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Duffy PE, Gorres JP, Healy SA, Fried M. Malaria vaccines: a new era of prevention and control. Nat Rev Microbiol 2024:10.1038/s41579-024-01065-7. [PMID: 39025972 DOI: 10.1038/s41579-024-01065-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/30/2024] [Indexed: 07/20/2024]
Abstract
Malaria killed over 600,000 people in 2022, a death toll that has not improved since 2015. Additionally, parasites and mosquitoes resistant to existing interventions are spreading across Africa and other regions. Vaccines offer hope to reduce the mortality burden: the first licensed malaria vaccines, RTS,S and R21, will be widely deployed in 2024 and should substantially reduce childhood deaths. In this Review, we provide an overview of the malaria problem and the Plasmodium parasite, then describe the RTS,S and R21 vaccines (the first vaccines for any human parasitic disease), summarizing their benefits and limitations. We explore next-generation vaccines designed using new knowledge of malaria pathogenesis and protective immunity, which incorporate antigens and platforms to elicit effective immune responses against different parasite stages in human or mosquito hosts. We describe a decision-making process that prioritizes malaria vaccine candidates for development in a resource-constrained environment. Future vaccines might improve upon the protective efficacy of RTS,S or R21 for children, or address the wider malaria scourge by preventing pregnancy malaria, reducing the burden of Plasmodium vivax or accelerating malaria elimination.
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Affiliation(s)
- Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
| | - J Patrick Gorres
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Sara A Healy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Michal Fried
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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2
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Joof F, Hu R, Saidi A, Seydel KB, Cohee LM, Zheng Y, Smith JD. Plasma from older children in Malawi inhibits Plasmodium falciparum binding in 3D brain microvessels. J Infect Dis 2024:jiae315. [PMID: 38875153 DOI: 10.1093/infdis/jiae315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 05/02/2024] [Accepted: 06/12/2024] [Indexed: 06/16/2024] Open
Abstract
A hallmark of cerebral malaria is sequestration of Plasmodium falciparum-infected erythrocytes (IEs) in the brain microcirculation. Antibodies contribute to malaria immunity, but it remains unclear whether functional antibodies targeting parasite-expressed ligand can block cytoadhesion in the brain. Here, we screened the plasma of older children and young adults in Malawi to characterize the antibody response against the P. falciparum-IE surface and used a bioengineered 3D human brain microvessel model incorporating variable flow dynamics to measure adhesion blocking responses. We found a strong correlation between surface antibody reactivity by flow cytometry and reduced P. falciparum-IE binding in 3D microvessels. Moreover, there was a threshold of surface antibody reactivity necessary to achieve robust inhibitory activity. Our findings provide evidence of the acquisition of adhesion blocking antibodies against cerebral binding variants in people exposed to stable P. falciparum transmission and suggest the quality of the inhibitory response can be influenced by flow dynamics.
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Affiliation(s)
- Fatou Joof
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA USA
| | - Ruoqian Hu
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Alex Saidi
- Blantyre Malaria Project, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Karl B Seydel
- Blantyre Malaria Project, Kamuzu University of Health Sciences, Blantyre, Malawi
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan, USA
| | - Lauren M Cohee
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Ying Zheng
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Joseph D Smith
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA USA
- Department of Pediatrics, School of Medicine, University of Washington, Seattle, WA, USA
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3
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Mahamar A, Traore M, Swihart B, Attaher O, Diarra BS, Santara G, Issiaka D, Barry A, Sidibé Y, Dicko YT, Keita S, Ndiaye O, Dicko A, Duffy PE, Fried M. Acquisition of antibodies that block Plasmodium falciparum adhesion to placental receptor chondroitin sulfate A with increasing gravidity in Malian women. Front Immunol 2024; 14:1330962. [PMID: 38274790 PMCID: PMC10808177 DOI: 10.3389/fimmu.2023.1330962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 12/20/2023] [Indexed: 01/27/2024] Open
Abstract
In malaria-endemic areas, pregnant women are more susceptible to Plasmodium falciparum infection, especially primigravidae. During pregnancy, parasites sequester in the placenta and bind to the receptor chondroitin sulfate (CSA). This unique adhesion is mediated by the parasite protein VAR2CSA expressed on the surface of infected erythrocytes (IE). Placental malaria is associated with poor pregnancy outcomes including perinatal mortality, preterm delivery, small for gestational age (SGA) and low birthweight deliveries. Over successive pregnancies, women acquire functional antibodies that inhibit IE adhesion to CSA. Here, we examine the development of anti-adhesion activity and the breadth of anti-adhesion activity as a function of number of previous pregnancies, using samples collected from pregnant women living in an area with high seasonal malaria transmission. Women reached plateau levels of anti-adhesion activity and breadth of anti-adhesion activity after 5 pregnancies. We related the level of anti-adhesion activity and reactivity with surface IE to SGA 19/232 pregnancies resulted in SGA, and report that an increase of 10% in median anti-adhesion activity reduced the odds of SGA by 13% and this relationship approached significance. Further, at an anti-adhesion activity level of 43.7%, an increase of 10% in the breadth of activity significantly reduced the odds of SGA by 21.5%. Antibodies that recognize IE surface increased over successive pregnancies, but were not associated with a reduction in SGA. These results can serve as a guideline for assessing vaccine candidates aiming to reduce poor pregnancy outcomes associated with placental malaria.
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Affiliation(s)
- Almahamoudou Mahamar
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Moussa Traore
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Bruce Swihart
- Biostatistics Research Branch, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD, United States
| | - Oumar Attaher
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Bacary Soumana Diarra
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Gaoussou Santara
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Djibrilla Issiaka
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Amadou Barry
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Youssoufa Sidibé
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Yahia T. Dicko
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Sekouba Keita
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Oulematou Ndiaye
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Alassane Dicko
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali
| | - Patrick E. Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, United States
| | - Michal Fried
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, United States
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4
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LUUSE ARNOLDT, ALIDU HUSEINI, MAWULI1 MAWUSIADEPA, MUBARAK ABDULRAHMAN, GYAN BEN. Do Blood group and Sickle cell trait protect against placental malaria? J Public Health Afr 2023; 14:2817. [PMID: 38259428 PMCID: PMC10801398 DOI: 10.4081/jphia.2024.2817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024] Open
Abstract
Blood group O is reported to confer some degree of protection from severe malaria in endemic setting. This protection is believed to be due to reduced and smaller rosette formation in people of blood group O which can easily be cleared by the host immune system. Also, sickle cell trait (HbAS) is reported to disrupt the adhesion of infected erythrocytes to microvascular endothelial walls, which could protect pregnant women from placental malaria. We determined the association between HbAS and ABO blood group, and placental malaria amongst pregnant women of all parities. The study enrolled 221 pregnant women. Peripheral blood samples were taken for malaria smears, ABO blood grouping and haemoglobin (Hb) electrophoresis. A structured questionnaire was used to age, bed net usage, and the number of Sulphadoxine-pyrimethamine (SP) doses taken by a pregnant woman. Two hundred and twenty-one (221) pregnant women were enrolled and out of this number, 110 (49.8%) were primiparae and 111 (50.2%) multiparae, with a mean age of 23.7±5.2. Placental malaria (PM) prevalence by PCR detection was 19.4% (43/221). Of those who were malaria positive 58.1% (25/43) were primiparae. Primiparae who are of blood group O were more susceptible to PM [P=0.04, (OR); 2.85, 95% (Cl), 1.12-9.01]. But sickle cell trait did not reduce the prevalence of PM [P=0.84 (OR); 0.92, 95% (Cl), 0.43-1.99]. Non-blood group O primiparae women were protected against placental malaria. This could be why some primiparae women are protected from PM, just like multiparae women.
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Affiliation(s)
| | - HUSEINI ALIDU
- School of Allied Health Sciences, University of Health and Allied Sciences, Ho
| | - MAWUSI ADEPA MAWULI1
- Department of Biochemistry Cell and Molecular Biology, University of Ghana, Accra
- Department of Pathology, University of Ghana Medical School, College of Health Sciences, University of Ghana, Korle-Bu, Accra, Ghana
| | - ABDUL-RAHMAN MUBARAK
- West Africa Center for Cell Biology of Infectious Pathogens
- Department of Biochemistry Cell and Molecular Biology, University of Ghana, Accra
- Department of Pathology, University of Ghana Medical School, College of Health Sciences, University of Ghana, Korle-Bu, Accra, Ghana
| | - BEN GYAN
- Department of Biochemistry Cell and Molecular Biology, University of Ghana, Accra
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra
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5
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Roessner R, Michelarakis N, Gräter F, Aponte-Santamaría C. Mechanical forces control the valency of the malaria adhesin VAR2CSA by exposing cryptic glycan binding sites. PLoS Comput Biol 2023; 19:e1011726. [PMID: 38117828 PMCID: PMC10786402 DOI: 10.1371/journal.pcbi.1011726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 01/12/2024] [Accepted: 12/02/2023] [Indexed: 12/22/2023] Open
Abstract
Plasmodium falciparum (Pf) is responsible for the most lethal form of malaria. VAR2CSA is an adhesin protein expressed by this parasite at the membrane of infected erythrocytes for attachment to the placenta, leading to pregnancy-associated malaria. VAR2CSA is a large 355 kDa multidomain protein composed of nine extracellular domains, a transmembrane helix, and an intracellular domain. VAR2CSA binds to Chondroitin Sulphate A (CSA) of the proteoglycan matrix of the placenta. Shear flow, as the one occurring in blood, has been shown to enhance the (VAR2CSA-mediated) adhesion of Pf-infected erythrocytes on the CSA-matrix. However, the underlying molecular mechanism governing this enhancement has remained elusive. Here, we address this question by using equilibrium, force-probe, and docking-based molecular dynamics simulations. We subjected the VAR2CSA protein-CSA sugar complex to a force mimicking the tensile force exerted on this system due to the shear of the flowing blood. We show that upon this force exertion, VAR2CSA undergoes a large opening conformational transition before the CSA sugar chain dissociates from its main binding site. This preferential order of events is caused by the orientation of the molecule during elongation, as well as the strong electrostatic attraction of the sugar to the main protein binding site. Upon opening, two additional cryptic CSA binding sites get exposed and a functional dodecameric CSA molecule can be stably accommodated at these force-exposed positions. Thus, our results suggest that mechanical forces increase the avidity of VAR2CSA by turning it from a monovalent to a multivalent state. We propose this to be the molecular cause of the observed shear-enhanced adherence. Mechanical control of the valency of VAR2CSA is an intriguing hypothesis that can be tested experimentally and which is of relevance for the understanding of the malaria infection and for the development of anti placental-malaria vaccines targeting VAR2CSA.
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Affiliation(s)
- Rita Roessner
- Molecular Biomechanics Group, Heidelberg Institute for Theoretical Studies, Heidelberg, Germany
| | - Nicholas Michelarakis
- Molecular Biomechanics Group, Heidelberg Institute for Theoretical Studies, Heidelberg, Germany
| | - Frauke Gräter
- Molecular Biomechanics Group, Heidelberg Institute for Theoretical Studies, Heidelberg, Germany
- Interdisciplinary Center for Scientific Computing, Heidelberg University, Heidelberg, Germany
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6
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Doritchamou J, Nielsen MA, Chêne A, Viebig NK, Lambert LE, Sander AF, Semblat JP, Hundt S, Orr-Gonzalez S, Janitzek CM, Spiegel AJ, Clemmensen SB, Thomas ML, Nason MC, Snow-Smith M, Barnafo EK, Shiloach J, Chen BB, Nadakal S, Highsmith K, Ouahes T, Conteh S, Sharma A, Torano H, Butler B, Reiter K, Rausch KM, Scaria PV, Anderson C, Narum DL, Salanti A, Fried M, Theander TG, Gamain B, Duffy PE. Aotus nancymaae model predicts human immune response to the placental malaria vaccine candidate VAR2CSA. Lab Anim (NY) 2023; 52:315-323. [PMID: 37932470 PMCID: PMC10689237 DOI: 10.1038/s41684-023-01274-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 09/27/2023] [Indexed: 11/08/2023]
Abstract
Placental malaria vaccines (PMVs) are being developed to prevent severe sequelae of placental malaria (PM) in pregnant women and their offspring. The leading candidate vaccine antigen VAR2CSA mediates parasite binding to placental receptor chondroitin sulfate A (CSA). Despite promising results in small animal studies, recent human trials of the first two PMV candidates (PAMVAC and PRIMVAC) generated limited cross-reactivity and cross-inhibitory activity to heterologous parasites. Here we immunized Aotus nancymaae monkeys with three PMV candidates (PAMVAC, PRIMVAC and ID1-ID2a_M1010) adjuvanted with Alhydrogel, and exploited the model to investigate boosting of functional vaccine responses during PM episodes as well as with nanoparticle antigens. PMV candidates induced high levels of antigen-specific IgG with significant cross-reactivity across PMV antigens by enzyme-linked immunosorbent assay. Conversely, PMV antibodies recognized native VAR2CSA and blocked CSA adhesion of only homologous parasites and not of heterologous parasites. PM episodes did not significantly boost VAR2CSA antibody levels or serum functional activity; nanoparticle and monomer antigens alike boosted serum reactivity but not functional activities. Overall, PMV candidates induced functional antibodies with limited heterologous activity in Aotus monkeys, similar to responses reported in humans. The Aotus model appears suitable for preclinical downselection of PMV candidates and assessment of antibody boosting by PM episodes.
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Affiliation(s)
- Justin Doritchamou
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Morten A Nielsen
- Centre for Medical Parasitology at the Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
- Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark
| | - Arnaud Chêne
- Université Paris Cité and Université des Antilles, INSERM, BIGR, Paris, France
| | - Nicola K Viebig
- European Vaccine Initiative, UniversitätsKlinikum Heidelberg, Heidelberg, Germany
| | - Lynn E Lambert
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Adam F Sander
- Centre for Medical Parasitology at the Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
- Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark
| | | | - Sophia Hundt
- European Vaccine Initiative, UniversitätsKlinikum Heidelberg, Heidelberg, Germany
| | - Sachy Orr-Gonzalez
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Christoph Mikkel Janitzek
- Centre for Medical Parasitology at the Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
- Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark
| | - Alicia J Spiegel
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | | | - Marvin L Thomas
- Division of Veterinary Resources, Office of Research Services, National Institutes of Health, Bethesda, MD, USA
| | - Martha C Nason
- Biostatistics Research Branch, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Maryonne Snow-Smith
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Emma K Barnafo
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Joseph Shiloach
- Biotechnology Unit, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - Beth B Chen
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Steven Nadakal
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Kendrick Highsmith
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Tarik Ouahes
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Solomon Conteh
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Ankur Sharma
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Holly Torano
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Brandi Butler
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Karine Reiter
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Kelly M Rausch
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Puthupparampil V Scaria
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Charles Anderson
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - David L Narum
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Ali Salanti
- Centre for Medical Parasitology at the Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
- Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark
| | - Michal Fried
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Thor G Theander
- Centre for Medical Parasitology at the Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
- Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark
| | - Benoit Gamain
- Université Paris Cité and Université des Antilles, INSERM, BIGR, Paris, France
| | - Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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Walker IS, Rogerson SJ. Pathogenicity and virulence of malaria: Sticky problems and tricky solutions. Virulence 2023; 14:2150456. [PMID: 36419237 PMCID: PMC9815252 DOI: 10.1080/21505594.2022.2150456] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 11/25/2022] Open
Abstract
Infections with Plasmodium falciparum and Plasmodium vivax cause over 600,000 deaths each year, concentrated in Africa and in young children, but much of the world's population remain at risk of infection. In this article, we review the latest developments in the immunogenicity and pathogenesis of malaria, with a particular focus on P. falciparum, the leading malaria killer. Pathogenic factors include parasite-derived toxins and variant surface antigens on infected erythrocytes that mediate sequestration in the deep vasculature. Host response to parasite toxins and to variant antigens is an important determinant of disease severity. Understanding how parasites sequester, and how antibody to variant antigens could prevent sequestration, may lead to new approaches to treat and prevent disease. Difficulties in malaria diagnosis, drug resistance, and specific challenges of treating P. vivax pose challenges to malaria elimination, but vaccines and other preventive strategies may offer improved disease control.
