
|
32
|
de Cassan SC, Shakri AR, Llewellyn D, Elias SC, Cho JS, Goodman AL, Jin J, Douglas AD, Suwanarusk R, Nosten FH, Rénia L, Russell B, Chitnis CE, Draper SJ. Preclinical Assessment of Viral Vectored and Protein Vaccines Targeting the Duffy-Binding Protein Region II of Plasmodium Vivax. Front Immunol 2015. [PMID: 26217340 PMCID: PMC4495344 DOI: 10.3389/fimmu.2015.00348] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Malaria vaccine development has largely focused on Plasmodium falciparum; however, a reawakening to the importance of Plasmodium vivax has spurred efforts to develop vaccines against this difficult to treat and at times severe form of relapsing malaria, which constitutes a significant proportion of human malaria cases worldwide. The almost complete dependence of P. vivax red blood cell invasion on the interaction of the P. vivax Duffy-binding protein region II (PvDBP_RII) with the human Duffy antigen receptor for chemokines (DARC) makes this antigen an attractive vaccine candidate against blood-stage P. vivax. Here, we generated both preclinical and clinically compatible adenoviral and poxviral vectored vaccine candidates expressing the Salvador I allele of PvDBP_RII – including human adenovirus serotype 5 (HAdV5), chimpanzee adenovirus serotype 63 (ChAd63), and modified vaccinia virus Ankara (MVA) vectors. We report on the antibody and T cell immunogenicity of these vaccines in mice or rabbits, either used alone in a viral vectored prime-boost regime or in “mixed-modality” adenovirus prime – protein-in-adjuvant boost regimes (using a recombinant PvDBP_RII protein antigen formulated in Montanide®ISA720 or Abisco®100 adjuvants). Antibodies induced by these regimes were found to bind to native parasite antigen from P. vivax infected Thai patients and were capable of inhibiting the binding of PvDBP_RII to its receptor DARC using an in vitro binding inhibition assay. In recent years, recombinant ChAd63 and MVA vectors have been quickly translated into human clinical trials for numerous antigens from P. falciparum as well as a growing number of other pathogens. The vectors reported here are immunogenic in small animals, elicit antibodies against PvDBP_RII, and have recently entered clinical trials, which will provide the first assessment of the safety and immunogenicity of the PvDBP_RII antigen in humans.
Collapse
Affiliation(s)
| | - A Rushdi Shakri
- International Center for Genetic Engineering and Biotechnology , New Delhi , India
| | | | - Sean C Elias
- The Jenner Institute, University of Oxford , Oxford , UK
| | - Jee Sun Cho
- Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore , Singapore , Singapore ; Singapore Immunology Network, Agency for Science, Technology and Research (ASTAR) , Singapore , Singapore
| | - Anna L Goodman
- The Jenner Institute, University of Oxford , Oxford , UK
| | - Jing Jin
- The Jenner Institute, University of Oxford , Oxford , UK
| | | | - Rossarin Suwanarusk
- Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore , Singapore , Singapore ; Singapore Immunology Network, Agency for Science, Technology and Research (ASTAR) , Singapore , Singapore
| | - François H Nosten
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University , Mae Sot , Thailand
| | - Laurent Rénia
- Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore , Singapore , Singapore ; Singapore Immunology Network, Agency for Science, Technology and Research (ASTAR) , Singapore , Singapore
| | - Bruce Russell
- Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore , Singapore , Singapore
| | - Chetan E Chitnis
- International Center for Genetic Engineering and Biotechnology , New Delhi , India
| | - Simon J Draper
- The Jenner Institute, University of Oxford , Oxford , UK
| |
Collapse
|
33
|
Triggers of key calcium signals during erythrocyte invasion by Plasmodium falciparum. Nat Commun 2014; 4:2862. [PMID: 24280897 PMCID: PMC3868333 DOI: 10.1038/ncomms3862] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2013] [Accepted: 11/04/2013] [Indexed: 01/28/2023] Open
Abstract
Invasion of erythrocytes by Plasmodium falciparum merozoites is a complex multi-step process mediated by specific interactions between host receptors and parasite ligands. Reticulocyte-binding protein homologues (RHs) and erythrocyte-binding-like (EBL) proteins are discharged from specialized organelles and used in early steps of invasion. Here we show that monoclonal antibodies against PfRH1 (an RH) block merozoite invasion by specifically inhibiting calcium signalling in the parasite, whereas invasion-inhibiting monoclonal antibodies targeting EBA175 (an EBL protein) have no effect on signalling. We further show that inhibition of this calcium signalling prevents EBA175 discharge and thereby formation of the junction between parasite and host cell. Our results indicate that PfRH1 has an initial sensing as well as signal transduction role that leads to the subsequent release of EBA175. They also provide new insights on how RH-host cell interactions lead to essential downstream signalling events in the parasite, suggesting new targets for malaria intervention.
