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Abstract
Malaria has been the pre-eminent cause of early mortality in many parts of the world throughout much of the last five thousand years and, as a result, it is the strongest force for selective pressure on the human genome yet described. Around one third of the variability in the risk of severe and complicated malaria is now explained by additive host genetic effects. Many individual variants have been identified that are associated with malaria protection, but the most important all relate to the structure or function of red blood cells. They include the classical polymorphisms that cause sickle cell trait, α-thalassaemia, G6PD deficiency, and the major red cell blood group variants. More recently however, with improving technology and experimental design, others have been identified that include the Dantu blood group variant, polymorphisms in the red cell membrane protein ATP2B4, and several variants related to the immune response. Characterising how these genes confer their effects could eventually inform novel therapeutic approaches to combat malaria. Nevertheless, all together, only a small proportion of the heritable component of malaria resistance can be explained by the variants described so far, underscoring its complex genetic architecture and the need for continued research.
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Affiliation(s)
- Silvia N Kariuki
- Department of Epidemiology, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.
| | - Thomas N Williams
- Department of Epidemiology, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.
- Department of Medicine, Imperial College of Science and Technology, London, UK.
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2
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Cai FY, DeSimone TM, Hansen E, Jennings CV, Bei AK, Ahouidi AD, Mboup S, Duraisingh MT, Buckee CO. Accounting for red blood cell accessibility reveals distinct invasion strategies in Plasmodium falciparum strains. PLoS Comput Biol 2020; 16:e1007702. [PMID: 32315315 PMCID: PMC7194430 DOI: 10.1371/journal.pcbi.1007702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 05/01/2020] [Accepted: 01/31/2020] [Indexed: 11/19/2022] Open
Abstract
The growth of the malaria parasite Plasmodium falciparum in human blood causes all the symptoms of malaria. To proliferate, non-motile parasites must have access to susceptible red blood cells, which they invade using pairs of parasite ligands and host receptors that define invasion pathways. Parasites can switch invasion pathways, and while this flexibility is thought to facilitate immune evasion, it may also reflect the heterogeneity of red blood cell surfaces within and between hosts. Host genetic background affects red blood cell structure, for example, and red blood cells also undergo dramatic changes in morphology and receptor density as they age. The in vivo consequences of both the accessibility of susceptible cells, and their heterogeneous susceptibility, remain unclear. Here, we measured invasion of laboratory strains of P. falciparum relying on distinct invasion pathways into red blood cells of different ages. We estimated invasion efficiency while accounting for red blood cell accessibility to parasites. This approach revealed different tradeoffs made by parasite strains between the fraction of cells they can invade and their invasion rate into them, and we distinguish "specialist" strains from "generalist" strains in this context. We developed a mathematical model to show that generalist strains would lead to higher peak parasitemias in vivo compared to specialist strains with similar overall proliferation rates. Thus, the ecology of red blood cells may play a key role in determining the rate of P. falciparum parasite proliferation and malaria virulence.
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Affiliation(s)
- Francisco Y. Cai
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard TH Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Tiffany M. DeSimone
- Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Elsa Hansen
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard TH Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Cameron V. Jennings
- Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Amy K. Bei
- Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Ambroise D. Ahouidi
- Laboratory of Bacteriology and Virology, Le Dantec Hospital, Cheikh Anta Diop University, Dakar, Senegal
| | - Souleymane Mboup
- Laboratory of Bacteriology and Virology, Le Dantec Hospital, Cheikh Anta Diop University, Dakar, Senegal
| | - Manoj T. Duraisingh
- Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Caroline O. Buckee
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard TH Chan School of Public Health, Boston, Massachusetts, United States of America
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Fong MY, Lau YL, Jelip J, Ooi CH, Cheong FW. Genetic characterisation of the erythrocyte-binding protein (PkβII) of Plasmodium knowlesi isolates from Malaysia. J Genet 2019; 98:64. [PMID: 31544794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Plasmodium knowlesi contributes to the majority of human malaria incidences in Malaysia. Its uncontrollable passage among the natural monkey hosts can potentially lead to zoonotic outbreaks. The merozoite of this parasite invades host erythrocytes through interaction between its erythrocyte-binding proteins (EBPs) and their respective receptor on the erythrocytes. The regionII of P. knowlesi EBP, P. knowlesi beta (PkβII) protein is found to be mediating merozoite invasion into monkey erythrocytes by interacting with sialic acid receptors. Hence, the objective of this study was to investigate the genetic diversity, natural selection and haplotype grouping of PkβII of P. knowlesi isolates in Malaysia. Polymerase chain reaction amplifications of PkβII were performed on archived blood samples from Malaysia and 64 PkβII sequences were obtained. Sequence analysis revealed length polymorphism, and its amino acids at critical residues indicate the ability of PkβII to mediate P. knowlesi invasion into monkey erythrocytes. Low genetic diversity (π = 0.007) was observed in the PkβII of Malaysia Borneo compared to Peninsular Malaysia (π = 0.015). The PkβII was found to be under strong purifying selection to retain infectivity in monkeys and it plays a limited role in the zoonotic potential of P. knowlesi. Its haplotypes could be clustered into Peninsular Malaysia and Malaysia Borneo groups, indicating the existence of two distinct P. knowlesi parasites in Malaysia as reported in an earlier study.
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Affiliation(s)
- Mun Yik Fong
- Faculty of Medicine, Department of Parasitology, University of Malaya, 50603 Kuala Lumpur, Malaysia.
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Fong MY, Lau YL, Jelip J, Ooi CH, Cheong FW. Genetic characterisation of the erythrocyte-binding protein ($$\hbox {Pk}{\upbeta }\hbox {II}$$) of Plasmodium knowlesi isolates from Malaysia. J Genet 2019. [DOI: 10.1007/s12041-019-1109-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Urusova D, Carias L, Huang Y, Nicolete VC, Popovici J, Roesch C, Salinas ND, Dechavanne S, Witkowski B, Ferreira MU, Adams JH, Gross ML, King CL, Tolia NH. Structural basis for neutralization of Plasmodium vivax by naturally acquired human antibodies that target DBP. Nat Microbiol 2019; 4:1486-1496. [PMID: 31133752 PMCID: PMC6707876 DOI: 10.1038/s41564-019-0461-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 04/16/2019] [Indexed: 12/21/2022]
Abstract
The Plasmodium vivax Duffy binding protein (DBP) is a prime target of the protective immune response and a promising vaccine candidate for P. vivax malaria. Naturally acquired immunity (NAI) protects against malaria in adults residing in infection-endemic regions, and the passive transfer of malarial immunity confers protection. A vaccine that replicates NAI will effectively prevent disease. Here, we report the structures of DBP region II in complex with human-derived, neutralizing monoclonal antibodies obtained from an individual in a malaria-endemic area with naturally acquired immunity. We identified protective epitopes by X-ray crystallography, hydrogen-deuterium exchange mass spectrometry, mutational mapping, and P. vivax invasion studies. These approaches reveal that naturally-acquired human antibodies neutralize P. vivax by targeting the DARC–binding site and dimer interface of P. vivax DBP. Antibody binding is unaffected by polymorphisms in the vicinity of epitopes, suggesting the antibodies have evolved to engage multiple polymorphic variants of DBP. The human antibody epitopes are broadly conserved and are distinct from previously defined epitopes for broadly conserved murine mAbs. A library of globally conserved epitopes of neutralizing human antibodies opens new horizons for rational design of strain-transcending DBP-based vaccines and therapeutics against P. vivax.
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Affiliation(s)
- Darya Urusova
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, MO, USA
| | - Lenore Carias
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA
| | - Yining Huang
- Department of Chemistry, Washington University in St Louis, St Louis, MO, USA.,Bioproduct Research and Development, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA
| | | | - Jean Popovici
- Malaria Molecular Epidemiology Unit, Pasteur Institute in Cambodia, Phnom Penh, Cambodia
| | - Camille Roesch
- Malaria Molecular Epidemiology Unit, Pasteur Institute in Cambodia, Phnom Penh, Cambodia
| | - Nichole D Salinas
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Sebastien Dechavanne
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA
| | - Benoit Witkowski
- Malaria Molecular Epidemiology Unit, Pasteur Institute in Cambodia, Phnom Penh, Cambodia
| | | | - John H Adams
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL, USA
| | - Michael L Gross
- Department of Chemistry, Washington University in St Louis, St Louis, MO, USA
| | - Christopher L King
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA
| | - Niraj H Tolia
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, MO, USA. .,Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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Aniweh Y, Nyarko PB, Quansah E, Thiam LG, Awandare GA. SMIM1 at a glance; discovery, genetic basis, recent progress and perspectives. Parasite Epidemiol Control 2019; 5:e00101. [PMID: 30906890 PMCID: PMC6416411 DOI: 10.1016/j.parepi.2019.e00101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 12/28/2018] [Accepted: 03/06/2019] [Indexed: 11/18/2022] Open
Abstract
Recent elucidation of the genetic basis of the Vel blood group system has offered the field of blood transfusion medicine an additional consideration in determining the causes of hemolytic reactions after a patient is transfused. The identification of the SMIM1 gene to be responsible for the Vel blood group allows molecular based tools to be developed to further dissect the function of this antigen. Genetic signatures such as the homozygous 17 bp deletion and the heterozygous 17 bp deletion in combination with other single nucleotide polymorphisms (SNPs) and insertion sequences regulate the expression level of the gene. With this knowledge, it is now possible to study this antigen in-depth.
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Affiliation(s)
- Yaw Aniweh
- West Africa Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Prince B. Nyarko
- West Africa Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Evelyn Quansah
- West Africa Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Laty Gaye Thiam
- West Africa Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Gordon A. Awandare
- West Africa Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
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Moderately Neutralizing Epitopes in Nonfunctional Regions Dominate the Antibody Response to Plasmodium falciparum EBA-140. Infect Immun 2019; 87:IAI.00716-18. [PMID: 30642904 DOI: 10.1128/iai.00716-18] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 01/04/2019] [Indexed: 02/08/2023] Open
Abstract
Plasmodium falciparum erythrocyte-binding antigen 140 (EBA-140) plays a role in tight junction formation during parasite invasion of red blood cells and is a potential vaccine candidate for malaria. Individuals in areas where malaria is endemic possess EBA-140-specific antibodies, and individuals with high antibody titers to this protein have a lower rate of reinfection by parasites. The red blood cell binding segment of EBA-140 is comprised of two Duffy-binding-like domains, called F1 and F2, that together create region II. The sialic acid-binding pocket of F1 is essential for binding, whereas the sialic acid-binding pocket in F2 appears dispensable. Here, we show that immunization of mice with the complete region II results in poorly neutralizing antibodies. In contrast, immunization of mice with the functionally relevant F1 domain of region II results in antibodies that confer a 2-fold increase in parasite neutralization compared to that of the F2 domain. Epitope mapping of diverse F1 and F2 monoclonal antibodies revealed that the functionally relevant F1 sialic acid-binding pocket is a privileged site inaccessible to antibodies, that the F2 sialic acid-binding pocket contains a nonneutralizing epitope, and that two additional epitopes reside in F1 on the opposite face from the sialic acid-binding pocket. These studies indicate that focusing the immune response to the functionally important F1 sialic acid binding pocket improves the protective immune response of EBA-140. These results have implications for improving future vaccine designs and emphasize the importance of structural vaccinology for malaria.
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Human erythrocyte band 3 is a host receptor for Plasmodium falciparum glutamic acid-rich protein. Blood 2018; 133:470-480. [PMID: 30545833 DOI: 10.1182/blood-2018-07-865451] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 12/10/2018] [Indexed: 12/18/2022] Open
Abstract
Malaria remains a major global threat to human health and economic development. Microvascular lesions caused by Plasmodium falciparum-infected human erythrocytes/red blood cells are hallmarks of severe pathogenesis contributing to high mortality, particularly in children from sub-Saharan Africa. In this study, we used a phage display complementary DNA library screening strategy to identify P falciparum glutamic acid-rich protein (PfGARP) as a secreted ligand that recognizes an ectodomain of human erythrocyte anion-exchanger, band 3/AE1, as a host receptor. Domain mapping of PfGARP revealed distinct nonoverlapping repeats encoding the immune response epitopes and core erythrocyte-binding activity. Synthetic peptides derived from the erythrocyte-binding repeats of PfGARP induced erythrocyte aggregation reminiscent of the rosetting phenomenon. Using peptides derived from the immunogenic repeats, a quantitative immunoassay was developed to detect a selective immune response against PfGARP in human plasma samples obtained from patients in rural Mali, suggesting the feasibility of PfGARP as a potential biomarker of disease progression. Collectively, our results suggest that PfGARP may play a functional role in enhancing the adhesive properties of human erythrocytes by engaging band 3 as a host receptor. We propose that immunological and pharmacological inhibition of PfGARP may unveil new therapeutic options for mitigating lesions in cerebral and pregnancy-associated malaria.