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Affiliation(s)
- Isobel S Walker
- Department of Infectious Diseases, The University of Melbourne, The Doherty Institute, Melbourne, Australia
| | - Stephen J Rogerson
- Department of Infectious Diseases, The University of Melbourne, The Doherty Institute, Melbourne, Australia
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8
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Hassert M, Arumugam S, Harty JT. Memory CD8+ T cell-mediated protection against liver-stage malaria. Immunol Rev 2023; 316:84-103. [PMID: 37014087 PMCID: PMC10524177 DOI: 10.1111/imr.13202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 03/09/2023] [Accepted: 03/21/2023] [Indexed: 04/05/2023]
Abstract
Nearly half of the world's population is at risk of malaria, a disease caused by the protozoan parasite Plasmodium, which is estimated to cause more than 240,000,000 infections and kill more than 600,000 people annually. The emergence of Plasmodia resistant to chemoprophylactic treatment highlights the urgency to develop more effective vaccines. In this regard, whole sporozoite vaccination approaches in murine models and human challenge studies have provided substantial insight into the immune correlates of protection from malaria. From these studies, CD8+ T cells have come to the forefront, being identified as critical for vaccine-mediated liver-stage immunity that can prevent the establishment of the symptomatic blood stages and subsequent transmission of infection. However, the unique biological characteristics required for CD8+ T cell protection from liver-stage malaria dictate that more work must be done to design effective vaccines. In this review, we will highlight a subset of studies that reveal basic aspects of memory CD8+ T cell-mediated protection from liver-stage malaria infection.
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Affiliation(s)
- Mariah Hassert
- Department of Pathology, University of Iowa- Carver College of Medicine, Iowa City, IA, USA
| | - Sahaana Arumugam
- Department of Pathology, University of Iowa- Carver College of Medicine, Iowa City, IA, USA
- Medical Scientist Training Program, University of Iowa- Carver College of Medicine, Iowa City, IA, USA
- Interdisciplinary Graduate Program in Immunology, University of Iowa- Carver College of Medicine, Iowa City, IA, USA
| | - John T. Harty
- Department of Pathology, University of Iowa- Carver College of Medicine, Iowa City, IA, USA
- Interdisciplinary Graduate Program in Immunology, University of Iowa- Carver College of Medicine, Iowa City, IA, USA
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9
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Doritchamou JYA, Renn JP, Hviid L, Duffy PE. A conformational epitope in placental malaria vaccine antigen VAR2CSA: What does it teach us? PLoS Pathog 2023; 19:e1011370. [PMID: 37228009 PMCID: PMC10212100 DOI: 10.1371/journal.ppat.1011370] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023] Open
Abstract
VAR2CSA is the Plasmodium falciparum variant surface antigen that mediates binding of infected erythrocytes to chondroitin sulfate A (CSA) and their sequestration in intervillous spaces of the placenta, leading to placental malaria (PM). Relatively high polymorphism in VAR2CSA sequences has hindered development of a vaccine that induces broadly neutralizing immunity. Recent research has highlighted that a broadly reactive human monoclonal antibody, called PAM1.4, binds to multiple conserved residues of different subfragments of VAR2CSA, forming a conformational epitope. In this short perspective, we describe evidence that residues located in the interdomain-1 fragment of VAR2CSA within the PAM1.4 binding epitope might be critical to broad reactivity of the antibody. Future investigation into broadly reactive anti-VAR2CSA antibodies may be important for the following: (1) identification of similar conformation epitopes targeted by broadly neutralizing antibodies; and (2) understanding different immune evasion mechanisms used by placenta-binding parasites through VAR2CSA polymorphism in critical epitopes.
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Affiliation(s)
- Justin Y. A. Doritchamou
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, United States of America
| | - Jonathan P. Renn
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, United States of America
| | - Lars Hviid
- Centre for Medical Parasitology, Department of Microbiology and Immunology, University of Copenhagen and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Patrick E. Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, United States of America
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Fasanya A, Mohammed N, Saleh BH, Tijani MK, Teleka A, Quintana MDP, Hviid L, Persson KEM. Anti-phosphatidylserine antibody levels are low in multigravid pregnant women in a malaria-endemic area in Nigeria, and do not correlate with anti-VAR2CSA antibodies. Front Cell Infect Microbiol 2023; 13:1130186. [PMID: 37091678 PMCID: PMC10114609 DOI: 10.3389/fcimb.2023.1130186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 03/13/2023] [Indexed: 03/30/2023] Open
Abstract
Anemia is a common malaria-associated complication in pregnant women in endemic regions. Phosphatidylserine (PS) is exposed to the immune system during the massive destruction of red blood cells (RBCs) that accompany malaria, and antibodies against PS have been linked to anemia through destruction of uninfected RBCs. We determined levels of anti-PS IgG antibodies in pregnant women in Ibadan, Nigeria and correlated them to parameters of importance in development of anemia and immunity. Anti-PS correlated inversely with Packed Cell Volume (PCV), indicating that the antibodies could contribute to anemia. There was no correlation with anti-VAR2CSA IgG, haptoglobin or parasitemia, indicating that the modulation of anti-PS response is multifactorial in nature. Anti-PS levels were lowest in multigravidae compared to both primigravidae and secundigravidae and correlated inversely with age. In conclusion, lower levels of anti-PS in multigravidae could be beneficial in avoiding anemia.
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Affiliation(s)
- Adebimpe Fasanya
- Cellular Parasitology Programme, Cell Biology and Genetics Unit, Department of Zoology, University of Ibadan, Ibadan, Nigeria
| | - Nurat Mohammed
- Cellular Parasitology Programme, Cell Biology and Genetics Unit, Department of Zoology, University of Ibadan, Ibadan, Nigeria
| | - Bandar Hasan Saleh
- Department of Laboratory Medicine, Division of Clinical Chemistry and Pharmacology, Skåne University Hospital, Lund University, Lund, Sweden
- Department of Medical Microbiology and Parasitology, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Muyideen Kolapo Tijani
- Cellular Parasitology Programme, Cell Biology and Genetics Unit, Department of Zoology, University of Ibadan, Ibadan, Nigeria
- Department of Laboratory Medicine, Division of Clinical Chemistry and Pharmacology, Skåne University Hospital, Lund University, Lund, Sweden
- *Correspondence: Muyideen Kolapo Tijani, ; ; Kristina E. M. Persson,
| | - Alexandra Teleka
- Department of Laboratory Medicine, Division of Clinical Chemistry and Pharmacology, Skåne University Hospital, Lund University, Lund, Sweden
| | - Maria del Pilar Quintana
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lars Hviid
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Kristina E. M. Persson
- Department of Laboratory Medicine, Division of Clinical Chemistry and Pharmacology, Skåne University Hospital, Lund University, Lund, Sweden
- *Correspondence: Muyideen Kolapo Tijani, ; ; Kristina E. M. Persson,
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Disulfide bond and crosslinking analyses reveal inter-domain interactions that contribute to the rigidity of placental malaria VAR2CSA structure and formation of CSA binding channel. Int J Biol Macromol 2023; 226:143-158. [PMID: 36470436 DOI: 10.1016/j.ijbiomac.2022.11.258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 11/15/2022] [Accepted: 11/24/2022] [Indexed: 12/11/2022]
Abstract
VAR2CSA, a multidomain Plasmodium falciparum protein, mediates the adherence of parasite-infected red blood cells to chondroitin 4-sulfate (C4S) in the placenta, contributing to placental malaria. Therefore, detailed understanding of VAR2CSA structure likely help developing strategies to treat placental malaria. The VAR2CSA ectodomain consists of an N-terminal segment (NTS), six Duffy binding-like (DBL) domains, and three interdomains (IDs) present in sequence NTS-DBL1x-ID1-DBL2x-ID2-DBL3x-DBL4ε-ID3-DBL5ε-DBL6ε. Recent electron microscopy studies showed that VAR2CSA is compactly organized into a globular structure containing C4S-binding channel, and that DBL5ε-DBL6ε arm is attached to the NTS-ID3 core structure. However, the structural elements involved in inter-domain interactions that stabilize the VAR2CSA structure remain largely not understood. Here, limited proteolysis and peptide mapping by mass spectrometry showed that VAR2CSA contains several inter-domain disulfide bonds that stabilize its compact structure. Chemical crosslinking-mass spectrometry showed that all IDs interact with DBL4ε; additionally, IDs interact with other DBL domains, demonstrating that IDs are the key structural scaffolds that shape the functional NTS-ID3 core. Ligand binding analysis suggested that NTS considerably restricts the C4S binding. Overall, our study revealed that inter-domain disulfide bonds and interactions between IDs and DBL domains contribute to the stability of VAR2CSA structural architecture and formation of C4S-binding channel.
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Kassa MW, Hasang W, Barateiro A, Damelang T, Brewster J, Dombrowski JG, Longley RJ, Chung AW, Wunderlich G, Mueller I, Aitken EH, Marinho CRF, Rogerson SJ. Acquisition of antibodies to Plasmodium falciparum and Plasmodium vivax antigens in pregnant women living in a low malaria transmission area of Brazil. Malar J 2022; 21:360. [PMID: 36457056 PMCID: PMC9714246 DOI: 10.1186/s12936-022-04402-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 11/25/2022] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Pregnant women have increased susceptibility to Plasmodium falciparum malaria and acquire protective antibodies over successive pregnancies. Most studies that investigated malaria antibody responses in pregnant women are from high transmission areas in sub-Saharan Africa, while reports from Latin America are scarce and inconsistent. The present study sought to explore the development of antibodies against P. falciparum and Plasmodium vivax antigens in pregnant women living in a low transmission area in the Brazilian Amazon. METHODS In a prospective cohort study, plasma samples from 408 pregnant women (of whom 111 were infected with P. falciparum, 96 had infections with P. falciparum and P. vivax, and 201 had no Plasmodium infection) were used to measure antibody levels. Levels of IgG and opsonizing antibody to pregnancy-specific variant surface antigens (VSAs) on infected erythrocytes (IEs), 10 recombinant VAR2CSA Duffy binding like (DBL domains), 10 non-pregnancy-specific P. falciparum merozoite antigens, and 10 P. vivax antigens were measured by flow cytometry, ELISA, and multiplex assays. Antibody levels and seropositivity among the groups were compared. RESULTS Antibodies to VSAs on P. falciparum IEs were generally low but were higher in currently infected women and women with multiple P. falciparum episodes over pregnancy. Many women (21%-69%) had antibodies against each individual VAR2CSA DBL domain, and antibodies to DBLs correlated with each other (r ≥ 0.55, p < 0.0001), but not with antibody to VSA or history of infection. Infection with either malaria species was associated with higher seropositivity rate for antibodies against P. vivax proteins, adjusted odds ratios (95% CI) ranged from 5.6 (3.2, 9.7), p < 0.0001 for PVDBPII-Sal1 to 15.7 (8.3, 29.7), p < 0.0001 for PvTRAg_2. CONCLUSIONS Pregnant Brazilian women had low levels of antibodies to pregnancy-specific VSAs that increased with exposure. They frequently recognized both VAR2CSA DBL domains and P. vivax antigens, but only the latter varied with infection. Apparent antibody prevalence is highly dependent on the assay platform used.
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Affiliation(s)
- Meseret W. Kassa
- grid.1008.90000 0001 2179 088XDepartment of Medicine, University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Level 5, 792 Elizabeth St, University of Melbourne, Melbourne, VIC 3000 Australia
| | - Wina Hasang
- grid.1008.90000 0001 2179 088XDepartment of Infectious Diseases, University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC Australia
| | - André Barateiro
- grid.11899.380000 0004 1937 0722Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Timon Damelang
- grid.1008.90000 0001 2179 088XDepartment of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, University of Melbourne, Melbourne, VIC Australia
| | - Jessica Brewster
- grid.1042.70000 0004 0432 4889Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC Australia
| | - Jamille G. Dombrowski
- grid.11899.380000 0004 1937 0722Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Rhea J. Longley
- grid.1042.70000 0004 0432 4889Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC Australia ,grid.1008.90000 0001 2179 088XDepartment of Medical Biology, University of Melbourne, Melbourne, VIC Australia
| | - Amy W. Chung
- grid.1008.90000 0001 2179 088XDepartment of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, University of Melbourne, Melbourne, VIC Australia
| | - Gerhard Wunderlich
- grid.11899.380000 0004 1937 0722Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Ivo Mueller
- grid.1042.70000 0004 0432 4889Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC Australia ,grid.1008.90000 0001 2179 088XDepartment of Medical Biology, University of Melbourne, Melbourne, VIC Australia
| | - Elizabeth H. Aitken
- grid.1008.90000 0001 2179 088XDepartment of Infectious Diseases, University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC Australia ,grid.1008.90000 0001 2179 088XDepartment of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, University of Melbourne, Melbourne, VIC Australia
| | - Claudio R. F. Marinho
- grid.11899.380000 0004 1937 0722Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Stephen J. Rogerson
- grid.1008.90000 0001 2179 088XDepartment of Medicine, University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Level 5, 792 Elizabeth St, University of Melbourne, Melbourne, VIC 3000 Australia ,grid.1008.90000 0001 2179 088XDepartment of Infectious Diseases, University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne, VIC Australia
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Raghavan SSR, Dagil R, Lopez-Perez M, Conrad J, Bassi MR, Quintana MDP, Choudhary S, Gustavsson T, Wang Y, Gourdon P, Ofori MF, Christensen SB, Minja DTR, Schmiegelow C, Nielsen MA, Barfod L, Hviid L, Salanti A, Lavstsen T, Wang K. Cryo-EM reveals the conformational epitope of human monoclonal antibody PAM1.4 broadly reacting with polymorphic malarial protein VAR2CSA. PLoS Pathog 2022; 18:e1010924. [PMCID: PMC9668162 DOI: 10.1371/journal.ppat.1010924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 10/10/2022] [Indexed: 11/17/2022] Open
Abstract
Malaria during pregnancy is a major global health problem caused by infection with Plasmodium falciparum parasites. Severe effects arise from the accumulation of infected erythrocytes in the placenta. Here, erythrocytes infected by late blood-stage parasites adhere to placental chondroitin sulphate A (CS) via VAR2CSA-type P. falciparum erythrocyte membrane protein 1 (PfEMP1) adhesion proteins. Immunity to placental malaria is acquired through exposure and mediated through antibodies to VAR2CSA. Through evolution, the VAR2CSA proteins have diversified in sequence to escape immune recognition but retained their overall macromolecular structure to maintain CS binding affinity. This structural conservation may also have allowed development of broadly reactive antibodies to VAR2CSA in immune women. Here we show the negative stain and cryo-EM structure of the only known broadly reactive human monoclonal antibody, PAM1.4, in complex with VAR2CSA. The data shows how PAM1.4’s broad VAR2CSA reactivity is achieved through interactions with multiple conserved residues of different sub-domains forming conformational epitope distant from the CS binding site on the VAR2CSA core structure. Thus, while PAM1.4 may represent a class of antibodies mediating placental malaria immunity by inducing phagocytosis or NK cell-mediated cytotoxicity, it is likely that broadly CS binding-inhibitory antibodies target other epitopes at the CS binding site. Insights on both types of broadly reactive monoclonal antibodies may aid the development of a vaccine against placental malaria.
