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De Meulenaere K, Prajapati SK, Villasis E, Cuypers B, Kattenberg JH, Kasian B, Laman M, Robinson LJ, Gamboa D, Laukens K, Rosanas-Urgell A. Band 3–mediated Plasmodium vivax invasion is associated with transcriptional variation in PvTRAg genes. Front Cell Infect Microbiol 2022; 12:1011692. [PMID: 36250048 PMCID: PMC9563252 DOI: 10.3389/fcimb.2022.1011692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 09/09/2022] [Indexed: 11/13/2022] Open
Abstract
The Plasmodium vivax reticulocyte invasion process is still poorly understood, with only a few receptor-ligand interactions identified to date. Individuals with the Southeast Asian ovalocytosis (SAO) phenotype have a deletion in the band 3 protein on the surface of erythrocytes, and are reported to have a lower incidence of clinical P. vivax malaria. Based on this observation, band 3 has been put forward as a receptor for P. vivax invasion, although direct proof is still lacking. In this study, we combined functional ex vivo invasion assays and transcriptome sequencing to uncover a band 3–mediated invasion pathway in P. vivax and potential band 3 ligands. Invasion by P. vivax field isolates was 67%-71% lower in SAO reticulocytes compared with non-SAO reticulocytes. Reticulocyte invasion was decreased by 40% and 27%-31% when blocking with an anti-band 3 polyclonal antibody and a PvTRAg38 peptide, respectively. To identify new band 3 receptor candidates, we mRNA-sequenced schizont-stage isolates used in the invasion assays, and observed high transcriptional variability in multigene and invasion-related families. Transcriptomes of isolates with low or high dependency on band 3 for invasion were compared by differential expression analysis, which produced a list of band 3 ligand candidates with high representation of PvTRAg genes. Our ex vivo invasion assays have demonstrated that band 3 is a P. vivax invasion receptor and confirm previous in vitro studies showing binding between PvTRAg38 and band 3, although the lower and variable inhibition levels observed suggest the involvement of other ligands. By coupling transcriptomes and invasion phenotypes from the same isolates, we identified a list of band 3 ligand candidates, of which the overrepresented PvTRAg genes are the most promising for future research.
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Affiliation(s)
- Katlijn De Meulenaere
- Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp, Antwerp, Belgium
- Department of Computer Science, University of Antwerp, Antwerp, Belgium
- *Correspondence: Anna Rosanas-Urgell, ; Katlijn De Meulenaere,
| | - Surendra Kumar Prajapati
- Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp, Antwerp, Belgium
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Elizabeth Villasis
- Laboratorio de Malaria, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
- Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Bart Cuypers
- Department of Computer Science, University of Antwerp, Antwerp, Belgium
| | | | - Bernadine Kasian
- Vector-borne Diseases Unit, Papua New Guinea Institute for Medical Research, Madang, Papua New Guinea
| | - Moses Laman
- Vector-borne Diseases Unit, Papua New Guinea Institute for Medical Research, Madang, Papua New Guinea
| | - Leanne J. Robinson
- Vector-borne Diseases Unit, Papua New Guinea Institute for Medical Research, Madang, Papua New Guinea
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
- Health Security and Disease Elimination, Burnet Institute, Melbourne, VIC, Australia
| | - Dionicia Gamboa
- Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru
- Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Kris Laukens
- Department of Computer Science, University of Antwerp, Antwerp, Belgium
| | - Anna Rosanas-Urgell
- Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp, Antwerp, Belgium
- *Correspondence: Anna Rosanas-Urgell, ; Katlijn De Meulenaere,
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De SL, Ntumngia FB, Nicholas J, Adams JH. Progress towards the development of a P. vivax vaccine. Expert Rev Vaccines 2021; 20:97-112. [PMID: 33481638 PMCID: PMC7994195 DOI: 10.1080/14760584.2021.1880898] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 01/21/2021] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Plasmodium vivax causes significant public health problems in endemic regions. A vaccine to prevent disease is critical, considering the rapid spread of drug-resistant parasite strains, and the development of hypnozoites in the liver with potential for relapse. A minimally effective vaccine should prevent disease and transmission while an ideal vaccine provides sterile immunity. AREAS COVERED Despite decades of research, the complex life cycle, technical challenges and a lack of funding have hampered progress of P. vivax vaccine development. Here, we review the progress of potential P. vivax vaccine candidates from different stages of the parasite life cycle. We also highlight the challenges and important strategies for rational vaccine design. These factors can significantly increase immune effector mechanisms and improve the protective efficacy of these candidates in clinical trials to generate sustained protection over longer periods of time. EXPERT OPINION A vaccine that presents functionally-conserved epitopes from multiple antigens from various stages of the parasite life cycle is key to induce broadly neutralizing strain-transcending protective immunity to effectively disrupt parasite development and transmission.
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Affiliation(s)
- Sai Lata De
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Tampa – 33612, FL
| | - Francis B. Ntumngia
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Tampa – 33612, FL
| | - Justin Nicholas
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Tampa – 33612, FL
| | - John H. Adams
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Tampa – 33612, FL
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3
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Birget PLG, Schneider P, O’Donnell AJ, Reece SE. Adaptive phenotypic plasticity in malaria parasites is not constrained by previous responses to environmental change. EVOLUTION MEDICINE AND PUBLIC HEALTH 2019; 2019:190-198. [PMID: 31660151 PMCID: PMC6805783 DOI: 10.1093/emph/eoz028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 09/25/2019] [Indexed: 01/12/2023]
Abstract
Background and objectives Phenotypic plasticity enables organisms to maximize fitness by matching trait values to different environments. Such adaptive phenotypic plasticity is exhibited by parasites, which experience frequent environmental changes during their life cycle, between individual hosts and also in within-host conditions experienced during infections. Life history theory predicts that the evolution of adaptive phenotypic plasticity is limited by costs and constraints, but tests of these concepts are scarce. Methodology Here, we induce phenotypic plasticity in malaria parasites to test whether mounting a plastic response to an environmental perturbation constrains subsequent plastic responses to further environmental change. Specifically, we perturb red blood cell resource availability to induce Plasmodium chabaudi to alter the trait values of several phenotypes underpinning within-host replication and between-host transmission. We then transfer parasites to unperturbed hosts to examine whether constraints govern the parasites’ ability to alter these phenotypes in response to their new in-host environment. Results Parasites alter trait values in response to the within-host environment they are exposed to. We do not detect negative consequences, for within-host replication or between-host transmission, of previously mounting a plastic response to a perturbed within-host environment. Conclusions and implications We suggest that malaria parasites are highly plastic and adapted to adjusting their phenotypes in response to the frequent changes in the within-host conditions they experience during infections. Our findings support the growing body of evidence that medical interventions, such as anti-parasite drugs, induce plastic responses that are adaptive and can facilitate the survival and potentially, drug resistance of parasites. Lay Summary Malaria parasites have evolved flexible strategies to cope with the changing conditions they experience during infections. We show that using such flexible strategies does not impact upon the parasites’ ability to grow (resulting in disease symptoms) or transmit (spreading the disease).
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Affiliation(s)
- Philip L G Birget
- Institute of Evolutionary Biology and Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK
| | - Petra Schneider
- Institute of Evolutionary Biology and Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK
| | - Aidan J O’Donnell
- Institute of Evolutionary Biology and Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK
| | - Sarah E Reece
- Institute of Evolutionary Biology and Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK
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4
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Reid AJ, Talman AM, Bennett HM, Gomes AR, Sanders MJ, Illingworth CJR, Billker O, Berriman M, Lawniczak MK. Single-cell RNA-seq reveals hidden transcriptional variation in malaria parasites. eLife 2018; 7:33105. [PMID: 29580379 PMCID: PMC5871331 DOI: 10.7554/elife.33105] [Citation(s) in RCA: 130] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 03/04/2018] [Indexed: 12/18/2022] Open
Abstract
Single-cell RNA-sequencing is revolutionising our understanding of seemingly homogeneous cell populations but has not yet been widely applied to single-celled organisms. Transcriptional variation in unicellular malaria parasites from the Plasmodium genus is associated with critical phenotypes including red blood cell invasion and immune evasion, yet transcriptional variation at an individual parasite level has not been examined in depth. Here, we describe the adaptation of a single-cell RNA-sequencing (scRNA-seq) protocol to deconvolute transcriptional variation for more than 500 individual parasites of both rodent and human malaria comprising asexual and sexual life-cycle stages. We uncover previously hidden discrete transcriptional signatures during the pathogenic part of the life cycle, suggesting that expression over development is not as continuous as commonly thought. In transmission stages, we find novel, sex-specific roles for differential expression of contingency gene families that are usually associated with immune evasion and pathogenesis.
