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Bustamante LY, Bartholdson SJ, Crosnier C, Campos MG, Wanaguru M, Nguon C, Kwiatkowski DP, Wright GJ, Rayner JC. A full-length recombinant Plasmodium falciparum PfRH5 protein induces inhibitory antibodies that are effective across common PfRH5 genetic variants. Vaccine 2013; 31:373-9. [PMID: 23146673 PMCID: PMC3538003 DOI: 10.1016/j.vaccine.2012.10.106] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Revised: 10/19/2012] [Accepted: 10/30/2012] [Indexed: 12/20/2022]
Abstract
The lack of an effective licensed vaccine remains one of the most significant gaps in the portfolio of tools being developed to eliminate Plasmodium falciparum malaria. Vaccines targeting erythrocyte invasion - an essential step for both parasite development and malaria pathogenesis - have faced the particular challenge of genetic diversity. Immunity-driven balancing selection pressure on parasite invasion proteins often results in the presence of multiple, antigenically distinct, variants within a population, leading to variant-specific immune responses. Such variation makes it difficult to design a vaccine that covers the full range of diversity, and could potentially facilitate the evolution of vaccine-resistant parasite strains. In this study, we investigate the effect of genetic diversity on invasion inhibition by antibodies to a high priority P. falciparum invasion candidate antigen, P. falciparum Reticulocyte Binding Protein Homologue 5 (PfRH5). Previous work has shown that virally delivered PfRH5 can induce antibodies that protect against a wide range of genetic variants. Here, we show that a full-length recombinant PfRH5 protein expressed in mammalian cells is biochemically active, as judged by saturable binding to its receptor, basigin, and is able to induce antibodies that strongly inhibit P. falciparum growth and invasion. Whole genome sequencing of 290 clinical P. falciparum isolates from across the world identifies only five non-synonymous PfRH5 SNPs that are present at frequencies of 10% or more in at least one geographical region. Antibodies raised against the 3D7 variant of PfRH5 were able to inhibit nine different P. falciparum strains, which between them included all of the five most common PfRH5 SNPs in this dataset, with no evidence for strain-specific immunity. We conclude that protein-based PfRH5 vaccines are an urgent priority for human efficacy trials.
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Affiliation(s)
- Leyla Y. Bustamante
- Malaria Programme, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - S. Josefin Bartholdson
- Malaria Programme, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom
- Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - Cecile Crosnier
- Malaria Programme, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom
- Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - Marta G. Campos
- Malaria Programme, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - Madushi Wanaguru
- Malaria Programme, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom
- Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - Chea Nguon
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Dominic P. Kwiatkowski
- Malaria Programme, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - Gavin J. Wright
- Malaria Programme, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom
- Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - Julian C. Rayner
- Malaria Programme, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom
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Grüber A, Manimekalai MS, Preiser PR, Grüber G. Structural architecture and interplay of the nucleotide- and erythrocyte binding domain of the reticulocyte binding protein Py235 from Plasmodium yoelii. Int J Parasitol 2012; 42:1083-9. [DOI: 10.1016/j.ijpara.2012.07.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 06/18/2012] [Accepted: 07/06/2012] [Indexed: 10/28/2022]
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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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Muramatsu T. Basigin: a multifunctional membrane protein with an emerging role in infections by malaria parasites. Expert Opin Ther Targets 2012; 16:999-1011. [PMID: 22880881 DOI: 10.1517/14728222.2012.711818] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
INTRODUCTION Malaria is one of the most serious infectious diseases at the beginning of the twenty-first century. Various membrane proteins are present in Plasmodium falciparum, the principal malaria pathogen. Among them, P. falciparum reticulocyte-binding protein homolog 5 (PfRh5) is indispensable for erythrocyte invasion, and has become a promising vaccine target. Basigin (CD147, EMMPRIN) has been identified as the erythrocyte receptor of PfRh5, and shown to be essential for the invasion of multiple strains of the pathogen. AREAS COVERED Fundamental information on basigin is fully described, including structure as a member of the immunoglobulin superfamily and function based on its interactions with external molecules and with proteins within the same membrane. The involvement of basigin in many diseases such as cancer and inflammatory diseases is also described, the implication being that anti-basigin therapy might be helpful to treat certain illnesses. Finally, PfRh5 as a vaccine candidate is covered, and its interaction with basigin is evaluated. EXPERT OPINION The identification of basigin, a well-characterized membrane protein, as a receptor essential for malaria infection will contribute significantly to prevention and treatment of malaria. As an example, anti-basigin therapy can be considered an alternative approach to the treatment of drug-resistant malaria.
