1
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Akhouri RR, Goel S, Skoglund U. Cryo-electron microscopy of IgM-VAR2CSA complex reveals IgM inhibits binding of Plasmodium falciparum to Chondroitin Sulfate A. Nat Commun 2023; 14:6391. [PMID: 37828011 PMCID: PMC10570280 DOI: 10.1038/s41467-023-41838-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 09/20/2023] [Indexed: 10/14/2023] Open
Abstract
Placental malaria is caused by Plasmodium falciparum-infected erythrocytes (IEs) adhering to chondroitin sulfate proteoglycans in placenta via VAR2CSA-type PfEMP1. Human pentameric immunoglobulin M (IgM) binds to several types of PfEMP1, including VAR2CSA via its Fc domain. Here, a 3.6 Å cryo-electron microscopy map of the IgM-VAR2CSA complex reveals that two molecules of VAR2CSA bind to the Cµ4 of IgM through their DBL3X and DBL5ε domains. The clockwise and anti-clockwise rotation of the two VAR2CSA molecules on opposite faces of IgM juxtaposes C-termini of both VAR2CSA near the J chain, where IgM creates a wall between both VAR2CSA molecules and hinders its interaction with its receptor. To support this, we show when VAR2CSA is bound to IgM, its staining on IEs as well as binding of IEs to chondroitin sulfate A in vitro is severely compromised.
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Affiliation(s)
- Reetesh Raj Akhouri
- Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan.
- Indian Institute of Technology Madras, Chennai, India.
| | - Suchi Goel
- Indian Institute of Science Education and Research Tirupati, Tirupati, India
| | - Ulf Skoglund
- Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
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2
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Ji C, Shen H, Su C, Li Y, Chen S, Sharp TH, Xiao J. Plasmodium falciparum has evolved multiple mechanisms to hijack human immunoglobulin M. Nat Commun 2023; 14:2650. [PMID: 37156765 PMCID: PMC10167334 DOI: 10.1038/s41467-023-38320-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 04/25/2023] [Indexed: 05/10/2023] Open
Abstract
Plasmodium falciparum causes the most severe malaria in humans. Immunoglobulin M (IgM) serves as the first line of humoral defense against infection and potently activates the complement pathway to facilitate P. falciparum clearance. A number of P. falciparum proteins bind IgM, leading to immune evasion and severe disease. However, the underlying molecular mechanisms remain unknown. Here, using high-resolution cryo-electron microscopy, we delineate how P. falciparum proteins VAR2CSA, TM284VAR1, DBLMSP, and DBLMSP2 target IgM. Each protein binds IgM in a different manner, and together they present a variety of Duffy-binding-like domain-IgM interaction modes. We further show that these proteins interfere directly with IgM-mediated complement activation in vitro, with VAR2CSA exhibiting the most potent inhibitory effect. These results underscore the importance of IgM for human adaptation of P. falciparum and provide critical insights into its immune evasion mechanism.
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Affiliation(s)
- Chenggong Ji
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
- Changping Laboratory, Beijing, PR China
| | - Hao Shen
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Chen Su
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Yaxin Li
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Shihua Chen
- Joint Graduate Program of Peking-Tsinghua-NIBS, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Thomas H Sharp
- Department of Cell and Chemical Biology, Section Electron Microscopy, Leiden University Medical Center, 2300, RC, Leiden, The Netherlands
| | - Junyu Xiao
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China.
- Changping Laboratory, Beijing, PR China.
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China.
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3
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Tomlinson A, Semblat JP, Gamain B, Chêne A. VAR2CSA-Mediated Host Defense Evasion of Plasmodium falciparum Infected Erythrocytes in Placental Malaria. Front Immunol 2021; 11:624126. [PMID: 33633743 PMCID: PMC7900151 DOI: 10.3389/fimmu.2020.624126] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/23/2020] [Indexed: 12/04/2022] Open
Abstract
Over 30 million women living in P. falciparum endemic areas are at risk of developing malaria during pregnancy every year. Placental malaria is characterized by massive accumulation of infected erythrocytes in the intervillous space of the placenta, accompanied by infiltration of immune cells, particularly monocytes. The consequent local inflammation and the obstruction of the maternofetal exchanges can lead to severe clinical outcomes for both mother and child. Even if protection against the disease can gradually be acquired following successive pregnancies, the malaria parasite has developed a large panel of evasion mechanisms to escape from host defense mechanisms and manipulate the immune system to its advantage. Infected erythrocytes isolated from placentas of women suffering from placental malaria present a unique phenotype and express the pregnancy-specific variant VAR2CSA of the Plasmodium falciparum Erythrocyte Membrane Protein (PfEMP1) family at their surface. The polymorphic VAR2CSA protein is able to mediate the interaction of infected erythrocytes with a variety of host cells including placental syncytiotrophoblasts and leukocytes but also with components of the immune system such as non-specific IgM. This review summarizes the described VAR2CSA-mediated host defense evasion mechanisms employed by the parasite during placental malaria to ensure its survival and persistence.
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Affiliation(s)
- Alice Tomlinson
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Jean-Philippe Semblat
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Benoît Gamain
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Arnaud Chêne
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratory of Excellence GR-Ex, Paris, France
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4
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Doritchamou JYA, Suurbaar J, Tuikue Ndam N. Progress and new horizons toward a VAR2CSA-based placental malaria vaccine. Expert Rev Vaccines 2021; 20:215-226. [PMID: 33472449 DOI: 10.1080/14760584.2021.1878029] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Introduction: Several malaria vaccines are under various phases of development with some promising results. In placental malaria (PM) a deliberately anti-disease approach is considered as many studies have underlined the key role of VAR2CSA protein, which therefore represents the leading vaccine candidate. However, evidence indicates that VAR2CSA antigenic polymorphism remains an obstacle to overcome.Areas covered: This review analyzes the progress made thus far in developing a VAR2CSA-based vaccine, and addresses the current issues and challenges that must be overcome to develop an effective PM vaccine.Expert opinion: Phase I trials of PAMVAC and PRIMVAC VAR2CSA vaccines have shown more or less satisfactory results with regards to safety and immunogenicity. The second generation of VAR2CSA-based vaccines could benefit from optimization approaches to broaden the activity spectrum against various placenta-binding isolates through continued advances in the structural understanding of the interaction with CSA.
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Affiliation(s)
- Justin Yai Alamou Doritchamou
- Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Jennifer Suurbaar
- Université de Paris, MERIT, IRD, F-75006 Paris, France.,Noguchi Memorial Institute for Medical Research, Department of Immunology, University of Ghana, Accra, Ghana
| | - Nicaise Tuikue Ndam
- Université de Paris, MERIT, IRD, F-75006 Paris, France.,Noguchi Memorial Institute for Medical Research, Department of Immunology, University of Ghana, Accra, Ghana
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5
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Otto TD, Assefa SA, Böhme U, Sanders MJ, Kwiatkowski D, Berriman M, Newbold C. Evolutionary analysis of the most polymorphic gene family in falciparum malaria. Wellcome Open Res 2019; 4:193. [PMID: 32055709 PMCID: PMC7001760 DOI: 10.12688/wellcomeopenres.15590.1] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/26/2019] [Indexed: 12/22/2022] Open
Abstract
The var gene family of the human malaria parasite Plasmodium falciparum encode proteins that are crucial determinants of both pathogenesis and immune evasion and are highly polymorphic. Here we have assembled nearly complete var gene repertoires from 2398 field isolates and analysed a normalised set of 714 from across 12 countries. This therefore represents the first large scale attempt to catalogue the worldwide distribution of var gene sequences We confirm the extreme polymorphism of this gene family but also demonstrate an unexpected level of sequence sharing both within and between continents. We show that this is likely due to both the remnants of selective sweeps as well as a worrying degree of recent gene flow across continents with implications for the spread of drug resistance. We also address the evolution of the var repertoire with respect to the ancestral genes within the Laverania and show that diversity generated by recombination is concentrated in a number of hotspots. An analysis of the subdomain structure indicates that some existing definitions may need to be revised From the analysis of this data, we can now understand the way in which the family has evolved and how the diversity is continuously being generated. Finally, we demonstrate that because the genes are distributed across the genome, sequence sharing between genotypes acts as a useful population genetic marker.