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Affiliation(s)
- Adam J Reid
- Malaria Programme, Wellcome Sanger Institute, Cambridge, United Kingdom
| | - Arthur M Talman
- Malaria Programme, Wellcome Sanger Institute, Cambridge, United Kingdom
| | - Hayley M Bennett
- Malaria Programme, Wellcome Sanger Institute, Cambridge, United Kingdom
| | - Ana R Gomes
- Malaria Programme, Wellcome Sanger Institute, Cambridge, United Kingdom
| | - Mandy J Sanders
- Malaria Programme, Wellcome Sanger Institute, Cambridge, United Kingdom
| | | | - Oliver Billker
- Malaria Programme, Wellcome Sanger Institute, Cambridge, United Kingdom
| | - Matthew Berriman
- Malaria Programme, Wellcome Sanger Institute, Cambridge, United Kingdom
| | - Mara Kn Lawniczak
- Malaria Programme, Wellcome Sanger Institute, Cambridge, United Kingdom
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5
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Birget PLG, Repton C, O'Donnell AJ, Schneider P, Reece SE. Phenotypic plasticity in reproductive effort: malaria parasites respond to resource availability. Proc Biol Sci 2017; 284:20171229. [PMID: 28768894 PMCID: PMC5563815 DOI: 10.1098/rspb.2017.1229] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 06/28/2017] [Indexed: 12/11/2022] Open
Abstract
The trade-off between survival and reproduction is fundamental in the life history of all sexually reproducing organisms. This includes malaria parasites, which rely on asexually replicating stages for within-host survival and on sexually reproducing stages (gametocytes) for between-host transmission. The proportion of asexual stages that form gametocytes (reproductive effort) varies during infections-i.e. is phenotypically plastic-in response to changes in a number of within-host factors, including anaemia. However, how the density and age structure of red blood cell (RBC) resources shape plasticity in reproductive effort and impacts upon parasite fitness is controversial. Here, we examine how and why the rodent malaria parasite Plasmodium chabaudi alters its reproductive effort in response to experimental perturbations of the density and age structure of RBCs. We show that all four of the genotypes studied increase reproductive effort when the proportion of RBCs that are immature is elevated during host anaemia, and that the responses of the genotypes differ. We propose that anaemia (counterintuitively) generates a resource-rich environment in which parasites can afford to allocate more energy to reproduction (i.e. transmission) and that anaemia also exposes genetic variation to selection. From an applied perspective, adaptive plasticity in parasite reproductive effort could explain the maintenance of genetic variation for virulence and why anaemia is often observed as a risk factor for transmission in human infections.
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Affiliation(s)
- Philip L G Birget
- Institutes of Evolutionary Biology, and Immunology and Infection Research, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Charlotte Repton
- Institutes of Evolutionary Biology, and Immunology and Infection Research, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Aidan J O'Donnell
- Institutes of Evolutionary Biology, and Immunology and Infection Research, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Petra Schneider
- Institutes of Evolutionary Biology, and Immunology and Infection Research, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Sarah E Reece
- Institutes of Evolutionary Biology, and Immunology and Infection Research, University of Edinburgh, Edinburgh EH9 3FL, UK
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6
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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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7
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Yam XY, Brugat T, Siau A, Lawton J, Wong DS, Farah A, Twang JS, Gao X, Langhorne J, Preiser PR. Characterization of the Plasmodium Interspersed Repeats (PIR) proteins of Plasmodium chabaudi indicates functional diversity. Sci Rep 2016; 6:23449. [PMID: 26996203 PMCID: PMC4800443 DOI: 10.1038/srep23449] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 03/04/2016] [Indexed: 12/02/2022] Open
Abstract
Plasmodium multigene families play a central role in the pathogenesis of malaria. The Plasmodium interspersed repeat (pir) genes comprise the largest multigene family in many Plasmodium spp. However their function(s) remains unknown. Using the rodent model of malaria, Plasmodium chabaudi, we show that individual CIR proteins have differential localizations within infected red cell (iRBC), suggesting different functional roles in a blood-stage infection. Some CIRs appear to be located on the surface of iRBC and merozoites and are therefore well placed to interact with host molecules. In line with this hypothesis, we show for the first time that a subset of recombinant CIRs bind mouse RBCs suggesting a role for CIR in rosette formation and/or invasion. Together, our results unravel differences in subcellular localization and ability to bind mouse erythrocytes between the members of the cir family, which strongly suggest different functional roles in a blood-stage infection.
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Affiliation(s)
- Xue Yan Yam
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore
| | - Thibaut Brugat
- Francis Crick Institute, Mill Hill Laboratory, London, UK
| | - Anthony Siau
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore
| | | | - Daniel S Wong
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore
| | - Abdirahman Farah
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore.,Karolinska Institutet, Stockholm, Sweden
| | - Jing Shun Twang
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore
| | - Xiaohong Gao
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore
| | - Jean Langhorne
- Francis Crick Institute, Mill Hill Laboratory, London, UK
| | - Peter R Preiser
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore
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8
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Deroost K, Pham TT, Opdenakker G, Van den Steen PE. The immunological balance between host and parasite in malaria. FEMS Microbiol Rev 2015; 40:208-57. [PMID: 26657789 DOI: 10.1093/femsre/fuv046] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2015] [Indexed: 12/16/2022] Open
Abstract
Coevolution of humans and malaria parasites has generated an intricate balance between the immune system of the host and virulence factors of the parasite, equilibrating maximal parasite transmission with limited host damage. Focusing on the blood stage of the disease, we discuss how the balance between anti-parasite immunity versus immunomodulatory and evasion mechanisms of the parasite may result in parasite clearance or chronic infection without major symptoms, whereas imbalances characterized by excessive parasite growth, exaggerated immune reactions or a combination of both cause severe pathology and death, which is detrimental for both parasite and host. A thorough understanding of the immunological balance of malaria and its relation to other physiological balances in the body is of crucial importance for developing effective interventions to reduce malaria-related morbidity and to diminish fatal outcomes due to severe complications. Therefore, we discuss in this review the detailed mechanisms of anti-malarial immunity, parasite virulence factors including immune evasion mechanisms and pathogenesis. Furthermore, we propose a comprehensive classification of malaria complications according to the different types of imbalances.
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Affiliation(s)
- Katrien Deroost
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium The Francis Crick Institute, Mill Hill Laboratory, London, NW71AA, UK
| | - Thao-Thy Pham
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
| | - Ghislain Opdenakker
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
| | - Philippe E Van den Steen
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
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9
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Farooq F, Bergmann-Leitner ES. Immune Escape Mechanisms are Plasmodium's Secret Weapons Foiling the Success of Potent and Persistently Efficacious Malaria Vaccines. Clin Immunol 2015; 161:136-43. [PMID: 26342537 DOI: 10.1016/j.clim.2015.08.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 08/27/2015] [Indexed: 10/23/2022]
Abstract
Despite decades of active research, an efficacious vaccine mediating long-term protection is still not available. This review highlights various mechanisms and the different facets by which the parasites outsmart the immune system. An understanding of how the parasites escape immune recognition and interfere with the induction of a protective immune response that provides sterilizing immunity will be crucial to vaccine design.
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Affiliation(s)
- Fouzia Farooq
- Malaria Vaccine Branch, U.S. Military Malaria Research Program, Walter Reed Army Institute of Research, Silver Spring, MD 20910
| | - Elke S Bergmann-Leitner
- Malaria Vaccine Branch, U.S. Military Malaria Research Program, Walter Reed Army Institute of Research, Silver Spring, MD 20910.
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10
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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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11
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Gunalan K, Gao X, Yap SSL, Huang X, Preiser PR. The role of the reticulocyte-binding-like protein homologues of Plasmodium in erythrocyte sensing and invasion. Cell Microbiol 2012; 15:35-44. [PMID: 23046317 DOI: 10.1111/cmi.12038] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 09/17/2012] [Accepted: 10/01/2012] [Indexed: 11/27/2022]
Abstract
Malaria remains a serious public health problem with significant morbidity and mortality accounting for nearly 20% of all childhood deaths in Africa. The cyclical invasion, cytoadherence and destruction of the host's erythrocyte by the parasite are responsible for the observed disease pathology. The invasive form of the parasite, the merozoite, uses a complex set of interactions between parasite ligands and erythrocyte receptors that leads to the formation of a tight junction and ultimately successful erythrocyte invasion. Understanding the molecular mechanism underlying host cell recognition and invasion is crucial for the development of a targeted intervention strategy. Two parasite protein families termed reticulocyte-binding-like protein homologues (RBL) and the erythrocyte-binding-like (EBL) protein family are conserved in all Plasmodium species and have been shown to play an important role in host cell recognition and invasion. Over the last few years significant new insights have been gained in understanding the function of the RBL family and this review attempts to provide an update with a specific focus on the role of RBL in signal transduction pathways during invasion.