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Affiliation(s)
- Takashi Muramatsu
- Aichi Gakuin University, Faculty of Psychological and Physical Science, Department of Health Science, 12 Araike, Iwasaki-cho, Nisshin, Aichi 470-0195, Japan.
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Semenya AA, Tran TM, Meyer EV, Barnwell JW, Galinski MR. Two functional reticulocyte binding-like (RBL) invasion ligands of zoonotic Plasmodium knowlesi exhibit differential adhesion to monkey and human erythrocytes. Malar J 2012; 11:228. [PMID: 22770469 PMCID: PMC3464698 DOI: 10.1186/1475-2875-11-228] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 07/06/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Plasmodium knowlesi is a monkey malaria species that is becoming a serious public health concern infecting hundreds and perhaps thousands of humans in Southeast Asia. Invasion of erythrocytes by merozoites entails a cascade of molecular interactions. One step involves the adhesion of Plasmodium reticulocyte binding-like (RBL) proteins. Plasmodium knowlesi merozoites express only two RBL invasion ligands, known as Normocyte Binding Proteins (PkNBPXa and PkNBPXb). METHODS Overlapping N-terminal regions of PkNBPXa and PkNBPXb were expressed in COS7 cells and tested for surface expression and adhesion to rhesus monkey erythrocytes. Subsequent tests to study specific receptor ligand interactions included adhesion to a panel of human and non-human primate erythrocytes, enzymatic treatment, and site directed mutagenesis. RESULTS An N-terminal cysteine-rich region of PkNBPXb (PkNBPXb-II) exhibited specific adhesion to rhesus monkey erythrocytes. Mutation of four of five cysteines in PkNBPXb-II interfered with its surface expression on COS7 cells, suggesting disulphide bond conformation is critical for intracellular trafficking. Binding of PkNBPXb-II was abolished when rhesus erythrocytes were pre-treated with chymotrypsin, but not trypsin or neuraminidase. PkNBPXb-II also bound other Old World monkey species and gibbon erythrocytes. However, erythrocytes from other primate species including humans did not bind to PkNBPXb-II or native PkNBPXb. Importantly, unlike PkNBPXb, PkNBPXa bound human erythrocytes, and this binding was independent of the Duffy blood group determinant. CONCLUSIONS The data reported here begins to clarify the functional domains of the P. knowlesi RBLs. A binding domain has been identified and characterized in PkNBPXb. Notably, this study demonstrates that unlike PkNBPXb, PkNBPXa can bind to human erythrocytes, suggesting that PkNBPXa may function as a ligand to enable the invasion of P. knowlesi merozoites into human cells.
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Affiliation(s)
- Amma A Semenya
- Emory Vaccine Center and Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
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56
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Vaughan AM, Kappe SHI. Malaria vaccine development: persistent challenges. Curr Opin Immunol 2012; 24:324-31. [DOI: 10.1016/j.coi.2012.03.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Accepted: 03/26/2012] [Indexed: 12/25/2022]
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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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58
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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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The blood-stage malaria antigen PfRH5 is susceptible to vaccine-inducible cross-strain neutralizing antibody. Nat Commun 2011; 2:601. [PMID: 22186897 DOI: 10.1038/ncomms1615] [Citation(s) in RCA: 198] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Accepted: 11/28/2011] [Indexed: 11/08/2022] Open
Abstract
Current vaccine strategies against the asexual blood stage of Plasmodium falciparum are mostly focused on well-studied merozoite antigens that induce immune responses after natural exposure, but have yet to induce robust protection in any clinical trial. Here we compare human-compatible viral-vectored vaccines targeting ten different blood-stage antigens. We show that the full-length P. falciparum reticulocyte-binding protein homologue 5 (PfRH5) is highly susceptible to cross-strain neutralizing vaccine-induced antibodies, out-performing all other antigens delivered by the same vaccine platform. We find that, despite being susceptible to antibody, PfRH5 is unlikely to be under substantial immune selection pressure; there is minimal acquisition of anti-PfRH5 IgG antibodies in malaria-exposed Kenyans. These data challenge the widespread beliefs that any merozoite antigen that is highly susceptible to immune attack would be subject to significant levels of antigenic polymorphism, and that erythrocyte invasion by P. falciparum is a degenerate process involving a series of parallel redundant pathways.