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Affiliation(s)
- Thomas D. Otto
- Parasite Genetics, Wellcome Trust Sanger Institute, Hinxton, UK
- Institute of Infection, Immunity & Inflammation, MVLS, University of Glasgow, Glasgow, UK
| | - Sammy A. Assefa
- Parasite Genetics, Wellcome Trust Sanger Institute, Hinxton, UK
| | - Ulrike Böhme
- Parasite Genetics, Wellcome Trust Sanger Institute, Hinxton, UK
| | | | - Dominic Kwiatkowski
- Parasite Genetics, Wellcome Trust Sanger Institute, Hinxton, UK
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Pf3k consortium
- Parasite Genetics, Wellcome Trust Sanger Institute, Hinxton, UK
- Institute of Infection, Immunity & Inflammation, MVLS, University of Glasgow, Glasgow, UK
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Matt Berriman
- Parasite Genetics, Wellcome Trust Sanger Institute, Hinxton, UK
| | - Chris Newbold
- Parasite Genetics, Wellcome Trust Sanger Institute, Hinxton, UK
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
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6
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Storm J, Jespersen JS, Seydel KB, Szestak T, Mbewe M, Chisala NV, Phula P, Wang CW, Taylor TE, Moxon CA, Lavstsen T, Craig AG. Cerebral malaria is associated with differential cytoadherence to brain endothelial cells. EMBO Mol Med 2019; 11:emmm.201809164. [PMID: 30610112 PMCID: PMC6365927 DOI: 10.15252/emmm.201809164] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Sequestration of Plasmodium falciparum‐infected erythrocytes (IE) within the brain microvasculature is a hallmark of cerebral malaria (CM). Using a microchannel flow adhesion assay with TNF‐activated primary human microvascular endothelial cells, we demonstrate that IE isolated from Malawian paediatric CM cases showed increased binding to brain microvascular endothelial cells compared to IE from uncomplicated malaria (UM) cases. Further, UM isolates showed significantly greater adhesion to dermal than to brain microvascular endothelial cells. The major mediator of parasite adhesion is P. falciparum erythrocyte membrane protein 1, encoded by var genes. Higher levels of var gene transcripts predicted to bind host endothelial protein C receptor (EPCR) and ICAM‐1 were detected in CM isolates. These data provide further evidence for differential tissue binding in severe and uncomplicated malaria syndromes, and give additional support to the hypothesis that CM pathology is based on increased cytoadherence of IE in the brain microvasculature.
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Affiliation(s)
- Janet Storm
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK .,Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi.,College of Medicine, University of Malawi, Blantyre, Malawi
| | - Jakob S Jespersen
- Department of International Health, Immunology & Microbiology, Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Karl B Seydel
- College of Medicine, University of Malawi, Blantyre, Malawi.,Blantyre Malaria Project, College of Medicine, University of Malawi, Blantyre, Malawi.,Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, USA
| | - Tadge Szestak
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Maurice Mbewe
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Ngawina V Chisala
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Patricia Phula
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Christian W Wang
- Department of International Health, Immunology & Microbiology, Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Terrie E Taylor
- Blantyre Malaria Project, College of Medicine, University of Malawi, Blantyre, Malawi.,Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, USA
| | - Christopher A Moxon
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK.,Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - Thomas Lavstsen
- Department of International Health, Immunology & Microbiology, Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Alister G Craig
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK
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7
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Quintana MDP, Ecklu-Mensah G, Tcherniuk SO, Ditlev SB, Oleinikov AV, Hviid L, Lopez-Perez M. Comprehensive analysis of Fc-mediated IgM binding to the Plasmodium falciparum erythrocyte membrane protein 1 family in three parasite clones. Sci Rep 2019; 9:6050. [PMID: 30988351 PMCID: PMC6465264 DOI: 10.1038/s41598-019-42585-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 04/03/2019] [Indexed: 12/14/2022] Open
Abstract
PfEMP1 is a family of adhesive proteins expressed on the surface of Plasmodium falciparum-infected erythrocytes (IEs), where they mediate adhesion of IEs to a range of host receptors. Efficient PfEMP1-dependent IE sequestration often depends on soluble serum proteins, including IgM. Here, we report a comprehensive investigation of which of the about 60 var gene-encoded PfEMP1 variants per parasite genome can bind IgM via the Fc part of the antibody molecule, and which of the constituent domains of those PfEMP1 are involved. We erased the epigenetic memory of var gene expression in three distinct P. falciparum clones, 3D7, HB3, and IT4/FCR3 by promoter titration, and then isolated individual IEs binding IgM from malaria-unexposed individuals by fluorescence-activated single-cell sorting. The var gene transcription profiles of sub-clones measured by real-time qPCR were used to identify potential IgM-binding PfEMP1 variants. Recombinant DBL and CIDR domains corresponding to those variants were tested by ELISA and protein arrays to confirm their IgM-binding capacity. Selected DBL domains were used to raise specific rat anti-sera to select IEs with uniform expression of candidate PfEMP1 proteins. Our data document that IgM-binding PfEMP1 proteins are common in each of the three clones studied, and that the binding epitopes are mainly found in DBLε and DBLζ domains near the C-terminus.
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Affiliation(s)
- Maria Del Pilar Quintana
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Gertrude Ecklu-Mensah
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Sergey O Tcherniuk
- Charles E Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA
| | - Sisse Bolm Ditlev
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Andrew V Oleinikov
- Charles E Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, USA
| | - Lars Hviid
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark. .,Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark.
| | - Mary Lopez-Perez
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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8
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Seitz J, Morales-Prieto DM, Favaro RR, Schneider H, Markert UR. Molecular Principles of Intrauterine Growth Restriction in Plasmodium Falciparum Infection. Front Endocrinol (Lausanne) 2019; 10:98. [PMID: 30930847 PMCID: PMC6405475 DOI: 10.3389/fendo.2019.00098] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Accepted: 02/01/2019] [Indexed: 12/21/2022] Open
Abstract
Malaria in pregnancy still constitutes a particular medical challenge in tropical and subtropical regions. Of the five Plasmodium species that are pathogenic to humans, infection with Plasmodium falciparum leads to fulminant progression of the disease with massive impact on pregnancy. Severe anemia of the mother, miscarriage, stillbirth, preterm delivery and intrauterine growth restriction (IUGR) with reduced birth weight are frequent complications that lead to more than 10,000 maternal and 200,000 perinatal deaths annually in sub-Saharan Africa alone. P. falciparum can adhere to the placenta via the expression of the surface antigen VAR2CSA, which leads to sequestration of infected erythrocytes in the intervillous space. This process induces a placental inflammation with involvement of immune cells and humoral factors. Especially, monocytes get activated and change the release of soluble mediators, including a variety of cytokines. This proinflammatory environment contributes to disorders of angiogenesis, blood flow, autophagy, and nutrient transport in the placenta and erythropoiesis. Collectively, they impair placental functions and, consequently, fetal growth. The discovery that women in endemic regions develop a certain immunity against VAR2CSA-expressing parasites with increasing number of pregnancies has redefined the understanding of malaria in pregnancy and offers strategies for the development of vaccines. The following review gives an overview of molecular processes in P. falciparum infection in pregnancy which may be involved in the development of IUGR.
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Affiliation(s)
- Johanna Seitz
- Placenta Lab, Department of Obstetrics, Jena University Hospital, Jena, Germany
| | | | - Rodolfo R. Favaro
- Placenta Lab, Department of Obstetrics, Jena University Hospital, Jena, Germany
| | - Henning Schneider
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
- Department of Obstetrics and Gynecology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Udo Rudolf Markert
- Placenta Lab, Department of Obstetrics, Jena University Hospital, Jena, Germany
- *Correspondence: Udo Rudolf Markert
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9
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Borges da Silva H, Machado de Salles É, Lima-Mauro EF, Sardinha LR, Álvarez JM, D’Império Lima MR. CD28 deficiency leads to accumulation of germinal-center independent IgM+ experienced B cells and to production of protective IgM during experimental malaria. PLoS One 2018; 13:e0202522. [PMID: 30148845 PMCID: PMC6110469 DOI: 10.1371/journal.pone.0202522] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 08/03/2018] [Indexed: 12/04/2022] Open
Abstract
Protective immunity to blood-stage malaria is attributed to Plasmodium-specific IgG and effector-memory T helper 1 (Th1) cells. However, mice lacking the costimulatory receptor CD28 (CD28KO) maintain chronic parasitemia at low levels and do not succumb to infection, suggesting that other immune responses contribute to parasite control. We report here that CD28KO mice develop long-lasting non-sterile immunity and survive lethal parasite challenge. This protection correlated with a progressive increase of anti-parasite IgM serum levels during chronic infection. Serum IgM from chronically infected CD28KO mice recognize erythrocytes infected with mature parasites, and effectively control Plasmodium infection by promoting parasite lysis and uptake. These antibodies also recognize autoantigens and antigens from other pathogens. Chronically infected CD28KO mice have high numbers of IgM+ plasmocytes and experienced B cells, exhibiting a germinal-center independent Fas+GL7-CD38+CD73- phenotype. These cells are also present in chronically infected C57BL/6 mice although in lower numbers. Finally, IgM+ experienced B cells from cured C57BL/6 and CD28KO mice proliferate and produce anti-parasite IgM in response to infected erythrocytes. This study demonstrates that CD28 deficiency results in the generation of germinal-center independent IgM+ experienced B cells and the production of protective IgM during experimental malaria, providing evidence for an additional mechanism by which the immune system controls Plasmodium infection.