Collapse
|
34
|
Bargieri D, Lagal V, Andenmatten N, Tardieux I, Meissner M, Ménard R. Host cell invasion by apicomplexan parasites: the junction conundrum. PLoS Pathog 2014; 10:e1004273. [PMID: 25232721 PMCID: PMC4169498 DOI: 10.1371/journal.ppat.1004273] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Affiliation(s)
- Daniel Bargieri
- Institut Pasteur, Malaria Biology and Genetics Unit, Department of Parasitology and Mycology, Paris, France
| | - Vanessa Lagal
- Institut Cochin, Laboratory Barriers and Pathogens, INSERM U-1016, CNRS UMR-8104, University of Paris Descartes, Paris, France
| | - Nicole Andenmatten
- Institute of Infection, Immunity and Inflammation, Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, United Kingdom
| | - Isabelle Tardieux
- Institut Cochin, Laboratory Barriers and Pathogens, INSERM U-1016, CNRS UMR-8104, University of Paris Descartes, Paris, France
| | - Markus Meissner
- Institute of Infection, Immunity and Inflammation, Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, United Kingdom
| | - Robert Ménard
- Institut Pasteur, Malaria Biology and Genetics Unit, Department of Parasitology and Mycology, Paris, France
- * E-mail:
| |
Collapse
|
35
|
Ferreira AR, Singh B, Cabrera-Mora M, Magri De Souza AC, Queiroz Marques MT, Porto LCS, Santos F, Banic DM, Calvo-Calle JM, Oliveira-Ferreira J, Moreno A, Da Costa Lima-Junior J. Evaluation of naturally acquired IgG antibodies to a chimeric and non-chimeric recombinant species of Plasmodium vivax reticulocyte binding protein-1: lack of association with HLA-DRB1*/DQB1* in malaria exposed individuals from the Brazilian Amazon. PLoS One 2014; 9:e105828. [PMID: 25148251 PMCID: PMC4141821 DOI: 10.1371/journal.pone.0105828] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 07/24/2014] [Indexed: 02/06/2023] Open
Abstract
The development of modular constructs that include antigenic regions targeted by protective immune responses is an attractive approach for subunit vaccine development. However, a main concern of using these vaccine platforms is how to preserve the antigenic identity of conformational B cell epitopes. In the present study we evaluated naturally acquired antibody responses to a chimeric protein engineered to contain a previously defined immunodominant domain of the Plasmodium vivax reticulocyte binding protein-1 located between amino acid positions K435-I777. The construct also includes three regions of the cognate protein (F571-D587, I1745-S1786 and L2235-E2263) predicted to contain MHC class II promiscuous T cell epitopes. Plasma samples from 253 naturally exposed individuals were tested against this chimeric protein named PvRMC-RBP1 and a control protein that includes the native sequence PvRBP123-751 in comparative experiments to study the frequency of total IgG and IgG subclass reactivity. HLA-DRB1 and HLA-DQB1 allelic groups were typed by PCR-SSO to evaluate the association between major HLA class II alleles and antibody responses. We found IgG antibodies that recognized the chimeric PvRMC-RBP1 and the PvRBP123-751 in 47.1% and 60% of the studied population, respectively. Moreover, the reactivity index against both proteins were comparable and associated with time of exposure (p<0.0001) and number of previous malaria episodes (p<0.005). IgG subclass profile showed a predominance of cytophilic IgG1 over other subclasses against both proteins tested. Collectively these studies suggest that the chimeric PvRMC-RBP1 protein retained antigenic determinants in the PvRBP1435–777 native sequence. Although 52.9% of the population did not present detectable titers of antibodies to PvRMC-RBP1, genetic restriction to this chimeric protein does not seem to occur, since no association was observed between the HLA-DRB1* or HLA-DQB1* alleles and the antibody responses. This experimental evidence strongly suggests that the identity of the conformational B cell epitopes is preserved in the chimeric protein.