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Genetic Evidence for Erythrocyte Receptor Glycophorin B Expression Levels Defining a Dominant Plasmodium falciparum Invasion Pathway into Human Erythrocytes. Infect Immun 2017; 85:IAI.00074-17. [PMID: 28760933 PMCID: PMC5607420 DOI: 10.1128/iai.00074-17] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 07/17/2017] [Indexed: 01/18/2023] Open
Abstract
Plasmodium falciparum, the parasite that causes the deadliest form of malaria, has evolved multiple proteins known as invasion ligands that bind to specific erythrocyte receptors to facilitate invasion of human erythrocytes. The EBA-175/glycophorin A (GPA) and Rh5/basigin ligand-receptor interactions, referred to as invasion pathways, have been the subject of intense study. In this study, we focused on the less-characterized sialic acid-containing receptors glycophorin B (GPB) and glycophorin C (GPC). Through bioinformatic analysis, we identified extensive variation in glycophorin B (GYPB) transcript levels in individuals from Benin, suggesting selection from malaria pressure. To elucidate the importance of the GPB and GPC receptors relative to the well-described EBA-175/GPA invasion pathway, we used an ex vivo erythrocyte culture system to decrease expression of GPA, GPB, or GPC via lentiviral short hairpin RNA transduction of erythroid progenitor cells, with global surface proteomic profiling. We assessed the efficiency of parasite invasion into knockdown cells using a panel of wild-type P. falciparum laboratory strains and invasion ligand knockout lines, as well as P. falciparum Senegalese clinical isolates and a short-term-culture-adapted strain. For this, we optimized an invasion assay suitable for use with small numbers of erythrocytes. We found that all laboratory strains and the majority of field strains tested were dependent on GPB expression level for invasion. The collective data suggest that the GPA and GPB receptors are of greater importance than the GPC receptor, supporting a hierarchy of erythrocyte receptor usage in P. falciparum.
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Bei AK, Ahouidi AD, Dvorin JD, Miura K, Diouf A, Ndiaye D, Premji Z, Diakite M, Mboup S, Long CA, Duraisingh MT. Functional Analysis Reveals Geographical Variation in Inhibitory Immune Responses Against a Polymorphic Malaria Antigen. J Infect Dis 2017; 216:267-275. [PMID: 28605544 PMCID: PMC5853457 DOI: 10.1093/infdis/jix280] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Accepted: 06/08/2017] [Indexed: 12/28/2022] Open
Abstract
Background Plasmodium falciparum reticulocyte-binding protein homologue 2b (PfRh2b) is an invasion ligand that is a potential blood-stage vaccine candidate antigen; however, a naturally occurring deletion within an immunogenic domain is present at high frequencies in Africa and has been associated with alternative invasion pathway usage. Standardized tools that provide antigenic specificity in in vitro assays are needed to functionally assess the neutralizing potential of humoral responses against malaria vaccine candidate antigens. Methods Transgenic parasite lines were generated to express the PfRh2b deletion. Total immunoglobulin G (IgG) from individuals residing in malaria-endemic regions in Tanzania, Senegal, and Mali were used in growth inhibition assays with transgenic parasite lines. Results While the PfRh2b deletion transgenic line showed no change in invasion pathway utilization compared to the wild-type in the absence of specific antibodies, it outgrew wild-type controls in competitive growth experiments. Inhibition differences with total IgG were observed in the different endemic sites, ranging from allele-specific inhibition to allele-independent inhibitory immune responses. Conclusions The PfRh2b deletion may allow the parasite to escape neutralizing antibody responses in some regions. This difference in geographical inhibition was revealed using transgenic methodologies, which provide valuable tools for functionally assessing neutralizing antibodies against vaccine-candidate antigens in regions with varying malaria endemicity.
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Affiliation(s)
- Amy K Bei
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts
- Laboratory of Bacteriology and Virology, Le Dantec Hospital, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, Dakar, Senegal
- Laboratory of Parasitology and Mycology, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, Dakar, Senegal
| | - Ambroise D Ahouidi
- Laboratory of Bacteriology and Virology, Le Dantec Hospital, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, Dakar, Senegal
| | - Jeffrey D Dvorin
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts
- Division of Infectious Diseases, Boston Children's Hospital and Harvard Medical School, Massachusetts
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Ababacar Diouf
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Daouda Ndiaye
- Laboratory of Parasitology and Mycology, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, Dakar, Senegal
| | - Zul Premji
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar-es-Salaam, Tanzania
- Department of Pathology, Aga Khan University Hospital, Nairobi, Kenya
| | - Mahamadou Diakite
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Odontostomatology, University of Science, Techniques and Technologies of Bamako, Mali
| | - Souleymane Mboup
- Laboratory of Bacteriology and Virology, Le Dantec Hospital, Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, Dakar, Senegal
- Institut de Recherche en Santé, de Surveillance Epidemiologique et de Formations, Dakar, Senegal
| | - Carole A Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Manoj T Duraisingh
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts
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Aniweh Y, Gao X, Gunalan K, Preiser PR. PfRH2b specific monoclonal antibodies inhibit merozoite invasion. Mol Microbiol 2016; 102:386-404. [DOI: 10.1111/mmi.13468] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/18/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Yaw Aniweh
- Division of Molecular Genetics and Cell biology, School of Biological Sciences; Nanyang Technological University; 637551 Singapore
| | - Xiaohong Gao
- Division of Molecular Genetics and Cell biology, School of Biological Sciences; Nanyang Technological University; 637551 Singapore
| | - Karthigayan Gunalan
- Division of Molecular Genetics and Cell biology, School of Biological Sciences; Nanyang Technological University; 637551 Singapore
| | - Peter R. Preiser
- Division of Molecular Genetics and Cell biology, School of Biological Sciences; Nanyang Technological University; 637551 Singapore
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Ngoubangoye B, Boundenga L, Arnathau C, Mombo IM, Durand P, Tsoumbou TA, Otoro BV, Sana R, Okouga AP, Moukodoum N, Willaume E, Herbert A, Fouchet D, Rougeron V, Bâ CT, Ollomo B, Paupy C, Leroy EM, Renaud F, Pontier D, Prugnolle F. The host specificity of ape malaria parasites can be broken in confined environments. Int J Parasitol 2016; 46:737-44. [PMID: 27486075 DOI: 10.1016/j.ijpara.2016.06.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 06/09/2016] [Accepted: 06/16/2016] [Indexed: 01/04/2023]
Abstract
Recent studies have revealed a large diversity of Plasmodium spp. among African great apes. Some of these species are related to Plasmodium falciparum, the most virulent agent of human malaria (subgenus Laverania), and others to Plasmodium ovale, Plasmodium malariae and Plasmodium vivax (subgenus Plasmodium), three other human malaria agents. Laverania parasites exhibit strict host specificity in their natural environment. Plasmodium reichenowi, Plasmodium billcollinsi, Plasmodium billbrayi and Plasmodium gaboni infect only chimpanzees, while Plasmodium praefalciparum, Plasmodium blacklocki and Plasmodium adleri are restricted to gorillas and Plasmodium falciparum is pandemic in humans. This host specificity may be due to genetic and/or environmental factors. Infrastructures hosting captive primates, such as sanctuaries and health centres, usually concentrate different primate species, thus favouring pathogen exchanges. Using molecular tools, we analysed blood samples from captive non-human primates living in Gabon to evaluate the risk of Plasmodium spp. transfers between host species. We also included blood samples from workers taking care of primates to assess whether primate-human parasite transfers occurred. We detected four transfers of Plasmodium from gorillas towards chimpanzees, one from chimpanzees to gorillas, three from humans towards chimpanzees and one from humans to mandrills. No simian Plasmodium was found in the blood samples from humans working with primates. These findings demonstrate that the genetic barrier that determines the apparent host specificity of Laverania is not completely impermeable and that parasite exchanges between gorillas and chimpanzees are possible in confined environments.
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Affiliation(s)
- Barthélémy Ngoubangoye
- Centre de Primatologie, CIRMF, B.P. 769, Franceville, Gabon; Laboratoire de Biométrie et Biologie Evolutive, UMR5558, Université Lyon 1, France; LabEx ECOFECT, Eco-evolutionary Dynamics of Infectious Diseases, University of Lyon, France.
| | - Larson Boundenga
- Unité de Biodiversité, Ecologie et Evolution des Parasites, CIRMF, B.P. 769, Franceville, Gabon; Laboratoire d'Écologie et Biologie Evolutive, Département de Biologie Animale, Faculté des Sciences et Techniques, Université Cheikh Anta Diop de Dakar, BP5005, Senegal.
| | - Céline Arnathau
- Laboratoire MIVEGEC, UM-CNRS 5290-IRD 224, IRD Montpellier, France
| | - Illich Manfred Mombo
- Laboratoire MIVEGEC, UM-CNRS 5290-IRD 224, IRD Montpellier, France; Département de Zoonoses et maladies émergentes, CIRMF, B.P. 769, Franceville, Gabon
| | - Patrick Durand
- Laboratoire MIVEGEC, UM-CNRS 5290-IRD 224, IRD Montpellier, France
| | | | | | - Rick Sana
- Centre de Primatologie, CIRMF, B.P. 769, Franceville, Gabon
| | - Alain-Prince Okouga
- Unité de Biodiversité, Ecologie et Evolution des Parasites, CIRMF, B.P. 769, Franceville, Gabon
| | - Nancy Moukodoum
- Unité de Biodiversité, Ecologie et Evolution des Parasites, CIRMF, B.P. 769, Franceville, Gabon
| | - Eric Willaume
- Parc de La Lékédi, Société d'Exploitation du Parc de La Lékédi/Entreprise de Recherche et d'Activités Métallurgiques/Compagnie Minière de l'Ogooué, BP 52, Bakoumba, Gabon
| | - Anaïs Herbert
- Centre de Primatologie, CIRMF, B.P. 769, Franceville, Gabon
| | - David Fouchet
- Laboratoire de Biométrie et Biologie Evolutive, UMR5558, Université Lyon 1, France; LabEx ECOFECT, Eco-evolutionary Dynamics of Infectious Diseases, University of Lyon, France
| | - Virginie Rougeron
- Unité de Biodiversité, Ecologie et Evolution des Parasites, CIRMF, B.P. 769, Franceville, Gabon; Laboratoire MIVEGEC, UM-CNRS 5290-IRD 224, IRD Montpellier, France
| | - Cheikh Tidiane Bâ
- Laboratoire d'Écologie et Biologie Evolutive, Département de Biologie Animale, Faculté des Sciences et Techniques, Université Cheikh Anta Diop de Dakar, BP5005, Senegal
| | - Benjamin Ollomo
- Unité de Biodiversité, Ecologie et Evolution des Parasites, CIRMF, B.P. 769, Franceville, Gabon
| | - Christophe Paupy
- Laboratoire MIVEGEC, UM-CNRS 5290-IRD 224, IRD Montpellier, France
| | - Eric M Leroy
- Laboratoire MIVEGEC, UM-CNRS 5290-IRD 224, IRD Montpellier, France
| | - François Renaud
- Unité de Biodiversité, Ecologie et Evolution des Parasites, CIRMF, B.P. 769, Franceville, Gabon
| | - Dominique Pontier
- Laboratoire de Biométrie et Biologie Evolutive, UMR5558, Université Lyon 1, France; LabEx ECOFECT, Eco-evolutionary Dynamics of Infectious Diseases, University of Lyon, France
| | - Franck Prugnolle
- Unité de Biodiversité, Ecologie et Evolution des Parasites, CIRMF, B.P. 769, Franceville, Gabon; Laboratoire MIVEGEC, UM-CNRS 5290-IRD 224, IRD Montpellier, France
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Baculovirus-expressed Plasmodium reichenowi EBA-140 merozoite ligand is host specific. Parasitol Int 2016; 65:708-714. [PMID: 27443851 DOI: 10.1016/j.parint.2016.07.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 07/14/2016] [Accepted: 07/15/2016] [Indexed: 12/23/2022]
Abstract
Plasmodium reichenowi, an ape malaria parasite is morphologically identical and genetically similar to Plasmodium falciparum, infects chimpanzees but not humans. Genomic studies revealed that all primate malaria parasites belong to Laverania subgenus. Laverania parasites exhibit strict host specificity, but the molecular mechanisms underlying these host restrictions remain unexplained. Plasmodium merozoites express multiple binding ligands that recognize specific receptors on erythrocytes, including micronemal proteins belonging to P. falciparum EBL family. It was shown that erythrocyte binding antigen-175 (EBA-175), erythrocyte binding ligand-1 (EBL-1), erythrocyte binding antigen-140 (EBA-140) recognize erythrocyte surface sialoglycoproteins - glycophorins A, B, C, respectively. EBA-140 merozoite ligand hijacks glycophorin C (GPC), a minor erythrocyte sialoglycoprotein, to invade the erythrocyte through an alternative invasion pathway. A homolog of P. falciparum EBA-140 protein was identified in P. reichenowi. The amino acid sequences of both EBA-140 ligands are very similar, especially in the conservative erythrocyte binding region (Region II). It has been suggested that evolutionary changes in the sequence of EBL proteins may be associated with Plasmodium host restriction. In this study we obtained, for the first time, the recombinant P. reichenowi EBA-140 ligand Region II using baculovirus expression vector system. We show that the ape EBA-140 Region II is host specific and binds to chimpanzee erythrocytes in the dose and sialic acid dependent manner. Further identification of the erythrocyte receptor for this ape ligand is of great interests, since it may reveal the molecular basis of host restriction of both P. reichenowi and its deadliest human counterpart, P. falciparum.