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Affiliation(s)
- Henrique Borges da Silva
- Departamento de Imunologia, Instituto de Ciências Biomédicas (ICB), Universidade de São Paulo (USP), São Paulo, Brazil
- * E-mail: (HBdS); (MRDL)
| | - Érika Machado de Salles
- Departamento de Imunologia, Instituto de Ciências Biomédicas (ICB), Universidade de São Paulo (USP), São Paulo, Brazil
| | | | | | - José Maria Álvarez
- Departamento de Imunologia, Instituto de Ciências Biomédicas (ICB), Universidade de São Paulo (USP), São Paulo, Brazil
| | - Maria Regina D’Império Lima
- Departamento de Imunologia, Instituto de Ciências Biomédicas (ICB), Universidade de São Paulo (USP), São Paulo, Brazil
- * E-mail: (HBdS); (MRDL)
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10
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Wahlgren M, Goel S, Akhouri RR. Variant surface antigens of Plasmodium falciparum and their roles in severe malaria. Nat Rev Microbiol 2017; 15:479-491. [DOI: 10.1038/nrmicro.2017.47] [Citation(s) in RCA: 142] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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11
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Hsieh FL, Turner L, Bolla JR, Robinson CV, Lavstsen T, Higgins MK. The structural basis for CD36 binding by the malaria parasite. Nat Commun 2016; 7:12837. [PMID: 27667267 PMCID: PMC5052687 DOI: 10.1038/ncomms12837] [Citation(s) in RCA: 140] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 08/04/2016] [Indexed: 12/18/2022] Open
Abstract
CD36 is a scavenger receptor involved in fatty acid metabolism, innate immunity and angiogenesis. It interacts with lipoprotein particles and facilitates uptake of long chain fatty acids. It is also the most common target of the PfEMP1 proteins of the malaria parasite, Plasmodium falciparum, tethering parasite-infected erythrocytes to endothelial receptors. This prevents their destruction by splenic clearance and allows increased parasitaemia. Here we describe the structure of CD36 in complex with long chain fatty acids and a CD36-binding PfEMP1 protein domain. A conserved hydrophobic pocket allows the hugely diverse PfEMP1 protein family to bind to a conserved phenylalanine residue at the membrane distal tip of CD36. This phenylalanine is also required for CD36 to interact with lipoprotein particles. By targeting a site on CD36 that is required for its physiological function, PfEMP1 proteins maintain the ability to tether to the endothelium and avoid splenic clearance. Targeting of the CD36 scavenger receptor by the malaria parasite effector PfEMP1 prevents splenic clearance of infected erythrocytes. Here, the authors propose that diverse PfEMP1 achieve this by binding to a conserved phenylalanine residue in CD36 that is also required for lipoprotein binding.
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Affiliation(s)
- Fu-Lien Hsieh
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Louise Turner
- Centre for Medical Parasitology, Department of International Health, Immunology &Microbiology, University of Copenhagen and Department of Infectious Diseases, Rigshospitalet, Copenhagen 1017, Denmark
| | - Jani Reddy Bolla
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks, Oxford OX1 3QZ, UK
| | - Carol V Robinson
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks, Oxford OX1 3QZ, UK
| | - Thomas Lavstsen
- Centre for Medical Parasitology, Department of International Health, Immunology &Microbiology, University of Copenhagen and Department of Infectious Diseases, Rigshospitalet, Copenhagen 1017, Denmark
| | - Matthew K Higgins
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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12
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Jespersen JS, Wang CW, Mkumbaye SI, Minja DT, Petersen B, Turner L, Petersen JE, Lusingu JP, Theander TG, Lavstsen T. Plasmodium falciparum var genes expressed in children with severe malaria encode CIDRα1 domains. EMBO Mol Med 2016; 8:839-50. [PMID: 27354391 PMCID: PMC4967939 DOI: 10.15252/emmm.201606188] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Most severe Plasmodium falciparum infections are experienced by young children. Severe symptoms are precipitated by vascular sequestration of parasites expressing a particular subset of the polymorphic P. falciparum erythrocyte membrane protein 1 (PfEMP1) adhesion molecules. Parasites binding human endothelial protein C receptor (EPCR) through the CIDRα1 domain of certain PfEMP1 were recently associated with severe malaria in children. However, it has remained unclear to which extend the EPCR‐binding CIDRα1 domains epitomize PfEMP1 expressed in severe malaria. Here, we characterized the near full‐length transcripts dominating the var transcriptome in children with severe malaria and found that the only common feature of the encoded PfEMP1 was CIDRα1 domains. Such genes were highly and dominantly expressed in both children with severe malarial anaemia and cerebral malaria. These observations support the hypothesis that the CIDRα1‐EPCR interaction is key to the pathogenesis of severe malaria and strengthen the rationale for pursuing a vaccine or adjunctive treatment aiming at inhibiting or reducing the damaging effects of this interaction.
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Affiliation(s)
- Jakob S Jespersen
- Centre for Medical Parasitology, Department of Immunology & Microbiology, University of Copenhagen, Copenhagen, Denmark Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Christian W Wang
- Centre for Medical Parasitology, Department of Immunology & Microbiology, University of Copenhagen, Copenhagen, Denmark Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Sixbert I Mkumbaye
- Kilimanjaro Christian Medical University College, Kilimanjaro Clinical Research Institute, Moshi, Tanzania
| | - Daniel Tr Minja
- National Institute for Medical Research, Tanga Research Centre, Tanga, Tanzania
| | - Bent Petersen
- Centre for Biological Sequence Analysis, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Louise Turner
- Centre for Medical Parasitology, Department of Immunology & Microbiology, University of Copenhagen, Copenhagen, Denmark Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Jens Ev Petersen
- Centre for Medical Parasitology, Department of Immunology & Microbiology, University of Copenhagen, Copenhagen, Denmark Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - John Pa Lusingu
- Centre for Medical Parasitology, Department of Immunology & Microbiology, University of Copenhagen, Copenhagen, Denmark Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark National Institute for Medical Research, Tanga Research Centre, Tanga, Tanzania
| | - Thor G Theander
- Centre for Medical Parasitology, Department of Immunology & Microbiology, University of Copenhagen, Copenhagen, Denmark Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Thomas Lavstsen
- Centre for Medical Parasitology, Department of Immunology & Microbiology, University of Copenhagen, Copenhagen, Denmark Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
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13
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Crosnier C, Iqbal Z, Knuepfer E, Maciuca S, Perrin AJ, Kamuyu G, Goulding D, Bustamante LY, Miles A, Moore SC, Dougan G, Holder AA, Kwiatkowski DP, Rayner JC, Pleass RJ, Wright GJ. Binding of Plasmodium falciparum Merozoite Surface Proteins DBLMSP and DBLMSP2 to Human Immunoglobulin M Is Conserved among Broadly Diverged Sequence Variants. J Biol Chem 2016; 291:14285-14299. [PMID: 27226583 PMCID: PMC4933183 DOI: 10.1074/jbc.m116.722074] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Indexed: 11/17/2022] Open
Abstract
Diversity at pathogen genetic loci can be driven by host adaptive immune selection pressure and may reveal proteins important for parasite biology. Population-based genome sequencing of Plasmodium falciparum, the parasite responsible for the most severe form of malaria, has highlighted two related polymorphic genes called dblmsp and dblmsp2, which encode Duffy binding-like (DBL) domain-containing proteins located on the merozoite surface but whose function remains unknown. Using recombinant proteins and transgenic parasites, we show that DBLMSP and DBLMSP2 directly and avidly bind human IgM via their DBL domains. We used whole genome sequence data from over 400 African and Asian P. falciparum isolates to show that dblmsp and dblmsp2 exhibit extreme protein polymorphism in their DBL domain, with multiple variants of two major allelic classes present in every population tested. Despite this variability, the IgM binding function was retained across diverse sequence representatives. Although this interaction did not seem to have an effect on the ability of the parasite to invade red blood cells, binding of DBLMSP and DBLMSP2 to IgM inhibited the overall immunoreactivity of these proteins to IgG from patients who had been exposed to the parasite. This suggests that IgM binding might mask these proteins from the host humoral immune system.
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Affiliation(s)
- Cécile Crosnier
- Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom; Malaria Programme, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - Zamin Iqbal
- Wellcome Trust Centre for Human Genetics, Oxford OX3 7BN, United Kingdom
| | - Ellen Knuepfer
- Francis Crick Institute, Mill Hill Laboratory, London NW7 1AA, United Kingdom
| | - Sorina Maciuca
- Wellcome Trust Centre for Human Genetics, Oxford OX3 7BN, United Kingdom
| | - Abigail J Perrin
- Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom; Malaria Programme, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - Gathoni Kamuyu
- Malaria Programme, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - David Goulding
- Microbial Pathogenesis Laboratory, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - Leyla Y Bustamante
- Malaria Programme, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - Alistair Miles
- Malaria Programme, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom; Wellcome Trust Centre for Human Genetics, Oxford OX3 7BN, United Kingdom
| | - Shona C Moore
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom; Warwick Systems Biology Centre, Senate House, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Gordon Dougan
- Microbial Pathogenesis Laboratory, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - Anthony A Holder
- Francis Crick Institute, Mill Hill Laboratory, London NW7 1AA, United Kingdom
| | - Dominic P Kwiatkowski
- Malaria Programme, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom; Wellcome Trust Centre for Human Genetics, Oxford OX3 7BN, United Kingdom
| | - Julian C Rayner
- Malaria Programme, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - Richard J Pleass
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom
| | - Gavin J Wright
- Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom; Malaria Programme, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom.
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14
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Pleass RJ, Moore SC, Stevenson L, Hviid L. Immunoglobulin M: Restrainer of Inflammation and Mediator of Immune Evasion by Plasmodium falciparum Malaria. Trends Parasitol 2015; 32:108-119. [PMID: 26597020 DOI: 10.1016/j.pt.2015.09.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 09/16/2015] [Accepted: 09/23/2015] [Indexed: 02/06/2023]
Abstract
Immunoglobulin M (IgM) is an ancient antibody class that is found in all vertebrates, with the exception of coelacanths, and is indispensable in both innate and adaptive immunity. The equally ancient human malaria parasite, Plasmodium falciparum, formed an intimate relationship with IgM with which it co-evolved. In this article, we discuss the association between IgM and human malaria parasites, building on several recent publications that implicate IgM as a crucial molecule that determines both host and parasite survival. Consequently, a better understanding of this association may lead to the development of improved intervention strategies.