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Affiliation(s)
- Karthigayan Gunalan
- Division of Molecular Genetics & Cell Biology, School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
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12
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RETRACTED ARTICLE: Alternative pathways of erythrocyte invasion, parasite multiplication potential and severity of the clinical episode of P. falciparum malaria in the Peruvian Amazon. Parasitol Res 2012; 110:1019. [DOI: 10.1007/s00436-011-2663-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2011] [Accepted: 09/27/2011] [Indexed: 11/26/2022]
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13
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Tulone C, Sponaas AM, Raiber EA, Tabor AB, Langhorne J, Chain BM. Differential requirement for cathepsin D for processing of the full length and C-terminal fragment of the malaria antigen MSP1. PLoS One 2011; 6:e24886. [PMID: 22053177 PMCID: PMC3203867 DOI: 10.1371/journal.pone.0024886] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 08/23/2011] [Indexed: 11/19/2022] Open
Abstract
Merozoite Surface Protein 1 is expressed on the surface of malaria merozoites and is important for invasion of the malaria parasite into erythrocytes. MSP1-specific CD4 T cell responses and antibody can confer protective immunity in experimental models of malaria. In this study we explore the contributions of cathepsins D and E, two aspartic proteinases previously implicated in antigen processing, to generating MSP1 CD4 T-cell epitopes for presentation. The absence of cathepsin D, a late endosome/lysosomal enzyme, is associated with a reduced presentation of MSP1 both following in vitro processing of the epitope MSP1 from infected erythrocytes by bone marrow-derived dendritic cells, and following in vivo processing by splenic CD11c+ dendritic cells. By contrast, processing and presentation of the soluble recombinant protein fragment of MSP1 is unaffected by the absence of cathepsin D, but is inhibited when both cathepsin D and E are absent. The role of different proteinases in generating the CD4 T cell repertoire, therefore, depends on the context in which an antigen is introduced to the immune system.
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Affiliation(s)
- Calogero Tulone
- Division of Infection and Immunity, University College London, London, United Kingdom
| | - Anne-Marit Sponaas
- Division of Parasitology MRC National Institute of Medical Research, London, United Kingdom
| | - Eun-Ang Raiber
- Department of Chemistry, University College London, London, United Kingdom
| | - Alethea B. Tabor
- Department of Chemistry, University College London, London, United Kingdom
| | - Jean Langhorne
- Division of Parasitology MRC National Institute of Medical Research, London, United Kingdom
| | - Benny M. Chain
- Division of Infection and Immunity, University College London, London, United Kingdom
- * E-mail:
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14
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Shibui A, Doi J, Tolba MEM, Shiraishi C, Sato Y, Ishikawa S, Watanabe J, Nogami S, Nakae S, Sugano S, Hozumi N. N-acetylglucosaminyltransferase V-deficiency increases susceptibility to murine malaria. Exp Parasitol 2011; 129:318-21. [PMID: 21767537 DOI: 10.1016/j.exppara.2011.07.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Revised: 06/23/2011] [Accepted: 07/01/2011] [Indexed: 11/30/2022]
Abstract
It is considered that several glycoproteins on erythrocytes in mammalian species are involved in malaria parasite infection. To elucidate the role of N-glycans on malaria parasite infection, we induced experimental murine malaria infection (using Plasmodium berghei ANKA) in mice deficient in N-acetylglucosaminyltransferase V (Mgat5), which is one of the enzymes involved in β1,6-GlcNAc N-glycan biosynthesis. After infection, Mgat5(-/-) mice showed severe body weight loss and parasitemia compared with wild-type mice. The Mgat5(-/-) mice, but not wild-type mice, also showed severe pathology accompanied by marked infiltration of plasma cells into the lungs and liver. These results suggest that β1,6-GlcNAc N-glycans on/in host erythrocytes may interfere with invasion of the parasites and progression to severe malaria.
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Affiliation(s)
- Akiko Shibui
- Department of Medical Genomics, Graduate School of Frontier Sciences, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
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15
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Linkage maps from multiple genetic crosses and loci linked to growth-related virulent phenotype in Plasmodium yoelii. Proc Natl Acad Sci U S A 2011; 108:E374-82. [PMID: 21690382 DOI: 10.1073/pnas.1102261108] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Plasmodium yoelii is an excellent model for studying malaria pathogenesis that is often intractable to investigate using human parasites; however, genetic studies of the parasite have been hindered by lack of genome-wide linkage resources. Here, we performed 14 genetic crosses between three pairs of P. yoelii clones/subspecies, isolated 75 independent recombinant progeny from the crosses, and constructed a high-resolution linkage map for this parasite. Microsatellite genotypes from the progeny formed 14 linkage groups belonging to the 14 parasite chromosomes, allowing assignment of sequence contigs to chromosomes. Growth-related virulent phenotypes from 25 progeny of one of the crosses were significantly associated with a major locus on chromosome 13 and with two secondary loci on chromosomes 7 and 10. The chromosome 10 and 13 loci are both linked to day 5 parasitemia, and their effects on parasite growth rate are independent but additive. The locus on chromosome 7 is associated with day 10 parasitemia. The chromosome 13 locus spans ~220 kb of DNA containing 51 predicted genes, including the P. yoelii erythrocyte binding ligand, in which a C741Y substitution in the R6 domain is implicated in the change of growth rate. Similarly, the chromosome 10 locus spans ~234 kb with 71 candidate genes, containing a member of the 235-kDa rhoptry proteins (Py235) that can bind to the erythrocyte surface membrane. Atypical virulent phenotypes among the progeny were also observed. This study provides critical tools and information for genetic investigations of virulence and biology of P. yoelii.
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16
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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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17
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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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18
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Basak S, Gayen S, Ramalingam JK, Grüber A, Preiser PR, Grüber G. NMR solution structure of NBD94(483-502) of the nucleotide-binding domain of the Plasmodium yoelii reticulocyte-binding protein Py235. FEMS Microbiol Lett 2011; 318:152-8. [PMID: 21366672 DOI: 10.1111/j.1574-6968.2011.02253.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Invasion of the erythrocyte by the invasive form of the malaria parasite, the merozoite, is a complex process involving numerous parasite proteins. The reticulocyte-binding protein homologues (RH) family of merozoite proteins has been previously shown to play an important role in the invasion process. Previously, it has been shown that the RH proteins of Plasmodium yoelii, Py235, play a role as an ATP/ADP sensor. Binding of Py235 to the erythrocyte surface is increased in the presence of ATP, while ADP has an inhibitory effect. The sensor domain of Py235 is called NBD94 and the segment that has been shown to covalently bind the adenine nucleotide is made up by the residues (483) FNEIKEKLKHYNFDDFVKEE(502) . Here, we report on the solution nuclear magnetic resonance structure of this peptide (NBD94(483-502) ) showing the presence of an α-helix between amino acid residues 485 and 491. The N- and C-terminal segments of the structure bend at tyrosine 493, a residue important for ATP binding. Importantly, erythrocyte-binding assays demonstrate that NBD94(483-502) can directly interfere with the binding of native Py235 to erythrocytes, suggesting a direct role of this region in erythrocyte binding. The data will provide the foundation for future studies to identify new compounds that directly interfere with the invasion process.
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Affiliation(s)
- Sandip Basak
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
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19
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Targeted disruption of py235ebp-1: invasion of erythrocytes by Plasmodium yoelii using an alternative Py235 erythrocyte binding protein. PLoS Pathog 2011; 7:e1001288. [PMID: 21379566 PMCID: PMC3040676 DOI: 10.1371/journal.ppat.1001288] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Accepted: 01/10/2011] [Indexed: 11/19/2022] Open
Abstract
Plasmodium yoelii YM asexual blood stage parasites express multiple members of the py235 gene family, part of the super-family of genes including those coding for Plasmodium vivax reticulocyte binding proteins and Plasmodium falciparum RH proteins. We previously identified a Py235 erythrocyte binding protein (Py235EBP-1, encoded by the PY01365 gene) that is recognized by protective mAb 25.77. Proteins recognized by a second protective mAb 25.37 have been identified by mass spectrometry and are encoded by two genes, PY01185 and PY05995/PY03534. We deleted the PY01365 gene and examined the phenotype. The expression of the members of the py235 family in both the WT and gene deletion parasites was measured by quantitative RT-PCR and RNA-Seq. py235ebp-1 expression was undetectable in the knockout parasite, but transcription of other members of the family was essentially unaffected. The knockout parasites continued to react with mAb 25.77; and the 25.77-binding proteins in these parasites were the PY01185 and PY05995/PY03534 products. The PY01185 product was also identified as erythrocyte binding. There was no clear change in erythrocyte invasion profile suggesting that the PY01185 gene product (designated PY235EBP-2) is able to fulfill the role of EBP-1 by serving as an invasion ligand although the molecular details of its interaction with erythrocytes have not been examined. The PY01365, PY01185, and PY05995/PY03534 genes are part of a distinct subset of the py235 family. In P. falciparum, the RH protein genes are under epigenetic control and expression correlates with binding to distinct erythrocyte receptors and specific invasion pathways, whereas in P. yoelii YM all the genes are expressed and deletion of one does not result in upregulation of another. We propose that simultaneous expression of multiple Py235 ligands enables invasion of a wide range of host erythrocytes even in the presence of antibodies to one or more of the proteins and that this functional redundancy at the protein level gives the parasite phenotypic plasticity in the absence of differences in gene expression.