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Ord RL, Rodriguez M, Lobo CA. Malaria invasion ligand RH5 and its prime candidacy in blood-stage malaria vaccine design. Hum Vaccin Immunother 2016; 11:1465-73. [PMID: 25844685 DOI: 10.1080/21645515.2015.1026496] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
With drug resistance to available therapeutics continuing to develop against Plasmodium falciparum malaria, the development of an effective vaccine candidate remains a major research goal. Successful interruption of invasion of parasites into erythrocytes during the blood stage of infection will prevent the severe clinical symptoms and complications associated with malaria. Previously studied blood stage antigens have highlighted the hurdles that are inherent to this life-cycle stage, namely that highly immunogenic antigens are also globally diverse, resulting in protection only against the vaccine strain, or that naturally acquired immunity to blood stage antigens do not always correlate with actual protection. The blood stage antigen reticulocyte binding homolog RH5 is essential for parasite viability, has globally limited diversity, and is associated with protection from disease. Here we summarize available information on this invasion ligand and recent findings that highlight its candidacy for inclusion in a blood-stage malaria vaccine.
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Affiliation(s)
- Rosalynn L Ord
- a Blood-Borne Parasites; Lindsley Kimball Research Institute; New York Blood Center ; New York , NY , USA
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15
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Lauron EJ, Aw Yeang HX, Taffner SM, Sehgal RNM. De novo assembly and transcriptome analysis of Plasmodium gallinaceum identifies the Rh5 interacting protein (ripr), and reveals a lack of EBL and RH gene family diversification. Malar J 2015; 14:296. [PMID: 26243218 PMCID: PMC4524024 DOI: 10.1186/s12936-015-0814-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Accepted: 07/20/2015] [Indexed: 01/01/2023] Open
Abstract
Background Malaria parasites that infect birds can have narrow or broad host-tropisms. These differences in host specificity make avian malaria a useful model for studying the evolution and transmission of parasite assemblages across geographic ranges. The molecular mechanisms involved in host-specificity and the biology of avian malaria parasites in general are important aspects of malaria pathogenesis that warrant further examination. Here, the transcriptome of the malaria parasite Plasmodium gallinaceum was characterized to investigate the biology and the conservation of genes across various malaria parasite species. Methods The P. gallinaceum transcriptome was annotated and KEGG pathway mapping was performed. The ripr gene and orthologous genes that play critical roles in the purine salvage pathway were identified and characterized using bioinformatics and phylogenetic methods. Results Analysis of the transcriptome sequence database identified essential genes of the purine salvage pathway in P. gallinaceum that shared high sequence similarity to Plasmodium falciparum when compared to other mammalian Plasmodium spp. However, based on the current sequence data, there was a lack of orthologous genes that belonged to the erythrocyte-binding-like (EBL) and reticulocyte-binding-like homologue (RH) family in P. gallinaceum. In addition, an orthologue of the Rh5 interacting protein (ripr) was identified. Conclusions These findings suggest that the pathways involved in parasite red blood cell invasion are significantly different in avian Plasmodium parasites, but critical metabolic pathways are conserved throughout divergent Plasmodium taxa. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0814-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Elvin J Lauron
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA.
| | - Han Xian Aw Yeang
- Rheumatology Division, Washington University School of Medicine, St. Louis, MO, USA.
| | - Samantha M Taffner
- Rheumatology Division, Washington University School of Medicine, St. Louis, MO, USA.
| | - Ravinder N M Sehgal
- Department of Biology, San Francisco State University, San Francisco, CA, USA.
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Expression, Purification, and Biological Characterization of Babesia microti Apical Membrane Antigen 1. Infect Immun 2015. [PMID: 26195550 DOI: 10.1128/iai.00168-15] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The intraerythrocytic apicomplexan Babesia microti, the primary causative agent of human babesiosis, is a major public health concern in the United States and elsewhere. Apicomplexans utilize a multiprotein complex that includes a type I membrane protein called apical membrane antigen 1 (AMA1) to invade host cells. We have isolated the full-length B. microti AMA1 (BmAMA1) gene and determined its nucleotide sequence, as well as the amino acid sequence of the AMA1 protein. This protein contains an N-terminal signal sequence, an extracellular region, a transmembrane region, and a short conserved cytoplasmic tail. It shows the same domain organization as the AMA1 orthologs from piroplasm, coccidian, and haemosporidian apicomplexans but differs from all other currently known piroplasmida, including other Babesia and Theileria species, in lacking two conserved cysteines in highly variable domain III of the extracellular region. Minimal polymorphism was detected in BmAMA1 gene sequences of parasite isolates from six babesiosis patients from Nantucket. Immunofluorescence microscopy studies showed that BmAMA1 is localized on the cell surface and cytoplasm near the apical end of the parasite. Native BmAMA1 from parasite lysate and refolded recombinant BmAMA1 (rBmAMA1) expressed in Escherichia coli reacted with a mouse anti-BmAMA1 antibody using Western blotting. In vitro binding studies showed that both native BmAMA1 and rBmAMA1 bind to human red blood cells (RBCs). This binding is trypsin and chymotrypsin treatment sensitive but neuraminidase independent. Incubation of B. microti parasites in human RBCs with a mouse anti-BmAMA1 antibody inhibited parasite growth by 80% in a 24-h assay. Based on its antigenically conserved nature and potential role in RBC invasion, BmAMA1 should be evaluated as a vaccine candidate.
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Lauron EJ, Oakgrove KS, Tell LA, Biskar K, Roy SW, Sehgal RNM. Transcriptome sequencing and analysis of Plasmodium gallinaceum reveals polymorphisms and selection on the apical membrane antigen-1. Malar J 2014; 13:382. [PMID: 25261185 PMCID: PMC4182871 DOI: 10.1186/1475-2875-13-382] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 09/17/2014] [Indexed: 11/15/2022] Open
Abstract
Background Plasmodium erythrocyte invasion genes play a key role in malaria parasite transmission, host-specificity and immuno-evasion. However, the evolution of the genes responsible remains understudied. Investigating these genes in avian malaria parasites, where diversity is particularly high, offers new insights into the processes that confer malaria pathogenesis. These parasites can pose a significant threat to birds and since birds play crucial ecological roles they serve as important models for disease dynamics. Comprehensive knowledge of the genetic factors involved in avian malaria parasite invasion is lacking and has been hampered by difficulties in obtaining nuclear data from avian malaria parasites. Thus the first Illumina-based de novo transcriptome sequencing and analysis of the chicken parasite Plasmodium gallinaceum was performed to assess the evolution of essential Plasmodium genes. Methods White leghorn chickens were inoculated intravenously with erythrocytes containing P. gallinaceum. cDNA libraries were prepared from RNA extracts collected from infected chick blood and sequencing was run on the HiSeq2000 platform. Orthologues identified by transcriptome sequencing were characterized using phylogenetic, ab initio protein modelling and comparative and population-based methods. Results Analysis of the transcriptome identified several orthologues required for intra-erythrocytic survival and erythrocyte invasion, including the rhoptry neck protein 2 (RON2) and the apical membrane antigen-1 (AMA-1). Ama-1 of avian malaria parasites exhibits high levels of genetic diversity and evolves under positive diversifying selection, ostensibly due to protective host immune responses. Conclusion Erythrocyte invasion by Plasmodium parasites require AMA-1 and RON2 interactions. AMA-1 and RON2 of P. gallinaceum are evolutionarily and structurally conserved, suggesting that these proteins may play essential roles for avian malaria parasites to invade host erythrocytes. In addition, host-driven selection presumably results in the high levels of genetic variation found in ama-1 of avian Plasmodium species. These findings have implications for investigating avian malaria epidemiology and population dynamics. Moreover, this work highlights the P. gallinaceum transcriptome as an important public resource for investigating the diversity and evolution of essential Plasmodium genes. Electronic supplementary material The online version of this article (doi:10.1186/1475-2875-13-382) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Elvin J Lauron
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA.
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18
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Critical glycosylated residues in exon three of erythrocyte glycophorin A engage Plasmodium falciparum EBA-175 and define receptor specificity. mBio 2014; 5:e01606-14. [PMID: 25205096 PMCID: PMC4173783 DOI: 10.1128/mbio.01606-14] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Erythrocyte invasion is an essential step in the pathogenesis of malaria. The erythrocyte binding-like (EBL) family of Plasmodium falciparum proteins recognizes glycophorins (Gp) on erythrocytes and plays a critical role in attachment during invasion. However, the molecular basis for specific receptor recognition by each parasite ligand has remained elusive, as is the case with the ligand/receptor pair P. falciparum EBA-175 (PfEBA-175)/GpA. This is due largely to difficulties in producing properly glycosylated and functional receptors. Here, we developed an expression system to produce recombinant glycosylated and functional GpA, as well as mutations and truncations. We identified the essential binding region and determinants for PfEBA-175 engagement, demonstrated that these determinants are required for the inhibition of parasite growth, and identified the glycans important in mediating the PfEBA-175–GpA interaction. The results suggest that PfEBA-175 engages multiple glycans of GpA encoded by exon 3 and that the presentation of glycans is likely required for high-avidity binding. The absence of exon 3 in GpB and GpE due to a splice site mutation confers specific recognition of GpA by PfEBA-175. We speculate that GpB and GpE may have arisen due to selective pressure to lose the PfEBA-175 binding site in GpA. The expression system described here has wider application for examining other EBL members important in parasite invasion, as well as additional pathogens that recognize glycophorins. The ability to define critical binding determinants in receptor-ligand interactions, as well as a system to genetically manipulate glycosylated receptors, opens new avenues for the design of interventions that disrupt parasite invasion. Plasmodium falciparum uses distinct ligands that bind host cell receptors for invasion of red blood cells (RBCs) during malaria infection. A key entry pathway involves P. falciparum EBA-175 (PfEBA-175) recognizing glycophorin A (GpA) on RBCs. Despite knowledge of this protein-protein interaction, the complete mechanism for specific receptor engagement is not known. PfEBA-175 recognizes GpA but is unable to engage the related RBC receptor GpB or GpE. Understanding the necessary elements that enable PfEBA-175 to specifically recognize GpA is critical in developing specific and potent inhibitors of PfEBA-175 that disrupt host cell invasion and aid in malaria control. Here, we describe a novel system to produce and manipulate the host receptor GpA. Using this system, we probed the elements in GpA necessary for engagement and thus for host cell invasion. These studies have important implications for understanding how ligands and receptors interact and for the future development of malaria interventions.