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Affiliation(s)
- Sai Sundar Rajan Raghavan
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Robert Dagil
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Mary Lopez-Perez
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Julian Conrad
- Swedish National Cryo-EM Facility, Science for Life Laboratories, Solna, Sweden
| | - Maria Rosaria Bassi
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Maria del Pilar Quintana
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Swati Choudhary
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Tobias Gustavsson
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Yong Wang
- Joint Research Centre for Engineering Biology, Zhejiang University-University of Edinburgh Institute, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Pontus Gourdon
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Michael Fokuo Ofori
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Sebastian Boje Christensen
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | | | - Christentze Schmiegelow
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Morten Agertoug Nielsen
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Lea Barfod
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Lars Hviid
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Ali Salanti
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Thomas Lavstsen
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, and Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
- * E-mail: (TL); (KW)
| | - Kaituo Wang
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- * E-mail: (TL); (KW)
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Rotich AK, Takashima E, Yanow SK, Gitaka J, Kanoi BN. Towards identification and development of alternative vaccines against pregnancy-associated malaria based on naturally acquired immunity. FRONTIERS IN TROPICAL DISEASES 2022. [DOI: 10.3389/fitd.2022.988284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Pregnant women are particularly susceptible to Plasmodium falciparum malaria, leading to substantial maternal and infant morbidity and mortality. While highly effective malaria vaccines are considered an essential component towards malaria elimination, strides towards development of vaccines for pregnant women have been minimal. The leading malaria vaccine, RTS,S/AS01, has modest efficacy in children suggesting that it needs to be strengthened and optimized if it is to be beneficial for pregnant women. Clinical trials against pregnancy-associated malaria (PAM) focused on the classical VAR2CSA antigen are ongoing. However, additional antigens have not been identified to supplement these initiatives despite the new evidence that VAR2CSA is not the only molecule involved in pregnancy-associated naturally acquired immunity. This is mainly due to a lack of understanding of the immune complexities in pregnancy coupled with difficulties associated with expression of malaria recombinant proteins, low antigen immunogenicity in humans, and the anticipated complications in conducting and implementing a vaccine to protect pregnant women. With the accelerated evolution of molecular technologies catapulted by the global pandemic, identification of novel alternative vaccine antigens is timely and feasible. In this review, we discuss approaches towards novel antigen discovery to support PAM vaccine studies.
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Massamba JE, Djontu JC, Vouvoungui CJ, Kobawila C, Ntoumi F. Plasmodium falciparum multiplicity of infection and pregnancy outcomes in Congolese women from southern Brazzaville, Republic of Congo. Malar J 2022; 21:114. [PMID: 35366882 PMCID: PMC8976437 DOI: 10.1186/s12936-022-04105-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 02/24/2022] [Indexed: 11/30/2022] Open
Abstract
Background Investigating whether the multiplicity of Plasmodium falciparum infection (MOI) is related to pregnancy outcomes, is of interest in sub-Saharan area where malaria is highly endemic. The present study aimed to characterize the genetic diversity of P. falciparum in women at delivery from Southern Brazzaville, and investigate whether the MOI is associated with maternal anaemia, preterm delivery, or low birth weight. Methods This was a cross sectional study carried out with samples collected between March 2014 and April 2015 from 371 women recruited at delivery at a Health Centre in southern Brazzaville, Republic of Congo. Matched peripheral, placental, and cord blood collected from each of the women at delivery were used for the detection of P. falciparum microscopic and submicroscopic parasitaemia, and parasite DNA genotyping by nested PCR. Results From 371 recruited women, 27 were positive to microscopic malaria parasitaemia while 223 women harboured submicroscopic parasitaemia. All msp-1 block 2 family allelic types (K1, MAD20 and RO33) were observed in all the three compartments of blood, with K1 being most abundant. K1 (with 12, 10, and 08 alleles in the peripheral, placental, and cord blood respectively) and MAD20 (with 10, 09, and 06 alleles in the respective blood compartments) were more diverse compared to RO33 (with 06, 06, and 05 alleles in the respective blood compartments). From the 250 women with microscopic and/or submicroscopic parasitaemia, 38.5%, 30.5%, and 18.4% of peripheral, placental and cord blood sample, respectively, harboured more than one parasite clone, and polyclonal infection was more prevalent in the peripheral blood of women with microscopic parasitaemia (54.5%) compared to those with submicroscopic parasitaemia (36.7%) (p = 0.02). The mean multiplicity of genotypes per microscopic and submicroscopic infection in peripheral blood was higher in anemic women (2.00 ± 0.23 and 1.66 ± 0.11, respectively) than in non-anaemic women (1.36 ± 0.15 and 1.45 ± 0.06, respectively) (p = 0.03 and 0.06). In logistic regression, women infected with four or more clones of the parasite were 9.4 times more likely to be anaemic than women harbouring one clone. This association, however, was only observed with the peripheral blood infection. No significant association was found between the MOI and low birth weight or preterm delivery. Conclusions These results indicate that the genetic diversity of P. falciparum is high in pregnant women from southern Brazzaville in the Republic of Congo, and the multiplicity of the infection might represent a risk for maternal anaemia.
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Doritchamou JY, Renn JP, Jenkins B, Fried M, Duffy PE. A single full-length VAR2CSA ectodomain variant purifies broadly neutralizing antibodies against placental malaria isolates. eLife 2022; 11:76264. [PMID: 35103596 PMCID: PMC8959597 DOI: 10.7554/elife.76264] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 01/31/2022] [Indexed: 11/13/2022] Open
Abstract
Placental malaria (PM) is a deadly syndrome most frequent and severe in first pregnancies. PM results from accumulation of Plasmodium falciparum-infected erythrocytes (IE) that express the surface antigen VAR2CSA and bind to chondroitin sulfate A (CSA) in the placenta. Women become PM-resistant over successive pregnancies as they develop anti-adhesion and anti-VAR2CSA antibodies, supporting VAR2CSA as the leading PM-vaccine candidate. However, the first VAR2CSA subunit vaccines failed to induce broadly neutralizing antibody and it is known that naturally acquired antibodies target both variant-specific and conserved epitopes. It is crucial to determine whether effective vaccines will require incorporation of many or only a single VAR2CSA variants. Here, IgG from multigravidae was sequentially purified on five full-length VAR2CSA ectodomain variants, thereby depleting IgG reactivity to each. The five VAR2CSA variants purified ~0.7% of total IgG and yielded both strain-transcending and strain-specific reactivity to VAR2CSA and IE-surface antigen. In two independent antibody purification/depletion experiments with permutated order of VAR2CSA variants, IgG purified on the first VAR2CSA antigen displayed broad cross-reactivity to both recombinant and native VAR2CSA variants, and inhibited binding of all isolates to CSA. IgG remaining after depletion on all variants showed significantly reduced binding-inhibition activity compared to initial total IgG. These findings demonstrate that a single VAR2CSA ectodomain variant displays conserved epitopes that are targeted by neutralizing (or binding-inhibitory) antibodies shared by multiple parasite strains, including maternal isolates. This suggests that a broadly effective PM-vaccine can be achieved with a limited number of VAR2CSA variants. Contracting malaria during pregnancy – especially a first pregnancy – can lead to a severe, placental form of the disease that is often fatal. Red blood cells infected with the malaria parasite Plasmodium falciparum display a protein, VAR2CSA, which can recognize and bind CSA molecules present on placental cells and in placental blood spaces. This leads to the infected blood cells accumulating in the placenta and inducing harmful inflammation. Having been exposed to the parasite in prior pregnancies generates antibodies that target VAR2CSA, stopping the infected blood cells from latching onto placental CSA or tagging them for immune destruction. Overall, this makes placental malaria less severe in following pregnancies, and suggests that vaccines could be developed based on VAR2CSA. However, this protein has regions that can vary in structure, meaning that P. falciparaum can generate many VAR2CSA variants. Individuals exposed to the parasite naturally generate antibodies that block a wide array of variants from attaching to CSA. In contrast, first-generation vaccines based on VAR2CSA fragments have only induced variant-specific antibodies, therefore offering limited protection against infection. As a response, Doritchamou et al. set out to find VAR2CSA structures that could be recognized by antibodies targeting an array of variants. Blood was obtained from women who had had multiple pregnancies and were immune to malaria. Their plasma was passed over five different large VAR2CSA variants in order to isolate and purify antibodies that attached to these structures. Doritchamou et al. found that antibodies binding to individual VAR2CSA structures could also recognise a wide array of VAR2CSA variants and blocked all tested parasites from sticking to CSA. While further research is needed, these findings highlight antibodies that cross-react to diverse VAR2CSA variants and could be used to design more effective vaccines targeting placental malaria.
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Affiliation(s)
- Justin Ya Doritchamou
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, United States
| | - Jonathan P Renn
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, United States
| | - Bethany Jenkins
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, United States
| | - Michal Fried
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, Rockville, United States
| | - Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, Bethesda, United States
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Kassa MW, Hasang W, Rogerson SJ. Antibody-Dependent THP-1 Cell-Mediated Phagocytosis of Plasmodium falciparum-Infected Erythrocytes. Methods Mol Biol 2022; 2470:617-628. [PMID: 35881378 DOI: 10.1007/978-1-0716-2189-9_46] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Antibodies that recognize variant surface antigens (VSAs) expressed on Plasmodium falciparum-infected erythrocytes (IEs) opsonize IEs for phagocytic clearance. The anti-VSA antibodies promote antibody-dependent cellular phagocytosis (ADCP) of IEs by interacting with innate immune cells. ADCP is an important immune effector mechanism of parasite clearance. ADCP can be a tool to assess the efficacy of vaccine-induced antibodies, in addition to measuring the neutralizing ability of antibodies. Here, we developed and validated an efficient and high-throughput plate-based flow cytometric assay to measure ADCP of IEs using the human monocytic THP-1 cell line. This flow cytometric assay can be used to analyze the level of naturally acquired or vaccine-induced opsonic antibodies in large cohorts.
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Affiliation(s)
- Meseret Workineh Kassa
- Department of Medicine, The Doherty Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - Wina Hasang
- Department of Medicine, The Doherty Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - Stephen John Rogerson
- Department of Medicine, The Doherty Institute, The University of Melbourne, Melbourne, VIC, Australia.
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Renn JP, Doritchamou JYA, Duffy PE. Expression of Large Full-Length PfEMP1 Proteins in HEK293 Cells. Methods Mol Biol 2022; 2470:283-298. [PMID: 35881353 DOI: 10.1007/978-1-0716-2189-9_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a family of proteins expressed on the surface of red blood cells infected by Plasmodium falciparum. PfEMP1 proteins play a vital role in parasite virulence, and thus are important vaccine candidates to prevent severe disease. VAR2CSA is one specific PfEMP1 essential for pregnancy malaria pathogenesis, and the primary target in pregnancy malaria vaccine development. However, similar to other PfEMP1 proteins, expression of recombinant full-length VAR2CSA is difficult due to its large size, multidomain architecture and high cysteine content. To date, there has been success using higher ordered expression systems (such as mammalian and insect cells) to generate folded and active VAR2CSA. However, recent improvements with mammalian expression systems including cell lines and promoters have pushed the boundaries of yields. Here, we describe a modified protocol beyond current systems that enhances yields of full-length VAR2CSA and can generate higher quantities of material for protein structural and functional characterization.
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Affiliation(s)
- Jonathan Paul Renn
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Justin Yai Alamou Doritchamou
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Patrick Emmet Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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Oleinikov AV. Malaria Parasite Plasmodium falciparum Proteins on the Surface of Infected Erythrocytes as Targets for Novel Drug Discovery. BIOCHEMISTRY (MOSCOW) 2022; 87:S192-S177. [PMID: 35501996 PMCID: PMC8802247 DOI: 10.1134/s0006297922140152] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Specific adhesion (sequestration) of Plasmodium falciparum parasite-infected erythrocytes (IEs) in deep vascular beds can cause severe complications resulting in death. This review describes our work on the discovery, characterization, and optimization of novel inhibitors that specifically prevent adhesion of IEs to the host vasculature during severe malaria, especially its placental and cerebral forms. The main idea of using anti-adhesion drugs in severe malaria is to release sequestered parasites (or prevent additional sequestration) as quickly as possible. This may significantly improve the outcomes for patients with severe malaria by decreasing local and systemic inflammation associated with the disease and reestablishing the microvascular blood flow. To identify anti-malarial adhesion-inhibiting molecules, we have developed a high-throughput (HT) screening approach and found a number of promising leads that can be further developed into anti-adhesion drugs providing an efficient adjunct therapy against severe forms of malaria.
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Affiliation(s)
- Andrew V Oleinikov
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33428, USA.