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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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61
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Crosnier C, Bustamante LY, Bartholdson SJ, Bei AK, Theron M, Uchikawa M, Mboup S, Ndir O, Kwiatkowski DP, Duraisingh MT, Rayner JC, Wright GJ. Basigin is a receptor essential for erythrocyte invasion by Plasmodium falciparum. Nature 2011; 480:534-7. [PMID: 22080952 PMCID: PMC3245779 DOI: 10.1038/nature10606] [Citation(s) in RCA: 468] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 10/03/2011] [Indexed: 12/11/2022]
Abstract
Erythrocyte invasion by Plasmodium falciparum is central to the pathogenesis of malaria. Invasion requires a series of extracellular recognition events between erythrocyte receptors and ligands on the merozoite, the invasive form of the parasite. None of the few known receptor-ligand interactions involved are required in all parasite strains, indicating that the parasite is able to access multiple redundant invasion pathways. Here, we show that we have identified a receptor-ligand pair that is essential for erythrocyte invasion in all tested P. falciparum strains. By systematically screening a library of erythrocyte proteins, we have found that the Ok blood group antigen, basigin, is a receptor for PfRh5, a parasite ligand that is essential for blood stage growth. Erythrocyte invasion was potently inhibited by soluble basigin or by basigin knockdown, and invasion could be completely blocked using low concentrations of anti-basigin antibodies; importantly, these effects were observed across all laboratory-adapted and field strains tested. Furthermore, Ok(a-) erythrocytes, which express a basigin variant that has a weaker binding affinity for PfRh5, had reduced invasion efficiencies. Our discovery of a cross-strain dependency on a single extracellular receptor-ligand pair for erythrocyte invasion by P. falciparum provides a focus for new anti-malarial therapies.
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Affiliation(s)
- Cécile Crosnier
- Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1HH, UK
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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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63
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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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65
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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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66
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Reiling L, Richards JS, Fowkes FJI, Barry AE, Triglia T, Chokejindachai W, Michon P, Tavul L, Siba PM, Cowman AF, Mueller I, Beeson JG. Evidence that the erythrocyte invasion ligand PfRh2 is a target of protective immunity against Plasmodium falciparum malaria. THE JOURNAL OF IMMUNOLOGY 2010; 185:6157-67. [PMID: 20962255 DOI: 10.4049/jimmunol.1001555] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Abs targeting blood-stage Ags of Plasmodium falciparum are important in acquired immunity to malaria, but major targets remain unclear. The P. falciparum reticulocyte-binding homologs (PfRh) are key ligands used by merozoites during invasion of erythrocytes. PfRh2a and PfRh2b are functionally important members of this family and may be targets of protective immunity, but their potential role in human immunity has not been examined. We expressed eight recombinant proteins covering the entire PfRh2 common region, as well as PfRh2a- and PfRh2b-specific regions. Abs were measured among a cohort of 206 Papua New Guinean children who were followed prospectively for 6 mo for reinfection and malaria. At baseline, Abs were associated with increasing age and active infection. High levels of IgG to all PfRh2 protein constructs were strongly associated with protection from symptomatic malaria and high-density parasitemia. The predominant IgG subclasses were IgG1 and IgG3, with little IgG2 and IgG4 detected. To further understand the significance of PfRh2 as an immune target, we analyzed PfRh2 sequences and found that polymorphisms are concentrated in an N-terminal region of the protein and seem to be under diversifying selection, suggesting immune pressure. Cluster analysis arranged the sequences into two main groups, suggesting that many of the haplotypes identified may be antigenically similar. These findings provide evidence suggesting that PfRh2 is an important target of protective immunity in humans and that Abs act by controlling blood-stage parasitemia and support its potential for vaccine development.