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Plasmodium falciparum double C2 domain protein, PfDOC2, binds to calcium when associated with membranes. Exp Parasitol 2014; 144:91-5. [DOI: 10.1016/j.exppara.2014.06.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 06/02/2014] [Accepted: 06/23/2014] [Indexed: 11/23/2022]
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Ord RL, Caldeira JC, Rodriguez M, Noe A, Chackerian B, Peabody DS, Gutierrez G, Lobo CA. A malaria vaccine candidate based on an epitope of the Plasmodium falciparum RH5 protein. Malar J 2014; 13:326. [PMID: 25135070 PMCID: PMC4152569 DOI: 10.1186/1475-2875-13-326] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 08/08/2014] [Indexed: 12/12/2022] Open
Abstract
Background The Plasmodium falciparum protein RH5 is an adhesin molecule essential for parasite invasion of erythrocytes. Recent studies show that anti-PfRH5 sera have potent invasion-inhibiting activities, supporting the idea that the PfRH5 antigen could form the basis of a vaccine. Therefore, epitopes recognized by neutralizing anti-PfRH5 antibodies could themselves be effective vaccine immunogens if presented in a sufficiently immunogenic fashion. However, the exact regions within PfRH5 that are targets of this invasion-inhibitory activity have yet to be identified. Methods A battery of anti-RH5 monoclonal antibodies (mAbs) were produced and screened for their potency by inhibition of invasion assays in vitro. Using an anti-RH5 mAb that completely inhibited invasion as the selecting mAb, affinity-selection using random sequence peptide libraries displayed on virus-like particles of bacteriophage MS2 (MS2 VLPs) was performed. VLPs were sequenced to identify the specific peptide epitopes they encoded and used to raise specific antisera that was in turn tested for inhibition of invasion. Results Three anti-RH5 monoclonals (0.1 mg/mL) were able to inhibit invasion in vitro by >95%. Affinity-selection with one of these mAbs yielded a VLP which yielded a peptide whose sequence is identical to a portion of PfRH5 itself. The VLP displaying the peptide binds strongly to the antibody, and in immunized animals elicits an anti-PfRH5 antibody response. The resulting antisera against the specific VLP inhibit parasite invasion of erythrocytes more than 90% in vitro. Conclusions Here, data is presented from an anti-PfRH5 mAb that completely inhibits erythrocyte invasion by parasites in vitro, one of the few anti-malarial monoclonal antibodies reported to date that completely inhibits invasion with such potency, adding to other studies that highlight the potential of PfRH5 as a vaccine antigen. The specific neutralization sensitive epitope within RH5 has been identified, and antibodies against this epitope also elicit high anti-invasion activity, suggesting this epitope could form the basis of an effective vaccine against malaria.
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Affiliation(s)
| | | | | | | | | | | | | | - Cheryl A Lobo
- Department of Blood-Borne Parasites, New York Blood Center, New York, NY 10065, USA.
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21
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Yalcindag E, Rougeron V, Elguero E, Arnathau C, Durand P, Brisse S, Diancourt L, Aubouy A, Becquart P, D'Alessandro U, Fontenille D, Gamboa D, Maestre A, Ménard D, Musset L, Noya O, Veron V, Wide A, Carme B, Legrand E, Chevillon C, Ayala FJ, Renaud F, Prugnolle F. Patterns of selection onPlasmodium falciparumerythrocyte-binding antigens after the colonization of the New World. Mol Ecol 2014; 23:1979-93. [DOI: 10.1111/mec.12696] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Erhan Yalcindag
- MIVEGEC (Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle); UMR CNRS 5290/IRD 224; Université Montpellier 1; Université Montpellier 2; CHRU de Montpellier; 39 Avenue Charles Flahault 34295 Montpellier France
- Department of Botany and Zoology; Faculty of Science; Masaryk University; Kotlářská 2 611 37 Brno Czech Republic
| | - Virginie Rougeron
- MIVEGEC (Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle); UMR CNRS 5290/IRD 224; Université Montpellier 1; Université Montpellier 2; CHRU de Montpellier; 39 Avenue Charles Flahault 34295 Montpellier France
- Centre International de Recherches Médicales de Franceville (CIRMF); BP 769 Franceville Gabon
| | - Eric Elguero
- MIVEGEC (Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle); UMR CNRS 5290/IRD 224; Université Montpellier 1; Université Montpellier 2; CHRU de Montpellier; 39 Avenue Charles Flahault 34295 Montpellier France
| | - Céline Arnathau
- MIVEGEC (Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle); UMR CNRS 5290/IRD 224; Université Montpellier 1; Université Montpellier 2; CHRU de Montpellier; 39 Avenue Charles Flahault 34295 Montpellier France
| | - Patrick Durand
- MIVEGEC (Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle); UMR CNRS 5290/IRD 224; Université Montpellier 1; Université Montpellier 2; CHRU de Montpellier; 39 Avenue Charles Flahault 34295 Montpellier France
| | - Sylvain Brisse
- Institut Pasteur; Plate-forme Génotypage des Pathogènes et Santé Publique; 28 Rue du docteur Roux 75724 Paris France
| | - Laure Diancourt
- Institut Pasteur; Plate-forme Génotypage des Pathogènes et Santé Publique; 28 Rue du docteur Roux 75724 Paris France
| | - Agnes Aubouy
- Institut de Recherche pour le Développement (IRD); UMR152; Université Paul Sabatier; 35 Chemin des Maraîchers 31062 Toulouse France
| | - Pierre Becquart
- MIVEGEC (Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle); UMR CNRS 5290/IRD 224; Université Montpellier 1; Université Montpellier 2; CHRU de Montpellier; 39 Avenue Charles Flahault 34295 Montpellier France
| | | | - Didier Fontenille
- MIVEGEC (Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle); UMR CNRS 5290/IRD 224; Université Montpellier 1; Université Montpellier 2; CHRU de Montpellier; 39 Avenue Charles Flahault 34295 Montpellier France
| | - Dionicia Gamboa
- Instituto de Medicina Tropical Alexander Von Humboldt; Universidad Peruana Cayetano Heredia; AP 4314 Lima 100 Peru
| | - Amanda Maestre
- Grupo Salud y Comunidad; Facultad de Medicina; Universidad de Antioquía; Medellín Colombia
| | - Didier Ménard
- Molecular Epidemiology Unit; Pasteur Institute of Cambodia; 5 Boulevard Monivong - PO Box 983 Phnom Penh Cambodia
| | - Lise Musset
- Parasitology laboratory; Institut Pasteur de Guyane; BP6010 97306 Cayenne Cedex French Guiana
| | - Oscar Noya
- Centro para Estudios Sobre Malaria; Instituto de Altos Estudios en Salud “Dr. Arnoldo Gabaldón”-INH; Ministerio del Poder Popular para la Salud; Instituto de Medicina Tropical; Universidad Central de Venezuela; Caracas Venezuela
| | | | - Albina Wide
- Centro para Estudios Sobre Malaria; Instituto de Altos Estudios en Salud “Dr. Arnoldo Gabaldón”-INH; Ministerio del Poder Popular para la Salud; Instituto de Medicina Tropical; Universidad Central de Venezuela; Caracas Venezuela
| | - Bernard Carme
- Centre d'Investigation Clinique Epidémiologie Clinique Antilles; Guyane CIC-EC 802; Cayenne General Hospital; Cayenne French Guiana
| | - Eric Legrand
- Parasitology laboratory; Institut Pasteur de Guyane; BP6010 97306 Cayenne Cedex French Guiana
| | - Christine Chevillon
- MIVEGEC (Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle); UMR CNRS 5290/IRD 224; Université Montpellier 1; Université Montpellier 2; CHRU de Montpellier; 39 Avenue Charles Flahault 34295 Montpellier France
| | - Francisco J. Ayala
- Department of Ecology and Evolutionary Biology; University of California; Irvine CA 92697 USA
| | - François Renaud
- MIVEGEC (Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle); UMR CNRS 5290/IRD 224; Université Montpellier 1; Université Montpellier 2; CHRU de Montpellier; 39 Avenue Charles Flahault 34295 Montpellier France
| | - Franck Prugnolle
- MIVEGEC (Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle); UMR CNRS 5290/IRD 224; Université Montpellier 1; Université Montpellier 2; CHRU de Montpellier; 39 Avenue Charles Flahault 34295 Montpellier France
- Centre International de Recherches Médicales de Franceville (CIRMF); BP 769 Franceville Gabon
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Affiliation(s)
- Gavin J. Wright
- Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
- Malaria Programme, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
- * E-mail: (GJW); (JCR)
| | - Julian C. Rayner
- Malaria Programme, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
- * E-mail: (GJW); (JCR)
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Kobayashi K, Takano R, Takemae H, Sugi T, Ishiwa A, Gong H, Recuenco FC, Iwanaga T, Horimoto T, Akashi H, Kato K. Analyses of interactions between heparin and the apical surface proteins of Plasmodium falciparum. Sci Rep 2013; 3:3178. [PMID: 24212193 PMCID: PMC3822384 DOI: 10.1038/srep03178] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 10/23/2013] [Indexed: 11/23/2022] Open
Abstract
Heparin, a sulfated glycoconjugate, reportedly inhibits the blood-stage growth of the malaria parasite Plasmodium falciparum. Elucidation of the inhibitory mechanism is valuable for developing novel invasion-blocking treatments based on heparin. Merozoite surface protein 1 has been reported as a candidate target of heparin; however, to better understand the molecular mechanisms involved, we characterized the molecules that bind to heparin during merozoite invasion. Here, we show that heparin binds only at the apical tip of the merozoite surface and that multiple heparin-binding proteins localize preferentially in the apical organelles. To identify heparin-binding proteins, parasite proteins were fractionated by means of heparin affinity chromatography and subjected to immunoblot analysis with ligand-specific antibodies. All tested members of the Duffy and reticulocyte binding-like families bound to heparin with diverse affinities. These findings suggest that heparin masks the apical surface of merozoites and blocks interaction with the erythrocyte membrane after initial attachment.
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Affiliation(s)
- Kyousuke Kobayashi
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, the University of Tokyo
- Division of Stem Cell Processing, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, the University of Tokyo
- Division of Host-Parasite Interaction, Department of Microbiology and Immunology, Institute of Medical Science, the University of Tokyo
| | - Ryo Takano
- National Research Center for Protozoan Disease, Obihiro University of Agriculture and Veterinary Medicine
| | - Hitoshi Takemae
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, the University of Tokyo
- National Research Center for Protozoan Disease, Obihiro University of Agriculture and Veterinary Medicine
| | - Tatsuki Sugi
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, the University of Tokyo
- National Research Center for Protozoan Disease, Obihiro University of Agriculture and Veterinary Medicine
| | - Akiko Ishiwa
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, the University of Tokyo
- National Research Center for Protozoan Disease, Obihiro University of Agriculture and Veterinary Medicine
| | - Haiyan Gong
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, the University of Tokyo
| | - Frances C. Recuenco
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, the University of Tokyo
- National Research Center for Protozoan Disease, Obihiro University of Agriculture and Veterinary Medicine
| | - Tatsuya Iwanaga
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, the University of Tokyo
| | - Taisuke Horimoto
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, the University of Tokyo
| | - Hiroomi Akashi
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, the University of Tokyo
| | - Kentaro Kato
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, the University of Tokyo
- National Research Center for Protozoan Disease, Obihiro University of Agriculture and Veterinary Medicine
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Hans N, Singh S, Pandey AK, Reddy KS, Gaur D, Chauhan VS. Identification and characterization of a novel Plasmodium falciparum adhesin involved in erythrocyte invasion. PLoS One 2013; 8:e74790. [PMID: 24058628 PMCID: PMC3772933 DOI: 10.1371/journal.pone.0074790] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 08/05/2013] [Indexed: 11/18/2022] Open
Abstract
Malaria remains a major health problem worldwide. All clinical symptoms of malaria are attributed to the asexual blood stages of the parasite life cycle. Proteins resident in apical organelles and present on the surface of P. falciparum merozoites are considered promising candidates for the development of blood stage malaria vaccines. In the present study, we have identified and characterized a microneme associated antigen, PfMA [PlasmoDB Gene ID: PF3D7_0316000, PFC0700c]. The gene was selected by applying a set of screening criteria such as transcriptional upregulation at late schizogony, inter-species conservation and the presence of signal sequence or transmembrane domains. The gene sequence of PfMA was found to be conserved amongst various Plasmodium species. We experimentally demonstrated that the transcript for PfMA was expressed only in the late blood stages of parasite consistent with a putative role in erythrocyte invasion. PfMA was localized by immunofluorescence and immuno-electron microscopy to be in the micronemes, an apical organelle of merozoites. The functional role of the PfMA protein in erythrocyte invasion was identified as a parasite adhesin involved in direct attachment with the target erythrocyte. PfMA was demonstrated to bind erythrocytes in a sialic acid independent, chymotrypsin and trypsin resistant manner and its antibodies inhibited P. falciparum erythrocyte invasion. Invasion of erythrocytes is a complex multistep process that involves a number of redundant ligand-receptor interactions many of which still remain unknown and even uncharacterized. Our work has identified and characterized a novel P. falciparum adhesin involved in erythrocyte invasion.