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20
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Renn JP, Doritchamou JYA, Tentokam BCN, Morrison RD, Cowles MV, Burkhardt M, Ma R, Tolia NH, Fried M, Duffy PE. Allelic variants of full-length VAR2CSA, the placental malaria vaccine candidate, differ in antigenicity and receptor binding affinity. Commun Biol 2021; 4:1309. [PMID: 34799664 PMCID: PMC8604988 DOI: 10.1038/s42003-021-02787-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 10/14/2021] [Indexed: 11/16/2022] Open
Abstract
Plasmodium falciparum-infected erythrocytes (IE) sequester in the placenta via surface protein VAR2CSA, which binds chondroitin sulfate A (CSA) expressed on the syncytiotrophoblast surface, causing placental malaria (PM) and severe adverse outcomes in mothers and their offspring. VAR2CSA belongs to the PfEMP1 variant surface antigen family; PfEMP1 proteins mediate IE adhesion and facilitate parasite immunoevasion through antigenic variation. Here we produced deglycosylated (native-like) and glycosylated versions of seven recombinant full-length VAR2CSA ectodomains and compared them for antigenicity and adhesiveness. All VAR2CSA recombinants bound CSA with nanomolar affinity, and plasma from Malian pregnant women demonstrated antigen-specific reactivity that increased with gravidity and trimester. However, allelic and glycosylation variants differed in their affinity to CSA and their serum reactivities. Deglycosylated proteins (native-like) showed higher CSA affinity than glycosylated proteins for all variants except NF54. Further, the gravidity-related increase in serum VAR2CSA reactivity (correlates with acquisition of protective immunity) was absent with the deglycosylated form of atypical M200101 VAR2CSA with an extended C-terminal region. Our findings indicate significant inter-allelic differences in adhesion and seroreactivity that may contribute to the heterogeneity of clinical presentations, which could have implications for vaccine design. Full-length VAR2CSA is a potential placental malaria vaccine candidate and in this study, Renn et al. compare antigenicity and receptor binding affinity of different allelic variants in blood samples from pregnant women. Their data show that inter-allelic differences may contribute to the heterogeneity of clinical presentations, which could have implications for vaccine design.
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Affiliation(s)
- Jonathan P Renn
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Justin Y A Doritchamou
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Bergeline C Nguemwo Tentokam
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Robert D Morrison
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Matthew V Cowles
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Martin Burkhardt
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Rui Ma
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Niraj H Tolia
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Michal Fried
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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21
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Afucosylated Plasmodium falciparum-specific IgG is induced by infection but not by subunit vaccination. Nat Commun 2021; 12:5838. [PMID: 34611164 PMCID: PMC8492741 DOI: 10.1038/s41467-021-26118-w] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 09/11/2021] [Indexed: 01/02/2023] Open
Abstract
Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family members mediate receptor- and tissue-specific sequestration of infected erythrocytes (IEs) in malaria. Antibody responses are a central component of naturally acquired malaria immunity. PfEMP1-specific IgG likely protects by inhibiting IE sequestration and through IgG-Fc Receptor (FcγR) mediated phagocytosis and killing of antibody-opsonized IEs. The affinity of afucosylated IgG to FcγRIIIa is up to 40-fold higher than fucosylated IgG, resulting in enhanced antibody-dependent cellular cytotoxicity. Most IgG in plasma is fully fucosylated, but afucosylated IgG is elicited in response to enveloped viruses and to paternal alloantigens during pregnancy. Here we show that naturally acquired PfEMP1-specific IgG is strongly afucosylated in a stable and exposure-dependent manner, and efficiently induces FcγRIIIa-dependent natural killer (NK) cell degranulation. In contrast, immunization with a subunit PfEMP1 (VAR2CSA) vaccine results in fully fucosylated specific IgG. These results have implications for understanding protective natural- and vaccine-induced immunity to malaria. Here, Larsen et al. describe differences in Fc fucosylation of P. falciparum PfEMP1-specific IgG produced in response to natural infection versus VAR2CSA-type subunit vaccination, which leads to differences in the ability to induce FcγRIIIa-dependent natural killer cell degranulation.
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22
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Larsen MD, Lopez-Perez M, Dickson EK, Ampomah P, Tuikue Ndam N, Nouta J, Koeleman CAM, Ederveen ALH, Mordmüller B, Salanti A, Nielsen MA, Massougbodji A, van der Schoot CE, Ofori MF, Wuhrer M, Hviid L, Vidarsson G. Afucosylated Plasmodium falciparum-specific IgG is induced by infection but not by subunit vaccination. Nat Commun 2021. [PMID: 34611164 DOI: 10.1101/2021.04.23.441082v1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family members mediate receptor- and tissue-specific sequestration of infected erythrocytes (IEs) in malaria. Antibody responses are a central component of naturally acquired malaria immunity. PfEMP1-specific IgG likely protects by inhibiting IE sequestration and through IgG-Fc Receptor (FcγR) mediated phagocytosis and killing of antibody-opsonized IEs. The affinity of afucosylated IgG to FcγRIIIa is up to 40-fold higher than fucosylated IgG, resulting in enhanced antibody-dependent cellular cytotoxicity. Most IgG in plasma is fully fucosylated, but afucosylated IgG is elicited in response to enveloped viruses and to paternal alloantigens during pregnancy. Here we show that naturally acquired PfEMP1-specific IgG is strongly afucosylated in a stable and exposure-dependent manner, and efficiently induces FcγRIIIa-dependent natural killer (NK) cell degranulation. In contrast, immunization with a subunit PfEMP1 (VAR2CSA) vaccine results in fully fucosylated specific IgG. These results have implications for understanding protective natural- and vaccine-induced immunity to malaria.
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Affiliation(s)
- Mads Delbo Larsen
- Department of Experimental Immunohematology, Sanquin Research, Amsterdam, The Netherlands.,Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Mary Lopez-Perez
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Emmanuel Kakra Dickson
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Paulina Ampomah
- Department of Biomedical Sciences, School of Allied Health Sciences, University of Cape Coast, Cape Coast, Ghana
| | | | - Jan Nouta
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands
| | - Carolien A M Koeleman
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Benjamin Mordmüller
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands.,Institut für Tropenmedizin, Universitätsklinikum Tübingen, Tübingen, Germany
| | - Ali Salanti
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Morten Agertoug Nielsen
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Achille Massougbodji
- Centre d'Etude et de Recherche sur le Paludisme Associé à la Grossesse et à l'Enfance (CERPAGE), Faculté des Sciences de la Santé, Université d'Abomey-Calavi, Godomey, Benin
| | - C Ellen van der Schoot
- Department of Experimental Immunohematology, Sanquin Research, Amsterdam, The Netherlands.,Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Michael F Ofori
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Manfred Wuhrer
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands
| | - Lars Hviid
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark. .,Centre for Medical Parasitology, Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark.
| | - Gestur Vidarsson
- Department of Experimental Immunohematology, Sanquin Research, Amsterdam, The Netherlands. .,Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.
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23
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Immunoprofiles associated with controlled human malaria infection and naturally acquired immunity identify a shared IgA pre-erythrocytic immunoproteome. NPJ Vaccines 2021; 6:115. [PMID: 34518543 PMCID: PMC8438027 DOI: 10.1038/s41541-021-00363-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 07/29/2021] [Indexed: 12/12/2022] Open
Abstract
Knowledge of the Plasmodium falciparum antigens that comprise the human liver stage immunoproteome is important for pre-erythrocytic vaccine development, but, compared with the erythrocytic stage immunoproteome, more challenging to classify. Previous studies of P. falciparum antibody responses report IgG and rarely IgA responses. We assessed IgG and IgA antibody responses in adult sera collected during two controlled human malaria infection (CHMI) studies in malaria-naïve volunteers and in 1- to 6-year-old malaria-exposed Malian children on a 251 P. falciparum antigen protein microarray. IgG profiles in the two CHMI groups were equivalent and differed from Malian children. IgA profiles were robust in the CHMI groups and a subset of Malian children. We describe immunoproteome differences in naïve vs. exposed individuals and report pre-erythrocytic proteins recognized by the immune system. IgA responses detected in this study expand the list of pre-erythrocytic antigens for further characterization as potential vaccine candidates.
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24
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Megli CJ, Coyne CB. Infections at the maternal-fetal interface: an overview of pathogenesis and defence. Nat Rev Microbiol 2021; 20:67-82. [PMID: 34433930 PMCID: PMC8386341 DOI: 10.1038/s41579-021-00610-y] [Citation(s) in RCA: 147] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/15/2021] [Indexed: 02/08/2023]
Abstract
Infections are a major threat to human reproductive health, and infections in pregnancy can cause prematurity or stillbirth, or can be vertically transmitted to the fetus leading to congenital infection and severe disease. The acronym ‘TORCH’ (Toxoplasma gondii, other, rubella virus, cytomegalovirus, herpes simplex virus) refers to pathogens directly associated with the development of congenital disease and includes diverse bacteria, viruses and parasites. The placenta restricts vertical transmission during pregnancy and has evolved robust mechanisms of microbial defence. However, microorganisms that cause congenital disease have likely evolved diverse mechanisms to bypass these defences. In this Review, we discuss how TORCH pathogens access the intra-amniotic space and overcome the placental defences that protect against microbial vertical transmission. Infections during pregnancy can be associated with devastating outcomes for the pregnant mother and developing fetus. In this Review, Megli and Coyne discuss placental defences and provide an overview of how various viral, bacterial and parasitic pathogens traverse the maternal–fetal interface and cause disease.
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Affiliation(s)
- Christina J Megli
- Division of Maternal-Fetal Medicine, Division of Reproductive Infectious Disease, Department of Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh School of Medicine and the Magee Womens Research Institute, Pittsburgh, PA, USA.
| | - Carolyn B Coyne
- Department of Molecular Genetics and Microbiology and the Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, USA.
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25
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Opi DH, Boyle MJ, McLean ARD, Reiling L, Chan JA, Stanisic DI, Ura A, Mueller I, Fowkes FJI, Rogerson SJ, Beeson JG. Reduced risk of placental parasitemia associated with complement fixation on Plasmodium falciparum by antibodies among pregnant women. BMC Med 2021; 19:201. [PMID: 34425801 PMCID: PMC8383393 DOI: 10.1186/s12916-021-02061-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 07/13/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The pathogenesis of malaria in pregnancy (MiP) involves accumulation of P. falciparum-infected red blood cells (pRBCs) in the placenta, contributing to poor pregnancy outcomes. Parasite accumulation is primarily mediated by P. falciparum erythrocyte membrane protein 1 (PfEMP1). Magnitude of IgG to pRBCs has been associated with reduced risk of MiP in some studies, but associations have been inconsistent. Further, antibody effector mechanisms are poorly understood, and the role of antibody complement interactions is unknown. METHODS Studying a longitudinal cohort of pregnant women (n=302) from a malaria-endemic province in Papua New Guinea (PNG), we measured the ability of antibodies to fix and activate complement using placental binding pRBCs and PfEMP1 recombinant domains. We determined antibody-mediated complement inhibition of pRBC binding to the placental receptor, chondroitin sulfate A (CSA), and associations with protection against placental parasitemia. RESULTS Some women acquired antibodies that effectively promoted complement fixation on placental-binding pRBCs. Complement fixation correlated with IgG1 and IgG3 antibodies, which dominated the response. There was, however, limited evidence for membrane attack complex activity or pRBC lysis or killing. Importantly, a higher magnitude of complement fixing antibodies was prospectively associated with reduced odds of placental infection at delivery. Using genetically modified P. falciparum and recombinant PfEMP1 domains, we found that complement-fixing antibodies primarily targeted a specific variant of PfEMP1 (known as VAR2CSA). Furthermore, complement enhanced the ability of antibodies to inhibit pRBC binding to CSA, which was primarily mediated by complement C1q protein. CONCLUSIONS These findings provide new insights into mechanisms mediating immunity to MiP and reveal potential new strategies for developing malaria vaccines that harness antibody-complement interactions.
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Affiliation(s)
- D Herbert Opi
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, 3004, Australia. .,Department of Immunology, Monash University, Melbourne, Australia. .,Department of Medicine at the Doherty Institute, University of Melbourne, Melbourne, Australia.
| | - Michelle J Boyle
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, 3004, Australia.,Human Malaria Immunology Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | | | - Linda Reiling
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, 3004, Australia
| | - Jo-Anne Chan
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, 3004, Australia.,Department of Immunology, Monash University, Melbourne, Australia.,Department of Medicine at the Doherty Institute, University of Melbourne, Melbourne, Australia
| | - Danielle I Stanisic
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea.,Institute for Glycomics, Griffith University, Southport, Queensland, Australia
| | - Alice Ura
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Ivo Mueller
- Walter and Eliza Hall Institute of Medical Research, Parkville, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, Australia.,Institute Pasteur, Paris, France
| | - Freya J I Fowkes
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, 3004, Australia.,Department of Infectious Diseases, Monash University, Melbourne, Australia.,Centre for Epidemiology and Biostatistics, University of Melbourne, Melbourne, Australia.,Department of Epidemiology and Preventative Medicine, Monash University, Melbourne, Australia
| | - Stephen J Rogerson
- Department of Medicine at the Doherty Institute, University of Melbourne, Melbourne, Australia
| | - James G Beeson
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, 3004, Australia. .,Department of Immunology, Monash University, Melbourne, Australia. .,Department of Medicine at the Doherty Institute, University of Melbourne, Melbourne, Australia. .,Department of Microbiology, Monash University, Clayton, Australia.
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26
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Aitken EH, Damelang T, Ortega-Pajares A, Alemu A, Hasang W, Dini S, Unger HW, Ome-Kaius M, Nielsen MA, Salanti A, Smith J, Kent S, Hogarth PM, Wines BD, Simpson JA, Chung AW, Rogerson SJ. Developing a multivariate prediction model of antibody features associated with protection of malaria-infected pregnant women from placental malaria. eLife 2021; 10:e65776. [PMID: 34181872 PMCID: PMC8241440 DOI: 10.7554/elife.65776] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 06/16/2021] [Indexed: 12/15/2022] Open
Abstract
Background Plasmodium falciparum causes placental malaria, which results in adverse outcomes for mother and child. P. falciparum-infected erythrocytes that express the parasite protein VAR2CSA on their surface can bind to placental chondroitin sulfate A. It has been hypothesized that naturally acquired antibodies towards VAR2CSA protect against placental infection, but it has proven difficult to identify robust antibody correlates of protection from disease. The objective of this study was to develop a prediction model using antibody features that could identify women protected from placental malaria. Methods We used a systems serology approach with elastic net-regularized logistic regression, partial least squares discriminant analysis, and a case-control study design to identify naturally acquired antibody features mid-pregnancy that were associated with protection from placental malaria at delivery in a cohort of 77 pregnant women from Madang, Papua New Guinea. Results The machine learning techniques selected 6 out of 169 measured antibody features towards VAR2CSA that could predict (with 86% accuracy) whether a woman would subsequently have active placental malaria infection at delivery. Selected features included previously described associations with inhibition of placental binding and/or opsonic phagocytosis of infected erythrocytes, and network analysis indicated that there are not one but multiple pathways to protection from placental malaria. Conclusions We have identified candidate antibody features that could accurately identify malaria-infected women as protected from placental infection. It is likely that there are multiple pathways to protection against placental malaria. Funding This study was supported by the National Health and Medical Research Council (Nos. APP1143946, GNT1145303, APP1092789, APP1140509, and APP1104975).
