1
|
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.
Collapse
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
| |
Collapse
|
2
|
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.
Collapse
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.
| |
Collapse
|
3
|
Wiser MF. Knobs, Adhesion, and Severe Falciparum Malaria. Trop Med Infect Dis 2023; 8:353. [PMID: 37505649 PMCID: PMC10385726 DOI: 10.3390/tropicalmed8070353] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 06/30/2023] [Accepted: 07/02/2023] [Indexed: 07/29/2023] Open
Abstract
Plasmodium falciparum can cause a severe disease with high mortality. A major factor contributing to the increased virulence of P. falciparum, as compared to other human malarial parasites, is the sequestration of infected erythrocytes in the capillary beds of organs and tissues. This sequestration is due to the cytoadherence of infected erythrocytes to endothelial cells. Cytoadherence is primarily mediated by a parasite protein expressed on the surface of the infected erythrocyte called P. falciparum erythrocyte membrane protein-1 (PfEMP1). PfEMP1 is embedded in electron-dense protuberances on the surface of the infected erythrocytes called knobs. These knobs are assembled on the erythrocyte membrane via exported parasite proteins, and the knobs function as focal points for the cytoadherence of infected erythrocytes to endothelial cells. PfEMP1 is a member of the var gene family, and there are approximately 60 antigenically distinct PfEMP1 alleles per parasite genome. Var gene expression exhibits allelic exclusion, with only a single allele being expressed by an individual parasite. This results in sequential waves of antigenically distinct infected erythrocytes and this antigenic variation allows the parasite to establish long-term chronic infections. A wide range of endothelial cell receptors can bind to the various PfEMP1 alleles, and thus, antigenic variation also results in a change in the cytoadherence phenotype. The cytoadherence phenotype may result in infected erythrocytes sequestering in different tissues and this difference in sequestration may explain the wide range of possible clinical manifestations associated with severe falciparum malaria.
Collapse
Affiliation(s)
- Mark F Wiser
- Department of Tropical Medicine and Infectious Disease, Tulane University School of Public Health and Tropical Medicine, 1440 Canal Street, New Orleans, LA 70112, USA
| |
Collapse
|
4
|
Izquierdo L. The glycobiology of plasmodium falciparum: New approaches and recent advances. Biotechnol Adv 2023; 66:108178. [PMID: 37216996 DOI: 10.1016/j.biotechadv.2023.108178] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 04/22/2023] [Accepted: 05/18/2023] [Indexed: 05/24/2023]
Abstract
Like any other microorganism, pathogenic protozoan parasites rely heavily on glycoconjugates and glycan binding proteins to protect themselves from the environment and to interact with their diverse hosts. A thorough comprehension of how glycobiology contributes to the survival and virulence of these organisms may reveal unknown aspects of their biology and may open much needed avenues for the design of new strategies against them. In the case of Plasmodium falciparum, which causes the vast majority of malaria cases and deaths, the restricted variety and the simplicity of its glycans seemed to confer limited significance to the role played by glycoconjugates in the parasite. Nonetheless, the last 10 to 15 years of research are revealing a clearer and more defined picture. Thus, the use of new experimental techniques and the results obtained provide new avenues for understanding the biology of the parasite, as well as opportunities for the development of much required new tools against malaria.
Collapse
Affiliation(s)
- Luis Izquierdo
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Catalonia, Spain; CIBER de Enfermedades Infecciosas, Madrid, Spain.
| |
Collapse
|
5
|
Wei L, Xu Y, Du M, Fan Y, Zou R, Xu X, Zhang Q, Zhang YZ, Wang W, Li F. A novel 4-O-endosulfatase with high potential for the structure-function studies of chondroitin sulfate/dermatan sulfate. Carbohydr Polym 2023; 305:120508. [PMID: 36737182 DOI: 10.1016/j.carbpol.2022.120508] [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] [Received: 07/26/2022] [Revised: 12/15/2022] [Accepted: 12/24/2022] [Indexed: 12/30/2022]
Abstract
The sulfation patterns of chondroitin sulfate (CS)/dermatan sulfate (DS), which encode unique biological information, play critical roles in the various biological functions of CS/DS chains. CS/DS sulfatases, which can specifically hydrolyze sulfate groups, could potentially be essential tools for deciphering and changing the biological information encoded by these sulfation patterns. However, endosulfatase with high activity to efficiently hydrolyze the sulfate groups inside CS/DS polysaccharides have rarely been identified, which hinders the practical applications of CS/DS sulfatases. Herein, a novel CS/DS 4-O-endosulfatase (endoBI4SF) with a strong ability to completely remove 4-O-sulfated groups inside various CS/DS polysaccharides was identified and successfully used to investigate the biological roles of 4-O-sulfated CS/DS in vitro and in vivo. This study provides a much-needed tool to tailor the sulfation patterns and explore the related functions of 4-O-sulfated CS/DS chains in vitro and in vivo.
Collapse
Affiliation(s)
- Lin Wei
- National Glycoengineering Research Center, Shandong Key Laboratory of Carbohydrate Chemistry and Glycobiology and State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Rd, Qingdao 266237, People's Republic of China
| | - Yingying Xu
- National Glycoengineering Research Center, Shandong Key Laboratory of Carbohydrate Chemistry and Glycobiology and State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Rd, Qingdao 266237, People's Republic of China
| | - Min Du
- National Glycoengineering Research Center, Shandong Key Laboratory of Carbohydrate Chemistry and Glycobiology and State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Rd, Qingdao 266237, People's Republic of China
| | - Ying Fan
- Qingdao Special Servicemen Recuperation Center of PLA Navy, Qingdao 266071, People's Republic of China
| | - Ruyi Zou
- National Glycoengineering Research Center, Shandong Key Laboratory of Carbohydrate Chemistry and Glycobiology and State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Rd, Qingdao 266237, People's Republic of China
| | - Xiangyu Xu
- National Glycoengineering Research Center, Shandong Key Laboratory of Carbohydrate Chemistry and Glycobiology and State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Rd, Qingdao 266237, People's Republic of China
| | - Qingdong Zhang
- School of Life Science and Technology, Weifang Medical University, 7166 Baotong West Street, Weifang 261053, People's Republic of China
| | - Yu-Zhong Zhang
- College of Marine Life Sciences, Ocean University of China, Qingdao, People's Republic of China
| | - Wenshuang Wang
- National Glycoengineering Research Center, Shandong Key Laboratory of Carbohydrate Chemistry and Glycobiology and State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Rd, Qingdao 266237, People's Republic of China.
| | - Fuchuan Li
- National Glycoengineering Research Center, Shandong Key Laboratory of Carbohydrate Chemistry and Glycobiology and State Key Laboratory of Microbial Technology, Shandong University, 72 Binhai Rd, Qingdao 266237, People's Republic of China; College of Marine Life Sciences, Ocean University of China, Qingdao, People's Republic of China.
| |
Collapse
|
6
|
Looker O, Dans MG, Bullen HE, Sleebs BE, Crabb BS, Gilson PR. The Medicines for Malaria Venture Malaria Box contains inhibitors of protein secretion in
Plasmodium falciparum
blood stage parasites. Traffic 2022; 23:442-461. [PMID: 36040075 PMCID: PMC9543830 DOI: 10.1111/tra.12862] [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: 05/04/2022] [Revised: 07/17/2022] [Accepted: 07/26/2022] [Indexed: 11/27/2022]
Abstract
Plasmodium falciparum parasites which cause malaria, traffic hundreds of proteins into the red blood cells (RBCs) they infect. These exported proteins remodel their RBCs enabling host immune evasion through processes such as cytoadherence that greatly assist parasite survival. As resistance to all current antimalarial compounds is rising new compounds need to be identified and those that could inhibit parasite protein secretion and export would both rapidly reduce parasite virulence and ultimately lead to parasite death. To identify compounds that inhibit protein export we used transgenic parasites expressing an exported nanoluciferase reporter to screen the Medicines for Malaria Venture Malaria Box of 400 antimalarial compounds with mostly unknown targets. The most potent inhibitor identified in this screen was MMV396797 whose application led to export inhibition of both the reporter and endogenous exported proteins. MMV396797 mediated blockage of protein export and slowed the rigidification and cytoadherence of infected RBCs—modifications which are both mediated by parasite‐derived exported proteins. Overall, we have identified a new protein export inhibitor in P. falciparum whose target though unknown, could be developed into a future antimalarial that rapidly inhibits parasite virulence before eliminating parasites from the host.
Collapse
Affiliation(s)
| | - Madeline G. Dans
- Burnet Institute Melbourne Australia
- School of Medicine Deakin University Geelong Australia
| | - Hayley E. Bullen
- Burnet Institute Melbourne Australia
- Department of Immunology and Microbiology University of Melbourne Melbourne Australia
| | - Brad E. Sleebs
- The Walter and Eliza Hall Institute of Medical Research Parkville Victoria Australia
- Department of Medical Biology The University of Melbourne Parkville Victoria Australia
| | - Brendan S. Crabb
- Burnet Institute Melbourne Australia
- Department of Immunology and Microbiology University of Melbourne Melbourne Australia
- Department of Immunology and Pathology Monash University Melbourne Australia
| | - Paul R. Gilson
- Burnet Institute Melbourne Australia
- Department of Immunology and Microbiology University of Melbourne Melbourne Australia
| |
Collapse
|
7
|
Osarfo J, Ampofo GD, Tagbor H. Trends of malaria infection in pregnancy in Ghana over the past two decades: a review. Malar J 2022; 21:3. [PMID: 34983534 PMCID: PMC8725495 DOI: 10.1186/s12936-021-04031-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 12/17/2021] [Indexed: 02/07/2023] Open
Abstract
Background There has been a global decline in malaria transmission over the past decade. However, not much is known of the impact of this observation on the burden of malaria infection in pregnancy in endemic regions including Ghana. A narrative review was undertaken to help describe trends in malaria infection in pregnancy in Ghana. Among others, such information is important in showing any progress made in malaria in pregnancy control. Methods To describe trends in pregnancy-associated malaria infection in Ghana, a search and review of literature reporting data on the prevalence of asymptomatic Plasmodium falciparum infection in pregnancy was conducted. Results Thirty-six (36) studies, conducted over 1994–2019, were included in the review. In the northern savannah zone with largely seasonal malaria transmission, prevalence appeared to reduce from about 50–60% in 1994–2010 to 13–26% by 2019. In the middle transitional/forest zone, where transmission is perennial with peaks in the rainy season, prevalence apparently reduced from 60% in the late 1990 s to about 5–20% by 2018. In the coastal savannah area, there was apparent reduction from 28 to 35% in 2003–2010 to 5–11% by 2018–2019. The burden of malaria infection in pregnancy continues to be highest among teenagers and younger-aged pregnant women and paucigravidae. Conclusions There appears to be a decline in asymptomatic parasite prevalence in pregnancy in Ghana though this has not been uniform across the different transmission zones. The greatest declines were noticeably in urban settings. Submicroscopic parasitaemia remains a challenge for control efforts. Further studies are needed to evaluate the impact of the reduced parasite prevalence on maternal anaemia and low birthweight and to assess the local burden of submicroscopic parasitaemia in relation to pregnancy outcomes. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-04031-3.