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Affiliation(s)
- Richard J Pleass
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
| | - Shona C Moore
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK; Warwick Systems Biology Centre, Senate House, University of Warwick, Coventry, CV4 7AL, UK
| | - Liz Stevenson
- Centre for Medical Parasitology, Department of Immunology and Microbiology (ISIM), Faculty of Health and Medical Sciences, University of Copenhagen and Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Lars Hviid
- Centre for Medical Parasitology, Department of Immunology and Microbiology (ISIM), Faculty of Health and Medical Sciences, University of Copenhagen and Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark.
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15
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Multiple Plasmodium falciparum Erythrocyte Membrane Protein 1 Variants per Genome Can Bind IgM via Its Fc Fragment Fcμ. Infect Immun 2015. [PMID: 26216422 PMCID: PMC4567627 DOI: 10.1128/iai.00337-15] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) adhesive proteins expressed on the surfaces of infected erythrocytes (IEs) are of key importance in the pathogenesis of P. falciparum malaria. Several structurally and functionally defined PfEMP1 types have been associated with severe clinical manifestations, such as cerebral malaria in children and placental malaria in pregnant women. PfEMP1 that can bind the Fc part of IgM (Fcμ) characterizes one such type, although the functional significance of this IgM binding to PfEMP1 remains unclear. In this study, we report the identification and functional analysis of five IgM-binding PfEMP1 proteins encoded by P. falciparum NF54. In addition to the VAR2CSA-type PFL0030c protein, already known to bind Fcμ and to mediate chondroitin sulfate A (CSA)-specific adhesion of IEs in the placenta, we found four PfEMP1 proteins not previously known to bind IgM this way. Although they all contained Duffy binding-like ε (DBLε) domains similar to those in VAR2CSA-type PfEMP1, they did not mediate IE adhesion to CSA, and IgM binding did not shield IEs from phagocytosis of IgG-opsonized IEs. In this way, these new IgM-binding PfEMP1 proteins resemble the rosette-mediating and IgM-binding PfEMP1 HB3VAR06, but none of them mediated formation of rosettes. We could map the capacity for Fc-specific IgM binding to DBLε domains near the C terminus for three of the four PfEMP1 proteins tested. Our study provides new evidence regarding Fc-dependent binding of IgM to PfEMP1, which appears to be a common and multifunctional phenotype.
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16
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McLEAN ARD, ATAIDE R, SIMPSON JA, BEESON JG, FOWKES FJI. Malaria and immunity during pregnancy and postpartum: a tale of two species. Parasitology 2015; 142:999-1015. [PMID: 25731914 PMCID: PMC4453920 DOI: 10.1017/s0031182015000074] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 12/19/2014] [Accepted: 01/16/2015] [Indexed: 11/07/2022]
Abstract
It is well established that pregnant women are at an increased risk of Plasmodium falciparum infection when compared to non-pregnant individuals and limited epidemiological data suggest Plasmodium vivax risk also increases with pregnancy. The risk of P. falciparum declines with successive pregnancies due to the acquisition of immunity to pregnancy-specific P. falciparum variants. However, despite similar declines in P. vivax risk with successive pregnancies, there is a paucity of evidence P. vivax-specific immunity. Cross-species immunity, as well as immunological and physiological changes that occur during pregnancy may influence the susceptibility to both P. vivax and P. falciparum. The period following delivery, the postpartum period, is relatively understudied and available epidemiological data suggests that it may also be a period of increased risk of infection to Plasmodium spp. Here we review the literature and directly compare and contrast the epidemiology, clinical pathogenesis and immunological features of P. vivax and P. falciparum in pregnancy, with a particular focus on studies performed in areas co-endemic for both species. Furthermore, we review the intriguing epidemiology literature of both P. falciparum and P. vivax postpartum and relate observations to the growing literature pertaining to malaria immunology in the postpartum period.
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Affiliation(s)
- A. R. D. McLEAN
- Macfarlane Burnet Institute of Medical Research, 85 Commercial Road, Melbourne, Victoria 3004, Australia
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Victoria, Australia
| | - R. ATAIDE
- Macfarlane Burnet Institute of Medical Research, 85 Commercial Road, Melbourne, Victoria 3004, Australia
| | - J. A. SIMPSON
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Victoria, Australia
| | - J. G. BEESON
- Macfarlane Burnet Institute of Medical Research, 85 Commercial Road, Melbourne, Victoria 3004, Australia
- Department of Microbiology, Monash University, Melbourne, Victoria, Australia
- Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia
| | - F. J. I. FOWKES
- Macfarlane Burnet Institute of Medical Research, 85 Commercial Road, Melbourne, Victoria 3004, Australia
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Victoria, Australia
- Department of Epidemiology and Preventive Medicine and Department of Infectious Diseases, Monash University, Commercial Road, Melbourne, Victoria 3004, Australia
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17
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Semblat JP, Ghumra A, Czajkowsky DM, Wallis R, Mitchell DA, Raza A, Rowe JA. Identification of the minimal binding region of a Plasmodium falciparum IgM binding PfEMP1 domain. Mol Biochem Parasitol 2015; 201:76-82. [PMID: 26094597 PMCID: PMC4539346 DOI: 10.1016/j.molbiopara.2015.06.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 05/22/2015] [Accepted: 06/08/2015] [Indexed: 11/29/2022]
Abstract
Many pathogens bind the Fc region of host immunoglobulin to evade immunity. We examined a Plasmodium falciparum IgM binding PfEMP1 domain TM284var1 DBL4ζ. We identified the minimal IgM binding region comprising subdomain 2 and flanking regions. Specific charged amino acids were mutated but did not markedly affect IgM binding. Existing models of PfEMP1-IgM interaction need to be revised.
Binding of host immunoglobulin is a common immune evasion mechanism demonstrated by microbial pathogens. Previous work showed that the malaria parasite Plasmodium falciparum binds the Fc-region of human IgM molecules, resulting in a coating of IgM on the surface of infected erythrocytes. IgM binding is a property of P. falciparum strains showing virulence-related phenotypes such as erythrocyte rosetting. The parasite ligands for IgM binding are members of the diverse P. falciparum Erythrocyte Membrane Protein One (PfEMP1) family. However, little is known about the amino acid sequence requirements for IgM binding. Here we studied an IgM binding domain from a rosette-mediating PfEMP1 variant, DBL4ζ of TM284var1, and found that the minimal IgM binding region mapped to the central region of the DBL domain, comprising all of subdomain 2 and adjoining parts of subdomains 1 and 3. Site-directed mutagenesis of charged amino acids within subdomain 2, predicted by molecular modelling to form the IgM binding site, showed no marked effect on IgM binding properties. Overall, this study identifies the minimal IgM binding region of a PfEMP1 domain, and indicates that the existing homology model of PfEMP1-IgM interaction is incorrect. Further work is needed to identify the specific interaction site for IgM within the minimal binding region of PfEMP1.
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Affiliation(s)
- Jean-Philippe Semblat
- Institute of Immunology and Infection Research, Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom
| | - Ashfaq Ghumra
- Institute of Immunology and Infection Research, Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom
| | - Daniel M Czajkowsky
- Bio-ID Center, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Russell Wallis
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, United Kingdom
| | - Daniel A Mitchell
- Clinical Sciences Research Laboratories, Warwick Medical School, Coventry CV2 2DX, United Kingdom
| | - Ahmed Raza
- Institute of Immunology and Infection Research, Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom
| | - J Alexandra Rowe
- Institute of Immunology and Infection Research, Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom.
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18
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Guiyedi V, Bécavin C, Herbert F, Gray J, Cazenave PA, Kombila M, Crisanti A, Fesel C, Pied S. Asymptomatic Plasmodium falciparum infection in children is associated with increased auto-antibody production, high IL-10 plasma levels and antibodies to merozoite surface protein 3. Malar J 2015; 14:162. [PMID: 25889717 PMCID: PMC4419484 DOI: 10.1186/s12936-015-0658-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 03/19/2015] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND Mechanisms of acquired protection to malaria in asymptomatic Plasmodium falciparum carriers are only partially understood. Among them, the role plays by the self-reactive antibodies has not been clarified yet. In this study, the relationship between repertoires of circulating self-reactive and parasite-specific immunoglobulin G (IgG), their correlation with cytokine levels, and their association with protection against malaria was investigated in asymptomatic Plasmodium falciparum-infected Gabonese children. METHODS The diversity of P. falciparum-specific antibody repertoire was analysed using a protein micro-array immunoassay, the total auto-antibody repertoire by quantitative immunoblotting and circulating cytokine levels were measured by ELISA in endemic controls (EC) and P. falciparum-infected children from Gabon with asymptomatic (AM) or mild malaria (MM). The association of self- and parasite-specific antibody repertoires with circulating cytokines was evaluated using single linkage hierarchical clustering, Kruskal-Wallis tests and Spearman's rank correlation. RESULTS Children with AM exhibited an IgG response to merozoite surface protein 3 (MSP3) but not to MSP1-19, although their levels of total P. falciparum-specific IgG were similar to those in the MM group. Moreover, the asymptomatic children had increased levels of autoantibodies recognising brain antigens. In addition, a correlation between IL-10 levels and parasite load was found in AM and MM children. These two groups also exhibited significant correlations between plasma levels of IL-10 and IFN-γ with age and with total plasma IgG levels. IL-10 and IFN-γ levels were also associated with auto-antibody responses in AM. CONCLUSIONS Altogether, these results indicate that a self-reactive polyclonal response associated with increased IgG to MSP3 and high plasma levels of IL-10 and IFN-γ may contribute to protective immune mechanisms triggered in asymptomatic P. falciparum infection in Gabonese children.