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Affiliation(s)
- Nidhi Hans
- Malaria Research Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Shailja Singh
- Malaria Research Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Alok K. Pandey
- Malaria Research Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - K. Sony Reddy
- Malaria Research Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Deepak Gaur
- Malaria Research Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Virander S. Chauhan
- Malaria Research Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
- * E-mail:
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Ntumngia FB, Schloegel J, McHenry AM, Barnes SJ, George MT, Kennedy S, Adams JH. Immunogenicity of single versus mixed allele vaccines of Plasmodium vivax Duffy binding protein region II. Vaccine 2013; 31:4382-8. [PMID: 23916294 DOI: 10.1016/j.vaccine.2013.07.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2013] [Revised: 06/21/2013] [Accepted: 07/02/2013] [Indexed: 11/17/2022]
Abstract
The Duffy binding protein (DBP) of Plasmodium vivax is vital for host erythrocyte invasion. DBP region II (DBPII) contains critical residues for receptor recognition and anti-DBPII antibodies have been shown to inhibit erythrocyte binding and invasion, thereby making the molecule an attractive vaccine candidate against P. vivax blood stages. Similar to other blood-stage antigens, allelic variation within the DBPII and associated strain-specific immunity is a major challenge for development of a broadly effective vaccine against P. vivax malaria. We hypothesized that immunization with a vaccine composed of multiple DBP alleles or a modified epitope DBP (DEKnull) will be more effective in producing a broadly reactive and inhibitory antibody response to diverse DBPII alleles than a single allele vaccine. In this study, we compared single, naturally occurring DBPII allele immunizations (Sal1, 7.18, P) and DEKnull with a combination of (Sal1, 7.18, P) alleles. Quantitative analysis by ELISA demonstrated that the multiple allele vaccine tend to be more immunogenic than any of the single allele vaccines when tested for reactivity against a panel of DBPII allelic variants whereas DEKnull was less immunogenic than the mixed-allele vaccine but similar in reactivity to the single allele vaccines. Further analysis for functional efficacy by in vitro erythrocyte-binding inhibition assays demonstrated that the multiple allele immunization produced a stronger strain-neutralizing response than the other vaccination strategies even though inhibition remained biased toward some alleles. Overall, there was no correlation between antibody titer and functional inhibition. These data suggest that a multiple allele vaccine may enhance immunogenicity of a DBPII vaccine but further investigation is required to optimize this vaccine strategy to achieve broader coverage against global P. vivax strains.
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Affiliation(s)
- Francis B Ntumngia
- Department of Global Health, College of Public Health, University of South Florida, 3720 Spectrum Boulevard, Suite 304, Tampa, FL 33612, USA
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Sampath S, Carrico C, Janes J, Gurumoorthy S, Gibson C, Melcher M, Chitnis CE, Wang R, Schief WR, Smith JD. Glycan masking of Plasmodium vivax Duffy Binding Protein for probing protein binding function and vaccine development. PLoS Pathog 2013; 9:e1003420. [PMID: 23853575 PMCID: PMC3681752 DOI: 10.1371/journal.ppat.1003420] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 04/30/2013] [Indexed: 11/19/2022] Open
Abstract
Glycan masking is an emerging vaccine design strategy to focus antibody responses to specific epitopes, but it has mostly been evaluated on the already heavily glycosylated HIV gp120 envelope glycoprotein. Here this approach was used to investigate the binding interaction of Plasmodium vivax Duffy Binding Protein (PvDBP) and the Duffy Antigen Receptor for Chemokines (DARC) and to evaluate if glycan-masked PvDBPII immunogens would focus the antibody response on key interaction surfaces. Four variants of PVDBPII were generated and probed for function and immunogenicity. Whereas two PvDBPII glycosylation variants with increased glycan surface coverage distant from predicted interaction sites had equivalent binding activity to wild-type protein, one of them elicited slightly better DARC-binding-inhibitory activity than wild-type immunogen. Conversely, the addition of an N-glycosylation site adjacent to a predicted PvDBP interaction site both abolished its interaction with DARC and resulted in weaker inhibitory antibody responses. PvDBP is composed of three subdomains and is thought to function as a dimer; a meta-analysis of published PvDBP mutants and the new DBPII glycosylation variants indicates that critical DARC binding residues are concentrated at the dimer interface and along a relatively flat surface spanning portions of two subdomains. Our findings suggest that DARC-binding-inhibitory antibody epitope(s) lie close to the predicted DARC interaction site, and that addition of N-glycan sites distant from this site may augment inhibitory antibodies. Thus, glycan resurfacing is an attractive and feasible tool to investigate protein structure-function, and glycan-masked PvDBPII immunogens might contribute to P. vivax vaccine development. An important goal of many vaccine efforts is to inhibit pathogen invasion of host cells, but few approaches exist to target vaccine antibodies on invasion blocking epitopes. Glycan masking is a vaccine design strategy to hide protein surfaces with carbohydrates and focus antibodies on exposed surfaces. This approach has mostly been evaluated on the heavily glycosylated HIV envelope glycoprotein, but it has never been tested on eukaryotic pathogens, such as Plasmodium, which have limited N-glycosylation machinery and therefore may provide a better platform to explore this strategy. Here, we used glycan masking to investigate the binding interaction between Plasmodium vivax Duffy binding protein (PvDBP) and the Duffy Antigen Receptor for Chemokines (DARC). This study showed that addition of an N-glycan site in a predicted host interaction surface abolished binding and potentially covered up an inhibitory antibody epitope. In contrast, addition of multiple N-glycan sites distant from predicted interaction surfaces did not inhibit binding but did slightly enhance elicitation of inhibitory antibodies. This analysis shows that glycan resurfacing offers an integrated approach to characterize protein function and immunogenicity and that glycan resurfacing of PvDBPII immunogens may have utility in P. vivax-malaria vaccine development.
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Affiliation(s)
- Sowmya Sampath
- Seattle Biomedical Research Institute, Seattle, Washington, United States of America
| | - Chris Carrico
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Joel Janes
- Seattle Biomedical Research Institute, Seattle, Washington, United States of America
| | - Sairam Gurumoorthy
- Seattle Biomedical Research Institute, Seattle, Washington, United States of America
| | - Claire Gibson
- Seattle Biomedical Research Institute, Seattle, Washington, United States of America
| | - Martin Melcher
- Seattle Biomedical Research Institute, Seattle, Washington, United States of America
| | - Chetan E. Chitnis
- International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Ruobing Wang
- Seattle Biomedical Research Institute, Seattle, Washington, United States of America
| | - William R. Schief
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
- Department of Immunology and Microbial Science and IAVI Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, California, United States of America
- Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail: (WRS); (JDS)
| | - Joseph D. Smith
- Seattle Biomedical Research Institute, Seattle, Washington, United States of America
- Department of Pathobiology, University of Washington, Seattle, Washington, United States of America
- * E-mail: (WRS); (JDS)
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Moreno-Pérez DA, Ruíz JA, Patarroyo MA. Reticulocytes: Plasmodium vivax target cells. Biol Cell 2013; 105:251-60. [PMID: 23458497 DOI: 10.1111/boc.201200093] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 02/22/2013] [Indexed: 02/05/2023]
Abstract
Reticulocytes represent the main invasion target for Plasmodium vivax, the second most prevalent parasite species around the world causing malaria in humans. In spite of these cells' importance in research into malaria, biological knowledge related to the nature of the host has been limited, given the technical difficulties present in working with them in the laboratory. Poor reticulocyte recovery from total blood, by different techniques, has hampered continuous in vitro P. vivax cultures being developed, thereby delaying basic investigation in this parasite species. Intense research during the last few years has led to advances being made in developing methodologies orientated towards obtaining enriched reticulocytes from differing sources, thereby providing invaluable information for developing new strategies aimed at preventing infection caused by malaria. This review describes the most recent studies related to obtaining reticulocytes and discusses approaches which could contribute towards knowledge regarding molecular interactions between target cell proteins and their main infective agent, P. vivax.
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Arévalo-Pinzón G, Curtidor H, Muñoz M, Suarez D, Patarroyo MA, Patarroyo ME. Rh1 high activity binding peptides inhibit high percentages of Plasmodium falciparum FVO strain invasion. Vaccine 2013; 31:1830-7. [PMID: 23398931 DOI: 10.1016/j.vaccine.2013.01.052] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 01/12/2013] [Accepted: 01/25/2013] [Indexed: 11/30/2022]
Abstract
Identifying the minimal functional regions of the proteins which the malaria parasite uses when invading its host cells constitutes the first and most important approach in an effective design for a chemically synthesised, multi-antigen, multi-stage, subunit-based vaccine. This work has been aimed at identifying the PfRh1 protein binding regions (residues 1-2580) belonging to the reticulocyte binding-like (RBL or P. falciparum Rh [PfRh]) family implicated in the parasite's alternative target cell invasion routes. Eighteen peptide regions (called high activity binding peptides - HABPs) binding to red blood cells (RBC) were identified in peptides mapped in a highly robust, specific and sensitive receptor-ligand assay. These HABPs were saturable in the experimental conditions assayed here and most had an alpha helix structure. Polymorphism studies revealed that only six of the eighteen HABPs identified had changes at amino acid level amongst the seven P. falciparum strains evaluated. Most HABPs' specific binding became altered when RBC were treated with neuraminidase, chymotrypsin and trypsin, suggesting differing sensitivity for RBC membrane receptors. After ascertaining that the Rh1 gene was transcribed and expressed in late-stage schizonts of the FCB-2 strain, invasion inhibition assays were carried out. When most of these HABPs were assayed in P. falciparum in vitro culture they were able to inhibit high percentages of FVO strain invasion compared to low inhibition percentages observed with the FCB-2 strain. This data shows small Rh1 regions' participation during invasion and suggests that these units should be included in further immunological and structural studies.
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Hayton K, Dumoulin P, Henschen B, Liu A, Papakrivos J, Wellems TE. Various PfRH5 polymorphisms can support Plasmodium falciparum invasion into the erythrocytes of owl monkeys and rats. Mol Biochem Parasitol 2013; 187:103-10. [PMID: 23305874 DOI: 10.1016/j.molbiopara.2012.12.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 12/15/2012] [Accepted: 12/17/2012] [Indexed: 12/29/2022]
Abstract
Aotus nancymaae, the owl monkey, provides a useful laboratory model for research to develop drugs and vaccines against human falciparum malaria; however, many Plasmodium falciparum parasites are unable to invade A. nancymaae erythrocytes, rendering the parasites noninfective to the monkeys. In previous work, we identified a key polymorphism that determined the inheritance of erythrocyte invasion in a genetic cross of two P. falciparum clones that were virulent (GB4) or noninfective (7G8) to A. nancymaae. This polymorphism, an isoleucine-to-lysine polymorphism at position 204 (I204K) of the GB4 erythrocyte binding protein PfRH5, was nevertheless not found in several other P. falciparum lines that could also invade A. nancymaae erythrocytes. Alternative PfRH5 polymorphisms occur at different positions in these virulent parasites, and additional polymorphisms are found in P. falciparum parasites that cannot infect A. nancymaae. By allelic replacement methods, we have introduced the polymorphisms of these A. nancymaae-virulent or noninfective parasites at codons 204, 347, 358, 362, 410, and 429 of the endogenous PfRH5 gene in the noninfective 7G8 line. 7G8 transformants expressing the polymorphisms of the A. nancymaae-virulent parasites show neuraminidase-sensitive (sialic acid-dependent) invasion into the monkey erythrocytes, whereas 7G8 transformants expressing the PfRH5 alleles of noninfective parasites show little or no invasion of these erythrocytes. Parasites harboring PfRH5 polymorphisms 204K or 204R are also able to invade rat erythrocytes and are differentially sensitive to the removal of surface sialic acids by neuraminidase. These studies offer insights into the PfRH5 receptor-binding domain and interactions that support the invasion of various primate and rodent erythrocytes by P. falciparum.