Collapse
Affiliation(s)
- Joseph Osarfo
- Department of Community Medicine, School of Medicine, University of Health and Allied Sciences, Ho, Volta Region, Ghana.
| | - Gifty Dufie Ampofo
- Department of Community Medicine, School of Medicine, University of Health and Allied Sciences, Ho, Volta Region, Ghana
| | - Harry Tagbor
- Department of Community Medicine, School of Medicine, University of Health and Allied Sciences, Ho, Volta Region, Ghana
| |
Collapse
|
8
|
Gamain B, Dorin-Semblat D. Extraction and Immunoprecipitation of VAR2CSA, the PfEMP1 Associated with Placental Malaria. Methods Mol Biol 2022; 2470:257-271. [PMID: 35881351 DOI: 10.1007/978-1-0716-2189-9_19] [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
The Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a key virulence factor for this human malaria parasite. During pregnancy, VAR2CSA is the only PfEMP1 variant expressed on the surface of infected erythrocytes that mediates adhesion to placenta cells and causes severe pregnancy outcomes.In this chapter, we present an optimized protocol to extract and immunoprecipitate endogenous VAR2CSA from the infected erythrocyte membrane phospholipid bilayer environment for subsequent characterization of the central role of VAR2CSA in placental malaria.
Collapse
|
9
|
Nguyen HHT, Azizan S, Yeoh LM, Tang J, Duffy MF. RNAseq of Infected Erythrocyte Surface Antigen-Encoding Genes. Methods Mol Biol 2022; 2470:185-209. [PMID: 35881347 DOI: 10.1007/978-1-0716-2189-9_15] [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
Massive parallel sequencing technology has greatly increased the breadth and depth of transcriptomic data that can be captured from P. falciparum samples. This has revolutionized in vitro studies but uptake has been slower in the analysis of clinical samples. The principal barriers are the removal of contaminating white blood cells in a malaria endemic setting and preservation of the RNA. We provide here detailed methods for the collection of purified infected erythrocytes and the preservation and extraction of RNA. We also provide methods for assessing and addressing contaminating RNA from erythroid cells, and a protocol for RNAseq library preparation optimized to maximize yield from low amounts of parasite mRNA. Finally, we provide some examples of RNAseq library characteristics that may fail quality control for other species but are in fact satisfactory for P. falciparum RNAseq.
Collapse
Affiliation(s)
- Hanh Hong Thi Nguyen
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
- Peter Doherty Institute, Melbourne, VIC, Australia
- Bio21 Institute, Parkville, VIC, Australia
| | - Suffian Azizan
- Bio21 Institute, Parkville, VIC, Australia
- School of BioSciences, The University of Melbourne, Parkville, VIC, Australia
| | - Lee Ming Yeoh
- Peter Doherty Institute, Melbourne, VIC, Australia
- Bio21 Institute, Parkville, VIC, Australia
- Department of Microbiology and Immunology, School of Biomedical Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Jingyi Tang
- School of Medicine, Faculty of Health, Deakin University, Waurn Ponds, VIC, Australia
| | - Michael F Duffy
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia.
- Peter Doherty Institute, Melbourne, VIC, Australia.
- Bio21 Institute, Parkville, VIC, Australia.
- Department of Microbiology and Immunology, School of Biomedical Sciences, The University of Melbourne, Parkville, VIC, Australia.
| |
Collapse
|
10
|
Tanaka M, Lanzer M. Receptor-Functionalized Lipid Membranes as Biomimetic Surfaces for Adhesion of Plasmodium falciparum-Infected Erythrocytes. Methods Mol Biol 2022; 2470:601-613. [PMID: 35881377 DOI: 10.1007/978-1-0716-2189-9_45] [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
Here, we describe a detailed protocol of how to manufacture biomimetic, host receptor-functionalized membranes and how to use them in adhesion assays. Receptor-functionalized membranes have the advantage that the receptor identity and the receptor density can be controlled, which, in turn, enables studies on the kinetics, dynamics and biomechanics of receptor/ligand interactions. Such information is difficult to obtain from currently used in vitro systems, including cultured primary human microvascular endothelial cells or receptor-coated surfaces, which often display either multiple receptors or receptors with uncertain density and arrangement.
Collapse
Affiliation(s)
- Motomu Tanaka
- Physical Chemistry of Biosystems, Heidelberg University, Heidelberg, Germany
- Center for Integrative Medicine and Physics, Institute for Advanced Study, Kyoto University, Kyoto, Japan
| | - Michael Lanzer
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Heidelberg, Germany.
| |
Collapse
|
11
|
Lopez-Perez M, Viwami F, Seidu Z, Jensen ATR, Doritchamou J, Ndam NT, Hviid L. PfEMP1-Specific Immunoglobulin G Reactivity Among Beninese Pregnant Women With Sickle Cell Trait. Open Forum Infect Dis 2021; 8:ofab527. [PMID: 34909438 PMCID: PMC8664683 DOI: 10.1093/ofid/ofab527] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 10/14/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Sickle cell trait (HbAS) protects against severe Plasmodium falciparum malaria but not against placental malaria (PM). In this study, P falciparum erythrocyte membrane protein (PfEMP1)-specific antibodies were measured in HbAA and HbAS Beninese pregnant women as a proxy of exposure to specific PfEMP1 variants. METHODS Plasma samples collected at delivery from 338 HbAA and 63 HbAS women were used to measure immunoglobulin (Ig)G levels to 6 recombinant PfEMP1 proteins and 3 corresponding native proteins expressed on the infected erythrocyte (IE) surface. Immunoglobulin G-mediated inhibition of VAR2CSA+ IEs adhesion to chondroitin sulfate A (CSA) was also tested. RESULTS Levels of PfEMP1-specific IgG were similar in the 2 groups, except for native IT4VAR09 on IEs, where IgG levels were significantly higher in HbAS women. Adjusted odds ratios for women with positive IgG to HB3VAR06 and PFD1235w suggest a lower risk of infection with these virulent variants among HbAS individuals. The percentage of IEs binding to CSA did not differ between HbAA and HbAS women, but it correlated positively with levels of anti-VAR2CSA and parity. Women with PM had lower levels of anti-VAR2CSA-specific IgG and lower IgG-mediated inhibition of IE adhesion to CSA. CONCLUSIONS The findings support similar malaria exposure in HbAA and HbAS women and a lack of HbAS-dependent protection against placental infection among pregnant women.
Collapse
Affiliation(s)
- Mary Lopez-Perez
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Firmine Viwami
- UMR 261 MERIT, Université de Paris, Institut de Recherche pour le Développement, Paris, France
- Institut de Recherche Clinique du Benin, Abomey Calavi, Benin
| | - Zakaria Seidu
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
- West Africa Centre for Cell Biology of Infectious Pathogens (WACCBIP), Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, Ghana
| | - Anja T R Jensen
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Nicaise Tuikue Ndam
- UMR 261 MERIT, Université de Paris, Institut de Recherche pour le Développement, Paris, France
- Institut de Recherche Clinique du Benin, Abomey Calavi, Benin
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - 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
| |
Collapse
|
12
|
Keitany GJ, Jenkins BJ, Obiakor HT, Daniel S, Muehlenbachs A, Semblat JP, Gamain B, Doritchamou JYA, Desai SA, MacDonald NJ, Narum DL, Morrison R, Saveria T, Vignali M, Oleinikov AV, Fried M, Duffy PE. An invariant protein that co-localizes with VAR2CSA on Plasmodium falciparum-infected red cells binds to chondroitin sulfate A. J Infect Dis 2021; 225:2011-2022. [PMID: 34718641 DOI: 10.1093/infdis/jiab550] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 10/25/2021] [Indexed: 11/14/2022] Open
Abstract
Plasmodium falciparum-infected red blood cells (iRBCs) bind and sequester in deep vascular beds, causing malaria-related disease and death. In pregnant women, VAR2CSA binds to chondroitin sulfate A (CSA) and mediates placental sequestration, making it the major placental malaria (PM) vaccine target. Here, we characterize an invariant protein associated with PM called Plasmodium falciparum chondroitin sulfate A ligand (PfCSA-L). Recombinant PfCSA-L binds both placental CSA and VAR2CSA with nanomolar affinity, and is coexpressed on the iRBC surface with VAR2CSA. Unlike VAR2CSA, which is anchored by a transmembrane domain, PfCSA-L is peripherally associated with the outer surface of knobs through high affinity protein-protein interactions with VAR2CSA. This suggests iRBC sequestration involves complexes of invariant and variant surface proteins, allowing parasites to maintain both diversity and function at the iRBC surface. PfCSA-L is a promising target for intervention because it is well conserved, exposed on infected cells, and expressed and localized with VAR2CSA.
Collapse
Affiliation(s)
- Gladys J Keitany
- Center for Infectious Disease Research, Seattle, WA, USA.,University of Washington, Department of Pathobiology, Seattle, WA, USA
| | - Bethany J Jenkins
- Laboratory of Malaria Immunology and Vaccinology, NIAID, NIH, Bethesda, MD, USA
| | - Harold T Obiakor
- Laboratory of Malaria Immunology and Vaccinology, NIAID, NIH, Bethesda, MD, USA
| | - Shaji Daniel
- Laboratory of Malaria Immunology and Vaccinology, NIAID, NIH, Bethesda, MD, USA
| | - Atis Muehlenbachs
- University of Washington Medical Center, Anatomic Pathology, Seattle, WA, USA
| | - Jean-Philippe Semblat
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, Inserm, F-75015, Paris, France
| | - Benoit Gamain
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, Inserm, F-75015, Paris, France
| | | | - Sanjay A Desai
- Laboratory of Malaria and Vector Research, NIAID, NIH, Rockville, MD
| | | | - David L Narum
- Laboratory of Malaria Immunology and Vaccinology, NIAID, NIH, Bethesda, MD, USA
| | | | - Tracy Saveria
- Center for Infectious Disease Research, Seattle, WA, USA
| | | | | | - Michal Fried
- Center for Infectious Disease Research, Seattle, WA, USA.,University of Washington, Department of Pathobiology, Seattle, WA, USA.,Laboratory of Malaria Immunology and Vaccinology, NIAID, NIH, Bethesda, MD, USA
| | - Patrick E Duffy
- Center for Infectious Disease Research, Seattle, WA, USA.,University of Washington, Department of Pathobiology, Seattle, WA, USA.,Laboratory of Malaria Immunology and Vaccinology, NIAID, NIH, Bethesda, MD, USA
| |
Collapse
|
13
|
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: 30] [Impact Index Per Article: 10.0] [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.
Collapse
|
14
|
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.