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Affiliation(s)
- Elizabeth H Aitken
- Department of Medicine, University of Melbourne, the Doherty InstituteMelbourneAustralia
| | - Timon Damelang
- Department of Microbiology and Immunology, University of Melbourne, the Doherty InstituteMelbourneAustralia
| | - Amaya Ortega-Pajares
- Department of Medicine, University of Melbourne, the Doherty InstituteMelbourneAustralia
| | - Agersew Alemu
- Department of Medicine, University of Melbourne, the Doherty InstituteMelbourneAustralia
| | - Wina Hasang
- Department of Medicine, University of Melbourne, the Doherty InstituteMelbourneAustralia
| | - Saber Dini
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of MelbourneMelbourneAustralia
| | - Holger W Unger
- Department of Medicine, University of Melbourne, the Doherty InstituteMelbourneAustralia
- Department of Obstetrics and Gynaecology, Royal Darwin HospitalDarwinAustralia
- Menzies School of Health ResearchDarwinAustralia
| | - Maria Ome-Kaius
- Walter and Eliza Hall Institute of Medical ResearchParkvilleAustralia
| | - Morten A Nielsen
- Centre for Medical Parasitology, Department of Microbiology and immunology, University of CopenhagenCopenhagenDenmark
| | - Ali Salanti
- Centre for Medical Parasitology, Department of Microbiology and immunology, University of CopenhagenCopenhagenDenmark
- Department of Infectious Disease, Copenhagen University HospitalCopenhagenDenmark
| | - Joe Smith
- Seattle Children’s Research InstituteSeattleUnited States
- Department of Pediatrics, University of WashingtonSeattleUnited States
| | - Stephen Kent
- Department of Microbiology and Immunology, University of Melbourne, the Doherty InstituteMelbourneAustralia
| | - P Mark Hogarth
- Seattle Children’s Research InstituteSeattleUnited States
- Immune Therapies Group, Centre for Biomedical Research, Burnet InstituteMelbourneAustralia
- Department of Clinical Pathology, University of MelbourneMelbourneAustralia
- Department of Immunology and Pathology, Monash UniversityMelbourneAustralia
| | - Bruce D Wines
- Immune Therapies Group, Centre for Biomedical Research, Burnet InstituteMelbourneAustralia
- Department of Clinical Pathology, University of MelbourneMelbourneAustralia
- Department of Immunology and Pathology, Monash UniversityMelbourneAustralia
| | - Julie A Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of MelbourneMelbourneAustralia
| | - Amy W Chung
- Department of Microbiology and Immunology, University of Melbourne, the Doherty InstituteMelbourneAustralia
| | - Stephen J Rogerson
- Department of Medicine, University of Melbourne, the Doherty InstituteMelbourneAustralia
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27
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McLean ARD, Opi DH, Stanisic DI, Cutts JC, Feng G, Ura A, Mueller I, Rogerson SJ, Beeson JG, Fowkes FJI. High Antibodies to VAR2CSA in Response to Malaria Infection Are Associated With Improved Birthweight in a Longitudinal Study of Pregnant Women. Front Immunol 2021; 12:644563. [PMID: 34220804 PMCID: PMC8242957 DOI: 10.3389/fimmu.2021.644563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 05/17/2021] [Indexed: 11/23/2022] Open
Abstract
Introduction Pregnant women have an increased risk of P. falciparum infection, which is associated with low birth weight and preterm delivery. VAR2CSA, a variant surface antigen expressed on the parasitized erythrocyte surface, enables sequestration in the placenta. Few studies have prospectively examined relationships between antibody responses during pregnancy and subsequent adverse birth outcomes, and there are limited data outside Africa. Methods Levels of IgG against VAR2CSA domains (DBL3; DBL5) and a VAR2CSA-expressing placental-binding P. falciparum isolate (PfCS2-IE) were measured in 301 women enrolled at their first visit to antenatal care which occurred mid-pregnancy (median = 26 weeks, lower and upper quartiles = 22, 28). Associations between antibody levels at enrolment and placental infection, birthweight and estimated gestational age at delivery were assessed by linear and logistic regression with adjustment for confounders. For all outcomes, effect modification by gravidity and peripheral blood P. falciparum infection at enrolment was assessed. Results Among women who had acquired P. falciparum infection at enrolment, those with higher levels of VAR2CSA antibodies (75th percentile) had infants with higher mean birthweight (estimates varied from +35g to +149g depending on antibody response) and reduced adjusted odds of placental infection (aOR estimates varied from 0.17 to 0.80), relative to women with lower levels (25th percentile) of VAR2CSA antibodies. However, among women who had not acquired an infection at enrolment, higher VAR2CSA antibodies were associated with increased odds of placental infection (aOR estimates varied from 1.10 to 2.24). Conclusions When infected by mid-pregnancy, a better immune response to VAR2CSA-expressing parasites may contribute to protecting against adverse pregnancy outcomes.
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Affiliation(s)
- Alistair R D McLean
- Burnet Institute, Melbourne, VIC, Australia.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - D Herbert Opi
- Burnet Institute, Melbourne, VIC, Australia.,Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia.,Department of Medicine at the Doherty Institute, University of Melbourne, Melbourne, VIC, Australia
| | - Danielle I Stanisic
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea.,Institute for Glycomics, Griffith University, Southport, QLD, Australia
| | - Julia C Cutts
- Burnet Institute, Melbourne, VIC, Australia.,Department of Medicine at the Doherty Institute, University of Melbourne, Melbourne, VIC, Australia
| | - Gaoqian Feng
- Burnet Institute, Melbourne, VIC, Australia.,Department of Medicine at the Doherty Institute, University of Melbourne, Melbourne, VIC, Australia
| | - Alice Ura
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Ivo Mueller
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea.,Population, Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Département Parasites et Insectes Vecteurs, Institute Pasteur, Paris, France
| | - Stephen J Rogerson
- Department of Medicine at the Doherty Institute, University of Melbourne, Melbourne, VIC, Australia
| | - James G Beeson
- Burnet Institute, Melbourne, VIC, Australia.,Department of Medicine at the Doherty Institute, University of Melbourne, Melbourne, VIC, Australia.,Department of Microbiology, Monash University, Clayton, VIC, Australia
| | - Freya J I Fowkes
- Burnet Institute, Melbourne, VIC, Australia.,Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, VIC, Australia.,Centre for Epidemiology and Biostatistics, University of Melbourne, Melbourne, VIC, Australia.,Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, VIC, Australia
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28
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Mahamar A, Andemel N, Swihart B, Sidibe Y, Gaoussou S, Barry A, Traore M, Attaher O, Dembele AB, Diarra BS, Keita S, Dicko A, Duffy PE, Fried M. Malaria infection is common and associated with perinatal mortality and preterm delivery despite widespread use of chemoprevention in Mali: an observational study 2010 to 2014. Clin Infect Dis 2021; 73:1355-1361. [PMID: 33846719 DOI: 10.1093/cid/ciab301] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND In malaria-endemic areas, pregnant women and especially first-time mothers are more susceptible to Plasmodium falciparum. Malaria diagnosis is often missed during pregnancy, since many women with placental malaria remain asymptomatic or have submicroscopic parasitemia, masking the association between malaria and pregnancy outcomes Severe maternal anemia and low birthweight deliveries are well-established sequelae, but few studies have confirmed the relationship between malaria infection and severe outcomes like perinatal mortality in high transmission zones. METHODS Pregnant women of any gestational age enrolled at antenatal clinic into a longitudinal cohort study in Ouelessebougou, Mali, an area of high seasonal malaria transmission. Follow-up visits included scheduled and unscheduled visits throughout pregnancy. Blood smear microscopy and PCR analysis were employed to detect both microscopic and submicroscopic infections, respectively. Intermittent preventative treatment in pregnancy with sulfadoxine-pyrimethamine (IPTp-SP) was documented and prompt treatment regardless of symptoms given upon malaria diagnosis. RESULTS Of the 1850 women followed through delivery, 72.6% of women received 2 or more IPTp-SP doses, 67.2% of women experienced at least one infection between enrollment up to and including delivery. Malaria infection increased the risks of stillbirth (adjusted-hazard ratio (aHR) 3.87, 95%CI 1.18-12.71) and preterm delivery (aHR 2.41, 95%CI 1.35-4.29) in primigravidae, and early neonatal death (death within 7 days) in secundigravidae and multigravidae (HR 6.30, 95%CI 1.41-28.15). CONCLUSIONS Malaria treatment after diagnosis, alongside IPTp-SP, is insufficient to prevent malaria-related stillbirth, early neonatal death and PTD. While IPTp-SP was beneficial in Mali during the study period, new tools are needed to improve pregnancy outcomes.
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Affiliation(s)
- Almahamoudou Mahamar
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako;, Bamako, Mali
| | - Naissem Andemel
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA
| | - Bruce Swihart
- Biostatistics Research Branch, National Institute of Allergy and Infectious Diseases, NIH, Rockville, Maryland, USA
| | - Youssoufa Sidibe
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako;, Bamako, Mali
| | - Santara Gaoussou
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako;, Bamako, Mali
| | - Amadou Barry
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako;, Bamako, Mali
| | - Moussa Traore
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako;, Bamako, Mali
| | - Oumar Attaher
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako;, Bamako, Mali
| | - Adama B Dembele
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako;, Bamako, Mali
| | - Bacary S Diarra
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako;, Bamako, Mali
| | - Sekouba Keita
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako;, Bamako, Mali
| | - Alassane Dicko
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako;, Bamako, Mali
| | - Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA
| | - Michal Fried
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA
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Abstract
Introduction: An effective vaccine against malaria forms a global health priority. Both naturally acquired immunity and sterile protection induced by irradiated sporozoite immunization were described decades ago. Still no vaccine exists that sufficiently protects children in endemic areas. Identifying immunological correlates of vaccine efficacy can inform rational vaccine design and potentially accelerate clinical development.Areas covered: We discuss recent research on immunological correlates of malaria vaccine efficacy, including: insights from state-of-the-art omics platforms and systems vaccinology analyses; functional anti-parasitic assays; pre-immunization predictors of vaccine efficacy; and comparison of correlates of vaccine efficacy against controlled human malaria infections (CHMI) and against naturally acquired infections.Expert Opinion: Effective vaccination may be achievable without necessarily understanding immunological correlates, but the relatively disappointing efficacy of malaria vaccine candidates in target populations is concerning. Hypothesis-generating omics and systems vaccinology analyses, alongside assessment of pre-immunization correlates, have the potential to bring about paradigm-shifts in malaria vaccinology. Functional assays may represent in vivo effector mechanisms, but have scarcely been formally assessed as correlates. Crucially, evidence is still meager that correlates of vaccine efficacy against CHMI correspond with those against naturally acquired infections in target populations. Finally, the diversity of immunological assays and efficacy endpoints across malaria vaccine trials remains a major confounder.
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Affiliation(s)
| | - Matthew B B McCall
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, The Netherlands.,Institut für Tropenmedizin, Universitätsklinikum Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
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Vanda K, Bobbili N, Matsunaga M, Chen JJ, Salanti A, Leke RFG, Taylor DW. The Development, Fine Specificity, and Importance of High-Avidity Antibodies to VAR2CSA in Pregnant Cameroonian Women Living in Yaoundé, an Urban City. Front Immunol 2021; 12:610108. [PMID: 33717094 PMCID: PMC7953046 DOI: 10.3389/fimmu.2021.610108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/07/2021] [Indexed: 11/25/2022] Open
Abstract
Pregnant women infected with Plasmodium falciparum often produce antibodies (Abs) to VAR2CSA, a ligand that binds to placental chondroitin sulfate A causing placental malaria (PM). Antibodies to VAR2CSA are associated with improved pregnancy outcomes. Antibody avidity is a surrogate marker for the extent of maturation of the humoral immune response. Little is known about high avidity Abs to VAR2CSA for women living in urban African cities. Therefore, this study sought to determine: i) if high avidity Abs to full-length VAR2CSA (FV2) increase with gravidity in women in Yaoundé, Cameroon exposed to ~ 0.3-1.1 infectious mosquito bites per month, ii) if high avidity Abs to FV2 are directed against a specific region of VAR2CSA, and iii) if having high avidity Abs to FV2 improve pregnancy outcomes. Plasma samples collected at delivery from 695 women who had Abs to FV2 were evaluated. Ab levels and the Avidity Index (AI), defined as the percent Abs remaining bound to FV2 after incubation with 3M NH4SCN, were determined. Similar Ab levels to FV2 were present in women of all gravidities (G1 through 6+; p=0.80), except significantly lower levels were detected in PM−negative (PM−) primigravidae (p <0.001). Median Ab avidities increased between gravidity 1 and 2 (p<0.001) and remained stable thereafter (G3-G6+: p=0.51). These results suggest that B cell clonal expansion began during the first pregnancy, with clonal selection primarily occurring during the second. However, the majority of women (84%) had AI <35, a level of high avidity Abs previously reported to be associated with improved pregnancy outcomes. When plasma from 107 Cameroonian women was tested against 8 different regions of FV2, high avidity Abs were predominately restricted to DBL5 with median AI of 50 compared to AI <25 for the other domains. The only significance influence of high avidity Abs on pregnancy outcome was that babies born to mothers with AI above the median were 104 g heavier than babies born to women with AI below the median (p=0.045). These results suggest that a vaccine that boosts maturation of the immune response to VAR2CSA may be beneficial for women residing in urban areas.
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Affiliation(s)
- Koko Vanda
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI, United States
| | - Naveen Bobbili
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI, United States
| | - Masako Matsunaga
- Department of Quantitative Health Sciences, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI, United States
| | - John J Chen
- Department of Quantitative Health Sciences, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI, United States
| | - Ali Salanti
- Centre for Medical Parasitology, Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen and Department of Infectious Disease, Copenhagen University Hospital, Copenhagen, Denmark
| | - Rose F G Leke
- Faculty of Medicine and Biomedical Research, The Biotechnology Center, University of Yaoundé 1, Yaoundé, Cameroon
| | - Diane Wallace Taylor
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI, United States
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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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Wiebe MC, Yanow SK. Do Antibodies to Malaria Surface Antigens Play a Role in Protecting Mothers From Maternal Anemia? Front Immunol 2020; 11:609957. [PMID: 33391279 PMCID: PMC7775498 DOI: 10.3389/fimmu.2020.609957] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 11/17/2020] [Indexed: 11/13/2022] Open
Abstract
Pregnancy-associated malaria (PAM) caused by Plasmodium falciparum can result in detrimental outcomes for both mother and infant, including low infant birth weight, preterm birth, maternal anemia, spontaneous abortion, and maternal and/or infant mortality. Maternal anemia is a particularly complex outcome, as the body must both maintain erythropoiesis and tolerance of the growing fetus, while directing a Th1 response against the parasite. Underlying the pathogenesis of PAM is the expression of variant surface antigens (VSAPAM) on the surface of infected red blood cells (iRBC) that mediate sequestration of the iRBC in the placenta. Naturally acquired antibodies to VSAPAM can block sequestration and activate opsonic phagocytosis, both associated with improved pregnancy outcomes. In this review, we ask whether VSAPAM antibodies can also protect mothers against malarial anemia. Studies were identified where VSAPAM antibody titres and/or function were associated with higher maternal hemoglobin levels, thus supporting additional protective mechanisms for these antibodies against PAM. Yet these associations were not widely observed, and many studies reported no association between protection from maternal anemia and VSAPAM antibodies. We discuss the epidemiological, biological and technical factors that may explain some of the variability among these studies. We appraise the current evidence of these complex interactions between PAM-specific immunity and maternal anemia, propose potential mechanisms, and discuss knowledge gaps.