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20
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Persson KE. Erythrocyte invasion and functionally inhibitory antibodies in Plasmodium falciparum malaria. Acta Trop 2010; 114:138-43. [PMID: 19481996 DOI: 10.1016/j.actatropica.2009.05.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Revised: 05/19/2009] [Accepted: 05/22/2009] [Indexed: 11/26/2022]
Abstract
Malaria is a disease that kills several million people every year. P. falciparum merozoites invade new erythrocytes every 48 h, causing fever, anemia and cerebral malaria. Effective immunity against malaria develops slowly and only after repeated exposure. Antibodies are an important part of this immunity. However, the antigens that mediate immunity by inducing functionally imperative antibodies have not yet been identified. This review gives an overview of the erythrocyte invasion process, which has been described to include several different antigens. Invasion inhibitory antibodies can inhibit merozoite penetration of new erythrocytes, and different methods for measurement of the presence of functionally important antibodies have been employed. ELISA, Invasion inhibition assays and ADCI are some of the methods discussed.
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21
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Chromatin-mediated epigenetic regulation in the malaria parasite Plasmodium falciparum. EUKARYOTIC CELL 2010; 9:1138-49. [PMID: 20453074 DOI: 10.1128/ec.00036-10] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Malaria is a major public health problem in many developing countries, with the malignant tertian parasite Plasmodium falciparum causing the most malaria-associated mortality. Extensive research, especially with the advancement of genomics and transfection tools, has highlighted the fundamental importance of chromatin-mediated gene regulation in the developmental program of this early-branching eukaryote. The Plasmodium parasite genomes reveal the existence of both canonical and variant histones that make up the nucleosomes, as well as a full collection of conserved enzymes for chromatin remodeling and histone posttranslational modifications (PTMs). Recent studies have identified a wide array of both conserved and novel histone PTMs in P. falciparum, indicating the presence of a complex and divergent "histone code." Genome-wide analysis has begun to decipher the nucleosome landscape and histone modifications associated with the dynamic organization of chromatin structures during the parasite's life cycle. Focused studies on malaria-specific phenomena such as antigenic variation and red cell invasion pathways shed further light on the involvement of epigenetic mechanisms in these processes. Here we review our current understanding of chromatin-mediated gene regulation in malaria parasites, with specific reference to exemplar studies on antigenic variation and host cell invasion.
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22
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Grüber A, Manimekalai MSS, Balakrishna AM, Hunke C, Jeyakanthan J, Preiser PR, Grüber G. Structural determination of functional units of the nucleotide binding domain (NBD94) of the reticulocyte binding protein Py235 of Plasmodium yoelii. PLoS One 2010; 5:e9146. [PMID: 20161776 PMCID: PMC2818847 DOI: 10.1371/journal.pone.0009146] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 01/22/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Invasion of the red blood cells (RBC) by the merozoite of malaria parasites involves a large number of receptor ligand interactions. The reticulocyte binding protein homologue family (RH) plays an important role in erythrocyte recognition as well as virulence. Recently, it has been shown that members of RH in addition to receptor binding may also have a role as ATP/ADP sensor. A 94 kDa region named Nucleotide-Binding Domain 94 (NBD94) of Plasmodium yoelii YM, representative of the putative nucleotide binding region of RH, has been demonstrated to bind ATP and ADP selectively. Binding of ATP or ADP induced nucleotide-dependent structural changes in the C-terminal hinge-region of NBD94, and directly impacted on the RBC binding ability of RH. METHODOLOGY/PRINCIPAL FINDINGS In order to find the smallest structural unit, able to bind nucleotides, and its coupling module, the hinge region, three truncated domains of NBD94 have been generated, termed NBD94(444-547), NBD94(566-663) and NBD94(674-793), respectively. Using fluorescence correlation spectroscopy NBD94(444-547) has been identified to form the smallest nucleotide binding segment, sensitive for ATP and ADP, which became inhibited by 4-Chloro-7-nitrobenzofurazan. The shape of NBD94(444-547) in solution was calculated from small-angle X-ray scattering data, revealing an elongated molecule, comprised of two globular domains, connected by a spiral segment of about 73.1 A in length. The high quality of the constructs, forming the hinge-region, NBD94(566-663) and NBD94(674-793) enabled to determine the first crystallographic and solution structure, respectively. The crystal structure of NBD94(566-663) consists of two helices with 97.8 A and 48.6 A in length, linked by a loop. By comparison, the low resolution structure of NBD94(674-793) in solution represents a chair-like shape with three architectural segments. CONCLUSIONS These structures give the first insight into how nucleotide binding impacts on the overall structure of RH and demonstrates the potential use of this region as a novel drug target.
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Affiliation(s)
- Ardina Grüber
- School of Biological Sciences, Nanyang Technological University, Singapore.
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23
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Migrating monocytes recruited to the spleen play an important role in control of blood stage malaria. Blood 2009; 114:5522-31. [PMID: 19837977 DOI: 10.1182/blood-2009-04-217489] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Host responses controlling blood-stage malaria include both innate and acquired immune effector mechanisms. During Plasmodium chabaudi infection in mice, a population of CD11b(high)Ly6C(+) monocytes are generated in bone marrow, most of which depend on the chemokine receptor CCR2 for migration from bone marrow to the spleen. In the absence of this receptor mice harbor higher parasitemias. Most importantly, splenic CD11b(high)Ly6C(+) cells from P chabaudi-infected wild-type mice significantly reduce acute-stage parasitemia in CCR2(-/-) mice. The CD11b(high)Ly6C(+) cells in this malaria infection display effector functions such as production of inducible nitric oxide synthase and reactive oxygen intermediates, and phagocytose P chabaudi parasites in vitro, and in a proportion of the cells, in vivo in the spleen, suggesting possible mechanisms of parasite killing. In contrast to monocyte-derived dendritic cells, CD11b(high)Ly6C(+) cells isolated from malaria-infected mice express low levels of major histocompatibility complex II and have limited ability to present the P chabaudi antigen, merozoite surface protein-1, to specific T-cell receptor transgenic CD4 T cells and fail to activate these T cells. We propose that these monocytes, which are rapidly produced in the bone marrow as part of the early defense mechanism against invading pathogens, are important for controlling blood-stage malaria parasites.
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24
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Wang CW, Hermsen CC, Sauerwein RW, Arnot DE, Theander TG, Lavstsen T. The Plasmodium falciparum var gene transcription strategy at the onset of blood stage infection in a human volunteer. Parasitol Int 2009; 58:478-80. [PMID: 19616120 DOI: 10.1016/j.parint.2009.07.004] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2008] [Revised: 06/22/2009] [Accepted: 07/06/2009] [Indexed: 11/25/2022]
Abstract
The var genes encode a family of adhesion receptor proteins, Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1), which profoundly influence malaria pathogenesis. Only a single var gene is transcribed and one PfEMP1 expressed per P.falciparum parasite. Here we present the in vivo transcript distribution of var genes in a P. falciparum-infected non-immune individual and show that the initial expression of PfEMP1 is based on a strategy that allows all or most variants of PfEMP1s to be expressed by the parasite population at the onset of the blood stage infection.
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Affiliation(s)
- Christian W Wang
- Department of International Health, Immunology, and Microbiology, University of Copenhagen, Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark.