Collapse
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.
| |
Collapse
|
15
|
Gamain B, Chêne A, Viebig NK, Tuikue Ndam N, Nielsen MA. Progress and Insights Toward an Effective Placental Malaria Vaccine. Front Immunol 2021; 12:634508. [PMID: 33717176 PMCID: PMC7947914 DOI: 10.3389/fimmu.2021.634508] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 01/06/2021] [Indexed: 12/03/2022] Open
Abstract
In areas where Plasmodium falciparum transmission is endemic, clinical immunity against malaria is progressively acquired during childhood and adults are usually protected against the severe clinical consequences of the disease. Nevertheless, pregnant women, notably during their first pregnancies, are susceptible to placental malaria and the associated serious clinical outcomes. Placental malaria is characterized by the massive accumulation of P. falciparum infected erythrocytes and monocytes in the placental intervillous spaces leading to maternal anaemia, hypertension, stillbirth and low birth weight due to premature delivery, and foetal growth retardation. Remarkably, the prevalence of placental malaria sharply decreases with successive pregnancies. This protection is associated with the development of antibodies directed towards the surface of P. falciparum-infected erythrocytes from placental origin. Placental sequestration is mediated by the interaction between VAR2CSA, a member of the P. falciparum erythrocyte membrane protein 1 family expressed on the infected erythrocytes surface, and the placental receptor chondroitin sulfate A. VAR2CSA stands today as the leading candidate for a placental malaria vaccine. We recently reported the safety and immunogenicity of two VAR2CSA-derived placental malaria vaccines (PRIMVAC and PAMVAC), spanning the chondroitin sulfate A-binding region of VAR2CSA, in both malaria-naïve and P. falciparum-exposed non-pregnant women in two distinct Phase I clinical trials (ClinicalTrials.gov, NCT02658253 and NCT02647489). This review discusses recent advances in placental malaria vaccine development, with a focus on the recent clinical data, and discusses the next clinical steps to undertake in order to better comprehend vaccine-induced immunity and accelerate vaccine development.
Collapse
Affiliation(s)
- Benoît Gamain
- Université de Paris, Inserm, Biologie Intégrée du Globule Rouge, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France
| | - Arnaud Chêne
- Université de Paris, Inserm, Biologie Intégrée du Globule Rouge, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France
| | - Nicola K Viebig
- European Vaccine Initiative, UniversitätsKlinikum Heidelberg, Heidelberg, Germany
| | | | - Morten A Nielsen
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| |
Collapse
|
16
|
Tomlinson A, Semblat JP, Gamain B, Chêne A. VAR2CSA-Mediated Host Defense Evasion of Plasmodium falciparum Infected Erythrocytes in Placental Malaria. Front Immunol 2021; 11:624126. [PMID: 33633743 PMCID: PMC7900151 DOI: 10.3389/fimmu.2020.624126] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/23/2020] [Indexed: 12/04/2022] Open
Abstract
Over 30 million women living in P. falciparum endemic areas are at risk of developing malaria during pregnancy every year. Placental malaria is characterized by massive accumulation of infected erythrocytes in the intervillous space of the placenta, accompanied by infiltration of immune cells, particularly monocytes. The consequent local inflammation and the obstruction of the maternofetal exchanges can lead to severe clinical outcomes for both mother and child. Even if protection against the disease can gradually be acquired following successive pregnancies, the malaria parasite has developed a large panel of evasion mechanisms to escape from host defense mechanisms and manipulate the immune system to its advantage. Infected erythrocytes isolated from placentas of women suffering from placental malaria present a unique phenotype and express the pregnancy-specific variant VAR2CSA of the Plasmodium falciparum Erythrocyte Membrane Protein (PfEMP1) family at their surface. The polymorphic VAR2CSA protein is able to mediate the interaction of infected erythrocytes with a variety of host cells including placental syncytiotrophoblasts and leukocytes but also with components of the immune system such as non-specific IgM. This review summarizes the described VAR2CSA-mediated host defense evasion mechanisms employed by the parasite during placental malaria to ensure its survival and persistence.
Collapse
Affiliation(s)
- Alice Tomlinson
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Jean-Philippe Semblat
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Benoît Gamain
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Arnaud Chêne
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratory of Excellence GR-Ex, Paris, France
| |
Collapse
|
17
|
Childs LM, Larremore DB. Network Models for Malaria: Antigens, Dynamics, and Evolution Over Space and Time. SYSTEMS MEDICINE 2021. [DOI: 10.1016/b978-0-12-801238-3.11512-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
|
18
|
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.
Collapse
|
19
|
PRIMVAC vaccine adjuvanted with Alhydrogel or GLA-SE to prevent placental malaria: a first-in-human, randomised, double-blind, placebo-controlled study. THE LANCET. INFECTIOUS DISEASES 2020; 20:585-597. [DOI: 10.1016/s1473-3099(19)30739-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 10/22/2019] [Accepted: 12/03/2019] [Indexed: 10/25/2022]
|
20
|
Gangnard S, Chêne A, Dechavanne S, Srivastava A, Avril M, Smith JD, Gamain B. VAR2CSA binding phenotype has ancient origin and arose before Plasmodium falciparum crossed to humans: implications in placental malaria vaccine design. Sci Rep 2019; 9:16978. [PMID: 31740695 PMCID: PMC6861233 DOI: 10.1038/s41598-019-53334-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 10/24/2019] [Indexed: 11/09/2022] Open
Abstract
VAR2CSA is a leading candidate for developing a placental malaria (PM) vaccine that would protect pregnant women living in malaria endemic areas against placental infections and improve birth outcomes. Two VAR2CSA-based PM vaccines are currently under clinical trials, but it is still unclear if the use of a single VAR2CSA variant will be sufficient to induce a broad enough humoral response in humans to cross-react with genetically diverse parasite populations. Additional immuno-focusing vaccine strategies may therefore be required to identify functionally conserved antibody epitopes in VAR2CSA. We explored the possibility that conserved epitopes could exist between VAR2CSA from the chimpanzee parasite Plasmodium reichenowi and Plasmodium falciparum sequences. Making use of VAR2CSA recombinant proteins originating from both species, we showed that VAR2CSA from P. reichenowi (Pr-VAR2CSA) binds to the placental receptor CSA with high specificity and affinity. Antibodies raised against Pr-VAR2CSA were able to recognize native VAR2CSA from different P. falciparum genotypes and to inhibit the interaction between CSA and P. falciparum-infected erythrocytes expressing different VAR2CSA variants. Our work revealed the existence of cross-species inhibitory epitopes in VAR2CSA and calls for pre-clinical studies assessing the efficacy of novel VAR2CSA-based cross-species boosting regimens.
Collapse
Affiliation(s)
- Stéphane Gangnard
- Université de Paris, UMR_S1134, BIGR, INSERM, F-75015, Paris, France.,Institut National de la Transfusion Sanguine, F-75015, Paris, France.,Laboratory of excellence GR-Ex, F-75015, Paris, France
| | - Arnaud Chêne
- Université de Paris, UMR_S1134, BIGR, INSERM, F-75015, Paris, France.,Institut National de la Transfusion Sanguine, F-75015, Paris, France.,Laboratory of excellence GR-Ex, F-75015, Paris, France
| | - Sébastien Dechavanne
- Université de Paris, UMR_S1134, BIGR, INSERM, F-75015, Paris, France.,Institut National de la Transfusion Sanguine, F-75015, Paris, France.,Laboratory of excellence GR-Ex, F-75015, Paris, France
| | - Anand Srivastava
- Université de Paris, UMR_S1134, BIGR, INSERM, F-75015, Paris, France.,Institut National de la Transfusion Sanguine, F-75015, Paris, France.,Laboratory of excellence GR-Ex, F-75015, Paris, France
| | - Marion Avril
- Seattle Children's Research Institute, Seattle, WA, 98109, USA
| | - Joseph D Smith
- Seattle Children's Research Institute, Seattle, WA, 98109, USA.,Department of Global Health, University of Washington, Seattle, WA, 98195, USA
| | - Benoît Gamain
- Université de Paris, UMR_S1134, BIGR, INSERM, F-75015, Paris, France. .,Institut National de la Transfusion Sanguine, F-75015, Paris, France. .,Laboratory of excellence GR-Ex, F-75015, Paris, France.
| |
Collapse
|
21
|
Avril M, Benjamin M, Dols MM, Smith JD. Interplay of Plasmodium falciparum and thrombin in brain endothelial barrier disruption. Sci Rep 2019; 9:13142. [PMID: 31511575 PMCID: PMC6739390 DOI: 10.1038/s41598-019-49530-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 08/19/2019] [Indexed: 01/05/2023] Open
Abstract
Recent concepts suggest that both Plasmodium falciparum factors and coagulation contribute to endothelial activation and dysfunction in pediatric cerebral malaria (CM) pathology. However, there is still limited understanding of how these complex inflammatory stimuli are integrated by brain endothelial cells. In this study, we examined how mature-stage P. falciparum infected erythrocytes (IE) interact with tumor necrosis factor α (TNFα) and thrombin in the activation and permeability of primary human brain microvascular endothelial cell (HBMEC) monolayers. Whereas trophozoite-stage P. falciparum-IE have limited effect on the viability of HBMEC or the secretion of pro-inflammatory cytokines or chemokines, except at super physiological parasite-host cell ratios, schizont-stage P. falciparum-IE induced low levels of cell death. Additionally, schizont-stage parasites were more barrier disruptive than trophozoite-stage P. falciparum-IE and prolonged thrombin-induced barrier disruption in both resting and TNFα-activated HBMEC monolayers. These results provide evidence that parasite products and thrombin may interact to increase brain endothelial permeability.
Collapse
Affiliation(s)
- Marion Avril
- Seattle Children's Research Institute, Seattle, WA, 98109, USA
| | - Max Benjamin
- Seattle Children's Research Institute, Seattle, WA, 98109, USA
| | | | - Joseph D Smith
- Seattle Children's Research Institute, Seattle, WA, 98109, USA. .,Department of Global Health, University of Washington, Seattle, WA, 98195, USA.
| |
Collapse
|
22
|
Phosphorylation of the VAR2CSA extracellular region is associated with enhanced adhesive properties to the placental receptor CSA. PLoS Biol 2019; 17:e3000308. [PMID: 31181082 PMCID: PMC6586358 DOI: 10.1371/journal.pbio.3000308] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 06/20/2019] [Accepted: 05/16/2019] [Indexed: 12/26/2022] Open
Abstract
Plasmodium falciparum is the main cause of disease and death from malaria. P. falciparum virulence resides in the ability of infected erythrocytes (IEs) to sequester in various tissues through the interaction between members of the polymorphic P. falciparum erythrocyte membrane protein 1 (PfEMP1) adhesin family to various host receptors. Here, we investigated the effect of phosphorylation of variant surface antigen 2-CSA (VAR2CSA), a member of the PfEMP1 family associated to placental sequestration, on its capacity to adhere to chondroitin sulfate A (CSA) present on the placental syncytium. We showed that phosphatase treatment of IEs impairs cytoadhesion to CSA. MS analysis of recombinant VAR2CSA phosphosites prior to and after phosphatase treatment, as well as of native VAR2CSA expressed on IEs, identified critical phosphoresidues associated with CSA binding. Site-directed mutagenesis on recombinant VAR2CSA of 3 phosphoresidues localised within the CSA-binding region confirmed in vitro their functional importance. Furthermore, using clustered regularly interspaced short palindromic repeats/CRISPR-associated protein-9 nuclease (CRISPR/Cas9), we generated a parasite line in which the phosphoresidue T934 is changed to alanine and showed that this mutation strongly impairs IEs cytoadhesion to CSA. Taken together, these results demonstrate that phosphorylation of the extracellular region of VAR2CSA plays a major role in IEs cytoadhesion to CSA and provide new molecular insights for strategies aiming to reduce the morbidity and mortality of PM.