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Affiliation(s)
- Vincent Guiyedi
- CIIL-Centre for Infection and Immunity of Lille, INSERM U1019 - CNRS UMR 8204, Lille University, Institut Pasteur de Lille, 1, rue du Professeur Calmette, Cedex 59019, Lille, France.
- Département de Parasitologie-Mycologie-Médecine Tropicale, Faculté de Médecine de Libreville, Université des Sciences de la Santé, Owendo, Gabon.
| | - Christophe Bécavin
- Département de Biologie Cellulaire et Infection, Institut Pasteur, Unité des Interactions Bactéries-Cellules, F-75015, Paris, France.
| | - Fabien Herbert
- CIIL-Centre for Infection and Immunity of Lille, INSERM U1019 - CNRS UMR 8204, Lille University, Institut Pasteur de Lille, 1, rue du Professeur Calmette, Cedex 59019, Lille, France.
| | - Julian Gray
- Department of Biological Sciences, London Imperial College, London, UK.
| | - Pierre-André Cazenave
- CIIL-Centre for Infection and Immunity of Lille, INSERM U1019 - CNRS UMR 8204, Lille University, Institut Pasteur de Lille, 1, rue du Professeur Calmette, Cedex 59019, Lille, France.
| | - Maryvonne Kombila
- Département de Parasitologie-Mycologie-Médecine Tropicale, Faculté de Médecine de Libreville, Université des Sciences de la Santé, Owendo, Gabon.
| | - Andrea Crisanti
- Department of Biological Sciences, London Imperial College, London, UK.
| | | | - Sylviane Pied
- CIIL-Centre for Infection and Immunity of Lille, INSERM U1019 - CNRS UMR 8204, Lille University, Institut Pasteur de Lille, 1, rue du Professeur Calmette, Cedex 59019, Lille, France.
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19
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Stevenson L, Huda P, Jeppesen A, Laursen E, Rowe JA, Craig A, Streicher W, Barfod L, Hviid L. Investigating the function of Fc-specific binding of IgM to Plasmodium falciparum erythrocyte membrane protein 1 mediating erythrocyte rosetting. Cell Microbiol 2015; 17:819-31. [PMID: 25482886 PMCID: PMC4737123 DOI: 10.1111/cmi.12403] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 11/28/2014] [Accepted: 12/01/2014] [Indexed: 02/02/2023]
Abstract
Acquired protection from Plasmodium falciparum malaria takes years to develop, probably reflecting the ability of the parasites to evade immunity. A recent example of this is the binding of the Fc region of IgM to VAR2CSA‐type PfEMP1. This interferes with specific IgG recognition and phagocytosis of opsonized infected erythrocytes (IEs) without compromising the placental IE adhesion mediated by this PfEMP1 type. IgM also binds via Fc to several other PfEMP1 proteins, where it has been proposed to facilitate rosetting (binding of uninfected erythrocytes to a central IE). To further dissect the functional role of Fc‐mediated IgM binding to PfEMP1, we studied the PfEMP1 protein HB3VAR06, which mediates rosetting and binds IgM. Binding of IgM to this PfEMP1 involved the Fc domains Cμ3‐Cμ4 in IgM and the penultimate DBL domain (DBLζ2) at the C‐terminus of HB3VAR06. However, IgM binding did not inhibit specific IgG labelling of HB3VAR06 or shield IgG‐opsonized IEs from phagocytosis. Instead, IgM was required for rosetting, and each pentameric IgM molecule could bind two HB3VAR06 molecules. Together, our data indicate that the primary function of Fc‐mediated IgM binding in rosetting is not to shield IE from specific IgG recognition and phagocytosis as in VAR2CSA‐type PfEMP1. Rather, the function appears to be strengthening of IE–erythrocyte interactions. In conclusion, our study provides new evidence on the molecular details and functional significance of rosetting, a long‐recognized marker of parasites that cause severe P. falciparum malaria.
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Affiliation(s)
- Liz Stevenson
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Pie Huda
- Niels Bohr Institute, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Anine Jeppesen
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Erik Laursen
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - J Alexandra Rowe
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, UK
| | - Alister Craig
- Liverpool School of Tropical Medicine, Liverpool, UK
| | - Werner Streicher
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lea Barfod
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Lars Hviid
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
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20
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Antigen reversal identifies targets of opsonizing IgGs against pregnancy-associated malaria. Infect Immun 2014; 82:4842-53. [PMID: 25156731 DOI: 10.1128/iai.02097-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Clinical immunity to pregnancy associated-malaria (PAM) in multigravida women has been attributed to antibodies that recognize VAR2CSA on the infected erythrocyte (IE) surface. The size and complexity of VAR2CSA have focused efforts on selecting one or more of its six Duffy binding-like (DBL) domains for vaccine development. Presently, however, there is no consensus as to which DBL domain(s) would be most effective in eliciting immunity. This is because antibodies to a number of the DBL domains have been found to block the adhesion of VAR2CSA-expressing erythrocytes to chondroitin sulfate A (CSA)-a major criterion for evaluating vaccine candidacy. Opsonization of IEs by cytophilic antibodies that recognize VAR2CSA represents an important yet understudied effector mechanism in acquired immunity to PAM. To date, no studies have sought to determine the targets of those antibodies. In this study, we found that IgGs from multigravida Malian women showed (i) higher reactivity to recombinant DBL domains by enzyme-linked immunosorbent assay (ELISA), (ii) more binding to VAR2CSA-expressing IEs, and (iii) greater opsonization of these IEs by human monocytic cells than IgGs from malaria-exposed Malian men and malaria-naive American adults. Preincubation of IgGs from multigravida women with recombinant DBL2χ, DBL3χ, or DBL5ε domains significantly diminished opsonization of VAR2CSA-expressing IEs by human monocytes. These data identify the DBL2χ, DBL3χ, and DBL5ε domains as the primary targets of opsonizing IgGs for the first time. Our study introduces a new approach to determining the antigenic targets of opsonizing IgGs in phagocytosis assays.
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21
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Ghumra A, Semblat JP, Ataide R, Kifude C, Adams Y, Claessens A, Anong DN, Bull PC, Fennell C, Arman M, Amambua-Ngwa A, Walther M, Conway DJ, Kassambara L, Doumbo OK, Raza A, Rowe JA. Induction of strain-transcending antibodies against Group A PfEMP1 surface antigens from virulent malaria parasites. PLoS Pathog 2012; 8:e1002665. [PMID: 22532802 PMCID: PMC3330128 DOI: 10.1371/journal.ppat.1002665] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2011] [Accepted: 03/08/2012] [Indexed: 12/22/2022] Open
Abstract
Sequence diversity in pathogen antigens is an obstacle to the development of interventions against many infectious diseases. In malaria caused by Plasmodium falciparum, the PfEMP1 family of variant surface antigens encoded by var genes are adhesion molecules that play a pivotal role in malaria pathogenesis and clinical disease. PfEMP1 is a major target of protective immunity, however, development of drugs or vaccines based on PfEMP1 is problematic due to extensive sequence diversity within the PfEMP1 family. Here we identified the PfEMP1 variants transcribed by P. falciparum strains selected for a virulence-associated adhesion phenotype (IgM-positive rosetting). The parasites transcribed a subset of Group A PfEMP1 variants characterised by an unusual PfEMP1 architecture and a distinct N-terminal domain (either DBLα1.5 or DBLα1.8 type). Antibodies raised in rabbits against the N-terminal domains showed functional activity (surface reactivity with live infected erythrocytes (IEs), rosette inhibition and induction of phagocytosis of IEs) down to low concentrations (<10 µg/ml of total IgG) against homologous parasites. Furthermore, the antibodies showed broad cross-reactivity against heterologous parasite strains with the same rosetting phenotype, including clinical isolates from four sub-Saharan African countries that showed surface reactivity with either DBLα1.5 antibodies (variant HB3var6) or DBLα1.8 antibodies (variant TM284var1). These data show that parasites with a virulence-associated adhesion phenotype share IE surface epitopes that can be targeted by strain-transcending antibodies to PfEMP1. The existence of shared surface epitopes amongst functionally similar disease-associated P. falciparum parasite isolates suggests that development of therapeutic interventions to prevent severe malaria is a realistic goal. Malaria remains one of the world's most deadly diseases. Life-threatening malaria is linked to a process called rosetting, in which malaria parasite-infected red blood cells bind to uninfected red cells to form aggregates that block blood flow in vital organs such as the brain. Current efforts to develop drugs or vaccines against rosetting are hindered by variation in the parasite rosette-mediating proteins, found on the surface of infected red cells. We studied these parasite-derived surface proteins and discovered that although they are variable, they share some common features. We raised antibodies against the rosette-mediating proteins, and found that they cross-reacted with multiple rosetting parasite strains from different countries around the world, including samples collected directly from African children with severe malaria. These findings provide new insights into malaria parasite interactions with human cells, and provide proof of principle that variable parasite molecules from virulent malaria parasites can induce strain-transcending antibodies. Hence, this work provides the foundation for the development of new therapies to treat or prevent life-threatening malaria.