Collapse
Affiliation(s)
- Amanda Ribeiro Ferreira
- Laboratory of Immunoparasitology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, (FIOCRUZ), Rio de Janeiro, RJ, Brazil
| | - Balwan Singh
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, United States of America
| | - Monica Cabrera-Mora
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, United States of America
| | - Alana Cristina Magri De Souza
- Laboratory of Immunoparasitology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, (FIOCRUZ), Rio de Janeiro, RJ, Brazil
| | | | | | - Fatima Santos
- National Health Foundation, Department of Entomology, Central Laboratory, Porto Velho, RO, Brazil
| | - Dalma Maria Banic
- Laboratory for Simuliidae and Onchocerciasis, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, (FIOCRUZ), Rio de Janeiro, RJ, Brazil
| | - J. Mauricio Calvo-Calle
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Joseli Oliveira-Ferreira
- Laboratory of Immunoparasitology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, (FIOCRUZ), Rio de Janeiro, RJ, Brazil
| | - Alberto Moreno
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, United States of America
- Division of Infectious Diseases, Department of Medicine, Emory University, Atlanta, Georgia, United States of America
- * E-mail: (AM); (JCLJ)
| | - Josué Da Costa Lima-Junior
- Laboratory of Immunoparasitology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, (FIOCRUZ), Rio de Janeiro, RJ, Brazil
- * E-mail: (AM); (JCLJ)
| |
Collapse
|
36
|
Valizadeh V, Zakeri S, Mehrizi AA, Djadid ND. Non-allele specific antibody responses to genetically distinct variant forms of Plasmodium vivax Duffy binding protein (PvDBP-II) in Iranians exposed to seasonal malaria transmission. Acta Trop 2014; 136:89-100. [PMID: 24704284 DOI: 10.1016/j.actatropica.2014.03.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2013] [Revised: 03/17/2014] [Accepted: 03/24/2014] [Indexed: 10/25/2022]
Abstract
Duffy binding protein (DBP) is a leading vaccine candidate of Plasmodium vivax. The binding domain of DBP (DBP-II) is polymorphic, that may be a major challenge for development of a broadly effective vaccine against vivax malaria. The present investigation was undertaken to explore whether the sequence diversity of DBP-II causes variation in naturally acquired anti-DBP-II antibodies. In this study, the five genetically distinct variants were expressed, and anti-DBP-II responses were measured in P. vivax-infected individuals (n=202). Finally, by performing immune-depletion ELISA experiments, antibody responses to the conserved sites of all allelic forms were evaluated using the corresponding and non-corresponding patients' sera (n=20). In this study, natural P. vivax infection produces IgG against all five examined variant forms of PvDBP-II with no statistically difference. Sequence analysis in the 20 selected samples (for antibody depletion experiment) showed eight distinct haplotypes, DBPI (n=1), DBPIII (n=3), DBPIV (n=1), DBPV (n=1), DBPVI (n=5), DBPIX (n=6), DBPX (n=1), and DBP XI (n=2). The results showed the presence of the cross-reactive antibody responses to heterologous variants of PvDBP-II in Iranian individuals who were infected with distinct allelic forms of the PvDBP-II. Therefore, it is proposed that the majority of antibodies recognized sharing B-cell epitopes and this could overcome the PvDBP-II variation as a one of the biggest challenges of PvDBP-II-based vaccine development.
Collapse
|
37
|
Grüring C, Moon RW, Lim C, Holder AA, Blackman MJ, Duraisingh MT. Human red blood cell-adapted Plasmodium knowlesi parasites: a new model system for malaria research. Cell Microbiol 2014; 16:612-20. [PMID: 24506567 DOI: 10.1111/cmi.12275] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 01/24/2014] [Accepted: 01/27/2014] [Indexed: 02/06/2023]
Abstract
Plasmodium knowlesi is a simian malaria parasite primarily infecting macaque species in Southeast Asia. Although its capacity to infect humans has been recognized since the early part of the last century, it has recently become evident that human infections are widespread and potentially life threatening. Historically, P. knowlesi has proven to be a powerful tool in early studies of malaria parasites, providing key breakthroughs in understanding many aspects of Plasmodium biology. However, the necessity to grow the parasite either in macaques or in vitro using macaque blood restricted research to laboratories with access to these resources. The recent adaptation of P. knowlesi to grow and proliferate in vitro in human red blood cells (RBCs) is therefore a substantial step towards revitalizing and expanding research on P. knowlesi. Furthermore, the development of a highly efficient transfection system to genetically modify the parasite makes P. knowlesi an ideal model to study parasite biology. In this review, we elaborate on the importance of P. knowlesi in earlier phases of malaria research and highlight the future potential of the newly available human adapted P. knowlesi parasite lines.