Collapse
|
23
|
Salinas ND, Tang WK, Tolia NH. Blood-Stage Malaria Parasite Antigens: Structure, Function, and Vaccine Potential. J Mol Biol 2019; 431:4259-4280. [PMID: 31103771 DOI: 10.1016/j.jmb.2019.05.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 04/22/2019] [Accepted: 05/08/2019] [Indexed: 10/26/2022]
Abstract
Plasmodium parasites are the causative agent of malaria, a disease that kills approximately 450,000 individuals annually, with the majority of deaths occurring in children under the age of 5 years and the development of a malaria vaccine is a global health priority. Plasmodium parasites undergo a complex life cycle requiring numerous diverse protein families. The blood stage of parasite development results in the clinical manifestation of disease. A vaccine that disrupts the blood stage is highly desired and will aid in the control of malaria. The blood stage comprises multiple steps: invasion of, asexual growth within, and egress from red blood cells. This review focuses on blood-stage antigens with emphasis on antigen structure, antigen function, neutralizing antibodies, and vaccine potential.
Collapse
Affiliation(s)
- Nichole D Salinas
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD,, 20892, USA
| | - Wai Kwan Tang
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD,, 20892, USA
| | - Niraj H Tolia
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD,, 20892, USA.
| |
Collapse
|
24
|
Sanchez CP, Karathanasis C, Sanchez R, Cyrklaff M, Jäger J, Buchholz B, Schwarz US, Heilemann M, Lanzer M. Single-molecule imaging and quantification of the immune-variant adhesin VAR2CSA on knobs of Plasmodium falciparum-infected erythrocytes. Commun Biol 2019; 2:172. [PMID: 31098405 PMCID: PMC6506540 DOI: 10.1038/s42003-019-0429-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 04/17/2019] [Indexed: 12/16/2022] Open
Abstract
PfEMP1 (erythrocyte membrane protein 1) adhesins play a pivotal role in the pathophysiology of falciparum malaria, by mediating sequestration of Plasmodium falciparum-infected erythrocytes in the microvasculature. PfEMP1 variants are expressed by var genes and are presented on membrane elevations, termed knobs. However, the organization of PfEMP1 on knobs is largely unclear. Here, we use super-resolution microscopy and genetically altered parasites expressing a modified var2csa gene in which the coding sequence of the photoactivatable mEOS2 was inserted to determine the number and distribution of PfEMP1 on single knobs. The data were verified by quantitative fluorescence-activated cell sorting analysis and immuno-electron microscopy together with stereology methods. We show that knobs contain 3.3 ± 1.7 and 4.3 ± 2.5 PfEMP1 molecules, predominantly placed on the knob tip, in parasitized erythrocytes containing wild type and sickle haemoglobin, respectively. The ramifications of our findings for cytoadhesion and immune evasion are discussed.
Collapse
Affiliation(s)
- Cecilia P. Sanchez
- Center of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Christos Karathanasis
- Institute for Physical and Theoretical Chemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt, Germany
| | - Rodrigo Sanchez
- Center of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Marek Cyrklaff
- Center of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Julia Jäger
- Institute for Theoretical Physics, Heidelberg University, Philosophenweg 16, 69120 Heidelberg, Germany
| | - Bernd Buchholz
- Department of Hematology and Oncology, University Children’s Hospital, Medical Faculty Mannheim, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany
| | - Ulrich S. Schwarz
- Institute for Theoretical Physics, Heidelberg University, Philosophenweg 16, 69120 Heidelberg, Germany
- BioQuant-Center for Quantitative Biology, Heidelberg University, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany
| | - Mike Heilemann
- Institute for Physical and Theoretical Chemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt, Germany
- BioQuant-Center for Quantitative Biology, Heidelberg University, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany
| | - Michael Lanzer
- Center of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| |
Collapse
|
25
|
Chauvet M, Tétard M, Cottrell G, Aussenac F, Brossier E, Denoyel L, Hanny M, Lohezic M, Milet J, Ndam NT, Pineau D, Roman J, Luty AJF, Gamain B, Migot-Nabias F, Merckx A. Impact of Hemoglobin S Trait on Cell Surface Antibody Recognition of Plasmodium falciparum-Infected Erythrocytes in Pregnancy-Associated Malaria. Open Forum Infect Dis 2019; 6:ofz156. [PMID: 31041352 PMCID: PMC6483131 DOI: 10.1093/ofid/ofz156] [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: 11/26/2018] [Accepted: 03/21/2019] [Indexed: 11/24/2022] Open
Abstract
Background Sickle cell trait (HbAS) confers partial protection against malaria by reducing the adhesion of Plasmodium falciparum-infected erythrocytes to host receptors, but little is known about its potential protection against placental malaria. Methods Using flow cytometry, we assessed the recognition of HbAA and HbAS VAR2CSA-expressing infected erythrocytes, by plasma from 159 Beninese pregnant women with either HbAA (normal) or HbAS. Using multivariate linear models adjusted for gravidity, parasite infection at delivery, glucose-6-phosphate dehydrogenase deficiency, and α-thalassemia carriage, we observed significantly reduced cell surface antibody binding of HbAS-infected erythrocytes by plasma from HbAS compared with HbAA women (P < 10–3). Results The difference in cell surface antibody binding was only observed when infected erythrocytes and plasma were associated according to the same hemoglobin genotype. Similar levels of VAR2CSA-specific antibody were measured by enzyme-linked immunosorbent assay in the 2 groups, suggesting that the altered interaction between VAR2CSA and HbAS women’s antibodies could reflect abnormal display of VAR2CSA on HbAS erythrocytes. Conclusions Our data stress the need for assessments of erythrocyte disorders such as the sickle cell trait in a population group when studying immunological responses to P falciparum.
Collapse
Affiliation(s)
- Margaux Chauvet
- MERIT, Institut de Recherche pour le Développement (IRD), Université Sorbonne Paris Cité, Université Paris Descartes, France.,Laboratoire d'Excellence GR-Ex, Paris, France
| | - Marilou Tétard
- UMR_S1134, Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge, Laboratoire d'Excellence GR-Ex, Paris, France
| | - Gilles Cottrell
- MERIT, Institut de Recherche pour le Développement (IRD), Université Sorbonne Paris Cité, Université Paris Descartes, France.,Centre d'Etude et de Recherche pour le Paludisme Associé à la Grossesse et à l'Enfance, Cotonou, Benin
| | - Florentin Aussenac
- Centre d'Etude et de Recherche pour le Paludisme Associé à la Grossesse et à l'Enfance, Cotonou, Benin
| | - Emeline Brossier
- MERIT, Institut de Recherche pour le Développement (IRD), Université Sorbonne Paris Cité, Université Paris Descartes, France
| | - Luc Denoyel
- MERIT, Institut de Recherche pour le Développement (IRD), Université Sorbonne Paris Cité, Université Paris Descartes, France
| | - Marion Hanny
- MERIT, Institut de Recherche pour le Développement (IRD), Université Sorbonne Paris Cité, Université Paris Descartes, France
| | - Murielle Lohezic
- MERIT, Institut de Recherche pour le Développement (IRD), Université Sorbonne Paris Cité, Université Paris Descartes, France.,Laboratoire d'Excellence GR-Ex, Paris, France
| | - Jacqueline Milet
- MERIT, Institut de Recherche pour le Développement (IRD), Université Sorbonne Paris Cité, Université Paris Descartes, France
| | - Nicaise Tuikue Ndam
- MERIT, Institut de Recherche pour le Développement (IRD), Université Sorbonne Paris Cité, Université Paris Descartes, France.,Laboratoire d'Excellence GR-Ex, Paris, France.,Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon
| | - Damien Pineau
- MERIT, Institut de Recherche pour le Développement (IRD), Université Sorbonne Paris Cité, Université Paris Descartes, France
| | - Jocelyne Roman
- MERIT, Institut de Recherche pour le Développement (IRD), Université Sorbonne Paris Cité, Université Paris Descartes, France
| | - Adrian J F Luty
- MERIT, Institut de Recherche pour le Développement (IRD), Université Sorbonne Paris Cité, Université Paris Descartes, France.,Laboratoire d'Excellence GR-Ex, Paris, France.,Centre d'Etude et de Recherche pour le Paludisme Associé à la Grossesse et à l'Enfance, Cotonou, Benin
| | - Benoît Gamain
- UMR_S1134, Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge, Laboratoire d'Excellence GR-Ex, Paris, France
| | - Florence Migot-Nabias
- MERIT, Institut de Recherche pour le Développement (IRD), Université Sorbonne Paris Cité, Université Paris Descartes, France.,Laboratoire d'Excellence GR-Ex, Paris, France
| | - Anaïs Merckx
- MERIT, Institut de Recherche pour le Développement (IRD), Université Sorbonne Paris Cité, Université Paris Descartes, France.,Laboratoire d'Excellence GR-Ex, Paris, France
| |
Collapse
|
26
|
Chêne A, Gangnard S, Guadall A, Ginisty H, Leroy O, Havelange N, Viebig NK, Gamain B. Preclinical immunogenicity and safety of the cGMP-grade placental malaria vaccine PRIMVAC. EBioMedicine 2019; 42:145-156. [PMID: 30885725 PMCID: PMC6491931 DOI: 10.1016/j.ebiom.2019.03.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 02/26/2019] [Accepted: 03/04/2019] [Indexed: 11/28/2022] Open
Abstract
Background VAR2CSA is the lead antigen for developing a vaccine that would protect pregnant women against placental malaria. A multi-system feasibility study has identified E. coli as a suitable bacterial expression platform allowing the production of recombinant VAR2CSA-DBL1x-2x (PRIMVAC) to envisage a prompt transition to current Good Manufacturing Practice (cGMP) vaccine production. Methods Extensive process developments were undertaken to produce cGMP grade PRIMVAC to permit early phase clinical trials. PRIMVAC stability upon storage was assessed over up to 3 years. A broad toxicology investigation was carried out in rats allowing meanwhile the analysis of PRIMVAC immunogenicity. Findings We describe the successful cGMP production of 4. 65 g of PRIMVAC. PRIMVAC drug product was stable and potent for up to 3 years upon storage at −20 °C and showed an absence of toxicity in rats. PRIMVAC adjuvanted with Alhydrogel® or GLA-SE was able to generate antibodies able to recognize VAR2CSA expressed at the surface of erythrocytes infected with different strains. These antibodies also inhibit the interaction of the homologous NF54-CSA strain and to a lower extend of heterologous strains to CSA. Interpretation This work paved the way for the clinical development of an easily scalable low cost effective vaccine that could protect against placental malaria and prevent an estimated 10,000 maternal and 200,000 infant deaths annually. Fund This work was supported by a grant from the Bundesministerium für Bildung und Forschung (BMBF), Germany through Kreditanstalt für Wiederaufbau (KfW) (Reference No: 202060457) and through funding from Irish Aid, Department of Foreign Affairs and Trade, Ireland.