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Affiliation(s)
- Madeleine C Wiebe
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, Canada
| | - Stephanie K Yanow
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, AB, Canada.,School of Public Health, University of Alberta, Edmonton, AB, Canada
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Kalinjuma AV, Darling AM, Mugusi FM, Abioye AI, Okumu FO, Aboud S, Masanja H, Hamer DH, Hertzmark E, Fawzi WW. Factors associated with sub-microscopic placental malaria and its association with adverse pregnancy outcomes among HIV-negative women in Dar es Salaam, Tanzania: a cohort study. BMC Infect Dis 2020; 20:796. [PMID: 33109111 PMCID: PMC7590608 DOI: 10.1186/s12879-020-05521-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 10/16/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria infection during pregnancy has negative health consequences for both mothers and offspring. Sub-microscopic malaria infection during pregnancy is common in most African countries. We sought to identify factors associated with sub-microscopic placental malaria, and its association with adverse pregnancy outcomes among HIV-negative pregnant women in Dar es Salaam, Tanzania. METHODS We recruited a cohort of pregnant women during their first trimester and assessed for the occurrence of placental malaria and pregnancy outcomes. The follow-up was done monthly from recruitment until delivery. Histopathology placental malaria positive results were defined as the presence of malaria pigment or parasitized erythrocytes on the slide (histology-positive (HP)), and the sub-microscopic placental infection was defined as positive Plasmodium falciparum DNA by polymerase chain reaction (DNA PCR) amplification in a negative histopathology test. Adverse pregnancy outcomes investigated included low birth weight (birth weight below 2.5 kg), prematurity (live birth below 37 weeks), and small-for-gestational-age (SGA) (live born with a birth weight below 10th percentile for gestational age and sex). Weighted baseline category logit, log-binomial, and log-Poisson models were used to assess factors associated with placental malaria, and its association with adverse pregnancy outcomes. RESULTS Among 1115 women who had histopathology and DNA PCR performed, 93 (8%) had HP placental infection, and 136 (12%) had the sub-microscopic placental infection. The risk of sub-microscopic placental malaria was greater in women who did not use mosquito prevention methods such as bed nets, fumigation, or mosquito coils (odds ratio (OR) = 1.75; 95% confidence interval (CI): 1.05-2.92; P = 0.03) and in women who were anemic (OR = 1.59; 95% CI: 1.20-2.11; P = 0.001). Women who were underweight had reduced odds of sub-microscopic placental malaria infection (OR = 0.33; 95% CI: 0.17-0.62; P = 0.001). Women who were overweight/obese had 1.48 times higher the odds of HP placental malaria compared to normal weight (OR = 1.48; 95% CI: 1.03-2.11; P = 0.03). HP placental malaria infection was associated with an increased risk of SGA births (RR = 1.30, 95% CI: 0.98-1.72, P = 0.07). In contrast, the sub-microscopic infection was associated with a reduced risk of SGA births (RR = 0.61, 95% CI: 0.43-0.88, P = 0.01). Placental malaria was not associated with low birth weight or prematurity. CONCLUSION Malaria prevention methods and maternal nutrition status during early pregnancy were important predictors of sub-microscopic placental malaria. More research is needed to understand sub-microscopic placental malaria and the possible mechanisms mediating the association between placental malaria and SGA.
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Affiliation(s)
- Aneth Vedastus Kalinjuma
- Department of Intervention and Clinical Trials, Ifakara Health Institute, P.O. Box 53, Ifakara, Morogoro, Tanzania.
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
| | - Anne Marie Darling
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Ferdinand M Mugusi
- Departments of Internal Medicine; and Microbiology and Immunology, School of Medicine, Muhimbili University of Health and Allied Sciences, Dar-es-Salaam, Tanzania
| | - Ajibola Ibraheem Abioye
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Fredros O Okumu
- Department of Intervention and Clinical Trials, Ifakara Health Institute, P.O. Box 53, Ifakara, Morogoro, Tanzania
| | - Said Aboud
- Departments of Internal Medicine; and Microbiology and Immunology, School of Medicine, Muhimbili University of Health and Allied Sciences, Dar-es-Salaam, Tanzania
| | - Honorati Masanja
- Department of Intervention and Clinical Trials, Ifakara Health Institute, P.O. Box 53, Ifakara, Morogoro, Tanzania
| | - Davidson H Hamer
- Department of Global Health, Boston University School of Public Health, Boston, MA, USA
- Section of Infectious Diseases, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Ellen Hertzmark
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Wafaie W Fawzi
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA, USA
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Clark RL. Teratogen update: Malaria in pregnancy and the use of antimalarial drugs in the first trimester. Birth Defects Res 2020; 112:1403-1449. [PMID: 33079495 DOI: 10.1002/bdr2.1798] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 08/20/2020] [Indexed: 02/04/2023]
Abstract
Malaria is a particular problem in pregnancy because of enhanced sensitivity, the possibility of placental malaria, and adverse effects on pregnancy outcome. Artemisinin-containing combination therapies (ACTs) are the most effective antimalarials known. WHO recommends 7-day quinine therapy for uncomplicated Plasmodium falciparum malaria in the first trimester despite the superior tolerability and efficacy of 3-day ACT regimens because artemisinins caused embryolethality and/or cardiovascular malformations at relatively low doses in rats, rabbits, and monkeys. The developmental toxicity of artesunate, artemether, and DHA were similar in rats but artesunate was embryotoxic at lower doses in rabbits (5 mg/kg/day) than artemether (no effect level = 25 mg/kg/day). In clinical studies in Africa, treatment with artemether-lumefantrine in the first trimester was observed to be highly efficacious and the miscarriage rate (≤3.1%) was similar to no antimalarial treatment (2.6%). When data from the first-trimester use of largely artesunate-based therapies in Thailand were pooled together, there was no difference in miscarriage rate compared to quinine. However, individually, artesunate-mefloquine was associated with a higher miscarriage rate (15/71 = 21%) compared to other artemisinin-based therapies including 7-day artesunate + clindamycin (2/50 = 4%) and quinine (92/842 = 11%). Thus, appropriate statistical comparisons of individual ACT groups are needed prior to assuming that they all have the same risk for developmental toxicity. Current limitations in the assessment of the safety of ACTs in the first trimester are a lack of exposures early in gestation (gestational weeks 6-7), limited postnatal evaluation for cardiovascular malformations, and the pooling of all ACTs for the assessment of risk.
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Affiliation(s)
- Robert L Clark
- Artemis Pharmaceutical Research, Saint Augustine, Florida, USA
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35
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Mordmüller B, Sulyok M, Egger-Adam D, Resende M, de Jongh WA, Jensen MH, Smedegaard HH, Ditlev SB, Soegaard M, Poulsen L, Dyring C, Calle CL, Knoblich A, Ibáñez J, Esen M, Deloron P, Ndam N, Issifou S, Houard S, Howard RF, Reed SG, Leroy O, Luty AJF, Theander TG, Kremsner PG, Salanti A, Nielsen MA. First-in-human, Randomized, Double-blind Clinical Trial of Differentially Adjuvanted PAMVAC, A Vaccine Candidate to Prevent Pregnancy-associated Malaria. Clin Infect Dis 2020; 69:1509-1516. [PMID: 30629148 PMCID: PMC6792113 DOI: 10.1093/cid/ciy1140] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 01/03/2019] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Malaria in pregnancy has major impacts on mother and child health. To complement existing interventions, such as intermittent preventive treatment and use of impregnated bed nets, we developed a malaria vaccine candidate with the aim of reducing sequestration of asexual "blood-stage" parasites in the placenta, the major virulence mechanism. METHODS The vaccine candidate PAMVAC is based on a recombinant fragment of VAR2CSA, the Plasmodium falciparum protein responsible for binding to the placenta via chondroitin sulfate A (CSA). Healthy, adult malaria-naive volunteers were immunized with 3 intramuscular injections of 20 μg (n = 9) or 50 μg (n = 27) PAMVAC, adjuvanted with Alhydrogel or glucopyranosyl lipid adjuvant in stable emulsion (GLA-SE) or in a liposomal formulation with QS21 (GLA-LSQ). Allocation was random and double blind. The vaccine was given every 4 weeks. Volunteers were observed for 6 months following last immunization. RESULTS All PAMVAC formulations were safe and well tolerated. A total of 262 adverse events (AEs) occurred, 94 (10 grade 2 and 2 grade 3) at least possibly related to the vaccine. No serious AEs occurred. Distribution and severity of AEs were similar in all arms. PAMVAC was immunogenic in all participants. PAMVAC-specific antibody levels were highest with PAMVAC-GLA-SE. The antibodies inhibited binding of VAR2CSA expressing P. falciparum-infected erythrocytes to CSA in a standardized functional assay. CONCLUSIONS PAMVAC formulated with Alhydrogel or GLA-based adjuvants was safe, well tolerated, and induced functionally active antibodies. Next, PAMVAC will be assessed in women before first pregnancies in an endemic area. CLINICAL TRIALS REGISTRATION EudraCT 2015-001827-21; ClinicalTrials.gov NCT02647489.
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Affiliation(s)
- Benjamin Mordmüller
- Institut für Tropenmedizin, Universitätsklinikum Tübingen and Deutsches Zentrum für Infektionsforschung, Germany.,Centre de Recherches Médicales de Lambaréné, Gabon
| | - Mihály Sulyok
- Institut für Tropenmedizin, Universitätsklinikum Tübingen and Deutsches Zentrum für Infektionsforschung, Germany
| | - Diane Egger-Adam
- Institut für Tropenmedizin, Universitätsklinikum Tübingen and Deutsches Zentrum für Infektionsforschung, Germany
| | - Mafalda Resende
- Centre for Medical Parasitology at Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Copenhagen University Hospital
| | | | - Mette H Jensen
- Centre for Medical Parasitology at Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Copenhagen University Hospital
| | - Helle Holm Smedegaard
- Centre for Medical Parasitology at Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Copenhagen University Hospital
| | - Sisse B Ditlev
- Centre for Medical Parasitology at Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Copenhagen University Hospital
| | | | | | | | - Carlos Lamsfus Calle
- Institut für Tropenmedizin, Universitätsklinikum Tübingen and Deutsches Zentrum für Infektionsforschung, Germany
| | - Annette Knoblich
- Institut für Tropenmedizin, Universitätsklinikum Tübingen and Deutsches Zentrum für Infektionsforschung, Germany
| | - Javier Ibáñez
- Institut für Tropenmedizin, Universitätsklinikum Tübingen and Deutsches Zentrum für Infektionsforschung, Germany
| | - Meral Esen
- Institut für Tropenmedizin, Universitätsklinikum Tübingen and Deutsches Zentrum für Infektionsforschung, Germany.,Centre de Recherches Médicales de Lambaréné, Gabon
| | - Philippe Deloron
- Mère et Enfant face aux Infections Tropicales, Institut de Recherche pour le Développement, Université Paris 5, Sorbonne Paris Cité, France
| | - Nicaise Ndam
- Mère et Enfant face aux Infections Tropicales, Institut de Recherche pour le Développement, Université Paris 5, Sorbonne Paris Cité, France
| | - Saadou Issifou
- Fondation pour la Recherche Scientifique and Institut de Recherche Clinique du Bénin, Cotonou
| | | | | | - Steven G Reed
- Infectious Disease Research Institute, Seattle, Washington
| | - Odile Leroy
- European Vaccine Initiative, Heidelberg, Germany
| | - Adrian J F Luty
- Mère et Enfant face aux Infections Tropicales, Institut de Recherche pour le Développement, Université Paris 5, Sorbonne Paris Cité, France
| | - Thor G Theander
- Centre for Medical Parasitology at Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Copenhagen University Hospital
| | - Peter G Kremsner
- Institut für Tropenmedizin, Universitätsklinikum Tübingen and Deutsches Zentrum für Infektionsforschung, Germany.,Centre de Recherches Médicales de Lambaréné, Gabon
| | - Ali Salanti
- Centre for Medical Parasitology at Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Copenhagen University Hospital
| | - Morten A Nielsen
- Centre for Medical Parasitology at Department of Immunology and Microbiology, University of Copenhagen and Department of Infectious Diseases, Copenhagen University Hospital
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Antibodies to full-length and the DBL5 domain of VAR2CSA in pregnant women after long-term implementation of intermittent preventive treatment in Etoudi, Cameroon. PLoS One 2020; 15:e0237671. [PMID: 32797068 PMCID: PMC7428160 DOI: 10.1371/journal.pone.0237671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 07/30/2020] [Indexed: 12/02/2022] Open
Abstract
In high malaria transmission settings, the use of sulfadoxine-pyrimethamine-based intermittent preventive treatment during pregnancy (IPTp-SP) has resulted in decreased antibody (Ab) levels to VAR2CSA. However, information of Ab levels in areas of low or intermediate malaria transmission after long-term implementation of IPTp-SP is still lacking. The present study sought to evaluate antibody prevalence and levels in women at delivery in Etoudi, a peri-urban area in the capital of Yaoundé, Cameroon, that is a relatively low-malaria transmission area. Peripheral plasma samples from 130 pregnant women were collected at delivery and tested for IgG to the full-length recombinant VAR2CSA (FV2) and its most immunogenic subdomain, DBL5. The study was conducted between 2013 and 2015, approximately ten years after implementation of IPTp-SP in Cameroon. About 8.6% of the women attending the clinic had placental malaria (PM). One, two or 3 doses of SP did not impact significantly on either the percentage of women with Ab to FV2 and DBL5 or Ab levels in Ab-positive women compared to women not taking SP. The prevalence of Ab to FV2 and DBL5 was only 36.9% and 36.1%, respectively. Surprisingly, among women who had PM at delivery, only 61.5% and 57.7% had Ab to FV2 and DBL5, respectively, with only 52.9% and 47.1% in PM-positive paucigravidae and 77.7% of multigravidae having Ab to both antigens. These results suggest that long-term implementation of IPTp-SP in a low-malaria transmission area results in few women having Ab to VAR2CSA.