Collapse
Affiliation(s)
- Christof Grüring
- Department of Immunology & Infectious Diseases, Harvard School of Public Health, Boston, MA, 02115, USA
| | | | | | | | | | | |
Collapse
|
38
|
Menard D, Chan ER, Benedet C, Ratsimbasoa A, Kim S, Chim P, Do C, Witkowski B, Durand R, Thellier M, Severini C, Legrand E, Musset L, Nour BYM, Mercereau-Puijalon O, Serre D, Zimmerman PA. Whole genome sequencing of field isolates reveals a common duplication of the Duffy binding protein gene in Malagasy Plasmodium vivax strains. PLoS Negl Trop Dis 2013; 7:e2489. [PMID: 24278487 PMCID: PMC3836732 DOI: 10.1371/journal.pntd.0002489] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 09/07/2013] [Indexed: 12/02/2022] Open
Abstract
Background Plasmodium vivax is the most prevalent human malaria parasite, causing serious public health problems in malaria-endemic countries. Until recently the Duffy-negative blood group phenotype was considered to confer resistance to vivax malaria for most African ethnicities. We and others have reported that P. vivax strains in African countries from Madagascar to Mauritania display capacity to cause clinical vivax malaria in Duffy-negative people. New insights must now explain Duffy-independent P. vivax invasion of human erythrocytes. Methods/Principal Findings Through recent whole genome sequencing we obtained ≥70× coverage of the P. vivax genome from five field-isolates, resulting in ≥93% of the Sal I reference sequenced at coverage greater than 20×. Combined with sequences from one additional Malagasy field isolate and from five monkey-adapted strains, we describe here identification of DNA sequence rearrangements in the P. vivax genome, including discovery of a duplication of the P. vivax Duffy binding protein (PvDBP) gene. A survey of Malagasy patients infected with P. vivax showed that the PvDBP duplication was present in numerous locations in Madagascar and found in over 50% of infected patients evaluated. Extended geographic surveys showed that the PvDBP duplication was detected frequently in vivax patients living in East Africa and in some residents of non-African P. vivax-endemic countries. Additionally, the PvDBP duplication was observed in travelers seeking treatment of vivax malaria upon returning home. PvDBP duplication prevalence was highest in west-central Madagascar sites where the highest frequencies of P. vivax-infected, Duffy-negative people were reported. Conclusions/Significance The highly conserved nature of the sequence involved in the PvDBP duplication suggests that it has occurred in a recent evolutionary time frame. These data suggest that PvDBP, a merozoite surface protein involved in red cell adhesion is rapidly evolving, possibly in response to constraints imposed by erythrocyte Duffy negativity in some human populations. Malaria results from infection of human red blood cells (RBC) by Plasmodium parasite's merozoite. For Plasmodium vivax the process of RBC invasion has been hypothesized to depend on interactions between the parasite's Duffy binding protein (PvDBP) and human Duffy blood group antigen because Duffy-negative people (most often people of African descent) were shown to be highly resistant to RBC infection and disease. Over the past five years, researchers are reporting with increasing frequency that Duffy-negative individuals are infected with P. vivax. This raises new questions as to how P. vivax infects the RBC when the Duffy blood group antigen is not available. Here we show that the parasite's Duffy binding protein gene has been duplicated in multiple P. vivax strains, especially at high prevalence in Madagascar. The specificity and prevalence of this polymorphism suggest that the parasite genome has responded to the barrier of Duffy negativity through the duplication of the PvDBP gene. Our results indicate that the PvDBP duplication is a recent event and provide novel research avenues to understand alternative pathways for P. vivax RBC invasion.
Collapse
Affiliation(s)
- Didier Menard
- Unité d'Epidémiologie Moléculaire du Paludisme, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
- * E-mail: (DM); (OMP); (DS); (PAZ)
| | - Ernest R. Chan
- Genomic Medicine Institute, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, United States of America
| | - Christophe Benedet
- Unité d'Epidémiologie Moléculaire du Paludisme, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Arsène Ratsimbasoa
- Direction de la lutte contre les maladies infectieuses, Ministère de la santé, du planning familial et de la protection sociale du Madagascar, Antananarivo, Madagascar
| | - Saorin Kim
- Unité d'Epidémiologie Moléculaire du Paludisme, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Pheaktra Chim
- Unité d'Epidémiologie Moléculaire du Paludisme, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Catherine Do
- Unité d'Epidémiologie Moléculaire du Paludisme, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Benoit Witkowski
- Unité d'Epidémiologie Moléculaire du Paludisme, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Remy Durand
- Laboratoire de Parasitologie-Mycologie, Hôpital Avicenne, AP-HP, Bobigny, France
| | - Marc Thellier
- National Center for Malaria Research, AP-HP, CHU Pitie Salpêtrière, Paris, France
| | - Carlo Severini
- Department of Infectious, Parasitic and Immunomediated Diseases, Istituto Superiore di Sanità (ISS), Rome, Italy
| | - Eric Legrand
- Laboratoire de parasitologie, National Reference Centre of Malaria Resistance in French Guiana and West Indies, Institut Pasteur de la Guyane, Cayenne, French Guiana
| | - Lise Musset
- Laboratoire de parasitologie, National Reference Centre of Malaria Resistance in French Guiana and West Indies, Institut Pasteur de la Guyane, Cayenne, French Guiana
| | - Bakri Y. M. Nour
- Blue Nile National Institute for Communicable Diseases, University of Gezira, Wad Medani, Sudan
| | - Odile Mercereau-Puijalon
- Unité d'lmmunologie Moléculaire des Parasites, Institut Pasteur, Paris, France
- * E-mail: (DM); (OMP); (DS); (PAZ)
| | - David Serre
- Genomic Medicine Institute, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, United States of America
- * E-mail: (DM); (OMP); (DS); (PAZ)
| | - Peter A. Zimmerman
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail: (DM); (OMP); (DS); (PAZ)
| |
Collapse
|
39
|
Mueller I, Galinski MR, Tsuboi T, Arevalo-Herrera M, Collins WE, King CL. Natural acquisition of immunity to Plasmodium vivax: epidemiological observations and potential targets. ADVANCES IN PARASITOLOGY 2013; 81:77-131. [PMID: 23384622 DOI: 10.1016/b978-0-12-407826-0.00003-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Population studies show that individuals acquire immunity to Plasmodium vivax more quickly than Plasmodium falciparum irrespective of overall transmission intensity, resulting in the peak burden of P. vivax malaria in younger age groups. Similarly, actively induced P. vivax infections in malaria therapy patients resulted in faster and generally more strain-transcending acquisition of immunity than P. falciparum infections. The mechanisms behind the more rapid acquisition of immunity to P. vivax are poorly understood. Natural acquired immune responses to P. vivax target both pre-erythrocytic and blood-stage antigens and include humoral and cellular components. To date, only a few studies have investigated the association of these immune responses with protection, with most studies focussing on a few merozoite antigens (such as the Pv Duffy binding protein (PvDBP), the Pv reticulocyte binding proteins (PvRBPs), or the Pv merozoite surface proteins (PvMSP1, 3 & 9)) or the circumsporozoite protein (PvCSP). Naturally acquired transmission-blocking (TB) immunity (TBI) was also found in several populations. Although limited, these data support the premise that developing a multi-stage P. vivax vaccine may be feasible and is worth pursuing.