Collapse
Affiliation(s)
- Arnaud Chêne
- Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge UMR_S1134, Severe Malaria Pathogenesis group, Laboratoire d'Excellence GR-Ex, Paris, France
| | - Stéphane Gangnard
- Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge UMR_S1134, Severe Malaria Pathogenesis group, Laboratoire d'Excellence GR-Ex, Paris, France
| | - Anna Guadall
- Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge UMR_S1134, Severe Malaria Pathogenesis group, Laboratoire d'Excellence GR-Ex, Paris, France
| | - Hervé Ginisty
- GTP Technology, l'Occitane, 31670 Labège, Cedex, France
| | - Odile Leroy
- European Vaccine Initiative, UniversitätsKlinikum Heidelberg, Voßstraße 2, 69115 Heidelberg, Germany
| | - Nicolas Havelange
- European Vaccine Initiative, UniversitätsKlinikum Heidelberg, Voßstraße 2, 69115 Heidelberg, Germany
| | - Nicola K Viebig
- European Vaccine Initiative, UniversitätsKlinikum Heidelberg, Voßstraße 2, 69115 Heidelberg, Germany
| | - Benoît Gamain
- Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge UMR_S1134, Severe Malaria Pathogenesis group, Laboratoire d'Excellence GR-Ex, Paris, France.
| |
Collapse
|
27
|
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.
Collapse
Affiliation(s)
- Johanna Seitz
- Placenta Lab, Department of Obstetrics, Jena University Hospital, Jena, Germany
| | | | - Rodolfo R. Favaro
- Placenta Lab, Department of Obstetrics, Jena University Hospital, Jena, Germany
| | - Henning Schneider
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
- Department of Obstetrics and Gynecology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Udo Rudolf Markert
- Placenta Lab, Department of Obstetrics, Jena University Hospital, Jena, Germany
- *Correspondence: Udo Rudolf Markert
| |
Collapse
|
28
|
IgG Responses to the Plasmodium falciparum Antigen VAR2CSA in Colombia Are Restricted to Pregnancy and Are Not Induced by Exposure to Plasmodium vivax. Infect Immun 2018; 86:IAI.00136-18. [PMID: 29784859 PMCID: PMC6056870 DOI: 10.1128/iai.00136-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 05/11/2018] [Indexed: 12/20/2022] Open
Abstract
Clinical immunity to malaria is associated with the acquisition of IgG specific for members of the Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family of clonally variant antigens on the surface of infected erythrocytes (IEs). The VAR2CSA subtype of PfEMP1 mediates IE binding in the placenta. Clinical immunity to malaria is associated with the acquisition of IgG specific for members of the Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family of clonally variant antigens on the surface of infected erythrocytes (IEs). The VAR2CSA subtype of PfEMP1 mediates IE binding in the placenta. VAR2CSA-specific IgG is normally acquired only after exposure to placental parasites. However, it was recently reported that men and children from Colombia often have high levels of functional VAR2CSA-specific IgG. This potentially undermines the current understanding of malaria immunity in pregnant women, and we thus conducted a study to assess further the levels of VAR2CSA-specific IgG in pregnant and nonpregnant Colombians. Plasma IgG against two full-length recombinant PfEMP1 proteins (one of the VAR2CSA type and one not) produced in baculovirus-transfected insect cells was detected frequently among Colombian men, children, and pregnant women with acute or previous malaria exposure. In contrast, IgG reactivity to a homologous full-length VAR2CSA-type protein expressed in Chinese hamster ovary (CHO) cells was low and infrequent among the Colombian plasma samples, as was reactivity to both corresponding native PfEMP1 proteins. Moreover, human and rabbit antibodies specific for Plasmodium vivax Duffy-binding protein (PvDBP), a protein with some homology to PfEMP1, did not react with VAR2CSA-type recombinant or native proteins, although the mouse monoclonal and PvDBP-specific antibody 3D10 was weakly reactive with recombinant proteins expressed in baculovirus-transfected insect cells. Our data indicate that the previously reported Colombian IgG reactivity to recombinant VAR2CSA is not malaria specific and that the acquisition of VAR2CSA-specific IgG is restricted to pregnancy, in Colombia and elsewhere.
Collapse
|
29
|
Down-selection of the VAR2CSA DBL1-2 expressed in E. coli as a lead antigen for placental malaria vaccine development. NPJ Vaccines 2018; 3:28. [PMID: 30038803 PMCID: PMC6050242 DOI: 10.1038/s41541-018-0064-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 04/24/2018] [Accepted: 05/17/2018] [Indexed: 02/03/2023] Open
Abstract
Over 50 million women are exposed to the risk of malaria during pregnancy every year. Malaria during pregnancy is a leading global cause of maternal morbidity and adverse pregnancy outcomes. Adhesion of Plasmodium falciparum-infected erythrocytes to placental chondroitin-4-sulfate (CSA) has been linked to the severe disease outcome of placental malaria. Accumulated evidence strongly supports VAR2CSA as the leading placental malaria vaccine candidate. Recombinant proteins encompassing the VAR2CSA high affinity CSA binding site have been generated, and their activity as immunogens that elicit functional (inhibitory) and cross-reactive antibodies against CSA-binding parasites assessed. The expression of His-tagged proteins was compared in four different expression systems and their capacity to bind specifically to CSA was analyzed. CHO cells and E. coli SHuffle cells were the two expression systems able to express some of the recombinant proteins in reasonable amounts. Larger analytical scale production of DBL1x-2× (3D7) and DBL3x-4ε (FCR3) best expressed in CHO and E. coli SHuffle cells were performed. Purified proteins were administered to rats either alone or adjuvanted with human approved adjuvants. Analysis of the functionality and cross-reactivity of the induced antibodies allowed us to down-select the DBL1x-2(3D7) expressed in E. coli SHuffle cells as the best antigen to be transitioned to further clinical development in order to protect future pregnant women living in malaria endemic areas against the severe clinical outcomes of placental malaria. A mix of the right parasitic protein with the right production method has yielded a vaccine candidate for placental malaria. Primarily affecting first-time pregnant women, placental malaria is estimated to cause 200,000 infant deaths and 10,000 maternal deaths annually. In this study, led by Benoît Gamain, researchers from France’s INSERM and Germany’s European Vaccine Initiative assayed a combination of proteins designed to target and block a key pathogenic mechanism of parasite-infected red blood cells. Finding the highest performing protein, the researchers also used an Escherichia coli expression system able to replicate and fold the complex protein correctly. During tests, this protein/vector combination bested others in production qualities and immunogenicity. The team’s efforts laid the foundations for a scalable, low-cost vaccine that is currently undergoing clinical trials.
Collapse
|
30
|
Abstract
Eukaryotic pathogens must survive in different hosts, respond to changing environments, and exploit specialized niches to propagate. Plasmodium parasites cause human malaria during bloodstream infections, where they must persist long enough to be transmitted. Parasites have evolved diverse strategies of variant gene expression that control critical biological processes of blood-stage infections, including antigenic variation, erythrocyte invasion, innate immune evasion, and nutrient acquisition, as well as life-cycle transitions. Epigenetic mechanisms within the parasite are being elucidated, with discovery of epigenomic marks associated with gene silencing and activation, and the identification of epigenetic regulators and chromatin proteins that are required for the switching and maintenance of gene expression. Here, we review the key epigenetic processes that facilitate transition through the parasite life cycle and epigenetic regulatory mechanisms utilized by Plasmodium parasites to survive changing environments and consider epigenetic switching in the context of the outcome of human infections.
Collapse
Affiliation(s)
- Manoj T Duraisingh
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, USA; ,
| | - Kristen M Skillman
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, USA; ,
| |
Collapse
|
31
|
Fastman Y, Assaraf S, Rose M, Milrot E, Basore K, Arasu BS, Desai SA, Elbaum M, Dzikowski R. An upstream open reading frame (uORF) signals for cellular localization of the virulence factor implicated in pregnancy associated malaria. Nucleic Acids Res 2018; 46:4919-4932. [PMID: 29554358 PMCID: PMC6007598 DOI: 10.1093/nar/gky178] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 02/27/2018] [Accepted: 03/01/2018] [Indexed: 12/17/2022] Open
Abstract
Plasmodium falciparum, the causative agent of the deadliest form of human malaria, alternates expression of variable antigens, encoded by members of a multi-copy gene family named var. In var2csa, the var gene implicated in pregnancy-associated malaria, translational repression is regulated by a unique upstream open reading frame (uORF) found only in its 5' UTR. Here, we report that this translated uORF significantly alters both transcription and posttranslational protein trafficking. The parasite can alter a protein's destination without any modifications to the protein itself, but instead by an element within the 5' UTR of the transcript. This uORF-dependent localization was confirmed by single molecule STORM imaging, followed by fusion of the uORF to a reporter gene which changes its cellular localization from cytoplasmic to ER-associated. These data point towards a novel regulatory role of uORF in protein trafficking, with important implications for the pathology of pregnancy-associated malaria.
Collapse
Affiliation(s)
- Yair Fastman
- Department of Microbiology and Molecular Genetics, The Institute for Medical Research Israel - Canada, The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Shany Assaraf
- Department of Microbiology and Molecular Genetics, The Institute for Medical Research Israel - Canada, The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Miriam Rose
- Department of Microbiology and Molecular Genetics, The Institute for Medical Research Israel - Canada, The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Elad Milrot
- Electron Microscopy Unit, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Katherine Basore
- The Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - B Sivanandam Arasu
- The Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Sanjay A Desai
- The Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Michael Elbaum
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ron Dzikowski
- Department of Microbiology and Molecular Genetics, The Institute for Medical Research Israel - Canada, The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| |
Collapse
|
32
|
Carrington E, Otto TD, Szestak T, Lennartz F, Higgins MK, Newbold CI, Craig AG. In silico guided reconstruction and analysis of ICAM-1-binding var genes from Plasmodium falciparum. Sci Rep 2018; 8:3282. [PMID: 29459671 PMCID: PMC5818487 DOI: 10.1038/s41598-018-21591-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 02/07/2018] [Indexed: 11/23/2022] Open
Abstract
The Plasmodium falciparum variant surface antigen PfEMP1 expressed on the surface of infected erythrocytes is thought to play a major role in the pathology of severe malaria. As the sequence pool of the var genes encoding PfEMP1 expands there are opportunities, despite the high degree of sequence diversity demonstrated by this gene family, to reconstruct full-length var genes from small sequence tags generated from patient isolates. To test whether this is possible we have used a set of recently laboratory adapted ICAM-1-binding parasite isolates to generate sequence tags and, from these, to identify the full-length PfEMP1 being expressed by them. In a subset of the strains available we were able to produce validated, full-length var gene sequences and use these to conduct biophysical analyses of the ICAM-1 binding regions.