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Doesn’t It All Come Down to Function? How To Correlate VAR2CSA Antibodies with Protection. mSphere 2020; 5:5/3/e00521-20. [PMID: 32581073 PMCID: PMC7316495 DOI: 10.1128/msphere.00521-20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Cutts JC, Agius PA, Zaw Lin, Powell R, Moore K, Draper B, Simpson JA, Fowkes FJI. Pregnancy-specific malarial immunity and risk of malaria in pregnancy and adverse birth outcomes: a systematic review. BMC Med 2020; 18:14. [PMID: 31941488 PMCID: PMC6964062 DOI: 10.1186/s12916-019-1467-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 11/11/2019] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND In endemic areas, pregnant women are highly susceptible to Plasmodium falciparum malaria characterized by the accumulation of parasitized red blood cells (pRBC) in the placenta. In subsequent pregnancies, women develop protective immunity to pregnancy-associated malaria and this has been hypothesized to be due to the acquisition of antibodies to the parasite variant surface antigen VAR2CSA. In this systematic review we provide the first synthesis of the association between antibodies to pregnancy-specific P. falciparum antigens and pregnancy and birth outcomes. METHODS We conducted a systematic review and meta-analysis of population-based studies (published up to 07 June 2019) of pregnant women living in P. falciparum endemic areas that examined antibody responses to pregnancy-specific P. falciparum antigens and outcomes including placental malaria, low birthweight, preterm birth, peripheral parasitaemia, maternal anaemia, and severe malaria. RESULTS We searched 6 databases and identified 33 studies (30 from Africa) that met predetermined inclusion and quality criteria: 16 studies contributed estimates in a format enabling inclusion in meta-analysis and 17 were included in narrative form only. Estimates were mostly from cross-sectional data (10 studies) and were heterogeneous in terms of magnitude and direction of effect. Included studies varied in terms of antigens tested, methodology used to measure antibody responses, and epidemiological setting. Antibody responses to pregnancy-specific pRBC and VAR2CSA antigens, measured at delivery, were associated with placental malaria (9 studies) and may therefore represent markers of infection, rather than correlates of protection. Antibody responses to pregnancy-specific pRBC, but not recombinant VAR2CSA antigens, were associated with trends towards protection from low birthweight (5 studies). CONCLUSIONS Whilst antibody responses to several antigens were positively associated with the presence of placental and peripheral infections, this review did not identify evidence that any specific antibody response is associated with protection from pregnancy-associated malaria across multiple populations. Further prospective cohort studies using standardized laboratory methods to examine responses to a broad range of antigens in different epidemiological settings and throughout the gestational period, will be necessary to identify and prioritize pregnancy-specific P. falciparum antigens to advance the development of vaccines and serosurveillance tools targeting pregnant women.
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Affiliation(s)
- Julia C Cutts
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, 3004, Australia.
| | - Paul A Agius
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, 3004, Australia.,Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia
| | - Zaw Lin
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, 3004, Australia.,Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
| | - Rosanna Powell
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, 3004, Australia
| | - Kerryn Moore
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, 3004, Australia.,Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
| | - Bridget Draper
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, 3004, Australia
| | - Julie A Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
| | - Freya J I Fowkes
- Burnet Institute, 85 Commercial Road, Melbourne, Victoria, 3004, Australia. .,Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia. .,Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia. .,Department of Infectious Diseases, Monash University, Melbourne, Australia.
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Doritchamou JYA, Morrison R, Renn JP, Ribeiro J, Duan J, Fried M, Duffy PE. Placental malaria vaccine candidate antigen VAR2CSA displays atypical domain architecture in some Plasmodium falciparum strains. Commun Biol 2019; 2:457. [PMID: 31840102 PMCID: PMC6897902 DOI: 10.1038/s42003-019-0704-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 11/13/2019] [Indexed: 12/15/2022] Open
Abstract
Two vaccines based on Plasmodium falciparum protein VAR2CSA are currently in clinical evaluation to prevent placental malaria (PM), but a deeper understanding of var2csa variability could impact vaccine design. Here we identified atypical extended or truncated VAR2CSA extracellular structures and confirmed one extended structure in a Malian maternal isolate, using a novel protein fragment assembly method for RNA-seq and DNA-seq data. Extended structures included one or two additional DBL domains downstream of the conventional NTS-DBL1X-6ɛ domain structure, with closest similarity to DBLɛ in var2csa and non-var2csa genes. Overall, 4/82 isolates displayed atypical VAR2CSA structures. The maternal isolate expressing an extended VAR2CSA bound to CSA, but its recombinant VAR2CSA bound less well to CSA than VAR2CSANF54 and showed lower reactivity to naturally acquired parity-dependent antibody. Our protein fragment sequence assembly approach has revealed atypical VAR2CSA domain architectures that impact antigen reactivity and function, and should inform the design of VAR2CSA-based vaccines.
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Affiliation(s)
- Justin Y. A. Doritchamou
- Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD USA
| | - Robert Morrison
- Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD USA
| | - Jonathan P. Renn
- Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD USA
| | - Jose Ribeiro
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD USA
| | - Junhui Duan
- Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD USA
| | - Michal Fried
- Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD USA
| | - Patrick E. Duffy
- Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD USA
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Gnidehou S, Mitran CJ, Arango E, Banman S, Mena A, Medawar E, Lima BAS, Doritchamou J, Rajwani J, Jin A, Gavina K, Ntumngia F, Duffy P, Narum D, Ndam NT, Nielsen MA, Salanti A, Kano FS, Carvalho LH, Adams JH, Maestre A, Good MF, Yanow SK. Cross-Species Immune Recognition Between Plasmodium vivax Duffy Binding Protein Antibodies and the Plasmodium falciparum Surface Antigen VAR2CSA. J Infect Dis 2019; 219:110-120. [PMID: 30534974 DOI: 10.1093/infdis/jiy467] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 07/24/2018] [Indexed: 01/23/2023] Open
Abstract
Background In pregnancy, Plasmodium falciparum parasites express the surface antigen VAR2CSA, which mediates adherence of red blood cells to chondroitin sulfate A (CSA) in the placenta. VAR2CSA antibodies are generally acquired during infection in pregnancy and are associated with protection from placental malaria. We observed previously that men and children in Colombia also had antibodies to VAR2CSA, but the origin of these antibodies was unknown. Here, we tested whether infection with Plasmodium vivax is an alternative mechanism of acquisition of VAR2CSA antibodies. Methods We analyzed sera from nonpregnant Colombians and Brazilians exposed to P. vivax and monoclonal antibodies raised against P. vivax Duffy binding protein (PvDBP). Cross-reactivity to VAR2CSA was characterized by enzyme-linked immunosorbent assay, immunofluorescence assay, and flow cytometry, and antibodies were tested for inhibition of parasite binding to CSA. Results Over 50% of individuals had antibodies that recognized VAR2CSA. Affinity-purified PvDBP human antibodies and a PvDBP monoclonal antibody recognized VAR2CSA, showing that PvDBP can give rise to cross-reactive antibodies. Importantly, the monoclonal antibody inhibited parasite binding to CSA, which is the primary in vitro correlate of protection from placental malaria. Conclusions These data suggest that PvDBP induces antibodies that functionally recognize VAR2CSA, revealing a novel mechanism of cross-species immune recognition to falciparum malaria.
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Affiliation(s)
- Sédami Gnidehou
- Department of Biology, Campus Saint-Jean, University of Alberta, Edmonton, Canada
| | | | - Eliana Arango
- Grupo Salud y Comunidad, Facultad de Medicina, Medellín, Colombia
| | - Shanna Banman
- School of Public Health, University of Alberta, Edmonton, Canada
| | - Angie Mena
- School of Public Health, University of Alberta, Edmonton, Canada
| | - Evelyn Medawar
- School of Public Health, University of Alberta, Edmonton, Canada
| | | | - Justin Doritchamou
- National Institute of Allergy and Infectious Diseases, Rockville, Maryland
| | - Jahanara Rajwani
- School of Public Health, University of Alberta, Edmonton, Canada
| | - Albert Jin
- School of Public Health, University of Alberta, Edmonton, Canada
| | - Kenneth Gavina
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Canada
| | | | - Patrick Duffy
- National Institute of Allergy and Infectious Diseases, Rockville, Maryland
| | - David Narum
- National Institute of Allergy and Infectious Diseases, Rockville, Maryland
| | | | - Morten A Nielsen
- Department of Immunology and Microbiology, Center for Medical Parasitology, University of Copenhagen, Denmark
| | - Ali Salanti
- Department of Immunology and Microbiology, Center for Medical Parasitology, University of Copenhagen, Denmark
| | | | | | | | - Amanda Maestre
- Grupo Salud y Comunidad, Facultad de Medicina, Medellín, Colombia
| | - Michael F Good
- Institute for Glycomics, Griffith University, Gold Coast, Australia
| | - Stephanie K Yanow
- School of Public Health, University of Alberta, Edmonton, Canada.,Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Canada
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41
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Liu J, Mosavati B, Oleinikov AV, Du E. Biosensors for Detection of Human Placental Pathologies: A Review of Emerging Technologies and Current Trends. Transl Res 2019; 213:23-49. [PMID: 31170377 PMCID: PMC6783355 DOI: 10.1016/j.trsl.2019.05.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/13/2019] [Accepted: 05/14/2019] [Indexed: 02/06/2023]
Abstract
Substantial growth in the biosensor research has enabled novel, sensitive and point-of-care diagnosis of human diseases in the last decade. This paper presents an overview of the research in the field of biosensors that can potentially predict and diagnosis of common placental pathologies. A survey of biomarkers in maternal circulation and their characterization methods is presented, including markers of oxidative stress, angiogenic factors, placental debris, and inflammatory biomarkers that are associated with various pathophysiological processes in the context of pregnancy complications. Novel biosensors enabled by microfluidics technology and nanomaterials is then reviewed. Representative designs of plasmonic and electrochemical biosensors for highly sensitive and multiplexed detection of biomarkers, as well as on-chip sample preparation and sensing for automatic biomarker detection are illustrated. New trends in organ-on-a-chip based placental disease models are highlighted to illustrate the capability of these in vitro disease models in better understanding the complex pathophysiological processes, including mass transfer across the placental barrier, oxidative stress, inflammation, and malaria infection. Biosensor technologies that can be potentially embedded in the placental models for real time, label-free monitoring of these processes and events are suggested. Merger of cell culture in microfluidics and biosensing can provide significant potential for new developments in advanced placental models, and tools for diagnosis, drug screening and efficacy testing.
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Affiliation(s)
- Jia Liu
- College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, Florida
| | - Babak Mosavati
- College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, Florida
| | - Andrew V Oleinikov
- Charles E. Schmidt College of Medicine, Department of Biomedical Science, Florida Atlantic University, Boca Raton, Florida
| | - E Du
- College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, Florida; Charles E. Schmidt College of Science, Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida.
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Functional Antibodies against Placental Malaria Parasites Are Variant Dependent and Differ by Geographic Region. Infect Immun 2019; 87:IAI.00865-18. [PMID: 30988054 DOI: 10.1128/iai.00865-18] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 04/05/2019] [Indexed: 02/06/2023] Open
Abstract
During pregnancy, Plasmodium falciparum-infected erythrocytes (IE) accumulate in the intervillous spaces of the placenta by binding to chondroitin sulfate A (CSA) and elicit inflammatory responses that are associated with poor pregnancy outcomes. Primigravidae lack immunity to IE that sequester in the placenta and thus are susceptible to placental malaria (PM). Women become resistant to PM over successive pregnancies as antibodies to placental IE are acquired. Here, we assayed plasma collected at delivery from Malian and Tanzanian women of different parities for total antibody levels against recombinant VAR2CSA antigens (FCR3 allele), and for surface reactivity and binding inhibition and opsonizing functional activities against IE using two CSA-binding laboratory isolates (FCR3 and NF54). Overall, antibody reactivity to VAR2CSA recombinant proteins and to CSA-binding IE was higher in multigravidae than in primigravidae. However, plasma from Malian gravid women reacted more strongly with FCR3 whereas Tanzanian plasma preferentially reacted with NF54. Further, acquisition of functional antibodies was variant dependent: binding inhibition of P. falciparum strain NF54 (P < 0.001) but not of the strain FCR3 increased significantly with parity, while only opsonizing activity against FCR3 (P < 0.001) increased significantly with parity. In addition, opsonizing and binding inhibition activities of plasma of multigravidae were significantly correlated in assays of FCR3 (r = 0.4, P = 0.01) but not of NF54 isolates; functional activities did not correlate in plasma from primigravidae. These data suggest that IE surface-expressed epitopes involved in each functional activity differ among P. falciparum strains. Consequently, geographic bias in circulating strains may impact antibody functions. Our study has implications for the development of PM vaccines aiming to achieve broad protection against various parasite strains.
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43
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Attaher O, Mahamar A, Swihart B, Barry A, Diarra BS, Kanoute MB, Dembele AB, Keita S, Gaoussou S, Issiaka D, Dicko A, Duffy PE, Fried M. Age-dependent increase in antibodies that inhibit Plasmodium falciparum adhesion to a subset of endothelial receptors. Malar J 2019; 18:128. [PMID: 30971252 PMCID: PMC6458601 DOI: 10.1186/s12936-019-2764-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 04/03/2019] [Indexed: 11/30/2022] Open
Abstract
Background Plasmodium falciparum-infected erythrocytes (IE) sequester in deep vascular beds where their adhesion is mediated by an array of endothelial surface receptors. Because parasite adhesion has been associated with disease, antibodies that block this activity may confer protective immunity. Here, levels of plasma anti-adhesion activity and surface reactivity against freshly collected IEs from malaria-infected children were measured in a Malian birth cohort and related to child age and malaria infection history. Methods Plasma samples from children enrolled at birth in a longitudinal cohort study of mother–infant pairs in Ouelessebougou, Mali were collected at multiple time points during follow-up visits. Anti-adhesion antibodies (i.e., inhibit IE binding to any of several endothelial receptors) and reactivity with surface IE proteins were measured using a binding inhibition assay and by flow cytometry, respectively. Results Levels of antibodies that inhibit the binding of children’s IE to the receptors ICAM-1, integrin α3β1 and laminin increased with age. The breadth of antibodies that inhibit ICAM-1 and laminin adhesion (defined as the proportion of IE isolates whose binding was reduced by ≥ 50%) also significantly increased with age. The number of malaria infections prior to plasma collection was associated with levels of plasma reactivity to IE surface proteins, but not levels of anti-adhesion activity. Conclusions Age is associated with increased levels of antibodies that reduce adhesion of children’s IE to three of the ten endothelial receptors evaluated here. These results suggest that anti-adhesion antibodies to some but not all endothelial receptors are acquired during the first few years of life. Electronic supplementary material The online version of this article (10.1186/s12936-019-2764-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Oumar Attaher
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, P.O Box 1805, Bamako, Mali
| | - Almahamoudou Mahamar
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, P.O Box 1805, Bamako, Mali
| | - Bruce Swihart
- Biostatistics Research Branch, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD, USA
| | - Amadou Barry
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, P.O Box 1805, Bamako, Mali
| | - Bacary S Diarra
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, P.O Box 1805, Bamako, Mali
| | - Moussa B Kanoute
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, P.O Box 1805, Bamako, Mali
| | - Adama B Dembele
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, P.O Box 1805, Bamako, Mali
| | - Sekouba Keita
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, P.O Box 1805, Bamako, Mali
| | - Santara Gaoussou
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, P.O Box 1805, Bamako, Mali
| | - Djibrilla Issiaka
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, P.O Box 1805, Bamako, Mali
| | - Alassane Dicko
- Malaria Research & Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, P.O Box 1805, Bamako, Mali
| | - Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD, USA
| | - Michal Fried
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD, USA.