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Affiliation(s)
- Ashfaq Ghumra
- Centre for Immunity, Infection and Evolution, Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Jean-Philippe Semblat
- Centre for Immunity, Infection and Evolution, Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Ricardo Ataide
- Centre for Immunity, Infection and Evolution, Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Carolyne Kifude
- Centre for Immunity, Infection and Evolution, Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Yvonne Adams
- Centre for Immunity, Infection and Evolution, Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Antoine Claessens
- Centre for Immunity, Infection and Evolution, Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Damian N. Anong
- Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Peter C. Bull
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Clare Fennell
- Centre for Immunity, Infection and Evolution, Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Monica Arman
- Centre for Immunity, Infection and Evolution, Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Michael Walther
- Medical Research Council Laboratories, Fajara, Banjul, The Gambia
| | - David J. Conway
- Medical Research Council Laboratories, Fajara, Banjul, The Gambia
| | - Lalla Kassambara
- Malaria Research and Training Centre, University of Bamako, Bamako, Mali
| | - Ogobara K. Doumbo
- Malaria Research and Training Centre, University of Bamako, Bamako, Mali
| | - Ahmed Raza
- Centre for Immunity, Infection and Evolution, Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - J. Alexandra Rowe
- Centre for Immunity, Infection and Evolution, Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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22
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Evasion of immunity to Plasmodium falciparum malaria by IgM masking of protective IgG epitopes in infected erythrocyte surface-exposed PfEMP1. Proc Natl Acad Sci U S A 2011; 108:12485-90. [PMID: 21746929 DOI: 10.1073/pnas.1103708108] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Plasmodium falciparum malaria is a major cause of mortality and severe morbidity. Its virulence is related to the parasite's ability to evade host immunity through clonal antigenic variation and tissue-specific adhesion of infected erythrocytes (IEs). The P. falciparum erythrocyte membrane protein 1 (PfEMP1) family is central to both. Here, we present evidence of a P. falciparum evasion mechanism not previously documented: the masking of PfEMP1-specific IgG epitopes by nonspecific IgM. Nonspecific IgM binding to erythrocytes infected by parasites expressing the PfEMP1 protein VAR2CSA (involved in placental malaria pathogenesis and protective immunity) blocked subsequent specific binding of human monoclonal IgG to the Duffy binding-like (DBL) domains DBL3X and DBL5ε of this PfEMP1 variant. Strikingly, a VAR2CSA-specific monoclonal antibody that binds outside these domains and can inhibit IE adhesion to the specific VAR2CSA receptor chondroitin sulfate A was unaffected. Nonspecific IgM binding protected the parasites from FcγR-dependent phagocytosis of VAR2CSA(+) IEs, but it did not affect IE adhesion to chondroitin sulfate A or lead to C1q deposition on IEs. Taken together, our results indicate that the VAR2CSA affinity for nonspecific IgM has evolved to allow placenta-sequestering P. falciparum to evade acquired protective immunity without compromising VAR2CSA function or increasing IE susceptibility to complement-mediated lysis. Furthermore, functionally important PfEMP1 epitopes not prone to IgM masking are likely to be particularly important targets of acquired protective immunity to P. falciparum malaria.
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23
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Avril M, Hathaway MJ, Srivastava A, Dechavanne S, Hommel M, Beeson JG, Smith JD, Gamain B. Antibodies to a full-length VAR2CSA immunogen are broadly strain-transcendent but do not cross-inhibit different placental-type parasite isolates. PLoS One 2011; 6:e16622. [PMID: 21326877 PMCID: PMC3034725 DOI: 10.1371/journal.pone.0016622] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Accepted: 01/01/2011] [Indexed: 11/22/2022] Open
Abstract
The high molecular weight, multidomain VAR2CSA protein mediating adhesion of Plasmodium falciparum-infected erythrocytes in the placenta is the leading candidate for a pregnancy malaria vaccine. However, it has been difficult so far to generate strong and consistent adhesion blocking antibody responses against most single-domain VAR2CSA immunogens. Recent advances in expression of the full-length recombinant protein showed it binds with much greater specificity and affinity to chondroitin sulphate A (CSA) than individual VAR2CSA domains. This raises the possibility that a specific CSA binding pocket(s) is formed in the full length antigen and could be an important target for vaccine development. In this study, we compared the immunogenicity of a full-length VAR2CSA recombinant protein containing all six Duffy binding-like (DBL) domains to that of a three-domain construct (DBL4-6) in mice and rabbits. Animals immunized with either immunogen acquired antibodies reacting with several VAR2CSA individual domains by ELISA, but antibody responses against the highly conserved DBL4 domain were weaker in animals immunized with full-length DBL1-6 recombinant protein compared to DBL4-6 recombinant protein. Both immunogens induced cross-reactive antibodies to several heterologous CSA-binding parasite lines expressing different VAR2CSA orthologues. However, antibodies that inhibited adhesion of parasites to CSA were only elicited in rabbits immunized with full-length immunogen and inhibition was restricted to the homologous CSA-binding parasite. These findings demonstrate that partial and full-length VAR2CSA immunogens induce cross-reactive antibodies, but inhibitory antibody responses to full-length immunogen were highly allele-specific and variable between animal species.
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MESH Headings
- Amino Acid Sequence/physiology
- Animals
- Antibodies, Protozoan/immunology
- Antibodies, Protozoan/pharmacology
- Antibodies, Protozoan/therapeutic use
- Antibody Specificity/immunology
- Antibody Specificity/physiology
- Antigens, Protozoan/chemistry
- Antigens, Protozoan/immunology
- Antigens, Protozoan/isolation & purification
- Cells, Cultured
- Cross Reactions/immunology
- Female
- Humans
- Immunization
- Malaria Vaccines/immunology
- Malaria Vaccines/pharmacology
- Malaria Vaccines/therapeutic use
- Malaria, Falciparum/parasitology
- Malaria, Falciparum/pathology
- Malaria, Falciparum/prevention & control
- Malaria, Falciparum/transmission
- Mice
- Mice, Inbred BALB C
- Placenta/immunology
- Placenta/parasitology
- Pregnancy
- Pregnancy Complications, Parasitic/parasitology
- Pregnancy Complications, Parasitic/pathology
- Pregnancy Complications, Parasitic/therapy
- Protein Isoforms/immunology
- Rabbits
- Species Specificity
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Affiliation(s)
- Marion Avril
- Seattle Biomedical Research Institute, Seattle, Washington, United States of America
| | - Marianne J. Hathaway
- Seattle Biomedical Research Institute, Seattle, Washington, United States of America
| | - Anand Srivastava
- Institut Pasteur, Unité de Biologie des Interactions Hôte-Parasite, Centre National de la Recherche Scientifique (CNRS), Unité de Recherche Associée (URA), 2581, Paris, France
| | - Sébastien Dechavanne
- Institut Pasteur, Unité de Biologie des Interactions Hôte-Parasite, Centre National de la Recherche Scientifique (CNRS), Unité de Recherche Associée (URA), 2581, Paris, France
| | - Mirja Hommel
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - James G. Beeson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Joseph D. Smith
- Seattle Biomedical Research Institute, Seattle, Washington, United States of America
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
- * E-mail: (BG); (JDS)
| | - Benoît Gamain
- Institut Pasteur, Unité de Biologie des Interactions Hôte-Parasite, Centre National de la Recherche Scientifique (CNRS), Unité de Recherche Associée (URA), 2581, Paris, France
- Institut National de la Transfusion Sanguine, Paris, France
- INSERM, UMRS 665, Paris, France
- Université Paris Diderot, Paris 7, Paris, France
- * E-mail: (BG); (JDS)
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24
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Czajkowsky DM, Salanti A, Ditlev SB, Shao Z, Ghumra A, Rowe JA, Pleass RJ. IgM, Fc mu Rs, and malarial immune evasion. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2010; 184:4597-603. [PMID: 20410497 PMCID: PMC2859470 DOI: 10.4049/jimmunol.1000203] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
IgM is an ancestral Ab class found in all jawed vertebrates, from sharks to mammals. This ancient ancestry is shared by malaria parasites (genus Plasmodium) that infect all classes of terrestrial vertebrates with whom they coevolved. IgM, the least studied and most enigmatic of the vertebrate Igs, was recently shown to form an intimate relationship with the malaria parasite Plasmodium falciparum. In this article, we discuss how this association might have come about, building on the recently determined structure of the human IgM pentamer, and how this interaction could affect parasite survival, particularly in light of the just-discovered Fc mu R localized to B and T cell surfaces. Because this parasite may exploit an interaction with IgM to limit immune detection, as well as to manipulate the immune response when detected, a better understanding of this association may prove critical for the development of improved vaccines or vaccination strategies.