Collapse
Affiliation(s)
- Eilidh Carrington
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
- Malaria Gene Regulation Lab, Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland
| | - Thomas D Otto
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
- Institute of Infection, Immunity and Inflammation, University of Glasgow, College of Medical, Veterinary and Life Sciences, Sir Graeme Davies Building, 120 University Place, Glasgow, G12 8TA, UK
| | - Tadge Szestak
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Frank Lennartz
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Matt K Higgins
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Chris I Newbold
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford, OX3 9DS, UK
| | - Alister G Craig
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
| |
Collapse
|
33
|
Frank V, Chushkin Y, Fröhlich B, Abuillan W, Rieger H, Becker AS, Yamamoto A, Rossetti FF, Kaufmann S, Lanzer M, Zontone F, Tanaka M. Lensless Tomographic Imaging of Near Surface Structures of Frozen Hydrated Malaria-Infected Human Erythrocytes by Coherent X-Ray Diffraction Microscopy. Sci Rep 2017; 7:14081. [PMID: 29074975 PMCID: PMC5658481 DOI: 10.1038/s41598-017-14586-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 10/12/2017] [Indexed: 12/02/2022] Open
Abstract
Lensless, coherent X-ray diffraction microscopy has been drawing considerable attentions for tomographic imaging of whole human cells. In this study, we performed cryogenic coherent X-ray diffraction imaging of human erythrocytes with and without malaria infection. To shed light on structural features near the surface, “ghost cells” were prepared by the removal of cytoplasm. From two-dimensional images, we found that the surface of erythrocytes after 32 h of infection became much rougher compared to that of healthy, uninfected erythrocytes. The Gaussian roughness of an infected erythrocyte surface (69 nm) is about two times larger than that of an uninfected one (31 nm), reflecting the formation of protein knobs on infected erythrocyte surfaces. Three-dimensional tomography further enables to obtain images of the whole cells with no remarkable radiation damage, whose accuracy was estimated using phase retrieval transfer functions to be as good as 64 nm for uninfected and 80 nm for infected erythrocytes, respectively. Future improvements in phase retrieval algorithm, increase in degree of coherence, and higher flux in combination with complementary X-ray fluorescence are necessary to gain both structural and chemical details of mesoscopic architectures, such as cytoskeletons, membraneous structures, and protein complexes, in frozen hydrated human cells, especially under diseased states.
Collapse
Affiliation(s)
- Viktoria Frank
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120, Heidelberg, Germany
| | - Yuriy Chushkin
- European Synchrotron Radiation Facility (ESRF), 38043, Grenoble, France.
| | - Benjamin Fröhlich
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120, Heidelberg, Germany
| | - Wasim Abuillan
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120, Heidelberg, Germany
| | - Harden Rieger
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120, Heidelberg, Germany.,Department of Infectious Diseases, Parasitology, University of Heidelberg, 69120, Heidelberg, Germany
| | - Alexandra S Becker
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120, Heidelberg, Germany
| | - Akihisa Yamamoto
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120, Heidelberg, Germany.,Institute for Integrated Cell-Material Sciences (WPI iCeMS), Kyoto University, 606-8501, Kyoto, Japan
| | - Fernanda F Rossetti
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120, Heidelberg, Germany.,Institute for Integrated Cell-Material Sciences (WPI iCeMS), Kyoto University, 606-8501, Kyoto, Japan
| | - Stefan Kaufmann
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120, Heidelberg, Germany
| | - Michael Lanzer
- Department of Infectious Diseases, Parasitology, University of Heidelberg, 69120, Heidelberg, Germany
| | - Federico Zontone
- European Synchrotron Radiation Facility (ESRF), 38043, Grenoble, France
| | - Motomu Tanaka
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120, Heidelberg, Germany. .,Institute for Integrated Cell-Material Sciences (WPI iCeMS), Kyoto University, 606-8501, Kyoto, Japan.
| |
Collapse
|
34
|
Charnaud SC, Dixon MWA, Nie CQ, Chappell L, Sanders PR, Nebl T, Hanssen E, Berriman M, Chan JA, Blanch AJ, Beeson JG, Rayner JC, Przyborski JM, Tilley L, Crabb BS, Gilson PR. The exported chaperone Hsp70-x supports virulence functions for Plasmodium falciparum blood stage parasites. PLoS One 2017; 12:e0181656. [PMID: 28732045 PMCID: PMC5521827 DOI: 10.1371/journal.pone.0181656] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 07/05/2017] [Indexed: 12/03/2022] Open
Abstract
Malaria is caused by five different Plasmodium spp. in humans each of which modifies the host erythrocyte to survive and replicate. The two main causes of malaria, P. falciparum and P. vivax, differ in their ability to cause severe disease, mainly due to differences in the cytoadhesion of infected erythrocytes (IE) in the microvasculature. Cytoadhesion of P. falciparum in the brain leads to a large number of deaths each year and is a consequence of exported parasite proteins, some of which modify the erythrocyte cytoskeleton while others such as PfEMP1 project onto the erythrocyte surface where they bind to endothelial cells. Here we investigate the effects of knocking out an exported Hsp70-type chaperone termed Hsp70-x that is present in P. falciparum but not P. vivax. Although the growth of Δhsp70-x parasites was unaffected, the export of PfEMP1 cytoadherence proteins was delayed and Δhsp70-x IE had reduced adhesion. The Δhsp70-x IE were also more rigid than wild-type controls indicating changes in the way the parasites modified their host erythrocyte. To investigate the cause of this, transcriptional and translational changes in exported and chaperone proteins were monitored and some changes were observed. We propose that PfHsp70-x is not essential for survival in vitro, but may be required for the efficient export and functioning of some P. falciparum exported proteins.
Collapse
Affiliation(s)
| | - Matthew W. A. Dixon
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Victoria, Australia
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | | | - Lia Chappell
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, United Kingdom
| | | | - Thomas Nebl
- Walter & Eliza Hall Institute, Melbourne, Victoria, Australia
| | - Eric Hanssen
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Matthew Berriman
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, United Kingdom
| | - Jo-Anne Chan
- Burnet Institute, Melbourne, Victoria, Australia
| | - Adam J. Blanch
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Victoria, Australia
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | | | - Julian C. Rayner
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, United Kingdom
| | | | - Leann Tilley
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Victoria, Australia
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Brendan S. Crabb
- Burnet Institute, Melbourne, Victoria, Australia
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Victoria, Australia
- Monash University, Melbourne, Victoria, Australia
| | - Paul R. Gilson
- Burnet Institute, Melbourne, Victoria, Australia
- Monash University, Melbourne, Victoria, Australia
- * E-mail:
| |
Collapse
|
35
|
CRISPR/Cas9 Genome Editing Reveals That the Intron Is Not Essential for var2csa Gene Activation or Silencing in Plasmodium falciparum. mBio 2017; 8:mBio.00729-17. [PMID: 28698275 PMCID: PMC5513710 DOI: 10.1128/mbio.00729-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Plasmodium falciparum relies on monoallelic expression of 1 of 60 var virulence genes for antigenic variation and host immune evasion. Each var gene contains a conserved intron which has been implicated in previous studies in both activation and repression of transcription via several epigenetic mechanisms, including interaction with the var promoter, production of long noncoding RNAs (lncRNAs), and localization to repressive perinuclear sites. However, functional studies have relied primarily on artificial expression constructs. Using the recently developed P. falciparum clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system, we directly deleted the var2csa P. falciparum 3D7_1200600 (Pf3D7_1200600) endogenous intron, resulting in an intronless var gene in a natural, marker-free chromosomal context. Deletion of the var2csa intron resulted in an upregulation of transcription of the var2csa gene in ring-stage parasites and subsequent expression of the PfEMP1 protein in late-stage parasites. Intron deletion did not affect the normal temporal regulation and subsequent transcriptional silencing of the var gene in trophozoites but did result in increased rates of var gene switching in some mutant clones. Transcriptional repression of the intronless var2csa gene could be achieved via long-term culture or panning with the CD36 receptor, after which reactivation was possible with chondroitin sulfate A (CSA) panning. These data suggest that the var2csa intron is not required for silencing or activation in ring-stage parasites but point to a subtle role in regulation of switching within the var gene family.IMPORTANCEPlasmodium falciparum is the most virulent species of malaria parasite, causing high rates of morbidity and mortality in those infected. Chronic infection depends on an immune evasion mechanism termed antigenic variation, which in turn relies on monoallelic expression of 1 of ~60 var genes. Understanding antigenic variation and the transcriptional regulation of monoallelic expression is important for developing drugs and/or vaccines. The var gene family encodes the antigenic surface proteins that decorate infected erythrocytes. Until recently, studying the underlying genetic elements that regulate monoallelic expression in P. falciparum was difficult, and most studies relied on artificial systems such as episomal reporter genes. Our study was the first to use CRISPR/Cas9 genome editing for the functional study of an important, conserved genetic element of var genes-the intron-in an endogenous, episome-free manner. Our findings shed light on the role of the var gene intron in transcriptional regulation of monoallelic expression.
Collapse
|
36
|
Tétard M, Milet J, Dechavanne S, Fievet N, Dorin-Semblat D, Elion J, Fairhurst RM, Deloron P, Tuikue-Ndam N, Gamain B. Heterozygous HbAC but not HbAS is associated with higher newborn birthweight among women with pregnancy-associated malaria. Sci Rep 2017; 7:1414. [PMID: 28469130 PMCID: PMC5431107 DOI: 10.1038/s41598-017-01495-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 03/28/2017] [Indexed: 12/21/2022] Open
Abstract
Pregnancy-associated malaria (PAM) is associated with poor pregnancy outcomes. Hemoglobin S (HbS) and hemoglobin C (HbC) mutations are frequently encountered in malaria-endemic areas of Africa, where they protect children from severe and uncomplicated Plasmodium falciparum malaria. However, scant epidemiological data exist on the impact of these Hb variants on PAM. A prospective cohort of 635 Beninese pregnant women was recruited before 24 weeks of gestational age and followed until the end of pregnancy. HbAA, HbAC, and HbAS genotypes were determined and tested for association with pregnancy outcomes and PAM indicators using linear and logistic multivariate models. Newborns from HbAC mothers had higher birthweights than those from HbAA mothers among women infected at any time during pregnancy (mean difference 182.9 g, p = 0.08), or during the first half of pregnancy (654.3 g, p = 0.0006). No such birthweight differences were observed between newborns from HbAS and HbAA mothers. HbAC and HbAS were not associated with other pregnancy outcomes or PAM indicators. In conclusion, HbAC but not HbAS is associated with an improved birth outcome in pregnant women with documented PAM. Higher-birthweight newborns from HbAC mothers may have a survival advantage that contributes to the natural selection of HbC in malaria-endemic areas.