Collapse
Affiliation(s)
- Ivo Mueller
- Walter + Eliza Hall Institute, Infection & Immunity Division, Parkville, Victoria, Australia
| | | | | | | | | | | |
Collapse
|
40
|
Plasmodium knowlesi: the emerging zoonotic malaria parasite. Acta Trop 2013; 125:191-201. [PMID: 23088834 DOI: 10.1016/j.actatropica.2012.10.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2012] [Revised: 10/03/2012] [Accepted: 10/14/2012] [Indexed: 11/20/2022]
Abstract
Plasmodium knowlesi was initially identified in the 30s as a natural Plasmodium of Macaca fascicularis monkey also capable of experimentally infecting humans. It gained a relative notoriety in the mid-30s as an alternative to Plasmodium vivax in the treatment of the general paralysis of the insane (neurosyphilis). In 1965 the first natural human infection was described in a US military surveyor coming back from the Pahang jungle of the Malaysian peninsula. P. knowlesi was again brought to the attention of the medical community when in 2004, Balbir Singh and his co-workers reported that about 58% of malaria cases observed in the Kapit district of the Malaysian Borneo were actually caused by P. knowlesi. In the following years several reports showed that P. knowlesi is much more widespread than initially thought with cases reported across Southeast Asia. This infection should also be considered in the differential diagnosis of any febrile travellers coming back from a recent travel to forested areas of Southeast Asia. P. knowlesi can cause severe malaria with a rate of 6-9% and with a case fatality rate of 3%. Respiratory distress, acute renal failure, shock and hyperbilirubinemia are the most frequently observed complications of severe P. knowlesi malaria. Chloroquine is considered the treatment of choice of uncomplicated malaria caused by P. knowlesi.
Collapse
|
41
|
Zimmerman PA, Ferreira MU, Howes RE, Mercereau-Puijalon O. Red blood cell polymorphism and susceptibility to Plasmodium vivax. ADVANCES IN PARASITOLOGY 2013; 81:27-76. [PMID: 23384621 PMCID: PMC3728992 DOI: 10.1016/b978-0-12-407826-0.00002-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Resistance to Plasmodium vivax blood-stage infection has been widely recognised to result from absence of the Duffy (Fy) blood group from the surface of red blood cells (RBCs) in individuals of African descent. Interestingly, recent studies from different malaria-endemic regions have begun to reveal new perspectives on the association between Duffy gene polymorphism and P. vivax malaria. In Papua New Guinea and the Americas, heterozygous carriers of a Duffy-negative allele are less susceptible to P. vivax infection than Duffy-positive homozygotes. In Brazil, studies show that the Fy(a) antigen, compared to Fy(b), is associated with lower binding to the P. vivax Duffy-binding protein and reduced susceptibility to vivax malaria. Additionally, it is interesting that numerous studies have now shown that P. vivax can infect RBCs and cause clinical disease in Duffy-negative people. This suggests that the relationship between P. vivax and the Duffy antigen is more complex than customarily described. Evidence of P. vivax Duffy-independent red cell invasion indicates that the parasite must be evolving alternative red cell invasion pathways. In this chapter, we review the evidence for P. vivax Duffy-dependent and Duffy-independent red cell invasion. We also consider the influence of further host gene polymorphism associated with malaria endemicity on susceptibility to vivax malaria. The interaction between the parasite and the RBC has significant potential to influence the effectiveness of P. vivax-specific vaccines and drug treatments. Ultimately, the relationships between red cell polymorphisms and P. vivax blood-stage infection will influence our estimates on the population at risk and efforts to eliminate vivax malaria.