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25
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Casares S, Richie TL. Immune evasion by malaria parasites: a challenge for vaccine development. Curr Opin Immunol 2009; 21:321-30. [DOI: 10.1016/j.coi.2009.05.015] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2009] [Revised: 04/26/2009] [Accepted: 05/12/2009] [Indexed: 11/26/2022]
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26
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In vitro effects of growth factors and hormones on three Perkinsus species and increased proliferation of P. marinus during cloning. Exp Parasitol 2009; 121:257-67. [DOI: 10.1016/j.exppara.2008.11.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2008] [Revised: 11/21/2008] [Accepted: 11/26/2008] [Indexed: 11/20/2022]
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27
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Reece SE, Ramiro RS, Nussey DH. Plastic parasites: sophisticated strategies for survival and reproduction? Evol Appl 2009; 2:11-23. [PMID: 20305703 PMCID: PMC2836026 DOI: 10.1111/j.1752-4571.2008.00060.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Accepted: 11/26/2008] [Indexed: 11/28/2022] Open
Abstract
Adaptive phenotypic plasticity in life history traits, behaviours, and strategies is ubiquitous in biological systems. It is driven by variation in selection pressures across environmental gradients and operates under constraints imposed by trade-offs. Phenotypic plasticity has been thoroughly documented for multicellular taxa, such as insects, birds and mammals, and in many cases the underlying selective pressures are well understood. Whilst unicellular parasites face many of the same selective pressures and trade-offs, plasticity in their phenotypic traits has been largely overlooked and remains poorly understood. Here, we demonstrate that evolutionary theory, developed to explain variation observed in the life-history traits of multicellular organisms, can be applied to parasites. Though our message is general - we can expect the life-histories of all parasites to have evolved phenotypic plasticity - we focus our discussion on malaria parasites. We use an evolutionary framework to explain the trade-offs that parasites face and how plasticity in their life history traits will be expressed according to changes in their in-host environment. Testing whether variation in parasites traits is adaptive will provide new and fundamental insights into the basic biology of parasites, their epidemiology and the processes of disease during individual infections.
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28
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Cunningham D, Fonager J, Jarra W, Carret C, Preiser P, Langhorne J. Rapid changes in transcription profiles of the Plasmodium yoelii yir multigene family in clonal populations: lack of epigenetic memory? PLoS One 2009; 4:e4285. [PMID: 19173007 PMCID: PMC2628738 DOI: 10.1371/journal.pone.0004285] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Accepted: 12/04/2008] [Indexed: 11/18/2022] Open
Abstract
The pir multigene family, found in the genomes of Plasmodium vivax, P. knowlesi and the rodent malaria species, encode variant antigens that could be targets of the immune response. Individual parasites of the rodent malaria Plasmodium yoelii, selected by micromanipulation, transcribe only 1 to 3 different pir (yir) suggesting tight transcriptional control at the level of individual cells. Using microarray and quantitative RT-PCR, we show that despite this very restricted transcription in a single cell, many yir genes are transcribed throughout the intra-erythrocytic asexual cycle. The timing and level of transcription differs between genes, with some being more highly transcribed in ring and trophozoite stages, whereas others are more highly transcribed in schizonts. Infection of immunodeficient mice with single infected erythrocytes results in populations of parasites each with transcriptional profiles different from that of the parent parasite population and from each other. This drift away from the original 'set' of transcribed genes does not appear to follow a preset pattern and "epigenetic memory" of the yir transcribed in the parent parasite can be rapidly lost. Thus, regulation of pir gene transcription may be different from that of the well-characterised multigene family, var, of Plasmodium falciparum.
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Affiliation(s)
- Deirdre Cunningham
- Division of Parasitology, National Institute for Medical Research, London, United Kingdom
| | - Jannik Fonager
- Division of Parasitology, National Institute for Medical Research, London, United Kingdom
| | - William Jarra
- Division of Parasitology, National Institute for Medical Research, London, United Kingdom
| | - Celine Carret
- Pathogen Microarrays Group, The Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Peter Preiser
- Bioscience Research Centre, Nanyang Technical University, Singapore
| | - Jean Langhorne
- Division of Parasitology, National Institute for Medical Research, London, United Kingdom
- * E-mail:
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29
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Erythrocyte invasion by Plasmodium falciparum: multiple ligand-receptor interactions and phenotypic switching. Subcell Biochem 2008; 47:46-57. [PMID: 18512340 DOI: 10.1007/978-0-387-78267-6_3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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30
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Abstract
The persistence of the human malaria parasite Plasmodium falciparum during blood stage proliferation in its host depends on the successive expression of variant molecules at the surface of infected erythrocytes. This variation is mediated by the differential control of a family of surface molecules termed PfEMP1 encoded by approximately 60 var genes. Each individual parasite expresses a single var gene at a time, maintaining all other members of the family in a transcriptionally silent state. PfEMP1/var enables parasitized erythrocytes to adhere within the microvasculature, resulting in severe disease. This review highlights key regulatory mechanisms thought to be critical for monoallelic expression of var genes. Antigenic variation is orchestrated by epigenetic factors including monoallelic var transcription at separate spatial domains at the nuclear periphery, differential histone marks on otherwise identical var genes, and var silencing mediated by telomeric heterochromatin. In addition, controversies surrounding var genetic elements in antigenic variation are discussed.
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Affiliation(s)
- Artur Scherf
- Biology of Host-Parasite Interactions Unit, CNRS URA2581, Institut Pasteur 75724 Paris, France.
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31
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Carlton JM, Adams JH, Silva JC, Bidwell SL, Lorenzi H, Caler E, Crabtree J, Angiuoli SV, Merino EF, Amedeo P, Cheng Q, Coulson RMR, Crabb BS, Del Portillo HA, Essien K, Feldblyum TV, Fernandez-Becerra C, Gilson PR, Gueye AH, Guo X, Kang'a S, Kooij TWA, Korsinczky M, Meyer EVS, Nene V, Paulsen I, White O, Ralph SA, Ren Q, Sargeant TJ, Salzberg SL, Stoeckert CJ, Sullivan SA, Yamamoto MM, Hoffman SL, Wortman JR, Gardner MJ, Galinski MR, Barnwell JW, Fraser-Liggett CM. Comparative genomics of the neglected human malaria parasite Plasmodium vivax. Nature 2008; 455:757-63. [PMID: 18843361 DOI: 10.1038/nature07327] [Citation(s) in RCA: 617] [Impact Index Per Article: 38.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Accepted: 08/08/2008] [Indexed: 11/09/2022]
Abstract
The human malaria parasite Plasmodium vivax is responsible for 25-40% of the approximately 515 million annual cases of malaria worldwide. Although seldom fatal, the parasite elicits severe and incapacitating clinical symptoms and often causes relapses months after a primary infection has cleared. Despite its importance as a major human pathogen, P. vivax is little studied because it cannot be propagated continuously in the laboratory except in non-human primates. We sequenced the genome of P. vivax to shed light on its distinctive biological features, and as a means to drive development of new drugs and vaccines. Here we describe the synteny and isochore structure of P. vivax chromosomes, and show that the parasite resembles other malaria parasites in gene content and metabolic potential, but possesses novel gene families and potential alternative invasion pathways not recognized previously. Completion of the P. vivax genome provides the scientific community with a valuable resource that can be used to advance investigation into this neglected species.
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Affiliation(s)
- Jane M Carlton
- The Institute for Genomic Research/J. Craig Venter Institute, 9704 Medical Research Drive, Rockville, Maryland 20850, USA.
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32
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Ramalingam JK, Hunke C, Gao X, Grüber G, Preiser PR. ATP/ADP binding to a novel nucleotide binding domain of the reticulocyte-binding protein Py235 of Plasmodium yoelii. J Biol Chem 2008; 283:36386-96. [PMID: 18957411 DOI: 10.1074/jbc.m803102200] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mechanism by which a malaria merozoite recognizes a suitable host cell is mediated by a cascade of receptor-ligand interactions. In addition to the availability of the appropriate receptors, intracellular ATP plays an important role in determining whether erythrocytes are suitable for merozoite invasion. Recent work has shown that ATP secreted from erythrocytes signals a number of cellular processes. To determine whether ATP signaling might be involved in merozoite invasion, we investigated whether known plasmodium invasion proteins contain nucleotide binding motifs. Domain mapping identified a putative nucleotide binding region within all members of the reticulocyte-binding protein homologue (RBL) family analyzed. A representative domain, termed here nucleotide binding domain 94 (NBD94), was expressed and demonstrated to specifically bind to ATP. Nucleotide affinities of NBD94 were determined by fluorescence correlation spectroscopy, where an increase in the binding of ATP is observed compared with ADP analogues. ATP binding was reduced by the known F1F0-ATP synthase inhibitor 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole. Fluorescence quenching and circular dichroism spectroscopy of NBD94 after binding of different nucleotides provide evidence for structural changes in this protein. Our data suggest that different structural changes induced by ATP/ADP binding to RBL could play an important role during the invasion process.