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Affiliation(s)
- Linda Reiling
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
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67
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Dvorin JD, Bei AK, Coleman BI, Duraisingh MT. Functional diversification between two related Plasmodium falciparum merozoite invasion ligands is determined by changes in the cytoplasmic domain. Mol Microbiol 2010; 75:990-1006. [PMID: 20487292 DOI: 10.1111/j.1365-2958.2009.07040.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The pathogenesis of Plasmodium falciparum depends on efficient invasion into host erythrocytes. Parasite ligands encoded by multi-gene families interact with erythrocyte receptors. P. falciparum reticulocyte binding protein homologues (PfRhs) are expressed at the apical surface of invasive merozoites and have divergent ectodomains that are postulated to bind different erythrocyte receptors. Variant expression of these paralogues results in the use of alternative invasion pathways. Two PfRh proteins, PfRh2a and PfRh2b, are identical for 2700 N-terminal amino acids and differ only in a C-terminal 500 amino acid region, which includes a unique ectodomain, transmembrane domain and cytoplasmic domain. Despite their similarity, PfRh2b is required for a well-defined invasion pathway while PfRh2a is not required or sufficient for this pathway. Mapping the genomic region encoding these proteins revealed a recombinogenic locus with PfRh2a and PfRh2b in a head-to-head orientation. We have generated viable PfRh2a/2b chimeric parasites to identify the regions required for alternative invasion pathway utilization. We find that the differential ability to use these pathways is conferred by the cytoplasmic domains of PfRh2a and PfRh2b, not the ectodomain or transmembrane regions. Our results highlight the importance of the cytoplasmic domain for functional diversification of a major adhesive ligand family in malaria parasites.
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Affiliation(s)
- Jeffrey D Dvorin
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA
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68
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Culleton R, Kaneko O. Erythrocyte binding ligands in malaria parasites: intracellular trafficking and parasite virulence. Acta Trop 2010; 114:131-7. [PMID: 19913491 DOI: 10.1016/j.actatropica.2009.10.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2009] [Revised: 10/19/2009] [Accepted: 10/28/2009] [Indexed: 10/20/2022]
Abstract
The intracellular trafficking of an Erythrocyte Binding Like (EBL) ligand has recently been shown to dramatically affect the multiplication rate and virulence of the rodent malaria parasite Plasmodium yoelii yoelii. In this review, we describe the current understanding of the role of EBL and other erythrocyte binding ligands in erythrocyte invasion, and discuss the mechanisms by which they may control multiplication rates and virulence in malaria parasites.
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69
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Proellocks NI, Coppel RL, Waller KL. Dissecting the apicomplexan rhoptry neck proteins. Trends Parasitol 2010; 26:297-304. [PMID: 20347614 DOI: 10.1016/j.pt.2010.02.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 11/13/2009] [Accepted: 02/26/2010] [Indexed: 10/19/2022]
Abstract
Apicomplexan parasites possess specialized secretory organelles (rhoptries and micronemes) that release their contents during host cell invasion. Although the rhoptries were once thought to be merely a bulbous 'protein reservoir' connected to an anterior neck region, the localization of a protein specifically to the neck suggested that this region was more than just a duct. Recent studies have shown that the rhoptry neck sub-compartment possesses a distinct protein repertoire. Some of these proteins share common features, including conservation across the phylum and involvement in tight-junction formation. A sub-group of rhoptry neck proteins, the RONs, their association with the microneme protein apical membrane antigen AMA1, and their involvement in invasion are discussed.