Collapse
Affiliation(s)
- Peter A Zimmerman
- Center for Global Health & Diseases, Case Western Reserve University, Cleveland, Ohio, USA.
| | | | | | | |
Collapse
|
42
|
Deponte M, Hoppe HC, Lee MC, Maier AG, Richard D, Rug M, Spielmann T, Przyborski JM. Wherever I may roam: Protein and membrane trafficking in P. falciparum-infected red blood cells. Mol Biochem Parasitol 2012; 186:95-116. [DOI: 10.1016/j.molbiopara.2012.09.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 09/21/2012] [Accepted: 09/24/2012] [Indexed: 11/27/2022]
|
43
|
Ntumngia FB, King CL, Adams JH. Finding the sweet spots of inhibition: understanding the targets of a functional antibody against Plasmodium vivax Duffy binding protein. Int J Parasitol 2012; 42:1055-62. [PMID: 23068913 DOI: 10.1016/j.ijpara.2012.09.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 09/11/2012] [Accepted: 09/14/2012] [Indexed: 11/26/2022]
Abstract
Plasmodium vivax Duffy binding protein region II (DBPII) is an essential ligand for reticulocyte invasion, thereby making this molecule an attractive vaccine candidate against asexual blood-stage P. vivax. Similar to other Plasmodium blood-stage vaccine candidates, strain-specific immunity due to DBPII allelic variation may complicate vaccine efficacy. Targeting immune responses to more conserved epitopes that are potential targets of strain-transcending neutralising immunity is necessary to avoid induction of strain-specific responses to dominant variant epitopes. In this article, we focus on different approaches to optimise the design of DBP immunogenicity to target conserved epitopes, which is important for developing a broadly effective vaccine against P. vivax.
Collapse
Affiliation(s)
- Francis B Ntumngia
- Department of Global Health, University of South Florida, Tampa, FL, USA
| | | | | |
Collapse
|
44
|
Brito CFAD, Ferreira MU. Molecular markers and genetic diversity of Plasmodium vivax. Mem Inst Oswaldo Cruz 2012; 106 Suppl 1:12-26. [PMID: 21881753 DOI: 10.1590/s0074-02762011000900003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Accepted: 06/08/2011] [Indexed: 11/22/2022] Open
Abstract
Enhanced understanding of the transmission dynamics and population genetics for Plasmodium vivax is crucial in predicting the emergence and spread of novel parasite phenotypes with major public health implications, such as new relapsing patterns, drug resistance and increased virulence. Suitable molecular markers are required for these population genetic studies. Here, we focus on two groups of molecular markers that are commonly used to analyse natural populations of P. vivax. We use markers under selective pressure, for instance, antigen-coding polymorphic genes, and markers that are not under strong natural selection, such as most minisatellite and microsatellite loci. First, we review data obtained using genes encoding for P. vivax antigens: circumsporozoite protein, merozoite surface proteins 1 and 3α, apical membrane antigen 1 and Duffy binding antigen. We next address neutral or nearly neutral molecular markers, especially microsatellite loci, providing a complete list of markers that have already been used in P. vivax populations studies. We also analyse the microsatellite loci identified in the P. vivax genome project. Finally, we discuss some practical uses for P. vivax genotyping, for example, detecting multiple-clone infections and tracking the geographic origin of isolates.
Collapse
|
45
|
Nóbrega de Sousa T, Carvalho LH, Alves de Brito CF. Worldwide genetic variability of the Duffy binding protein: insights into Plasmodium vivax vaccine development. PLoS One 2011; 6:e22944. [PMID: 21829672 PMCID: PMC3149059 DOI: 10.1371/journal.pone.0022944] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Accepted: 07/08/2011] [Indexed: 11/19/2022] Open
Abstract
The dependence of Plasmodium vivax on invasion mediated by Duffy binding protein (DBP) makes this protein a prime candidate for development of a vaccine. However, the development of a DBP-based vaccine might be hampered by the high variability of the protein ligand (DBPII), known to bias the immune response toward a specific DBP variant. Here, the hypothesis being investigated is that the analysis of the worldwide DBPII sequences will allow us to determine the minimum number of haplotypes (MNH) to be included in a DBP-based vaccine of broad coverage. For that, all DBPII sequences available were compiled and MNH was based on the most frequent nonsynonymous single nucleotide polymorphisms, the majority mapped on B and T cell epitopes. A preliminary analysis of DBPII genetic diversity from eight malaria-endemic countries estimated that a number between two to six DBP haplotypes (17 in total) would target at least 50% of parasite population circulating in each endemic region. Aiming to avoid region-specific haplotypes, we next analyzed the MNH that broadly cover worldwide parasite population. The results demonstrated that seven haplotypes would be required to cover around 60% of DBPII sequences available. Trying to validate these selected haplotypes per country, we found that five out of the eight countries will be covered by the MNH (67% of parasite populations, range 48–84%). In addition, to identify related subgroups of DBPII sequences we used a Bayesian clustering algorithm. The algorithm grouped all DBPII sequences in six populations that were independent of geographic origin, with ancestral populations present in different proportions in each country. In conclusion, in this first attempt to undertake a global analysis about DBPII variability, the results suggest that the development of DBP-based vaccine should consider multi-haplotype strategies; otherwise a putative P. vivax vaccine may not target some parasite populations.