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Affiliation(s)
- Jeya Kumar Ramalingam
- Division of Genomics and Genetics, School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
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33
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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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Cortés A. Switching Plasmodium falciparum genes on and off for erythrocyte invasion. Trends Parasitol 2008; 24:517-24. [PMID: 18805736 DOI: 10.1016/j.pt.2008.08.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2008] [Revised: 07/23/2008] [Accepted: 08/01/2008] [Indexed: 11/30/2022]
Abstract
Culture-adapted lines of the malaria parasite Plasmodium falciparum use alternative pathways for the invasion of erythrocytes. The expression of parasite ligands that are involved in the different pathways varies among parasite lines. Recently, several studies have attempted to characterize the use of different invasion pathways and the expression of specific invasion ligands in field isolates, opening the way to understand how invasion occurs in natural infections. In this review, these findings are discussed in the context of the most recent data on invasion by culture-adapted parasites to describe the current understanding of how wild parasites invade, how the variant expression of invasion ligands relates to switching between alternative invasion pathways and why so many different pathways are needed.
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Affiliation(s)
- Alfred Cortés
- ICREA and Institute for Research in Biomedicine, Barcelona Science Park, Barcelona 08028, Catalonia, Spain.
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DeSimone TM, Bei AK, Jennings CV, Duraisingh MT. Genetic analysis of the cytoplasmic domain of the PfRh2b merozoite invasion protein of Plasmodium falciparum. Int J Parasitol 2008; 39:399-405. [PMID: 18831976 DOI: 10.1016/j.ijpara.2008.08.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Revised: 08/19/2008] [Accepted: 08/31/2008] [Indexed: 11/15/2022]
Abstract
Apicomplexan parasites employ multiple adhesive ligands for recognition and entry into host cells. The Duffy binding-like (DBL) and the reticulocyte binding protein-like (RBL) families are central to the invasion of erythrocytes by the malaria parasite. These type-1 transmembrane proteins are composed of large ectodomains and small conserved cytoplasmic tail domains. The cytoplasmic tail domain of the micronemal DBL protein EBA-175 is required for a functional ligand-receptor interaction, but not for correct trafficking and localisation. Here we focus on the cytoplasmic tail domain of the rhoptry-localised Plasmodium falciparum RBL PfRh2b. We have identified a conserved sequence of six amino acids, enriched in acidic residues, in the cytoplasmic tail domains of RBL proteins from Plasmodium spp. Genetic analyses reveal that the entire cytoplasmic tail and the conserved motif within the cytoplasmic tail are indispensable for invasion P. falciparum. Site-directed mutagenesis of the conserved moiety reveals that changes in the order of the amino acids of the conserved moiety, but not the charge of the sequence, can be tolerated. Shuffling of the motif has no effect on either invasion phenotype or PfRh2b expression and trafficking. Although the PfRh2b gene can be readily disrupted, our results suggest that modification of the PfRh2b cytoplasmic tail results in strong dominant negative activity, highlighting important differences between the PfRh2b and EBA-175 invasion ligands.
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Rodriguez LE, Curtidor H, Urquiza M, Cifuentes G, Reyes C, Patarroyo ME. Intimate Molecular Interactions of P. falciparum Merozoite Proteins Involved in Invasion of Red Blood Cells and Their Implications for Vaccine Design. Chem Rev 2008; 108:3656-705. [DOI: 10.1021/cr068407v] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Hernando Curtidor
- Fundación Instituto de Inmunología de Colombia, Carrera 50 No. 26-00, Bogotá, Colombia
| | - Mauricio Urquiza
- Fundación Instituto de Inmunología de Colombia, Carrera 50 No. 26-00, Bogotá, Colombia
| | - Gladys Cifuentes
- Fundación Instituto de Inmunología de Colombia, Carrera 50 No. 26-00, Bogotá, Colombia
| | - Claudia Reyes
- Fundación Instituto de Inmunología de Colombia, Carrera 50 No. 26-00, Bogotá, Colombia
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37
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Gao X, Yeo KP, Aw SS, Kuss C, Iyer JK, Genesan S, Rajamanonmani R, Lescar J, Bozdech Z, Preiser PR. Antibodies targeting the PfRH1 binding domain inhibit invasion of Plasmodium falciparum merozoites. PLoS Pathog 2008; 4:e1000104. [PMID: 18617995 PMCID: PMC2438614 DOI: 10.1371/journal.ppat.1000104] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Accepted: 06/13/2008] [Indexed: 11/18/2022] Open
Abstract
Invasion by the malaria merozoite depends on recognition of specific erythrocyte surface receptors by parasite ligands. Plasmodium falciparum uses multiple ligands, including at least two gene families, reticulocyte binding protein homologues (RBLs) and erythrocyte binding proteins/ligands (EBLs). The combination of different RBLs and EBLs expressed in a merozoite defines the invasion pathway utilized and could also play a role in parasite virulence. The binding regions of EBLs lie in a conserved cysteine-rich domain while the binding domain of RBL is still not well characterized. Here, we identify the erythrocyte binding region of the P. falciparum reticulocyte binding protein homologue 1 (PfRH1) and show that antibodies raised against the functional binding region efficiently inhibit invasion. In addition, we directly demonstrate that changes in the expression of RBLs can constitute an immune evasion mechanism of the malaria merozoite.
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Affiliation(s)
- Xiaohong Gao
- Division of Genomics & Genetics, School of Biological Sciences, Nanyang Technological University, Singapore
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38
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Persson KEM, McCallum FJ, Reiling L, Lister NA, Stubbs J, Cowman AF, Marsh K, Beeson JG. Variation in use of erythrocyte invasion pathways by Plasmodium falciparum mediates evasion of human inhibitory antibodies. J Clin Invest 2008; 118:342-51. [PMID: 18064303 DOI: 10.1172/jci32138] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Accepted: 10/10/2007] [Indexed: 11/17/2022] Open
Abstract
Antibodies that inhibit Plasmodium falciparum invasion of erythrocytes are believed to be an important component of immunity against malaria. During blood-stage infection, P. falciparum can use different pathways for erythrocyte invasion by varying the expression and/or utilization of members of 2 invasion ligand families: the erythrocyte-binding antigens (EBAs) and reticulocyte-binding homologs (PfRhs). Invasion pathways can be broadly classified into 2 groups based on the use of sialic acid (SA) on the erythrocyte surface by parasite ligands. We found that inhibitory antibodies are acquired by malaria-exposed Kenyan children and adults against ligands of SA-dependent and SA-independent invasion pathways, and the ability of antibodies to inhibit erythrocyte invasion depended on the pathway used by P. falciparum isolates. Differential inhibition of P. falciparum lines that varied in their use of specific EBA and PfRh proteins pointed to these ligand families as major targets of inhibitory antibodies. Antibodies against recombinant EBA and PfRh proteins were acquired in an age-associated manner, and inhibitory antibodies against EBA175 appeared prominent among some individuals. These findings suggest that variation in invasion phenotype might have evolved as a mechanism that facilitates immune evasion by P. falciparum and that a broad inhibitory response against multiple ligands may be required for effective immunity.
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Affiliation(s)
- Kristina E M Persson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
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39
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Garcia CRS, de Azevedo MF, Wunderlich G, Budu A, Young JA, Bannister L. Plasmodium in the postgenomic era: new insights into the molecular cell biology of malaria parasites. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 266:85-156. [PMID: 18544493 DOI: 10.1016/s1937-6448(07)66003-1] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In this review, we bring together some of the approaches toward understanding the cellular and molecular biology of Plasmodium species and their interaction with their host red blood cells. Considerable impetus has come from the development of new methods of molecular genetics and bioinformatics, and it is important to evaluate the wealth of these novel data in the context of basic cell biology. We describe how these approaches are gaining valuable insights into the parasite-host cell interaction, including (1) the multistep process of red blood cell invasion by the merozoite; (2) the mechanisms by which the intracellular parasite feeds on the red blood cell and exports parasite proteins to modify its cytoadherent properties; (3) the modulation of the cell cycle by sensing the environmental tryptophan-related molecules; (4) the mechanism used to survive in a low Ca(2+) concentration inside red blood cells; (5) the activation of signal transduction machinery and the regulation of intracellular calcium; (6) transfection technology; and (7) transcriptional regulation and genome-wide mRNA studies in Plasmodium falciparum.