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70
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García J, Curtidor H, Pinzón CG, Patarroyo MA, Vanegas M, Forero M, Patarroyo ME. Well-Defined Regions of the Plasmodium falciparum Reticulocyte Binding Protein Homologue 4 Mediate Interaction with Red Blood Cell Membrane. J Med Chem 2009; 53:811-21. [DOI: 10.1021/jm901540n] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jeison García
- Fundación Instituto de Inmunología de Colombia FIDIC, Carrera 50 No. 26-20, Bogotá, Colombia
- Universidad del Rosario, Calle 14 No. 6-25, Bogotá, Colombia
| | - Hernando Curtidor
- Fundación Instituto de Inmunología de Colombia FIDIC, Carrera 50 No. 26-20, Bogotá, Colombia
- Universidad del Rosario, Calle 14 No. 6-25, Bogotá, Colombia
| | - Carlos G. Pinzón
- Fundación Instituto de Inmunología de Colombia FIDIC, Carrera 50 No. 26-20, Bogotá, Colombia
- Universidad del Rosario, Calle 14 No. 6-25, Bogotá, Colombia
| | - Manuel A. Patarroyo
- Fundación Instituto de Inmunología de Colombia FIDIC, Carrera 50 No. 26-20, Bogotá, Colombia
- Universidad del Rosario, Calle 14 No. 6-25, Bogotá, Colombia
| | - Magnolia Vanegas
- Fundación Instituto de Inmunología de Colombia FIDIC, Carrera 50 No. 26-20, Bogotá, Colombia
- Universidad del Rosario, Calle 14 No. 6-25, Bogotá, Colombia
| | - Martha Forero
- Fundación Instituto de Inmunología de Colombia FIDIC, Carrera 50 No. 26-20, Bogotá, Colombia
- Universidad del Rosario, Calle 14 No. 6-25, Bogotá, Colombia
| | - Manuel E. Patarroyo
- Fundación Instituto de Inmunología de Colombia FIDIC, Carrera 50 No. 26-20, Bogotá, Colombia
- Universidad Nacional de Colombia, Carrera 45 No. 26-85, Bogotá, Colombia
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71
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Antibodies to reticulocyte binding protein-like homologue 4 inhibit invasion of Plasmodium falciparum into human erythrocytes. Infect Immun 2009; 77:2427-35. [PMID: 19307208 DOI: 10.1128/iai.00048-09] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Plasmodium falciparum invasion into human erythrocytes relies on the interaction between multiple parasite ligands and their respective erythrocyte receptors. The sialic acid-independent invasion pathway is dependent on the expression of P. falciparum reticulocyte binding protein-like homologue 4 (PfRh4), as disruption of the gene abolishes the ability of parasites to switch to this pathway. We show that PfRh4 is present as an invasion ligand in culture supernatants as a 160-kDa proteolytic fragment. We confirm that PfRh4 binds to the surfaces of erythrocytes through recognition of an erythrocyte receptor that is neuraminidase resistant but trypsin and chymotrypsin sensitive. Serum antibodies from malaria-exposed individuals show reactivity against the binding domain of PfRh4. Purified immunoglobulin G raised in rabbits against the binding domain of PfRh4 blocked the binding of native PfRh4 to the surfaces of erythrocytes and inhibited erythrocyte invasion of parasites using sialic acid-independent invasion pathways and grown in neuraminidase-treated erythrocytes. Our results suggest PfRh4 is a potential vaccine candidate.