Collapse
Affiliation(s)
- Taís Nóbrega de Sousa
- Laboratory of Malaria, Centro de Pesquisa Rene Rachou/Fiocruz, Belo Horizonte, Brazil
| | - Luzia Helena Carvalho
- Laboratory of Malaria, Centro de Pesquisa Rene Rachou/Fiocruz, Belo Horizonte, Brazil
| | | |
Collapse
|
46
|
Super-resolution dissection of coordinated events during malaria parasite invasion of the human erythrocyte. Cell Host Microbe 2011; 9:9-20. [PMID: 21238943 DOI: 10.1016/j.chom.2010.12.003] [Citation(s) in RCA: 258] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 10/01/2010] [Accepted: 12/10/2010] [Indexed: 11/21/2022]
Abstract
Erythrocyte invasion by the merozoite is an obligatory stage in Plasmodium parasite infection and essential to malaria disease progression. Attempts to study this process have been hindered by the poor invasion synchrony of merozoites from the only in vitro culture-adapted human malaria parasite, Plasmodium falciparum. Using fluorescence, three-dimensional structured illumination, and immunoelectron microscopy of filtered merozoites, we analyze cellular and molecular events underlying each discrete step of invasion. Monitoring the dynamics of these events revealed that commitment to the process is mediated through merozoite attachment to the erythrocyte, triggering all subsequent invasion events, which then proceed without obvious checkpoints. Instead, coordination of the invasion process involves formation of the merozoite-erythrocyte tight junction, which acts as a nexus for rhoptry secretion, surface-protein shedding, and actomyosin motor activation. The ability to break down each molecular step allows us to propose a comprehensive model for the molecular basis of parasite invasion.
Collapse
|
47
|
Reticulocyte and erythrocyte binding-like proteins function cooperatively in invasion of human erythrocytes by malaria parasites. Infect Immun 2010; 79:1107-17. [PMID: 21149582 DOI: 10.1128/iai.01021-10] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Plasmodium falciparum causes the most severe form of malaria in humans and invades erythrocytes using multiple ligand-receptor interactions. Two important protein families involved in erythrocyte binding are the erythrocyte binding-like (EBL) and the reticulocyte binding-like (RBL or P. falciparum Rh [PfRh]) proteins. We constructed P. falciparum lines lacking expression of EBL proteins by creating single and double knockouts of the corresponding genes for eba-175, eba-181, and eba-140 and show that the EBL and PfRh proteins function cooperatively, consistent with them playing a similar role in merozoite invasion. We provide evidence that PfRh and EBL proteins functionally interact, as loss of function of EBA-181 ablates the ability of PfRh2a/b protein antibodies to inhibit merozoite invasion. Additionally, loss of function of some ebl genes results in selection for increased transcription of the PfRh family. This provides a rational basis for considering PfRh and EBL proteins for use as a combination vaccine against P. falciparum. We immunized rabbits with combinations of PfRh and EBL proteins to test the ability of antibodies to block merozoite invasion in growth inhibition assays. A combination of EBA-175, PfRh2a/b, and PfRh4 recombinant proteins induced antibodies that potently blocked merozoite invasion. This validates the use of a combination of these ligands as a potential vaccine that would have broad activity against P. falciparum.