Collapse
Affiliation(s)
- Marilou Tétard
- Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge, Laboratoire d'Excellence GR-Ex, Paris, France
| | - Jacqueline Milet
- Institut de Recherche pour le Développement, UMR 216, Mère et Enfant face aux Infections Tropicales, Paris, France.,COMUE Sorbonne Paris Cité, Faculté de Pharmacie, Paris, France
| | - Sébastien Dechavanne
- Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge, Laboratoire d'Excellence GR-Ex, Paris, France
| | - Nadine Fievet
- Institut de Recherche pour le Développement, UMR 216, Mère et Enfant face aux Infections Tropicales, Paris, France.,COMUE Sorbonne Paris Cité, Faculté de Pharmacie, Paris, France
| | - Dominique Dorin-Semblat
- Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge, Laboratoire d'Excellence GR-Ex, Paris, France
| | - Jacques Elion
- Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge, Laboratoire d'Excellence GR-Ex, Paris, France
| | - Rick M Fairhurst
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Philippe Deloron
- Institut de Recherche pour le Développement, UMR 216, Mère et Enfant face aux Infections Tropicales, Paris, France.,COMUE Sorbonne Paris Cité, Faculté de Pharmacie, Paris, France
| | - Nicaise Tuikue-Ndam
- Institut de Recherche pour le Développement, UMR 216, Mère et Enfant face aux Infections Tropicales, Paris, France.,COMUE Sorbonne Paris Cité, Faculté de Pharmacie, Paris, France
| | - Benoît Gamain
- Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, INTS, Unité Biologie Intégrée du Globule Rouge, Laboratoire d'Excellence GR-Ex, Paris, France.
| |
Collapse
|
37
|
Pehrson C, Salanti A, Theander TG, Nielsen MA. Pre-clinical and clinical development of the first placental malaria vaccine. Expert Rev Vaccines 2017; 16:613-624. [PMID: 28434376 DOI: 10.1080/14760584.2017.1322512] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
INTRODUCTION Malaria during pregnancy is a massive health problem in endemic areas. Placental malaria infections caused by Plasmodium falciparum are responsible for up to one million babies being born with a low birth weight every year. Significant efforts have been invested into preventing the condition. Areas covered: Pub Med was searched using the broad terms 'malaria parasite placenta' to identify studies of interactions between parasite and host, 'prevention of placental malaria' to identify current strategies to prevent placental malaria, and 'placental malaria vaccine' to identify pre-clinical vaccine development. However, all papers from these searches were not systematically included. Expert commentary: The first phase I clinical trials of vaccines are well underway. Trials testing efficacy are more complicated to carry out as only women that are exposed to parasites during pregnancy will contribute to endpoint measurements, further it may require extensive follow-up to establish protection. Future second generation vaccines may overcome the inherent challenges in making an effective placental malaria vaccine.
Collapse
Affiliation(s)
- Caroline Pehrson
- a Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Science , University of Copenhagen , Copenhagen , Denmark.,b Department of Infectious Diseases , Copenhagen University Hospital (Rigshospitalet) , Copenhagen , Denmark
| | - Ali Salanti
- a Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Science , University of Copenhagen , Copenhagen , Denmark.,b Department of Infectious Diseases , Copenhagen University Hospital (Rigshospitalet) , Copenhagen , Denmark
| | - Thor G Theander
- a Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Science , University of Copenhagen , Copenhagen , Denmark.,b Department of Infectious Diseases , Copenhagen University Hospital (Rigshospitalet) , Copenhagen , Denmark
| | - Morten A Nielsen
- a Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Science , University of Copenhagen , Copenhagen , Denmark.,b Department of Infectious Diseases , Copenhagen University Hospital (Rigshospitalet) , Copenhagen , Denmark
| |
Collapse
|
38
|
Duffy MF, Tang J, Sumardy F, Nguyen HHT, Selvarajah SA, Josling GA, Day KP, Petter M, Brown GV. Activation and clustering of a Plasmodium falciparum var gene are affected by subtelomeric sequences. FEBS J 2016; 284:237-257. [PMID: 27860263 DOI: 10.1111/febs.13967] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 10/12/2016] [Accepted: 11/15/2016] [Indexed: 11/30/2022]
Abstract
The Plasmodium falciparum var multigene family encodes the cytoadhesive, variant antigen PfEMP1. P. falciparum antigenic variation and cytoadhesion specificity are controlled by epigenetic switching between the single, or few, simultaneously expressed var genes. Most var genes are maintained in perinuclear clusters of heterochromatic telomeres. The active var gene(s) occupy a single, perinuclear var expression site. It is unresolved whether the var expression site forms in situ at a telomeric cluster or whether it is an extant compartment to which single chromosomes travel, thus controlling var switching. Here we show that transcription of a var gene did not require decreased colocalisation with clusters of telomeres, supporting var expression site formation in situ. However following recombination within adjacent subtelomeric sequences, the same var gene was persistently activated and did colocalise less with telomeric clusters. Thus, participation in stable, heterochromatic, telomere clusters and var switching are independent but are both affected by subtelomeric sequences. The var expression site colocalised with the euchromatic mark H3K27ac to a greater extent than it did with heterochromatic H3K9me3. H3K27ac was enriched within the active var gene promoter even when the var gene was transiently repressed in mature parasites and thus H3K27ac may contribute to var gene epigenetic memory.
Collapse
Affiliation(s)
- Michael F Duffy
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Victoria, Australia.,The School of BioSciences, Bio21, The University of Melbourne, Victoria, Australia
| | - Jingyi Tang
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Victoria, Australia.,The School of BioSciences, Bio21, The University of Melbourne, Victoria, Australia
| | - Fransisca Sumardy
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Victoria, Australia.,The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Hanh H T Nguyen
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Victoria, Australia.,The School of BioSciences, Bio21, The University of Melbourne, Victoria, Australia
| | - Shamista A Selvarajah
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Victoria, Australia.,The School of BioSciences, Bio21, The University of Melbourne, Victoria, Australia
| | - Gabrielle A Josling
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Victoria, Australia.,Department of Biochemistry and Molecular Biology, The Pennsylvania State University, State College, PA, USA
| | - Karen P Day
- The School of BioSciences, Bio21, The University of Melbourne, Victoria, Australia
| | - Michaela Petter
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Victoria, Australia.,The School of BioSciences, Bio21, The University of Melbourne, Victoria, Australia
| | - Graham V Brown
- The Nossal Institute for Global Health, The University of Melbourne, Victoria, Australia
| |
Collapse
|
39
|
Oxidative insult can induce malaria-protective trait of sickle and fetal erythrocytes. Nat Commun 2016; 7:13401. [PMID: 27824335 PMCID: PMC5105170 DOI: 10.1038/ncomms13401] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 09/29/2016] [Indexed: 01/06/2023] Open
Abstract
Plasmodium falciparum infections can cause severe malaria, but not every infected person develops life-threatening complications. In particular, carriers of the structural haemoglobinopathies S and C and infants are protected from severe disease. Protection is associated with impaired parasite-induced host actin reorganization, required for vesicular trafficking of parasite-encoded adhesins, and reduced cytoadherence of parasitized erythrocytes in the microvasculature. Here we show that aberrant host actin remodelling and the ensuing reduced cytoadherence result from a redox imbalance inherent to haemoglobinopathic and fetal erythrocytes. We further show that a transient oxidative insult to wild-type erythrocytes before infection with P. falciparum induces the phenotypic features associated with the protective trait of haemoglobinopathic and fetal erythrocytes. Moreover, pretreatment of mice with the pro-oxidative nutritional supplement menadione mitigate the development of experimental cerebral malaria. Our results identify redox imbalance as a causative principle of protection from severe malaria, which might inspire host-directed intervention strategies.
Collapse
|
40
|
Chêne A, Houard S, Nielsen MA, Hundt S, D'Alessio F, Sirima SB, Luty AJF, Duffy P, Leroy O, Gamain B, Viebig NK. Clinical development of placental malaria vaccines and immunoassays harmonization: a workshop report. Malar J 2016; 15:476. [PMID: 27639691 PMCID: PMC5027113 DOI: 10.1186/s12936-016-1527-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 09/08/2016] [Indexed: 01/01/2023] Open
Abstract
Placental malaria caused by Plasmodium falciparum infection constitutes a major health problem manifesting as severe disease and anaemia in the mother, impaired fetal development, low birth weight or spontaneous abortion. Prevention of placental malaria currently relies on two key strategies that are losing efficacy due to spread of resistance: long-lasting insecticide-treated nets and intermittent preventive treatment during pregnancy. A placental malaria vaccine would be an attractive, cost-effective complement to the existing control tools. Two placental malaria vaccine candidates are currently in Phase Ia/b clinical trials. During two workshops hosted by the European Vaccine Initiative, one in Paris in April 2014 and the other in Brussels in November 2014, the main actors in placental malaria vaccine research discussed the harmonization of clinical development plans and of the immunoassays with a goal to define standards that will allow comparative assessment of different placental malaria vaccine candidates. The recommendations of these workshops should guide researchers and clinicians in the further development of placental malaria vaccines.