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Affiliation(s)
- Celia R S Garcia
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, CEP 05508-900, São Paulo, SP, Brazil
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40
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Kottom TJ, Kennedy CC, Limper AH. Pneumocystis PCINT1, a molecule with integrin-like features that mediates organism adhesion to fibronectin. Mol Microbiol 2007; 67:747-61. [PMID: 18179594 DOI: 10.1111/j.1365-2958.2007.06093.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Pneumocystis species cause severe pneumonia during chronic immunosuppression, especially in patients with AIDS or malignancy. Adhesion of Pneumocystis to extracellular matrix proteins, particularly fibronectin, associated with alveolar epithelial cell surfaces, triggers organism proliferative pathways. Herein, we report the characterization of a novel Pneumocystis molecule with considerable structural features of an integrin-like extracellular matrix adhesion receptor. A PCINT1115 bp probe was initially identified from partial sequence present within the Pneumocystis genome project database. A full-length 3018 bp cDNA was subsequently obtained with extensive homology to the C-terminal region of Candida albicans INT1 (31% blastx), a gene originally described as encoding an integrin-like molecule implicated in adhesion, growth, and virulence. Sequence analysis of PCINT1 indicated that the Pneumocystis molecule contained both a putative internal RGD motif and four Metal Ion-Dependent Attachment Sites (MIDAS) motifs required for coordination of divalent cations, as well as a specific tyrosine residue found in the cytoplasmic tails of some integrin receptors and C. albicans INT1. Northern, Western and immunofluorescence studies demonstrated that the trophic forms of Pneumocystis, known to be the life cycle forms that tightly adhere to lung epithelium, expressed the molecule to a substantially greater degree than cystic forms. Heterologous expression of PCINT1 in yeast followed by application to human fibronectin-coated surfaces demonstrated these yeast display PCINT1 on their surfaces and subsequently gain the ability to bind fibronectin in a cation dependent fashion. Taken together, these results indicate that Pneumocystis expresses a novel integrin-like PCINT1 molecule sufficient to mediate interactions with extracellular matrix fibronectin, an integral component of host-cell organism interactions during this infection.
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Affiliation(s)
- Theodore J Kottom
- Thoracic Diseases Research Unit, Division of Pulmonary, Critical Care and Internal Medicine, Rochester, MN 55905, USA
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41
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Couper KN, Blount DG, Hafalla JCR, van Rooijen N, de Souza JB, Riley EM. Macrophage-mediated but gamma interferon-independent innate immune responses control the primary wave of Plasmodium yoelii parasitemia. Infect Immun 2007; 75:5806-18. [PMID: 17923512 PMCID: PMC2168355 DOI: 10.1128/iai.01005-07] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2007] [Revised: 09/11/2007] [Accepted: 09/29/2007] [Indexed: 01/25/2023] Open
Abstract
In most models of blood-stage malaria infection, proinflammatory immune responses are required for control of infection and elimination of parasites. We hypothesized therefore that the fulminant infections caused in mice by the lethal strain of Plasmodium yoelii (17XL) might be due to failure to activate a sufficient inflammatory response. Here we have compared the adaptive CD4+ T-cell and innate immune response to P. yoelii 17XL with that induced by the self-resolving, nonlethal strain of P. yoelii, 17X(NL). During the first 7 to 9 days of infection, splenic effector CD4+ T-cell responses were similar in mice with lethal and nonlethal infections with similar levels of activation in vivo and equivalent proliferation in vitro following mitogenic stimulation. Nonspecific T-cell hyporesponsiveness was observed at similar levels during both infections and was due, in part, to suppression mediated by CD11b+ cells. Importantly, however, RAG-/- mice were able to control the initial growth phase of nonlethal P. yoelii infection as effectively as wild-type mice, indicating that T cells and/or B cells play little, if any, role in control of the primary peak of parasitemia. Somewhat unexpectedly, we could find no clear role for either NK cells or gamma interferon (IFN-gamma) in controlling primary P. yoelii infection. In contrast, depletion of monocytes/macrophages exacerbated parasite growth and anemia during both lethal and nonlethal acute P. yoelii infections, indicating that there is an IFN-gamma-, NK cell-, and T-cell-independent pathway for induction of effector macrophages during acute malaria infection.
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Affiliation(s)
- Kevin N Couper
- Immunology Unit, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
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Iyer J, Grüner AC, Rénia L, Snounou G, Preiser PR. Invasion of host cells by malaria parasites: a tale of two protein families. Mol Microbiol 2007; 65:231-49. [PMID: 17630968 DOI: 10.1111/j.1365-2958.2007.05791.x] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Malaria parasites are obligate intracellular parasites whose invasive stages select and invade the unique host cell in which they can develop with exquisite specificity and efficacy. Most studies aimed at elucidating the molecules and the mechanisms implicated in the selection and invasion processes have been conducted on the merozoite, the stage that invades erythrocytes to perpetuate the pathological cycles of parasite multiplication in the blood. Bioinformatic analysis has helped identify the members of two parasite protein families, the reticulocyte-binding protein homologues (RBL) and erythrocyte binding like (EBL), in recently sequenced genomes of different Plasmodium species. In this article we review data from classical studies and gene disruption experiments that are helping to illuminate the role of these proteins in the selection-invasion processes. The manner in which subsets of proteins from each of the families act in concert suggests a model to explain the ability of the parasites to use alternate pathways of invasion. Future perspectives and implications are discussed.
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Affiliation(s)
- Jayasree Iyer
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore 637551, Singapore
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Yao C, Donelson JE, Wilson ME. Internal and surface-localized major surface proteases of Leishmania spp. and their differential release from promastigotes. EUKARYOTIC CELL 2007; 6:1905-12. [PMID: 17693594 PMCID: PMC2043387 DOI: 10.1128/ec.00073-07] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Major surface protease (MSP), also called GP63, is a virulence factor of Leishmania spp. protozoa. There are three pools of MSP, located either internally within the parasite, anchored to the surface membrane, or released into the extracellular environment. The regulation and biological functions of these MSP pools are unknown. We investigated here the trafficking and extrusion of surface versus internal MSPs. Virulent Leishmania chagasi undergo a growth-associated lengthening in the t(1/2) of surface-localized MSP, but this did not occur in the attenuated L5 strain. The release of surface-localized MSP was enhanced in a dose-dependent manner by MbetaCD, which chelates membrane cholesterol-ergosterol. Furthermore, incubation of promastigotes at 37 degrees C with Matrigel matrix, a soluble basement membrane extract of Engelbreth-Holm-Swarm tumor cells, stimulated the release of internal MSP but not of surface-located MSP. Taken together, these data indicate that MSP subpopulations in distinct cellular locations are released from the parasite under different environmental conditions. We hypothesize that the internal MSP with its lengthy t(1/2) does not serve as a pool for promastigote surface MSP in the sand fly vector but that it instead functions as an MSP pool ready for quick release upon inoculation of metacyclic promastigotes into mammals. We present a model in which these different MSP pools are released under distinct life cycle-specific conditions.
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Affiliation(s)
- Chaoqun Yao
- Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA.
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Petter M, Haeggström M, Khattab A, Fernandez V, Klinkert MQ, Wahlgren M. Variant proteins of the Plasmodium falciparum RIFIN family show distinct subcellular localization and developmental expression patterns. Mol Biochem Parasitol 2007; 156:51-61. [PMID: 17719658 DOI: 10.1016/j.molbiopara.2007.07.011] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Revised: 07/13/2007] [Accepted: 07/17/2007] [Indexed: 11/16/2022]
Abstract
In order to avoid immune recognition in favor of a chronic infection, the malaria parasite Plasmodium falciparum has developed means to express clonally variant antigens at the surface of the infected erythrocyte (IE). Proteins of the var and rif multicopy gene families, encoding PfEMP1 and RIFINs, respectively, have been implicated in these processes. Here, we studied members of the latter family and present data revealing different subcellular localization patterns for RIFIN variants belonging to two distinct subgroups, which have been designated A- and B-type RIFINs. While A-type RIFINs were found to be associated with the parasite and transported to the surface of infected erythrocytes via Maurer's clefts, B-type RIFINs appeared to be mostly retained inside the parasite. However, expression of both subtypes does not seem to be mutually exclusive. Moreover, both A- and B-type variants were also expressed in the merozoite, present either in the apical region (A-type) or in the cytosol (B-type). The presence of RIFINs in merozoites suggests that antigenic variation in P. falciparum is not only restricted to parasite-derived proteins at the IE surface, but the phenomenon also prevails in other life cycle stages. Interestingly, some RIFIN variants were detected only in intracellular stages and not in merozoites, pointing to differential developmental expression patterns for distinct members of this large protein family.