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72
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Meyer EVS, Semenya AA, Okenu DMN, Dluzewski AR, Bannister LH, Barnwell JW, Galinski MR. The reticulocyte binding-like proteins of P. knowlesi locate to the micronemes of merozoites and define two new members of this invasion ligand family. Mol Biochem Parasitol 2009; 165:111-21. [PMID: 19428658 DOI: 10.1016/j.molbiopara.2009.01.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Revised: 01/12/2009] [Accepted: 01/20/2009] [Indexed: 11/29/2022]
Abstract
Members of the reticulocyte binding-like protein (RBL) family are merozoite-expressed proteins hypothesized to be essential for effective invasion of host erythrocytes. Proteins of the RBL family were first defined as merozoite invasion ligands in Plasmodium vivax, and subsequently in Plasmodium falciparum and other malaria parasite species. Comparative studies are providing insights regarding the complexity and evolution of this family and the existence of possible functionally alternative members. Here, we report the experimental and bioinformatic characterization of two new rbl genes in the simian malaria parasite species Plasmodium knowlesi. Experimental analyses confirm that a P. knowlesi gene fragment orthologous to P. vivax reticulocyte binding protein-1 (pvrbp1) represents a highly degenerated pseudogene in the H strain as well as two other P. knowlesi strains. Our data also confirm that a gene orthologous to pvrbp2 is not present in the P. knowlesi genome. However, two very diverse but related functional rbl genes are present and are reported here as P. knowlesi normocyte binding protein Xa and Xb (pknbpxa and pknbpxb). Analysis of these two rbl genes in Southern hybridizations and BLAST searches established their relationship to newly identified members of the RBL family in P. vivax and other species of simian malaria. Rabbit antisera specific for recombinant PkNBPXa and PkNBPXb confirmed expression of the prospective high molecular weight proteins and localized these proteins to the apical end of merozoites. Their precise location, as determined by immuno-electron microscopy (IEM), was found to be within the microneme organelles. Importantly, PkNBPXa and PkNBPXb are shown here to bind to host erythrocytes, and discussion is centered on the importance of these proteins in host cell invasion.
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Affiliation(s)
- Esmeralda V S Meyer
- Emory Vaccine Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA
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73
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Rayner JC. The merozoite has landed: reticulocyte-binding-like ligands and the specificity of erythrocyte recognition. Trends Parasitol 2009; 25:104-6. [PMID: 19167927 DOI: 10.1016/j.pt.2008.11.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2008] [Revised: 11/21/2008] [Accepted: 11/25/2008] [Indexed: 11/16/2022]
Abstract
Plasmodium falciparum erythrocyte invasion depends on several imperfectly understood multiprotein families. Two recent papers have shifted our understanding of the P. falciparum reticulocyte-binding-like family to the level of individual amino acids by identifying an erythrocyte-binding domain in one ligand and showing that polymorphisms in another can change the species specificity of erythrocyte binding. Erythrocyte invasion might be even more complex and harder to target than previously thought.
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Affiliation(s)
- Julian C Rayner
- Sanger Institute Malaria Programme, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK.
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74
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Baum J, Chen L, Healer J, Lopaticki S, Boyle M, Triglia T, Ehlgen F, Ralph SA, Beeson JG, Cowman AF. Reticulocyte-binding protein homologue 5 - an essential adhesin involved in invasion of human erythrocytes by Plasmodium falciparum. Int J Parasitol 2008; 39:371-80. [PMID: 19000690 DOI: 10.1016/j.ijpara.2008.10.006] [Citation(s) in RCA: 185] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2008] [Accepted: 10/16/2008] [Indexed: 10/21/2022]
Abstract
Invasion of erythrocytes is a prerequisite in the life history of the malaria parasite. Members of the reticulocyte-binding homologue family (PfRh) have been implicated in the invasion process and in some cases have been shown to act as adhesins, binding to specific receptors on the erythrocyte surface. We have identified a further, putatively essential, PfRh family member in the most virulent human malaria Plasmodium falciparum, called PfRh5, which binds to an unknown class of glycosylated receptors on the erythrocyte surface. This protein is an atypical PfRh family member, being much smaller than others and lacking a transmembrane and cytosolic region at the C-terminus. This suggests it may be part of a functional protein complex. PfRh5 localises to the rhoptries in merozoites and follows the tight junction during the process of erythrocyte invasion. Furthermore, rabbit immune serum raised against a portion of the ecto-domain, inhibits parasite invasion in vitro. We hypothesise an essential role for the PfRh5 adhesin in erythrocyte selection and commitment to invasion. Given its small size, we believe PfRh5 may prove to be a valuable candidate for inclusion in a multi-component anti-malarial vaccine.
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Affiliation(s)
- Jake Baum
- Division of Infection and Immunity, The Walter & Eliza Hall Institute of Medical Research, Vic., Australia
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