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Affiliation(s)
- Karen Hayton
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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Lopez-Perez M, Villasis E, Machado RLD, Póvoa MM, Vinetz JM, Blair S, Gamboa D, Lustigman S. Plasmodium falciparum field isolates from South America use an atypical red blood cell invasion pathway associated with invasion ligand polymorphisms. PLoS One 2012; 7:e47913. [PMID: 23118907 PMCID: PMC3485327 DOI: 10.1371/journal.pone.0047913] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 09/17/2012] [Indexed: 12/02/2022] Open
Abstract
Studies of Plasmodium falciparum invasion pathways in field isolates have been limited. Red blood cell (RBC) invasion is a complex process involving two invasion protein families; Erythrocyte Binding-Like (EBL) and the Reticulocyte Binding-Like (PfRh) proteins, which are polymorphic and not fully characterized in field isolates. To determine the various P. falciparum invasion pathways used by parasite isolates from South America, we studied the invasion phenotypes in three regions: Colombia, Peru and Brazil. Additionally, polymorphisms in three members of the EBL (EBA-181, EBA-175 and EBL-1) and five members of the PfRh (PfRh1, PfRh2a, PfRh2b, PfRh4, PfRh5) families were determined. We found that most P. falciparum field isolates from Colombia and Peru invade RBCs through an atypical invasion pathway phenotypically characterized as resistant to all enzyme treatments (NrTrCr). Moreover, the invasion pathways and the ligand polymorphisms differed substantially among the Colombian and Brazilian isolates while the Peruvian isolates represent an amalgam of those present in the Colombian and Brazilian field isolates. The NrTrCr invasion profile was associated with the presence of the PfRh2a pepC variant, the PfRh5 variant 1 and EBA-181 RVNKN variant. The ebl and Pfrh expression levels in a field isolate displaying the NrTrCr profile also pointed to PfRh2a, PfRh5 and EBA-181 as being possibly the major players in this invasion pathway. Notably, our studies demonstrate the uniqueness of the Peruvian P. falciparum field isolates in terms of their invasion profiles and ligand polymorphisms, and present a unique opportunity for studying the ability of P. falciparum parasites to expand their invasion repertoire after being reintroduced to human populations. The present study is directly relevant to asexual blood stage vaccine design focused on invasion pathway proteins, suggesting that regional invasion variants and global geographical variation are likely to preclude a simple one size fits all type of vaccine.
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Affiliation(s)
- Mary Lopez-Perez
- Molecular Parasitology, Lindsley F. Kimball Research Institute, New York Blood Center, New York City, New York, United States of America
| | - Elizabeth Villasis
- Malaria Laboratory, Instituto de Medicina Tropical “Alexander von Humboldt” Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Ricardo L. D. Machado
- Center for Microorganism Investigations, Department of Dermatology, Parasitic and Infectious Diseases, Medicine School in São José do Rio Preto, São Paulo State, Brazil
| | - Marinete M. Póvoa
- Seção de Parasitologia, Instituto Evandro Chagas, Belém, Pará, Brazil
| | - Joseph M. Vinetz
- Malaria Laboratory, Instituto de Medicina Tropical “Alexander von Humboldt” Universidad Peruana Cayetano Heredia, Lima, Peru
- Division of Infectious Diseases, Department of Medicine, University of California San Diego, La Jolla, California, United States of America
- Departamento de Ciencias Celulares y Moleculares, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Silvia Blair
- Malaria Group, Sede de Investigación Universitaria, Universidad de Antioquia, Medellín, Colombia
| | - Dionicia Gamboa
- Malaria Laboratory, Instituto de Medicina Tropical “Alexander von Humboldt” Universidad Peruana Cayetano Heredia, Lima, Peru
- Departamento de Ciencias Celulares y Moleculares, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Sara Lustigman
- Molecular Parasitology, Lindsley F. Kimball Research Institute, New York Blood Center, New York City, New York, United States of America
- * E-mail:
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31
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Identification of a specific region of Plasmodium falciparum EBL-1 that binds to host receptor glycophorin B and inhibits merozoite invasion in human red blood cells. Mol Biochem Parasitol 2012; 183:23-31. [PMID: 22273481 DOI: 10.1016/j.molbiopara.2012.01.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 01/05/2012] [Accepted: 01/09/2012] [Indexed: 11/22/2022]
Abstract
The malaria parasite Plasmodium falciparum invades human erythrocytes through multiple pathways utilizing several ligand-receptor interactions. These interactions are broadly classified in two groups according to their dependency on sialic acid residues. Here, we focus on the sialic acid-dependent pathway by using purified glycophorins and red blood cells (RBCs) to screen a cDNA phage display library derived from P. falciparum FCR3 strain, a sialic acid-dependent strain. This screen identified several parasite proteins including the erythrocyte-binding ligand-1, EBL-1. The phage cDNA insert encoded the 69-amino acid peptide, termed F2i, which is located within the F2 region of the DBL domain, designated here as D2, of EBL-1. Recombinant D2 and F2i polypeptides bound to purified glycophorins and RBCs, and the F2i peptide was found to interfere with binding of D2 domain to its receptor. Both D2 and F2i polypeptides bound to trypsin-treated but not neuraminidase or chymotrypsin-treated erythrocytes, consistent with known glycophorin B resistance to trypsin, and neither the D2 nor F2i polypeptide bound to glycophorin B-deficient erythrocytes. Importantly, purified D2 and F2i polypeptides partially inhibited merozoite reinvasion in human erythrocytes. Our results show that the host erythrocyte receptor glycophorin B directly interacts with the DBL domain of parasite EBL-1, and the core binding site is contained within the 69 amino acid F2i region (residues 601-669) of the DBL domain. Together, these findings suggest that a recombinant F2i peptide with stabilized structure could provide a protective function at blood stage infection and represents a valuable addition to a multi-subunit vaccine against malaria.
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Ord RL, Rodriguez M, Yamasaki T, Takeo S, Tsuboi T, Lobo CA. Targeting sialic acid dependent and independent pathways of invasion in Plasmodium falciparum. PLoS One 2012; 7:e30251. [PMID: 22253925 PMCID: PMC3257272 DOI: 10.1371/journal.pone.0030251] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 12/16/2011] [Indexed: 02/04/2023] Open
Abstract
The pathology of malaria is a consequence of the parasitaemia which develops through the cyclical asexual replication of parasites in a patient's red blood cells. Multiple parasite ligand-erythrocyte receptor interactions must occur for successful Plasmodium invasion of the human red cell. Two major malaria ligand families have been implicated in these variable ligand-receptor interactions used by Plasmodium falciparum to invade human red cells: the micronemal proteins from the Erythrocyte Binding Ligands (EBL) family and the rhoptry proteins from the Reticulocyte binding Homolog (PfRH) family. Ligands from the EBL family largely govern the sialic acid (SA) dependent pathways of invasion and the RH family ligands (except for RH1) mediate SA independent invasion. In an attempt to dissect out the invasion inhibitory effects of antibodies against ligands from both pathways, we have used EBA-175 and RH5 as model members of each pathway. Mice were immunized with either region II of EBA-175 produced in Pichia pastoris or full-length RH5 produced by the wheat germ cell-free system, or a combination of the two antigens to look for synergistic inhibitory effects of the induced antibodies. Sera obtained from these immunizations were tested for native antigen recognition and for efficacy in invasion inhibition assays. Results obtained show promise for the potential use of such hybrid vaccines to induce antibodies that can block multiple parasite ligand-red cell receptor interactions and thus inhibit parasite invasion.
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Affiliation(s)
- Rosalynn Louise Ord
- Department of Blood-Borne Parasites, New York Blood Center, New York, New York, United States of America
| | - Marilis Rodriguez
- Department of Blood-Borne Parasites, New York Blood Center, New York, New York, United States of America
| | - Tsutomu Yamasaki
- Cell-Free Science and Technology Research Center, Ehime University, Matsuyama, Ehime, Japan
| | - Satoru Takeo
- Cell-Free Science and Technology Research Center, Ehime University, Matsuyama, Ehime, Japan
| | - Takafumi Tsuboi
- Cell-Free Science and Technology Research Center, Ehime University, Matsuyama, Ehime, Japan
- Venture Business Laboratory, Ehime University, Matsuyama, Ehime, Japan
- Ehime Proteo-Medicine Research Center, Ehime University, Toon, Ehime, Japan
| | - Cheryl A. Lobo
- Department of Blood-Borne Parasites, New York Blood Center, New York, New York, United States of America
- * E-mail:
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Conserved and variant epitopes of Plasmodium vivax Duffy binding protein as targets of inhibitory monoclonal antibodies. Infect Immun 2012; 80:1203-8. [PMID: 22215740 DOI: 10.1128/iai.05924-11] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Duffy binding protein (DBP) is a vital ligand for Plasmodium vivax blood-stage merozoite invasion, making the molecule an attractive vaccine candidate against vivax malaria. Similar to other blood-stage vaccine candidates, DBP allelic variation eliciting a strain-specific immunity may be a major challenge for development of a broadly effective vaccine against vivax malaria. To understand whether conserved epitopes can be the target of neutralizing anti-DBP inhibition, we generated a set of monoclonal antibodies to DBP and functionally analyzed their reactivity to a panel of allelic variants. Quantitative analysis by enzyme-linked immunosorbent assay (ELISA) determined that some monoclonal antibodies reacted strongly with epitopes conserved on all DBP variants tested, while reactivity of others was allele specific. Qualitative analysis characterized by anti-DBP functional inhibition using an in vitro erythrocyte binding inhibition assay indicated that there was no consistent correlation between the endpoint titers and functional inhibition. Some monoclonal antibodies were broadly inhibitory while inhibition of others varied significantly by target allele. These data demonstrate a potential for vaccine-elicited immunization to target conserved epitopes but optimization of DBP epitope target specificity and immunogenicity may be necessary for protection against diverse P. vivax strains.
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34
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A single amino acid change in the Plasmodium falciparum RH5 (PfRH5) human RBC binding sequence modifies its structure and determines species-specific binding activity. Vaccine 2012; 30:637-46. [DOI: 10.1016/j.vaccine.2011.11.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 08/27/2011] [Accepted: 11/03/2011] [Indexed: 11/23/2022]
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Tham WH, Healer J, Cowman AF. Erythrocyte and reticulocyte binding-like proteins of Plasmodium falciparum. Trends Parasitol 2011; 28:23-30. [PMID: 22178537 DOI: 10.1016/j.pt.2011.10.002] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 10/11/2011] [Accepted: 10/11/2011] [Indexed: 11/30/2022]
Abstract
The global agenda for malaria eradication would benefit from development of a highly efficacious vaccine that protects against disease and interrupts transmission of Plasmodium falciparum. It is likely that such a vaccine will be multi-component, with antigens from different stages of the parasite life cycle. In this review, inclusion of blood stage antigens in such a vaccine is discussed. Erythrocyte binding-like (EBL) and P. falciparum reticulocyte binding-like (PfRh) proteins are reviewed with respect to their function in erythrocyte invasion, their role in eliciting antibodies contributing to protective immunity and reduction of invasion, leading subsequently to inhibition of parasite multiplication.