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Clark RL. Genesis of placental sequestration in malaria and possible targets for drugs for placental malaria. Birth Defects Res 2019; 111:569-583. [PMID: 30919596 PMCID: PMC7432169 DOI: 10.1002/bdr2.1496] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/05/2019] [Accepted: 03/06/2019] [Indexed: 01/11/2023]
Abstract
Malaria during pregnancy results in intrauterine growth restriction, fetal anemia, and infant mortality. Women are more susceptible to malaria during pregnancy due to malaria‐induced inflammation and the sequestration of infected red blood cells in the placenta, which bind to the chondroitin sulfate portion of syndecan‐1 on the syncytiotrophoblast and in the intervillous space. Syndecan‐1 is a dimeric proteoglycan with an extracellular ectodomain that is cleaved from the transmembrane domain (referred to as “shedding”) by matrix metalloproteinases (MMPs), likely the secreted MMP‐9. The ectodomain includes four binding sites for chondroitin sulfate, which are proximal to the transmembrane domain, and six distal binding sites primarily for heparan sulfate. This “shedding” of syndecan‐1 is inhibited by the presence of the heparan sulfate chains, which can be removed by heparanase. The intervillous space contains fibrin strands and syndecan‐1 ectodomains free of heparan sulfate. The following is proposed as the sequence of events that leads to and is primarily responsible for sequestration in the intervillous space of the placenta. Inflammation associated with malaria triggers increased heparanase activity that degrades the heparan sulfate on the membrane‐bound syndecan‐1. Inflammation also upregulates MMP‐9 and the removal of heparan sulfate gives MMP‐9 access to cleave syndecan‐1, thereby releasing dimeric syndecan‐1 ectodomains with at least four chondroitin sulfate chains attached. These multivalent ectodomains bind infected RBCs together leading to their aggregation and entrapment in intervillous fibrin. This mechanism suggests possible new targets for anti‐placental malaria drugs such as the inhibition of MMP‐9. Doxycycline is an antimalarial drug which inhibits MMP‐9.
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Janitzek CM, Peabody J, Thrane S, H R Carlsen P, G Theander T, Salanti A, Chackerian B, A Nielsen M, Sander AF. A proof-of-concept study for the design of a VLP-based combinatorial HPV and placental malaria vaccine. Sci Rep 2019; 9:5260. [PMID: 30918267 PMCID: PMC6437161 DOI: 10.1038/s41598-019-41522-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 03/08/2019] [Indexed: 11/16/2022] Open
Abstract
In Africa, cervical cancer and placental malaria (PM) are a major public health concern. There is currently no available PM vaccine and the marketed Human Papillomavirus (HPV) vaccines are prohibitively expensive. The idea of a combinatorial HPV and PM vaccine is attractive because the target population for vaccination against both diseases, adolescent girls, would be overlapping in Sub-Saharan Africa. Here we demonstrate proof-of-concept for a combinatorial vaccine utilizing the AP205 capsid-based virus-like particle (VLP) designed to simultaneously display two clinically relevant antigens (the HPV RG1 epitope and the VAR2CSA PM antigen). Three distinct combinatorial VLPs were produced displaying one, two or five concatenated RG1 epitopes without obstructing the VLP’s capacity to form. Co-display of VAR2CSA was achieved through a split-protein Tag/Catcher interaction without hampering the vaccine stability. Vaccination with the combinatorial vaccine(s) was able to reduce HPV infection in vivo and induce anti-VAR2CSA IgG antibodies, which inhibited binding between native VAR2CSA expressed on infected red blood cells and chondroitin sulfate A in an in vitro binding-inhibition assay. These results show that the Tag/Catcher AP205 VLP system can be exploited to make a combinatorial vaccine capable of eliciting antibodies with dual specificity.
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Affiliation(s)
- Christoph M Janitzek
- Centre for Medical Parasitology at the Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark
| | - Julianne Peabody
- Department of Molecular Genetics & Microbiology, University of New Mexico School of Medicine, Albuquerque, USA
| | - Susan Thrane
- Centre for Medical Parasitology at the Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark
| | - Philip H R Carlsen
- Centre for Medical Parasitology at the Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark
| | - Thor G Theander
- Centre for Medical Parasitology at the Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark
| | - Ali Salanti
- Centre for Medical Parasitology at the Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark
| | - Bryce Chackerian
- Department of Molecular Genetics & Microbiology, University of New Mexico School of Medicine, Albuquerque, USA
| | - Morten A Nielsen
- Centre for Medical Parasitology at the Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark
| | - Adam F Sander
- Centre for Medical Parasitology at the Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark. .,Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark.
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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
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Healy SA, Fried M, Richie T, Bok K, Little M, August A, Riley L, Swamy GK, Wylie BJ, Menendez C, Muehlenbachs A, Doumbo O, Greenwood B, Billingsley PF, Hoffman SL, Duffy PE. Malaria vaccine trials in pregnant women: An imperative without precedent. Vaccine 2019; 37:763-770. [PMID: 30621913 DOI: 10.1016/j.vaccine.2018.12.025] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 12/11/2018] [Accepted: 12/13/2018] [Indexed: 11/28/2022]
Abstract
Pregnant women are highly susceptible to Plasmodium falciparum malaria, leading to substantial maternal, perinatal, and infant mortality. While malaria vaccine development has made significant progress in recent years, no trials of malaria vaccines have ever been conducted in pregnant women. In December 2016, an expert meeting was convened at NIAID, NIH, in Rockville, Maryland to deliberate on the rationale and design of malaria vaccine trials in pregnant women. The discussions highlighted the progress made over recent years in the field of maternal immunization for other infectious diseases, and the evolving regulatory and ethical environment, all of which support a new emphasis on testing malaria vaccines that offer direct benefits to pregnant women. Initial safety and immunogenicity studies of malaria vaccines will be conducted in non-pregnant adult volunteers. Subsequently, efficacy trials involving pregnant women will likely be conducted in malaria-endemic and often resource-poor environments where sufficiently high malaria incidence will allow vaccine activity to be measured. Such trials will need to meet all international standards to ensure the safety of mother and offspring, under oversight of appropriate ethical and regulatory bodies. The convened experts drafted a clinical development plan to test a malaria vaccine product during pregnancy, using as a case study PfSPZ Vaccine being developed by Sanaria Inc. that is currently in phase 2 testing. Following the expert recommendations, a pregnancy registry has been initiated in Ouelessebougou, Mali, to provide baseline information on maternal and fetal outcomes as a context for evaluating PfSPZ Vaccine safety in the future, and new regimens are being assessed that will be suitable for evaluation in pregnant women.
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Affiliation(s)
- Sara A Healy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Michal Fried
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | | | - Karin Bok
- National Vaccine Program Office (NVPO), Office of Assistant Secretary for Health, Washington, D.C., USA
| | - Maggie Little
- Kennedy Institute of Ethics, Georgetown University, Washington, D.C., USA
| | - Allison August
- Clinical Development, Moderna Therapeutics, Cambridge, MA, USA
| | - Laura Riley
- Obstetrics, Massachusetts General Hospital, Boston, MA, USA
| | - Geeta K Swamy
- Department of Obstetrics & Gynecology, Duke University, Durham, NC, USA
| | - Blair J Wylie
- Maternal-Fetal Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Clara Menendez
- Barcelona Institute for Global Health (ISGlobal), Hospital Clinic-Universitat de Barcelona, Spain
| | | | - Ogobara Doumbo
- Malaria Research and Training Center, Université de Bamako, Mali, Bamako, Mali
| | | | | | | | - Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA.
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48
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Tan J, Piccoli L, Lanzavecchia A. The Antibody Response to Plasmodium falciparum: Cues for Vaccine Design and the Discovery of Receptor-Based Antibodies. Annu Rev Immunol 2018; 37:225-246. [PMID: 30566366 DOI: 10.1146/annurev-immunol-042617-053301] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Plasmodium falciparum remains a serious public health problem and a continuous challenge for the immune system due to the complexity and diversity of the pathogen. Recent advances from several laboratories in the characterization of the antibody response to the parasite have led to the identification of critical targets for protection and revealed a new mechanism of diversification based on the insertion of host receptors into immunoglobulin genes, leading to the production of receptor-based antibodies. These advances have opened new possibilities for vaccine design and passive antibody therapies to provide sterilizing immunity and control blood-stage parasites.
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Affiliation(s)
- Joshua Tan
- Institute for Research in Biomedicine, Università della Svizzera italiana, 6500 Bellinzona, Switzerland; .,Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, United Kingdom.,Current affiliation: National Institute of Allergy and Infectious Diseases, Rockville, Maryland 20852, USA
| | - Luca Piccoli
- Institute for Research in Biomedicine, Università della Svizzera italiana, 6500 Bellinzona, Switzerland;
| | - Antonio Lanzavecchia
- Institute for Research in Biomedicine, Università della Svizzera italiana, 6500 Bellinzona, Switzerland; .,VIR Biotechnology, San Francisco, California 94158, USA
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49
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Association of Antibodies to VAR2CSA and Merozoite Antigens with Pregnancy Outcomes in Women Living in Yaoundé, Cameroon. Infect Immun 2018; 86:IAI.00166-18. [PMID: 29986889 DOI: 10.1128/iai.00166-18] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 06/22/2018] [Indexed: 11/20/2022] Open
Abstract
Plasmodium falciparum infections are serious in pregnant women, because VAR2CSA allows parasitized erythrocytes to sequester in the placenta, causing placental malaria (PM). In areas of endemicity, women have substantial malarial immunity prior to pregnancy, including antibodies to merozoite antigens, but produce antibodies to VAR2CSA only during pregnancy. The current study sought to determine the importance of antibodies to VAR2CSA and merozoite antigens in pregnant women in Yaoundé, Cameroon, where malaria transmission was relatively low. A total of 1,377 archival plasma samples collected at delivery were selected (at a 1:3 ratio of PM-positive [PM+] to PM-negative [PM-] women) and screened for antibodies to full-length VAR2CSA and 7 merozoite antigens. Results showed that many PM+ women and most PM- women lacked antibodies to VAR2CSA at delivery. Among PM+ women, antibodies to VAR2CSA were associated with a reduced risk of having high placental parasitemia (odds ratio [OR], 0.432; confidence interval [CI], 0.272, 0.687; P = 0.0004) and low-birth-weight (LBW) babies (OR = 0.444; CI, 0.247, 0.799; P = 0.0068), even during first pregnancies. Among antibodies to the 7 merozoite antigens, i.e., AMA1, EBA-175, MSP142, MSP2, MSP3, MSP11, and Pf41, only antibodies to MSP3, EBA-175, and Pf41 were associated with reduced risk for high placental parasitemias (P = 0.0389, 0.0291, and 0.0211, respectively) and antibodies to EBA-175 were associated with reduced risk of premature deliveries (P = 0.0211). However, after adjusting for multiple comparisons significance declined. Thus, in PM+ women, antibodies to VAR2CSA were associated with lower placental parasitemias and reduced prevalence of LBW babies in this low-transmission setting.
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50
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Mayor A, Dobaño C, Nhabomba A, Guinovart C, Jiménez A, Manaca MN, Aguilar R, Barbosa A, Rodríguez MH, Cisteró P, Quimice LM, Menéndez C, Aponte JJ, Ordi J, Chitnis CE, Alonso PL. IgM and IgG against Plasmodium falciparum lysate as surrogates of malaria exposure and protection during pregnancy. Malar J 2018; 17:182. [PMID: 29743114 PMCID: PMC5944166 DOI: 10.1186/s12936-018-2331-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 04/24/2018] [Indexed: 11/10/2022] Open
Abstract
Background Difficulties to disentangle the protective versus exposure role of anti-malarial antibodies hamper the identification of clinically-relevant immune targets. Here, factors affecting maternal IgG and IgMs against Plasmodium falciparum antigens, as well as their relationship with parasite infection and clinical outcomes, were assessed in mothers and their children. Antibody responses among 207 Mozambican pregnant women at delivery against MSP119, EBA175, AMA1, DBLα and parasite lysate (3D7, R29 and E8B parasite lines), as well as the surface of infected erythrocytes, were assessed by enzyme-linked immunosorbent assay and flow cytometry. The relationship between antibody levels, maternal infection and clinical outcomes was assessed by multivariate regression analysis. Results Placental infection was associated with an increase in maternal levels of IgGs and IgMs against a broad range of parasite antigens. The multivariate analysis including IgGs and IgMs showed that the newborn weight increased with increasing IgG levels against a parasite lysate, whereas the opposite association was found with IgMs. IgGs are markers of protection against poor pregnancy outcomes and IgMs of parasite exposure. Conclusions Adjusting the analysis for the simultaneous effect of IgMs and IgGs can contribute to account for heterogeneous exposure to P. falciparum when assessing immune responses effective against malaria in pregnancy. Electronic supplementary material The online version of this article (10.1186/s12936-018-2331-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alfredo Mayor
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Carrer Rosselló 153 (CEK Building), 08036, Barcelona, Spain. .,Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique.
| | - Carlota Dobaño
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Carrer Rosselló 153 (CEK Building), 08036, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Augusto Nhabomba
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Caterina Guinovart
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Carrer Rosselló 153 (CEK Building), 08036, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Alfons Jiménez
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Carrer Rosselló 153 (CEK Building), 08036, Barcelona, Spain.,CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | | | - Ruth Aguilar
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Carrer Rosselló 153 (CEK Building), 08036, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique.,CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Arnoldo Barbosa
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Carrer Rosselló 153 (CEK Building), 08036, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Mauricio H Rodríguez
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Carrer Rosselló 153 (CEK Building), 08036, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Pau Cisteró
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Carrer Rosselló 153 (CEK Building), 08036, Barcelona, Spain
| | - Lazaro M Quimice
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Clara Menéndez
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Carrer Rosselló 153 (CEK Building), 08036, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - John J Aponte
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Carrer Rosselló 153 (CEK Building), 08036, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Jaume Ordi
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Carrer Rosselló 153 (CEK Building), 08036, Barcelona, Spain
| | - Chetan E Chitnis
- International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Pedro L Alonso
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Carrer Rosselló 153 (CEK Building), 08036, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
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