Collapse
|
48
|
Henry-Halldin CN, Sepe D, Susapu M, McNamara DT, Bockarie M, King CL, Zimmerman PA. High-throughput molecular diagnosis of circumsporozoite variants VK210 and VK247 detects complex Plasmodium vivax infections in malaria endemic populations in Papua New Guinea. INFECTION GENETICS AND EVOLUTION 2010; 11:391-8. [PMID: 21147267 DOI: 10.1016/j.meegid.2010.11.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Revised: 10/11/2010] [Accepted: 11/24/2010] [Indexed: 12/01/2022]
Abstract
Malaria is endemic in lowland and coastal regions of Papua New Guinea (PNG), and is caused by Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae and Plasmodium ovale. Infection by P. vivax is attributed to distinct strains, VK210 and VK247, which differ in the sequence of the circumsporozoite protein (pvcsp). Here, based upon sequence polymorphisms in pvcsp, we developed a post-PCR ligation detection reaction-fluorescent microsphere assay (LDR-FMA) to distinguish these P. vivax strains. This diagnostic assay was designed to detect the presence of both VK210 and VK247 P. vivax strains simultaneously in a high-throughput 96-well format. Using this assay, we analyzed human blood samples from the Wosera (n=703) and Mugil (n=986) regions to evaluate the prevalence of these P. vivax strains. VK210 and VK247 strains were found in both study sites. In the Wosera, single infections with VK210 strain were observed to be most common (41.7%), followed by mixed-strain (36.8%) and VK247 single-strain infections (21.5%). Similarly, in Mugil, VK210 single-strain infections were most common (51.6%), followed by mixed-strain (34.4%) and VK247 single-strain infections (14%). These results suggest that the distribution of P. vivax infections was similar between the two study sites. Interestingly, we observed a non-random distribution of these two P. vivax strains, as mixed-strain infections were significantly more prevalent than expected in both study sites (Wosera and Mugil χ(2)p-value<0.001). Additionally, DNA sequence analysis of a subset of P. vivax infections showed that no individual pvcsp alleles were shared between the two study sites. Overall, our results illustrate that PNG malaria-endemic regions harbor a complex mixture of P. vivax strains, and emphasize the importance of malaria control strategies that would be effective against a highly diverse parasite population.
Collapse
Affiliation(s)
- Cara N Henry-Halldin
- Center for Global Health and Diseases, Case Western Reserve University, Wolstein Research Building, Room 4-125, 2103 Cornell Rd., Cleveland, OH 44106, USA
| | | | | | | | | | | | | |
Collapse
|
49
|
Sousa TN, Tarazona-Santos EM, Wilson DJ, Madureira AP, Falcão PRK, Fontes CJF, Gil LHS, Ferreira MU, Carvalho LH, Brito CFA. Genetic variability and natural selection at the ligand domain of the Duffy binding protein in Brazilian Plasmodium vivax populations. Malar J 2010; 9:334. [PMID: 21092207 PMCID: PMC3003673 DOI: 10.1186/1475-2875-9-334] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Accepted: 11/22/2010] [Indexed: 11/30/2022] Open
Abstract
Background Plasmodium vivax malaria is a major public health challenge in Latin America, Asia and Oceania, with 130-435 million clinical cases per year worldwide. Invasion of host blood cells by P. vivax mainly depends on a type I membrane protein called Duffy binding protein (PvDBP). The erythrocyte-binding motif of PvDBP is a 170 amino-acid stretch located in its cysteine-rich region II (PvDBPII), which is the most variable segment of the protein. Methods To test whether diversifying natural selection has shaped the nucleotide diversity of PvDBPII in Brazilian populations, this region was sequenced in 122 isolates from six different geographic areas. A Bayesian method was applied to test for the action of natural selection under a population genetic model that incorporates recombination. The analysis was integrated with a structural model of PvDBPII, and T- and B-cell epitopes were localized on the 3-D structure. Results The results suggest that: (i) recombination plays an important role in determining the haplotype structure of PvDBPII, and (ii) PvDBPII appears to contain neutrally evolving codons as well as codons evolving under natural selection. Diversifying selection preferentially acts on sites identified as epitopes, particularly on amino acid residues 417, 419, and 424, which show strong linkage disequilibrium. Conclusions This study shows that some polymorphisms of PvDBPII are present near the erythrocyte-binding domain and might serve to elude antibodies that inhibit cell invasion. Therefore, these polymorphisms should be taken into account when designing vaccines aimed at eliciting antibodies to inhibit erythrocyte invasion.
Collapse
Affiliation(s)
- Taís N Sousa
- Laboratory of Malaria, Centro de Pesquisa Rene Rachou/FIOCRUZ, Belo Horizonte, Brazil
| | | | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Abstract
Malaria remains one of the most devastating infectious diseases that threaten humankind. Human malaria is caused by five different species of Plasmodium parasites, each transmitted by the bite of female Anopheles mosquitoes. Plasmodia are eukaryotic protozoans with more than 5000 genes and a complex life cycle that takes place in the mosquito vector and the human host. The life cycle can be divided into pre-erythrocytic stages, erythrocytic stages and mosquito stages. Malaria vaccine research and development faces formidable obstacles because many vaccine candidates will probably only be effective in a specific species at a specific stage. In addition, Plasmodium actively subverts and escapes immune responses, possibly foiling vaccine-induced immunity. Although early successful vaccinations with irradiated, live-attenuated malaria parasites suggested that a vaccine is possible, until recently, most efforts have focused on subunit vaccine approaches. Blood-stage vaccines remain a primary research focus, but real progress is evident in the development of a partially efficacious recombinant pre-erythrocytic subunit vaccine and a live-attenuated sporozoite vaccine. It is unlikely that partially effective vaccines will eliminate malaria; however, they might prove useful in combination with existing control strategies. Elimination of malaria will probably ultimately depend on the development of highly effective vaccines.
Collapse
|