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Affiliation(s)
- Wai-Hong Tham
- Walter and Eliza Hall Institute of Medical Research, University of Melbourne, Parkville, VIC, Australia
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36
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Design and immunogenicity of a novel synthetic antigen based on the ligand domain of the Plasmodium vivax duffy binding protein. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2011; 19:30-6. [PMID: 22116684 DOI: 10.1128/cvi.05466-11] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Duffy binding protein is considered a leading vaccine candidate against asexual blood-stage Plasmodium vivax. The interaction of P. vivax merozoites with human reticulocytes through Duffy binding protein (DBP) and its cognate receptor is vital for parasite infection. The ligand domain of DBP (DBPII) is polymorphic, showing a diversity characteristic of selective immune pressure that tends to compromise vaccine efficacy associated with strain-specific immunity. A previous study resolved that a polymorphic region of DBPII was a dominant B-cell epitope target of human inhibitory anti-DBP antibodies, which we refer to as the DEK epitope for the amino acids in the SalI allele. We hypothesized that the polymorphic residues, which are not functionally important for erythrocyte binding but flank the receptor binding motif of DBPII, comprise variant epitopes that tend to divert the immune response away from more conserved epitopes. In this study, we designed, expressed, and evaluated the immunogenicity of a novel artificial DBPII allele, termed DEKnull, having nonpolar amino acids in the naturally occurring polymorphic charged residues of the DEK epitope. The DEKnull antigen retained erythrocyte-binding activity and elicited antibodies to shared epitopes of SalI DBPII from which it was derived. Our results confirmed that removal of the dominant variant epitope in the DEKnull vaccine lowered immunogenicity of DBPII, but inhibitory anti-DBPII antibodies were elicited against shared neutralizing epitopes on SalI. Focusing immune responses toward more conserved DBP epitopes may avoid development of a strain-specific immunity and enhance functional inhibition against broader range of DBPII variants.
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Binding activity, structure, and immunogenicity of synthetic peptides derived from Plasmodium falciparum CelTOS and TRSP proteins. Amino Acids 2011; 43:365-78. [PMID: 21952731 DOI: 10.1007/s00726-011-1087-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Accepted: 08/30/2011] [Indexed: 01/08/2023]
Abstract
Several sporozoite proteins have been associated with Plasmodium falciparum cell traversal and hepatocyte invasion, including the cell-traversal protein for ookinetes and sporozoites (CelTOS), and thrombospondin-related sporozoite protein (TRSP). CelTOS and TRSP amino acid sequences have been finely mapped to identify regions specifically binding to HeLa and HepG2 cells, respectively. Three high-activity binding peptides (HABPs) were found in CelTOS and one HABP was found in TRSP, all of them having high α-helical structure content. These HABPs' specific binding was sensitive to HeLa and HepG2 cells' pre-treatment with heparinase I and chondroitinase ABC. Despite their similarity at three-dimensional (3D) structural level, TRSP and TRAP HABPs located in the TSR domain did not compete for the same binding sites. CelTOS and TRSP HABPs were used as a template for designing modified sequences to then be assessed in the Aotus monkey experimental model. Antibodies directed against these modified HABPs were able to recognize both the native parasite protein by immunofluorescence assay and the recombinant protein (expressed in Escherichia coli) by Western blot and ELISA assays. The results suggested that these modified HABPs could be promising targets in designing a fully effective, antimalarial vaccine.
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38
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Chen L, Lopaticki S, Riglar DT, Dekiwadia C, Uboldi AD, Tham WH, O'Neill MT, Richard D, Baum J, Ralph SA, Cowman AF. An EGF-like protein forms a complex with PfRh5 and is required for invasion of human erythrocytes by Plasmodium falciparum. PLoS Pathog 2011; 7:e1002199. [PMID: 21909261 PMCID: PMC3164636 DOI: 10.1371/journal.ppat.1002199] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Accepted: 06/24/2011] [Indexed: 11/28/2022] Open
Abstract
Invasion of erythrocytes by Plasmodium falciparum involves a complex cascade of protein-protein interactions between parasite ligands and host receptors. The reticulocyte binding-like homologue (PfRh) protein family is involved in binding to and initiating entry of the invasive merozoite into erythrocytes. An important member of this family is PfRh5. Using ion-exchange chromatography, immunoprecipitation and mass spectroscopy, we have identified a novel cysteine-rich protein we have called P. falciparumRh5 interacting protein (PfRipr) (PFC1045c), which forms a complex with PfRh5 in merozoites. Mature PfRipr has a molecular weight of 123 kDa with 10 epidermal growth factor-like domains and 87 cysteine residues distributed along the protein. In mature schizont stages this protein is processed into two polypeptides that associate and form a complex with PfRh5. The PfRipr protein localises to the apical end of the merozoites in micronemes whilst PfRh5 is contained within rhoptries and both are released during invasion when they form a complex that is shed into the culture supernatant. Antibodies to PfRipr1 potently inhibit merozoite attachment and invasion into human red blood cells consistent with this complex playing an essential role in this process. The malaria parasite invades red blood cells by binding to proteins on the surface of this host cell. A family of proteins called P. falciparum reticulocyte binding-like homologue (PfRh) proteins are important for recognition of the red blood cell and activation of the invasion process. An important member of the PfRh family is PfRh5. We have identified a novel cysteine-rich protein we have called P. falciparumRh5 interacting protein (PfRipr), which forms a complex with PfRh5 in merozoites. PfRipr has 10 epidermal growth factor-like domains and is expressed in mature schizont stages where it is processed into two polypeptides that associate and form a complex with PfRh5. The PfRipr protein localises to the apical end of the merozoites in micronemes whilst PfRh5 is contained within rhoptries and both are released during invasion when they form a complex that is released into the culture supernatant. Antibodies to PfRipr1 can potently inhibit merozoite attachment and invasion into human red blood cells consistent with this complex playing an essential role in this process.
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Affiliation(s)
- Lin Chen
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Australia
| | - Sash Lopaticki
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - David T. Riglar
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Australia
| | - Chaitali Dekiwadia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Sciences and Biotechnology Institute, University of Melbourne, Melbourne, Australia
| | - Alex D. Uboldi
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Wai-Hong Tham
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Australia
| | - Matthew T. O'Neill
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Dave Richard
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Jake Baum
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Australia
| | - Stuart A. Ralph
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Sciences and Biotechnology Institute, University of Melbourne, Melbourne, Australia
| | - Alan F. Cowman
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Australia
- * E-mail:
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Grüber A, Gunalan K, Ramalingam JK, Manimekalai MSS, Grüber G, Preiser PR. Structural characterization of the erythrocyte binding domain of the reticulocyte binding protein homologue family of Plasmodium yoelii. Infect Immun 2011; 79:2880-8. [PMID: 21482683 PMCID: PMC3191949 DOI: 10.1128/iai.01326-10] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Accepted: 03/28/2011] [Indexed: 11/20/2022] Open
Abstract
Invasion of the host cell by the malaria parasite is a key step for parasite survival and the only stage of its life cycle where the parasite is extracellular, and it is therefore a target for an antimalaria intervention strategy. Multiple members of the reticulocyte binding protein homologues (RH) family are found in all plasmodia and have been shown to bind to host red blood cells directly. In the study described here, we delineated the erythrocyte binding domain (EBD) of one member of the RH family, termed Py235, from Plasmodium yoelii. Moreover, we have obtained the low-resolution structure of the EBD using small-angle X-ray scattering. Comparison of the EDB structure to other characterized Plasmodium receptor binding domains suggests that there may be an overall structural conservation. These findings may help in developing new approaches to target receptor ligand interactions mediated by parasite proteins.
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Affiliation(s)
- Ardina Grüber
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Karthigayan Gunalan
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Jeya Kumar Ramalingam
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | | | - Gerhard Grüber
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Peter R. Preiser
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
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Differences in erythrocyte receptor specificity of different parts of the Plasmodium falciparum reticulocyte binding protein homologue 2a. Infect Immun 2011; 79:3421-30. [PMID: 21628513 DOI: 10.1128/iai.00201-11] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Plasmodium falciparum reticulocyte-binding-like protein homologue (RH) and erythrocyte binding-like (EBL) protein families play important roles during invasion, though their exact roles are not clear. Both EBL and RH proteins are thought to directly bind different receptors on the surface of the erythrocyte, and the binding properties for a number of EBLs and RHs have been described. While P. falciparum RH1 (PfRH1) and PfRH4 have been shown to act directly in two alternative invasion pathways used by merozoites, the functions of PfRH2a and PfRH2b during invasion are less defined. Here, using monoclonal antibodies raised against a unique region of PfRH2a, we show that PfRH2a moves from the rhoptry neck to the moving junction during merozoite invasion. The movement of PfRH2a to the junction is independent of the invasion pathway used by the merozoite, suggesting an additional function of the protein that is independent of receptor binding. We further show that PfRH2a is processed both in the schizont and during invasion, resulting in proteins with different erythrocyte binding properties. Our findings suggest that PfRH2a and, most likely, the other members of the RH family, depending on their processing stage, can engage different receptors at different stages of the invasion process.
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Bapat D, Huang X, Gunalan K, Preiser PR. Changes in parasite virulence induced by the disruption of a single member of the 235 kDa rhoptry protein multigene family of Plasmodium yoelii. PLoS One 2011; 6:e20170. [PMID: 21625465 PMCID: PMC3098881 DOI: 10.1371/journal.pone.0020170] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Accepted: 04/26/2011] [Indexed: 11/18/2022] Open
Abstract
Invasion of the erythrocyte by the merozoites of the malaria parasite is a
complex process involving a range of receptor-ligand interactions. Two protein
families termed Erythrocyte Binding Like (EBL) proteins and Reticulocyte Binding
Protein Homologues (RH) play an important role in host cell recognition by the
merozoite. In the rodent malaria parasite, Plasmodium yoelii,
the 235 kDa rhoptry proteins (Py235) are coded for by a multigene family and are
members of the RH. In P. yoelii Py235 as well as a single
member of EBL have been shown to be key mediators of virulence enabling the
parasite to invade a wider range of host erythrocytes. One member of Py235,
PY01365 is most abundantly transcribed in parasite
populations and the protein specifically binds to erythrocytes and is recognized
by the protective monoclonal antibody 25.77, suggesting a key role of this
particular member in virulence. Recent studies have indicated that overall
levels of Py235 expression are essential for parasite virulence. Here we show
that disruption of PY01365 in the virulent YM line directly
impacts parasite virulence. Furthermore the disruption of
PY01365 leads to a reduction in the number of schizonts
that express members of Py235 that react specifically with the mcAb 25.77.
Erythrocyte binding assays show reduced binding of Py235 to red blood cells in
the PY01365 knockout parasite as compared to YM. While our
results identify PY01365 as a mediator of parasite virulence,
they also confirm that other members of Py235 are able to substitute for
PY01365.
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Affiliation(s)
- Devaki Bapat
- School of Biological Sciences, Nanyang Technological University,
Singapore, Singapore
| | - Ximei Huang
- School of Biological Sciences, Nanyang Technological University,
Singapore, Singapore
| | - Karthigayan Gunalan
- School of Biological Sciences, Nanyang Technological University,
Singapore, Singapore
| | - Peter R. Preiser
- School of Biological Sciences, Nanyang Technological University,
Singapore, Singapore
- * E-mail:
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Plasmodium falciparum reticulocyte binding-like homologue protein 2 (PfRH2) is a key adhesive molecule involved in erythrocyte invasion. PLoS One 2011; 6:e17102. [PMID: 21386888 PMCID: PMC3046117 DOI: 10.1371/journal.pone.0017102] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Accepted: 01/20/2011] [Indexed: 11/19/2022] Open
Abstract
Erythrocyte invasion by Plasmodium merozoites is a complex, multistep process that is mediated by a number of parasite ligand-erythrocyte receptor interactions. One such family of parasite ligands includes the P. falciparum reticulocyte binding homologue (PfRH) proteins that are homologous with the P. vivax reticulocyte binding proteins and have been shown to play a role in erythrocyte invasion. There are five functional PfRH proteins of which only PfRH2a/2b have not yet been demonstrated to bind erythrocytes. In this study, we demonstrated that native PfRH2a/2b is processed near the N-terminus yielding fragments of 220 kDa and 80 kDa that exhibit differential erythrocyte binding specificities. The erythrocyte binding specificity of the 220 kDa processed fragment of native PfRH2a/2b was sialic acid-independent, trypsin resistant and chymotrypsin sensitive. This specific binding phenotype is consistent with previous studies that disrupted the PfRH2a/2b genes and demonstrated that PfRH2b is involved in a sialic acid independent, trypsin resistant, chymotrypsin sensitive invasion pathway. Interestingly, we found that the smaller 80 kDa PfRH2a/2b fragment is processed from the larger 220 kDa fragment and binds erythrocytes in a sialic acid dependent, trypsin resistant and chymotrypsin sensitive manner. Thus, the two processed fragments of PfRH2a/2b differed with respect to their dependence on sialic acids for erythrocyte binding. Further, we mapped the erythrocyte binding domain of PfRH2a/2b to a conserved 40 kDa N-terminal region (rPfRH240) in the ectodomain that is common to both PfRH2a and PfRH2b. We demonstrated that recombinant rPfRH240 bound human erythrocytes with the same specificity as the native 220 kDa processed protein. Moreover, antibodies generated against rPfRH240 blocked erythrocyte invasion by P. falciparum through a sialic acid independent pathway. PfRH2a/2b thus plays a key role in erythrocyte invasion and its conserved receptor-binding domain deserves attention as a promising candidate for inclusion in a blood-stage malaria vaccine.