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Affiliation(s)
- Michaela Petter
- Bernhard-Nocht Institute for Tropical Medicine, Bernhard-Nocht-Strasse 74, 20359, Hamburg, Germany
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45
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Iyer JK, Amaladoss A, Genesan S, Ganesan S, Preiser PR. Variable expression of the 235 kDa rhoptry protein ofPlasmodium yoeliimediate host cell adaptation and immune evasion. Mol Microbiol 2007; 65:333-46. [PMID: 17590237 DOI: 10.1111/j.1365-2958.2007.05786.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The severity of infections caused by the malaria parasite Plasmodium is in part due to the rapid multiplication cycles in the blood of an infected individual. A fundamental step in this phenomenon is the invasion of selected erythrocytes of the host by the parasite. The py235 rhoptry protein multigene family of the rodent malaria parasite Plasmodium yoelii has been implicated in mediating host cell selection during erythrocyte invasion and virulence. Here we show using quantitative real-time polymerase chain reaction and Western blot analysis that variations in the amounts of py235 may be a mechanism that the parasite uses to define its host cell repertoire. High levels of py235 expression leads to a wider range of erythrocytes invaded and therefore increased virulence. In contrast, to evade PY235-specific immunity, the parasite downregulates py235 thereby decreasing the host cell repertoire and virulence. These results demonstrate a new mechanism where variations in the amounts of parasite ligand define the parasite host cell repertoire and enable it to evade host immunity.
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Affiliation(s)
- Jayasree Kaveri Iyer
- Division of Genomics and Genetics, School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
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46
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Kaneko O. Erythrocyte invasion: vocabulary and grammar of the Plasmodium rhoptry. Parasitol Int 2007; 56:255-62. [PMID: 17596999 DOI: 10.1016/j.parint.2007.05.003] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Revised: 05/21/2007] [Accepted: 05/22/2007] [Indexed: 11/29/2022]
Abstract
Malaria is a dangerous infectious disease caused by obligate intracellular protozoan Plasmodium parasites. In the vertebrate host, erythrocyte recognition and establishment of a nascent parasitophorous vacuole are essential processes, and are largely achieved using molecules located in the microorganelles of the invasive-stage parasites. Recent proteome analyses of the phylogenetically related Toxoplasma parasite have provided protein catalogs for these microorganelles, which can now be used to identify orthologous proteins in the Plasmodium genome. Of importance is the formation of a complex between the proteins secreted from the rhoptry neck portion (RONs) and micronemes (AMA1), which localize at the moving junction during parasite invagination into the host cell. In this article I review the largely unexplored paradigm of the malaria merozoite rhoptry, focusing on the high molecular weight rhoptry protein complex (the RhopH complex), and speculate on its grammar during invasion.
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Affiliation(s)
- Osamu Kaneko
- Department of Molecular Parasitology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime 791-0295, Japan.
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47
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Jennings CV, Ahouidi AD, Zilversmit M, Bei AK, Rayner J, Sarr O, Ndir O, Wirth DF, Mboup S, Duraisingh MT. Molecular analysis of erythrocyte invasion in Plasmodium falciparum isolates from Senegal. Infect Immun 2007; 75:3531-8. [PMID: 17470537 PMCID: PMC1932937 DOI: 10.1128/iai.00122-07] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human malaria parasite, Plasmodium falciparum, utilizes multiple ligand-receptor interactions for the invasion of human erythrocytes. Members of the reticulocyte binding protein homolog (PfRh) family have been shown to be critical for directing parasites to alternative erythrocyte receptors that define invasion pathways. Recent studies have identified gene amplification, sequence polymorphism, and variant expression of PfRh paralogs as mechanisms underlying discrimination between pathways for invasion. In this study, we find considerable heterogeneity in the invasion profiles of clonal, uncultured P. falciparum parasite isolates from a low-transmission area in Senegal. Molecular analyses revealed minimal variation in protein expression levels of the PfRh ligands, PfRh1, PfRh2a, and PfRh2b, and an absence of gene amplification in these isolates. However, significant sequence polymorphism was found within repeat regions of PfRh1, PfRh2a, and PfRh2b. Furthermore, we identified a large sequence deletion ( approximately 0.58 kb) in the C-terminal region of the PfRh2b gene at a high prevalence in this population. In contrast to findings of earlier studies, we found no associations between specific sequence variants and distinct invasion pathways. Overall these data highlight the importance of region-specific elaborations in PfRh sequence and expression polymorphisms, which has important implications in our understanding of how the malaria parasite responds to polymorphisms in erythrocyte receptors and/or evades the immune system.
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Affiliation(s)
- Cameron V Jennings
- Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA
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48
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Plasmodium yoelii: combinatorial expression of variants of the 235 kDa rhoptry antigen during infection. Exp Parasitol 2007; 116:354-60. [PMID: 17368448 DOI: 10.1016/j.exppara.2007.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2006] [Revised: 01/31/2007] [Accepted: 02/04/2007] [Indexed: 11/15/2022]
Abstract
The 235 kDa rhoptry protein Py235 of Plasmodium yoelii, has been implicated in erythrocyte invasion by the merozoite forms of the parasite. Py235 is encoded by a large, highly polymorphic gene family, members of which appear to be differentially transcribed. However, it is not clear how many variants are expressed at the protein level during an infection cycle and whether or not these variants are expressed selectively or combinatorially. Certain monoclonal antibodies to Py235 have been shown to attenuate parasite virulence upon passive transfer into mice, suggesting that this antigen or its derivatives may be useful vaccine candidates. To provide a basis for this, we sought to identify those variants that are recognised by the host immune system, and to establish the pattern of expression of the antigen in mice during infection. Using Py235 monoclonal antibodies as probes, we isolated distinct antigenic variants from an expression library, suggesting that the antigen repertoire is potentially large and that different Py235 variants may be produced during infection. The implications of these observations are discussed with respect to the ability of a cloned parasite line to express distinct antigenic variants in vivo.
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49
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Iyer JK, Fuller K, Preiser PR. Differences in the copy number of the py235 gene family in virulent and avirulent lines of Plasmodium yoelii. Mol Biochem Parasitol 2006; 150:186-91. [PMID: 16959335 DOI: 10.1016/j.molbiopara.2006.07.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2005] [Revised: 07/28/2006] [Accepted: 07/29/2006] [Indexed: 11/18/2022]
Abstract
The 235kDa rhoptry protein (Py235) of Plasmodium yoelii is coded for by a multigene family. Py235 has been implicated in host cell selection and virulence as antibodies against it have been shown to inhibit invasion of mature red blood cells of the normally virulent P. yoelii YM line and at least one member of this family directly binds to erythrocytes. Differences in py235 sequence and copy number have been postulated to be responsible for the differences in invasion phenotype seen in the avirulent P. yoelii YA line and the YM line. The newly available sequence data for P. yoelii 17X NL 1.1 has now made it possible to investigate this further. A number of approaches including real time PCR was used to determine the exact copy number of individual py235. Except for two cases in YA and one in YM there are no differences in py235 copy number between the two lines and 17X NL 1.1. Analysis of progeny of a genetic cross between YM and an avirulent strain AC yield similar limited variations in copy number. This study shows that the copy number of py235 in the analyzed P. yoelii strains is significantly lower than previous estimates and much more in line with the published genome sequence. The lower copy number as well as the limited difference of py235 in the virulent lines makes it highly unlikely that these are the factors contributing to the differences in invasion observed.
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Affiliation(s)
- Jayasree K Iyer
- Division of Genomics and Genetics, School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
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Ogun SA, Howell SA, Taylor HM, Holder AA. A member of the py235 gene family of Plasmodium yoelii encodes an erythrocyte binding protein recognised by a protective monoclonal antibody. Mol Biochem Parasitol 2006; 147:140-3. [PMID: 16516987 DOI: 10.1016/j.molbiopara.2006.02.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2005] [Revised: 01/13/2006] [Accepted: 02/01/2006] [Indexed: 11/16/2022]
MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Monoclonal/immunology
- Antibodies, Monoclonal/metabolism
- Antibodies, Protozoan/immunology
- Antibodies, Protozoan/metabolism
- Antigens, Protozoan/chemistry
- Antigens, Protozoan/genetics
- Antigens, Protozoan/metabolism
- Erythrocytes/parasitology
- Molecular Sequence Data
- Peptide Mapping
- Plasmodium yoelii/genetics
- Plasmodium yoelii/growth & development
- Plasmodium yoelii/metabolism
- Plasmodium yoelii/pathogenicity
- Protozoan Proteins/chemistry
- Protozoan Proteins/genetics
- Protozoan Proteins/metabolism
- Receptors, Cell Surface/chemistry
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/metabolism
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Affiliation(s)
- Solabomi A Ogun
- Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, UK.
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