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Affiliation(s)
- Daniel M. Czajkowsky
- Department of Molecular Physiology & Biological Physics, University of Virginia Health Sciences Center, P. O. Box 800736, Charlottesville, VA 22908, USA
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800, China
| | - Ali Salanti
- Centre for Medical Parasitology at Department of International Health, Immunology, and Microbiology, University of Copenhagen, Copenhagen University Hospital, Rigshospitalet, DK
| | - Sisse B Ditlev
- Centre for Medical Parasitology at Department of International Health, Immunology, and Microbiology, University of Copenhagen, Copenhagen University Hospital, Rigshospitalet, DK
| | - Zhifeng Shao
- Department of Molecular Physiology & Biological Physics, University of Virginia Health Sciences Center, P. O. Box 800736, Charlottesville, VA 22908, USA
- MOE Key Lab for Systems Biomedicine and National Lab for Oncogenes, Shanghai JiaoTong University, Shanghai 200240, China
| | - Ashfaq Ghumra
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, UK
- Institute of Genetics, and Parasite Biology and Immunogenetics Research Group, Queen’s Medical Centre, University of Nottingham, NG7 2UH, UK
| | - J. Alexandra Rowe
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, UK
| | - Richard J Pleass
- Institute of Genetics, and Parasite Biology and Immunogenetics Research Group, Queen’s Medical Centre, University of Nottingham, NG7 2UH, UK
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25
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Joergensen LM, Salanti A, Dobrilovic T, Barfod L, Hassenkam T, Theander TG, Hviid L, Arnot DE. The kinetics of antibody binding to Plasmodium falciparum VAR2CSA PfEMP1 antigen and modelling of PfEMP1 antigen packing on the membrane knobs. Malar J 2010; 9:100. [PMID: 20403153 PMCID: PMC2868858 DOI: 10.1186/1475-2875-9-100] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Accepted: 04/19/2010] [Indexed: 11/25/2022] Open
Abstract
Background Infected humans make protective antibody responses to the PfEMP1 adhesion antigens exported by Plasmodium falciparum parasites to the erythrocyte membrane, but little is known about the kinetics of this antibody-receptor binding reaction or how the topology of PfEMP1 on the parasitized erythrocyte membrane influences antibody association with, and dissociation from, its antigenic target. Methods A Quartz Crystal Microbalance biosensor was used to measure the association and dissociation kinetics of VAR2CSA PfEMP1 binding to human monoclonal antibodies. Immuno-fluorescence microscopy was used to visualize antibody-mediated adhesion between the surfaces of live infected erythrocytes and atomic force microscopy was used to obtain higher resolution images of the membrane knobs on the infected erythrocyte to estimate knob surface areas and model VAR2CSA packing density on the knob. Results Kinetic analysis indicates that antibody dissociation from the VAR2CSA PfEMP1 antigen is extremely slow when there is a high avidity interaction. High avidity binding to PfEMP1 antigens on the surface of P. falciparum-infected erythrocytes in turn requires bivalent cross-linking of epitopes positioned within the distance that can be bridged by antibody. Calculations of the surface area of the knobs and the possible densities of PfEMP1 packing on the knobs indicate that high-avidity cross-linking antibody reactions are constrained by the architecture of the knobs and the large size of PfEMP1 molecules. Conclusions High avidity is required to achieve the strongest binding to VAR2CSA PfEMP1, but the structures that display PfEMP1 also tend to inhibit cross-linking between PfEMP1 antigens, by holding many binding epitopes at distances beyond the 15-18 nm sweep radius of an antibody. The large size of PfEMP1 will also constrain intra-knob cross-linking interactions. This analysis indicates that effective vaccines targeting the parasite's vulnerable adhesion receptors should primarily induce strongly adhering, high avidity antibodies whose association rate constant is less important than their dissociation rate constant.
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Affiliation(s)
- Lars M Joergensen
- Centre for Medical Parasitology, Department of International Health, Immunology & Microbiology, Faculty of Health Sciences, University of Copenhagen and Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), CSS Øster Farimagsgade 5, Building 22 & 23, Postbox 2099, 1014 Copenhagen K, Denmark.
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26
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Sander AF, Salanti A, Lavstsen T, Nielsen MA, Magistrado P, Lusingu J, Ndam NT, Arnot DE. Multiple var2csa-type PfEMP1 genes located at different chromosomal loci occur in many Plasmodium falciparum isolates. PLoS One 2009; 4:e6667. [PMID: 19690615 PMCID: PMC2723927 DOI: 10.1371/journal.pone.0006667] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Accepted: 07/13/2009] [Indexed: 12/03/2022] Open
Abstract
Background The var2csa gene encodes a Plasmodium falciparum adhesion receptor which binds chondroitin sulfate A (CSA). This var gene is more conserved than other PfEMP1/var genes and is found in all P. falciparum isolates. In isolates 3D7, FCR3/It4 and HB3, var2csa is transcribed from a sub-telomeric position on the left arm of chromosome 12, but it is not known if this location is conserved in all parasites. Genome sequencing indicates that the var2csa gene is duplicated in HB3, but whether this is true in natural populations is uncertain. Methodology/Principal Findings To assess global variation in the VAR2CSA protein, sequence variation in the DBL2X region of var2csa genes in 54 P.falciparum samples was analyzed. Chromosome mapping of var2csa loci was carried out and a quantitative PCR assay was developed to estimate the number of var2csa genes in P.falciparum isolates from the placenta of pregnant women and from the peripheral circulation of other malaria patients. Sequence analysis, gene mapping and copy number quantitation in P.falciparum isolates indicate that there are at least two loci and that both var2csa-like genes can be transcribed. All VAR2CSA DBL2X domains fall into one of two distinct phylogenetic groups possessing one or the other variant of a large (∼26 amino acid) dimorphic motif, but whether either motif variant is linked to a specific locus is not known. Conclusions/Significance Two or more related but distinct var2csa-type PfEMP1/var genes exist in many P. falciparum isolates. One gene is on chromosome 12 but additional var2csa-type genes are on different chromosomes in different isolates. Multiplicity of var2csa genes appears more common in infected placentae than in samples from non-pregnant donors indicating a possible advantage of this genotype in pregnancy associated malaria.
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Affiliation(s)
- Adam F. Sander
- Centre for Medical Parasitology, Department of International Health, Immunology & Microbiology, Faculty of Health Sciences, University of Copenhagen & Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Ali Salanti
- Centre for Medical Parasitology, Department of International Health, Immunology & Microbiology, Faculty of Health Sciences, University of Copenhagen & Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Thomas Lavstsen
- Centre for Medical Parasitology, Department of International Health, Immunology & Microbiology, Faculty of Health Sciences, University of Copenhagen & Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Morten A. Nielsen
- Centre for Medical Parasitology, Department of International Health, Immunology & Microbiology, Faculty of Health Sciences, University of Copenhagen & Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Pamela Magistrado
- Centre for Medical Parasitology, Department of International Health, Immunology & Microbiology, Faculty of Health Sciences, University of Copenhagen & Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
- JMP-ENRICA Project, National Institute for Medical Research, Korogwe Laboratory, Tanga, Tanzania
| | - John Lusingu
- JMP-ENRICA Project, National Institute for Medical Research, Korogwe Laboratory, Tanga, Tanzania
| | - Nicaise Tuikue Ndam
- Institut de Recherche pour le Developpment, UR010, Universite Paris Descartes, Paris, France
| | - David E. Arnot
- Centre for Medical Parasitology, Department of International Health, Immunology & Microbiology, Faculty of Health Sciences, University of Copenhagen & Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
- Institute of Immunology & Infection Research, School of Biology, University of Edinburgh, Edinburgh, Scotland, United Kingdom
- * E-mail:
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27
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Ghumra A, Semblat JP, McIntosh RS, Raza A, Rasmussen IB, Braathen R, Johansen FE, Sandlie I, Mongini PK, Rowe JA, Pleass RJ. Identification of residues in the Cmu4 domain of polymeric IgM essential for interaction with Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1). THE JOURNAL OF IMMUNOLOGY 2008; 181:1988-2000. [PMID: 18641336 DOI: 10.4049/jimmunol.181.3.1988] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The binding of nonspecific human IgM to the surface of infected erythrocytes is important in rosetting, a major virulence factor in the pathogenesis of severe malaria due to Plasmodium falciparum, and IgM binding has also been implicated in placental malaria. Herein we have identified the IgM-binding parasite ligand from a virulent P. falciparum strain as PfEMP1 (TM284var1 variant), and localized the region within this PfEMP1 variant that binds IgM (DBL4beta domain). We have used this parasite IgM-binding protein to investigate the interaction with human IgM. Interaction studies with domain-swapped Abs, IgM mutants, and anti-IgM mAbs showed that PfEMP1 binds to the Fc portion of the human IgM H chain and requires the IgM Cmu4 domain. Polymerization of IgM was shown to be crucial for the interaction because PfEMP1 binding did not occur with mutant monomeric IgM molecules. These results with PfEMP1 protein have physiological relevance because infected erythrocytes from strain TM284 and four other IgM-binding P. falciparum strains showed analogous results to those seen with the DBL4beta domain. Detailed investigation of the PfEMP1 binding site on IgM showed that some of the critical amino acids in the IgM Cmu4 domain are equivalent to those regions of IgG and IgA recognized by Fc-binding proteins from bacteria, suggesting that this region of Ig molecules may be of major functional significance in host-microbe interactions. We have therefore shown that PfEMP1 is an Fc-binding protein of malaria parasites specific for polymeric human IgM, and that it shows functional similarities with Fc-binding proteins from pathogenic bacteria.