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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.
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44
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Boulanger MJ, Tonkin ML, Crawford J. Apicomplexan parasite adhesins: novel strategies for targeting host cell carbohydrates. Curr Opin Struct Biol 2010; 20:551-9. [DOI: 10.1016/j.sbi.2010.08.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Revised: 07/27/2010] [Accepted: 08/12/2010] [Indexed: 11/25/2022]
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Githui EK, Peterson DS, Aman RA, Abdi AI. Prevalence of 5' insertion mutants and analysis of single nucleotide polymorphism in the erythrocyte binding-like 1 (ebl-1) gene in Kenyan Plasmodium falciparum field isolates. INFECTION GENETICS AND EVOLUTION 2009; 10:834-9. [PMID: 19879379 DOI: 10.1016/j.meegid.2009.10.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2009] [Revised: 10/14/2009] [Accepted: 10/20/2009] [Indexed: 11/19/2022]
Abstract
Plasmodium merozoites attach to and invade red blood cells (RBCs) during the erythrocytic cycle. The invasion process requires recognition of RBC surface receptors by proteins of the Plasmodium Duffy binding like erythrocyte binding like (DBL-EBP) family. Clones and isolates of Plasmodium falciparum have varying abilities to utilize different RBC receptors, and multiple distinct pathways so far identified depend on glycophorins A, B, C, and as yet unidentified receptors. At present, five members of the DBL-EBP family have been identified in the P. falciparum genome, based on gene structure and amino acid sequence homology. The cardinal features of this family consist of conserved 5' and 3' cysteine-rich regions (regions II and VI, respectively) whose cysteine residues are highly conserved along with the majority of aromatic amino acids. In contrast to the single DBL-EBP family member in Plasmodium vivax, in P. falciparum all DBL-EBP family members have a duplication of the conserved 5' cysteine-rich region denoted as the F1 and F2 domains. These cysteine-rich regions are considered crucial in recognition of erythrocyte receptors and it has been shown that several bind to glycophorins on the erythrocyte surface. Several studies, on both field isolates and laboratory strains have uncovered a relatively high degree of sequence polymorphism in the DBP-EBL genes. This study is now extended to include field isolates collected from sites within Kenya. DNA isolated from blood samples of infected patients was utilized to amplify the region I sequence of ebl-1 gene in order to investigate polymorphism in the region immediately adjacent to the 5' cysteine-rich domains, and to determine the prevalence of an insertion mutant that effectively knocks out the gene.
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Affiliation(s)
- Elijah K Githui
- Molecular Genetics Laboratory, National Museums of Kenya, PO Box 40658, Nairobi, Kenya.
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46
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Wellems TE, Hayton K, Fairhurst RM. The impact of malaria parasitism: from corpuscles to communities. J Clin Invest 2009; 119:2496-505. [PMID: 19729847 DOI: 10.1172/jci38307] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Malaria continues to exert a tremendous health burden on human populations, reflecting astonishingly successful adaptations of the causative Plasmodium parasites. We discuss here how this burden has driven the natural selection of numerous polymorphisms in the genes encoding hemoglobin and other erythrocyte proteins and some effectors of immunity. Plasmodium falciparum, the most deadly parasite species in humans, displays a vigorous system of antigen variation to counter host defenses and families of functionally redundant ligands to invade human cells. Advances in genetics and genomics are providing fresh insights into the nature of these evolutionary adaptations, processes of parasite transmission and infection, and the difficult challenges of malaria control.
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Affiliation(s)
- Thomas E Wellems
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland 20892-8132, USA.
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Wilder JA, Hewett EK, Gansner ME. Molecular evolution of GYPC: evidence for recent structural innovation and positive selection in humans. Mol Biol Evol 2009; 26:2679-87. [PMID: 19679754 PMCID: PMC2775107 DOI: 10.1093/molbev/msp183] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
GYPC encodes two erythrocyte surface sialoglycoproteins in humans, glycophorin C and glycophorin D (GPC and GPD), via initiation of translation at two start codons on a single transcript. The malaria-causing parasite Plasmodium falciparum uses GPC as a means of invasion into the human red blood cell. Here, we examine the molecular evolution of GYPC among the Hominoidea (Greater and Lesser Apes) and also the pattern of polymorphism at the locus in a global human sample. We find an excess of nonsynonymous divergence among species that appears to be caused solely by accelerated evolution of GYPC in the human lineage. Moreover, we find that the ability of GYPC to encode both GPC and GPD is a uniquely human trait, caused by the evolution of the GPC start codon in the human lineage. The pattern of polymorphism among humans is consistent with a hitchhiking event at the locus, suggesting that positive natural selection affected GYPC in the relatively recent past. Because GPC is exploited by P. falciparum for invasion of the red blood cell, we hypothesize that selection for evasion of P. falciparum has caused accelerated evolution of GYPC in humans (relative to other primates) and that this positive selection has continued to act in the recent evolution of our species. These data suggest that malaria has played a powerful role in shaping molecules on the surface of the human red blood cell. In addition, our examination of GYPC reveals a novel mechanism of protein evolution: co-option of untranslated region (UTR) sequence following the formation of a new start codon. In the case of human GYPC, the ancestral protein (GPD) continues to be produced through leaky translation. Because leaky translation is a widespread phenomenon among genes and organisms, we suggest that co-option of UTR sequence may be an important source of protein innovation.
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Affiliation(s)
- Jason A Wilder
- Department of Biological Sciences, Northern Arizona University, USA.
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48
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Jiang L, Duriseti S, Sun P, Miller LH. Molecular basis of binding of the Plasmodium falciparum receptor BAEBL to erythrocyte receptor glycophorin C. Mol Biochem Parasitol 2009; 168:49-54. [PMID: 19563830 DOI: 10.1016/j.molbiopara.2009.06.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Revised: 06/10/2009] [Accepted: 06/21/2009] [Indexed: 10/20/2022]
Abstract
Plasmodium falciparum invades human erythrocytes by redundant pathways. Unlike Plasmodium vivax that has one Duffy Binding-Like (DBL) receptor, P. falciparum has four members of the DBL receptor family. Furthermore, one of these DBL genes, BAEBL, has polymorphisms at four amino acids in region II; each polymorphism binds to a different erythrocyte receptor. One BAEBL variant (VSTK) binds specifically to erythrocyte glycophorin C and binds poorly to neuraminidase-treated erythrocytes. When the amino acid threonine (T121) in BAEBL (VSTK) is changed to a lysine (VSKK), it no longer requires sialic acid as a receptor. To explore the molecular basis of sialic acid binding, we modeled the structure of region II of BAEBL (VSTK) on the crystal structure of a related DBL receptor, region II of erythrocyte binding antigen-175 (EBA-175). Four charged amino acids, R52, R114, E54 and D125, are predicted to surround T121 in BAEBL (VSTK). They were individually mutated to alanine (R52A, R114A, E54A, and D125A) or lysine (R52K, R114K) and expressed on the surface of Chinese hamster ovary (CHO-K1) cells. BAEBL (VSTK) with mutations in R52 or R114 of BAEBL (VSTK) bound neuraminidase-treated erythrocytes. Unlike the arginine mutations, E54A and D125A still bound poorly to neuraminidase-treated erythrocytes. These findings suggest that the two arginine residues surrounding T121 are critical for the binding specificity of BAEBL (VSTK) to sialic acid and suggest a role for arginine in sialic acid binding independent of its negative charge.
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Affiliation(s)
- Lubin Jiang
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12735 Twinbrook Parkway, Bethesda, MD 20892-8132, USA
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Chokejindachai W, Conway DJ. Case-control approach to identify Plasmodium falciparum polymorphisms associated with severe malaria. PLoS One 2009; 4:e5454. [PMID: 19421327 PMCID: PMC2674215 DOI: 10.1371/journal.pone.0005454] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Accepted: 04/08/2009] [Indexed: 11/19/2022] Open
Abstract
Background Studies to identify phenotypically-associated polymorphisms in the Plasmodium falciparum 23 Mb genome will require a dense array of marker loci. It was considered promising to undertake initial allelic association studies to prospect for virulence polymorphisms in Thailand, as the low endemicity would allow higher levels of linkage disequilibrium (LD) than would exist in more highly endemic areas. Methodology/Principal Findings Assessment of LD was first made with 11 microsatellite loci widely dispersed in the parasite genome, and 16 microsatellite loci covering a ∼140 kb region of chromosome 2 (an arbitrarily representative non-telomeric part of the genome), in a sample of 100 P. falciparum isolates. The dispersed loci showed minimal LD (Index of Association, ISA = 0.013, P = 0.10), while those on chromosome 2 showed significant LD values mostly between loci <5 kb apart. A disease association study was then performed comparing parasites in 113 severe malaria cases and 245 mild malaria controls. Genotyping was performed on almost all polymorphisms in the binding domains of three erythrocyte binding antigens (eba175, eba140 and eba181), and repeat sequence polymorphisms ∼2 kb apart in each of three reticulocyte binding homologues (Rh1, Rh2a/b, and Rh4). Differences between cases and controls were seen for (i) codons 388-90 in eba175, and (ii) a repeat sequence centred on Rh1 codon 667. Conclusions/Significance Allelic association studies on P. falciparum require dense genotypic markers, even in a population of only moderate endemicity that has more extensive LD than highly endemic populations. Disease-associated polymorphisms in the eba175 and Rh1 genes encode differences in the middle of previously characterised erythrocyte binding domains, marking these for further investigation.
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Affiliation(s)
- Watcharee Chokejindachai
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Department of Tropical Pediatrics, Faculty of Medicine, Mahidol University, Bangkok, Thailand
| | - David J. Conway
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Medical Research Council Laboratories, Fajara, Banjul, The Gambia
- * E-mail:
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50
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Glycophorin B is the erythrocyte receptor of Plasmodium falciparum erythrocyte-binding ligand, EBL-1. Proc Natl Acad Sci U S A 2009; 106:5348-52. [PMID: 19279206 DOI: 10.1073/pnas.0900878106] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In the war against Plasmodium, humans have evolved to eliminate or modify proteins on the erythrocyte surface that serve as receptors for parasite invasion, such as the Duffy blood group, a receptor for Plasmodium vivax, and the Gerbich-negative modification of glycophorin C for Plasmodium falciparum. In turn, the parasite counters with expansion and diversification of ligand families. The high degree of polymorphism in glycophorin B found in malaria-endemic regions suggests that it also may be a receptor for Plasmodium, but, to date, none has been identified. We provide evidence from erythrocyte-binding that glycophorin B is a receptor for the P. falciparum protein EBL-1, a member of the Duffy-binding-like erythrocyte-binding protein (DBL-EBP) receptor family. The erythrocyte-binding domain, region 2 of EBL-1, expressed on CHO-K1 cells, bound glycophorin B(+) but not glycophorin B-null erythrocytes. In addition, glycophorin B(+) but not glycophorin B-null erythrocytes adsorbed native EBL-1 from the P. falciparum culture supernatants. Interestingly, the Efe pygmies of the Ituri forest in the Democratic Republic of the Congo have the highest gene frequency of glycophorin B-null in the world, raising the possibility that the DBL-EBP family may have expanded in response to the high frequency of glycophorin B-null in the population.
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