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Affiliation(s)
- Ashfaq Ghumra
- Institute of Genetics, Queens Medical Centre, University of Nottingham, Nottingham, England, United Kingdom
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28
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Lutz HU, Miescher S. Natural antibodies in health and disease: An overview of the first international workshop on natural antibodies in health and disease. Autoimmun Rev 2008; 7:405-9. [DOI: 10.1016/j.autrev.2008.03.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Accepted: 03/12/2008] [Indexed: 12/12/2022]
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29
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Gamain B, Smith JD, Viebig NK, Gysin J, Scherf A. Pregnancy-associated malaria: Parasite binding, natural immunity and vaccine development. Int J Parasitol 2007; 37:273-83. [PMID: 17224156 DOI: 10.1016/j.ijpara.2006.11.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2006] [Revised: 11/21/2006] [Accepted: 11/22/2006] [Indexed: 11/26/2022]
Abstract
Humans living in areas of high malaria transmission gradually acquire, during the early years of life, protective clinical immunity to Plasmodium falciparum, limiting serious complications of malaria to young children. However, pregnant women become more susceptible to severe P. falciparum infections during their first pregnancy. Pregnancy associated malaria is coupled with massive accumulation of parasitised erythrocytes and monocytes in the placental intervillous blood spaces, contributing to disease and death in pregnant women and developing infants. Indirect evidence suggests that prevention may be possible by vaccinating women of childbearing age before their first pregnancy. This review aims to introduce the reader to the implications of malaria infection during pregnancy and to analyse recent findings towards the identification and characterisation of parasite encoded erythrocyte surface proteins expressed in malaria-infected pregnant women that are likely targets of protective immunity and have potential for vaccine development.
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Affiliation(s)
- Benoît Gamain
- Unité de Biologie des Interactions Hôte-Parasite, Institut Pasteur and CNRS, Paris, France
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30
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Avril M, Gamain B, Lépolard C, Viaud N, Scherf A, Gysin J. Characterization of anti-var2CSA-PfEMP1 cytoadhesion inhibitory mouse monoclonal antibodies. Microbes Infect 2006; 8:2863-71. [PMID: 17095277 DOI: 10.1016/j.micinf.2006.09.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2006] [Revised: 07/29/2006] [Accepted: 09/22/2006] [Indexed: 10/24/2022]
Abstract
Pregnancy-associated malaria (PAM) is associated with the massive sequestration of erythrocytes infected with CSA-binding parasites in the placenta. Natural protective immunity against PAM is acquired during the course of pregnancies, with the development of anti-PfEMP1 antibodies recognizing placental infected erythrocytes (IEs) from different geographical regions. Mouse monoclonal antibodies (mabs) were raised against Plasmodium falciparum variant surface proteins expressed by CSA-binding parasites. These mabs blocked 0-60% of CSA-binding parasite adhesion and immunoprecipitated a 350 kDa 125I-labeled PfEMP1(CSA). Two var2CSA domains expressed on the surface of CHO cells (DBL5epsilon and DBL6epsilon) were identified as the targets of three of four antibodies inhibiting CSA binding. Two of these antibodies also recognized either DBL2x or DBL3x, suggesting that some epitopes may be common to several var2CSA domains. These mabs also specifically selected CSA-binding IEs and facilitated the purification from IE extracts of the native var2CSA ligand. This purified ligand elicited antibodies in immunized mice inhibiting efficiently IE(CSA) cytoadhesion. Based on our findings, we provide the first demonstration that the parasite var2CSA surface protein can elicit inhibitory antibodies and define here the subunits of the var2CSA ligand suitable for use in vaccine development.
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Affiliation(s)
- Marion Avril
- Unité de Parasitologie Expérimentale, URA Institut Pasteur, Univ Med. EA 3282, IFR 48 Université de la Méditerranée 27, Bd. Jean Moulin, 13385, Marseille Cedex 05, France
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31
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Rasti N, Namusoke F, Chêne A, Chen Q, Staalsoe T, Klinkert MQ, Mirembe F, Kironde F, Wahlgren M. Nonimmune immunoglobulin binding and multiple adhesion characterize Plasmodium falciparum-infected erythrocytes of placental origin. Proc Natl Acad Sci U S A 2006; 103:13795-800. [PMID: 16945914 PMCID: PMC1564255 DOI: 10.1073/pnas.0601519103] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The harmful effects of pregnancy-associated malaria (PAM) are engendered by the heavy sequestration of Plasmodium falciparum-parasitized RBCs in the placenta. It is well documented that this process is mediated by interactions of parasite-encoded variant surface antigens and placental receptors. A P. falciparum erythrocyte membrane protein 1 variant, VAR2CSA, and the placental receptor chondroitin sulfate A (CSA) are currently the focus of PAM research. A role for immunoglobulins (IgG and IgM) from normal human serum and hyaluronic acid as additional receptors in placental sequestration have also been suggested. We show here (i) that CSA and nonimmune IgG/IgM binding are linked phenotypes of in vitro-adapted parasites, (ii) that a VAR2CSA variant shown to bind CSA also harbors IgG- and IgM-binding domains (DBL2-X, DBL5-epsilon, and DBL6-epsilon), and (iii) that IgG and IgM binding and adhesion to multiple receptors (IgG/IgM/HA/CSA) rather than the exclusive binding to CSA is a characteristic of fresh Ugandan placental isolates. These findings are of importance for the understanding of the pathogenesis of placental malaria and have implications for the ongoing efforts to develop a global PAM vaccine.
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Affiliation(s)
- Niloofar Rasti
- *Microbiology and Tumorbiology Center (MTC), Karolinska Institutet, SE-171 77 Stockholm, Sweden
- Swedish Institute for Infectious Disease Control (SMI), SE-171 82 Stockholm, Sweden
| | - Fatuma Namusoke
- Department of Obstetrics and Gynaecology, Mulago Hospital, Kampala, Uganda
| | - Arnaud Chêne
- Swedish Institute for Infectious Disease Control (SMI), SE-171 82 Stockholm, Sweden
- Center for Infectious Medicine (CIM), Karolinska University Hospital, SE-141 86 Huddinge, Sweden
| | - Qijun Chen
- *Microbiology and Tumorbiology Center (MTC), Karolinska Institutet, SE-171 77 Stockholm, Sweden
- Swedish Institute for Infectious Disease Control (SMI), SE-171 82 Stockholm, Sweden
| | - Trine Staalsoe
- Center for Medical Parasitology, Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), DK-2100 Copenhagen, Denmark
| | - Mo-Quen Klinkert
- Bernard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; and
| | - Florence Mirembe
- Department of Obstetrics and Gynaecology, Mulago Hospital, Kampala, Uganda
| | - Fred Kironde
- **Department of Biochemistry, Makerere University, Kampala, Uganda
| | - Mats Wahlgren
- *Microbiology and Tumorbiology Center (MTC), Karolinska Institutet, SE-171 77 Stockholm, Sweden
- Swedish Institute for Infectious Disease Control (SMI), SE-171 82 Stockholm, Sweden
- To whom correspondence should be addressed. E-mail:
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O'Donnell A, Raiko A, Clegg JB, Weatherall DJ, Allen SJ. Alpha+ -thalassaemia and pregnancy in a malaria endemic region of Papua New Guinea. Br J Haematol 2006; 135:235-41. [PMID: 16939488 DOI: 10.1111/j.1365-2141.2006.06274.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The effect of maternal alpha+ -thalassaemia on pregnancy was assessed in the north coastal region of Papua New Guinea (PNG), where malaria is hyperendemic and alpha+ -thalassaemia is extremely common. In a prospective study of 987 singleton hospital deliveries, we correlated maternal alpha-globin genotype with markers of reproductive fitness (age in primigravidae, gravidity, pregnancy interval and the number of miscarriages and stillbirths), Plasmodium falciparum(P. falciparum) infection of the mother and placenta, maternal haemoglobin, preterm delivery and birthweight. The frequency of the -alpha genotype in mothers was 0.61. Markers of reproductive fitness were similar in women with and without alpha+ -thalassaemia. Median haemoglobin concentration during pregnancy and after delivery was about 1.0 g/dl lower in homozygous alpha+ -thalassaemia than in women with a normal alpha- globin genotype (P < or = 0.001). The frequency of placental P. falciparum infection and systemic malaria infection after delivery showed no consistent relationship to alpha-globin genotype. The frequency of preterm delivery and low birthweight did not vary significantly according to maternal alpha-globin genotype. Maternal alpha+ -thalassaemia does not affect reproductive fitness or susceptibility to malaria during pregnancy. Although median haemoglobin concentration was significantly lower in mothers homozygous for alpha+ -thalassaemia than those with a normal alpha-globin genotype, this did not result in an adverse outcome of pregnancy.
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Affiliation(s)
- A O'Donnell
- Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford, UK.
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33
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Kraemer SM, Smith JD. A family affair: var genes, PfEMP1 binding, and malaria disease. Curr Opin Microbiol 2006; 9:374-80. [PMID: 16814594 DOI: 10.1016/j.mib.2006.06.006] [Citation(s) in RCA: 221] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2006] [Accepted: 06/19/2006] [Indexed: 11/15/2022]
Abstract
An immunovariant adhesion protein family in Plasmodium falciparum named erythrocyte membrane protein 1 (PfEMP1), encoded by var genes, is responsible for both antigenic variation and cytoadhesion of infected erythrocytes at blood microvasculature sites throughout the body. Elucidation of the genome sequence of P. falciparum has revealed that var genes can be classified into different groups, each with distinct 5' flanking sequences, chromosomal locations and gene orientations. Recent binding and serological comparisons suggest that this genomic organization might cause var genes to diversify into separately recombining adhesion groups that have different roles in infection and disease. Detailed understanding of PfEMP1 expression and receptor binding mechanisms during infection and of the antigenic relatedness of disease variants might lead to new approaches in prevention of malaria disease.
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Affiliation(s)
- Susan M Kraemer
- Seattle Biomedical Research Institute, Seattle, WA 98109-5219, USA
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