Collapse
Affiliation(s)
- Arnaud Chêne
- Unité Biologie Intégrée du Globule Rouge, Laboratoire d'Excellence GR-Ex, Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, Institut National de la Transfusion Sanguine, Paris, France
| | - Sophie Houard
- European Vaccine Initiative, UniversitätsKlinikum Heidelberg, Voßstraße 2, 69115, Heidelberg, Germany
| | - Morten A Nielsen
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Sophia Hundt
- European Vaccine Initiative, UniversitätsKlinikum Heidelberg, Voßstraße 2, 69115, Heidelberg, Germany
| | - Flavia D'Alessio
- European Vaccine Initiative, UniversitätsKlinikum Heidelberg, Voßstraße 2, 69115, Heidelberg, Germany
| | - Sodiomon B Sirima
- Centre National de Recherche et de Formation sur le Paludisme, 01 BP 2208, Ouagadougou 01, Burkina Faso
| | - Adrian J F Luty
- IRD MERIT UMR 216, 75006, Paris, France.,COMUE Sorbonne Paris Cité, Université Paris Descartes, Faculté des Sciences Pharmaceutiques et Biologiques, 75270, Paris, France
| | - Patrick Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Disease, National Institutes of Health, Rockville, MD, USA
| | - Odile Leroy
- European Vaccine Initiative, UniversitätsKlinikum Heidelberg, Voßstraße 2, 69115, Heidelberg, Germany
| | - Benoit Gamain
- Unité Biologie Intégrée du Globule Rouge, Laboratoire d'Excellence GR-Ex, Université Sorbonne Paris Cité, Université Paris Diderot, Inserm, Institut National de la Transfusion Sanguine, Paris, France
| | - Nicola K Viebig
- European Vaccine Initiative, UniversitätsKlinikum Heidelberg, Voßstraße 2, 69115, Heidelberg, Germany.
| |
Collapse
|
41
|
Pehrson C, Mathiesen L, Heno KK, Salanti A, Resende M, Dzikowski R, Damm P, Hansson SR, King CL, Schneider H, Wang CW, Lavstsen T, Theander TG, Knudsen LE, Nielsen MA. Adhesion of Plasmodium falciparum infected erythrocytes in ex vivo perfused placental tissue: a novel model of placental malaria. Malar J 2016; 15:292. [PMID: 27230523 PMCID: PMC4881162 DOI: 10.1186/s12936-016-1342-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 05/12/2016] [Indexed: 11/10/2022] Open
Abstract
Background Placental malaria occurs when Plasmodium falciparum infected erythrocytes sequester in the placenta. Placental parasite isolates bind to chondroitin sulphate A (CSA) by expression of VAR2CSA on the surface of infected erythrocytes, but may sequester by other VAR2CSA mediated mechanisms, such as binding to immunoglobulins. Furthermore, other parasite antigens have been associated with placental malaria. These findings have important implications for placental malaria vaccine design. The objective of this study was to adapt and describe a biologically relevant model of parasite adhesion in intact placental tissue. Results The ex vivo placental perfusion model was modified to study adhesion of infected erythrocytes binding to CSA, endothelial protein C receptor (EPCR) or a transgenic parasite where P. falciparum erythrocyte membrane protein 1 expression had been shut down. Infected erythrocytes expressing VAR2CSA accumulated in perfused placental tissue whereas the EPCR binding and the transgenic parasite did not. Soluble CSA and antibodies specific against VAR2CSA inhibited binding of infected erythrocytes. Conclusion The ex vivo model provides a novel way of studying receptor-ligand interactions and antibody mediated inhibition of binding in placental malaria. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1342-2) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Caroline Pehrson
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen and at Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark.
| | - Line Mathiesen
- Section of Environmental Health, Department of Public Health, University of Copenhagen, Øster Farimagsgade 5A, 1353, Copenhagen, Denmark
| | - Kristine K Heno
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen and at Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Ali Salanti
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen and at Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Mafalda Resende
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen and at Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Ron Dzikowski
- Department of Microbiology and Molecular Genetics, The Institute for Medical Research Israel-Canada, The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University-Hadassah Medical School, 91120, Jerusalem, Israel
| | - Peter Damm
- Department of Obstetrics, Rigshospitalet, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 9, 2100, Copenhagen Ø, Denmark
| | - Stefan R Hansson
- Division of Obstetrics and Gynecology, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Christopher L King
- Center for Global Health and Diseases, Case Western Reserve University and Veterans Affairs Medical Center, Cleveland, USA
| | - Henning Schneider
- Department of Obstetrics and Gynecology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Christian W Wang
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen and at Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Thomas Lavstsen
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen and at Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Thor G Theander
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen and at Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Lisbeth E Knudsen
- Section of Environmental Health, Department of Public Health, University of Copenhagen, Øster Farimagsgade 5A, 1353, Copenhagen, Denmark
| | - Morten A Nielsen
- Centre for Medical Parasitology at Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen and at Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark.
| |
Collapse
|
42
|
Doritchamou JYA, Herrera R, Aebig JA, Morrison R, Nguyen V, Reiter K, Shimp RL, MacDonald NJ, Narum DL, Fried M, Duffy PE. VAR2CSA Domain-Specific Analysis of Naturally Acquired Functional Antibodies to Plasmodium falciparum Placental Malaria. J Infect Dis 2016; 214:577-86. [PMID: 27190180 DOI: 10.1093/infdis/jiw197] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 05/05/2016] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Placental malaria is caused by Plasmodium falciparum-infected erythrocytes (IEs) that surface-express VAR2CSA and bind chondroitin sulfate A. The inflammatory response to placenta-sequestered parasites is associated with poor pregnancy outcomes, and protection may be mediated in part by VAR2CSA antibodies that block placental IE adhesion. METHODS In this study, we used a new approach to assess VAR2CSA domains for functional epitopes recognized by naturally acquired antibodies. Antigen-specific immunoglobulin (Ig) G targeting Duffy binding-like (DBL) domains from different alleles were sequentially purified from plasma pooled from multigravid women and then characterized using enzyme-linked immunosorbent assay, flow cytometry, and antiadhesion assays. RESULTS Different DBL domain-specific IgGs could react to homologous as well as heterologous antigens and parasites, suggesting that conserved epitopes are shared between allelic variants. Homologous blocking of IE binding was observed with ID1-DBL2-ID2a-, DBL4-, and DBL5-specific IgG (range, 42%-75%), whereas partial cross-inhibition activity was observed with purified IgG specific to ID1-DBL2-ID2a and DBL4 antigens. Plasma retained broadly neutralizing activity after complete depletion of these VAR2CSA specificities. CONCLUSIONS Broadly neutralizing antibodies of multigravidae are not depleted on VAR2CSA recombinant antigens, and hence development of VAR2CSA vaccines based on a single construct and variant might induce antibodies with limited broadly neutralizing activity.
Collapse
Affiliation(s)
- Justin Yai Alamou Doritchamou
- Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Disease, National Institute of Health, Rockville, Maryland
| | - Raul Herrera
- Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Disease, National Institute of Health, Rockville, Maryland
| | - Joan A Aebig
- Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Disease, National Institute of Health, Rockville, Maryland
| | - Robert Morrison
- Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Disease, National Institute of Health, Rockville, Maryland MOMS Project, Seattle Biomedical Research Institute, Washington
| | - Vu Nguyen
- Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Disease, National Institute of Health, Rockville, Maryland
| | - Karine Reiter
- Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Disease, National Institute of Health, Rockville, Maryland
| | - Richard L Shimp
- Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Disease, National Institute of Health, Rockville, Maryland
| | - Nicholas J MacDonald
- Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Disease, National Institute of Health, Rockville, Maryland
| | - David L Narum
- Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Disease, National Institute of Health, Rockville, Maryland
| | - Michal Fried
- Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Disease, National Institute of Health, Rockville, Maryland
| | - Patrick E Duffy
- Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Disease, National Institute of Health, Rockville, Maryland
| |
Collapse
|
43
|
Helms G, Dasanna AK, Schwarz US, Lanzer M. Modeling cytoadhesion of Plasmodium falciparum-infected erythrocytes and leukocytes-common principles and distinctive features. FEBS Lett 2016; 590:1955-71. [PMID: 26992823 PMCID: PMC5071704 DOI: 10.1002/1873-3468.12142] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 02/01/2016] [Accepted: 02/07/2016] [Indexed: 12/25/2022]
Abstract
Cytoadhesion of Plasmodium falciparum‐infected erythrocytes to the microvascular endothelial lining shares striking similarities to cytoadhesion of leukocytes. In both cases, adhesins are presented in structures that raise them above the cell surface. Another similarity is the enhancement of adhesion under physical force (catch bonding). Here, we review recent advances in our understanding of the molecular and biophysical mechanisms underlying cytoadherence in both cellular systems. We describe how imaging, flow chamber experiments, single‐molecule measurements, and computational modeling have been used to decipher the relevant processes. We conclude that although the parasite seems to induce processes that resemble the cytoadherence of leukocytes, the mechanics of erythrocytes is such that the resulting behavior in shear flow is fundamentally different.
Collapse
Affiliation(s)
- Gesa Helms
- Department of Infectious Diseases, Heidelberg University, Germany
| | - Anil Kumar Dasanna
- BioQuant, Heidelberg, Germany.,Institute for Theoretical Physics, Heidelberg University, Germany
| | - Ulrich S Schwarz
- BioQuant, Heidelberg, Germany.,Institute for Theoretical Physics, Heidelberg University, Germany
| | - Michael Lanzer
- Department of Infectious Diseases, Heidelberg University, Germany
| |
Collapse
|
44
|
Ndam NT, Denoeud-Ndam L, Doritchamou J, Viwami F, Salanti A, Nielsen MA, Fievet N, Massougbodji A, Luty AJF, Deloron P. Protective Antibodies against Placental Malaria and Poor Outcomes during Pregnancy, Benin. Emerg Infect Dis 2016; 21:813-23. [PMID: 25898123 PMCID: PMC4412227 DOI: 10.3201/eid2105.141626] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Immunity requires a vaccine that inhibits binding of infected erythrocytes to chondroitin sulfate. Placental malaria is caused by Plasmodium falciparum–infected erythrocytes that bind to placental tissue. Binding is mediated by VAR2CSA, a parasite antigen coded by the var gene, which interacts with chondroitin sulfate A (CSA). Consequences include maternal anemia and fetal growth retardation. Antibody-mediated immunity to placental malaria is acquired during successive pregnancies, but the target of VAR2CSA-specific protective antibodies is unclear. We assessed VAR2CSA-specific antibodies in pregnant women and analyzed their relationships with protection against placental infection, preterm birth, and low birthweight. Antibody responses to the N-terminal region of VAR2CSA during early pregnancy were associated with reduced risks for infections and low birthweight. Among women infected during pregnancy, an increase in CSA binding inhibition was associated with reduced risks for placental infection, preterm birth, and low birthweight. These data suggest that antibodies against VAR2CSA N-terminal region mediate immunity to placental malaria and associated outcomes. Our results validate current vaccine development efforts with VAR2CSA N-terminal constructs.
Collapse
MESH Headings
- Adult
- Antibodies, Protozoan/blood
- Antibodies, Protozoan/immunology
- Antibody Specificity/immunology
- Antigens, Protozoan/immunology
- Benin/epidemiology
- Erythrocytes/immunology
- Erythrocytes/parasitology
- Female
- Follow-Up Studies
- Humans
- Immunoglobulin G/blood
- Immunoglobulin G/immunology
- Infant
- Infant, Newborn
- Malaria/epidemiology
- Malaria/immunology
- Malaria/parasitology
- Malaria, Falciparum/epidemiology
- Malaria, Falciparum/immunology
- Malaria, Falciparum/parasitology
- Patient Outcome Assessment
- Placenta/parasitology
- Plasmodium falciparum/immunology
- Pregnancy
- Pregnancy Complications, Parasitic/epidemiology
- Pregnancy Complications, Parasitic/immunology
- Pregnancy Complications, Parasitic/parasitology
- Pregnancy Outcome
- Protein Binding
- Risk Factors
- Young Adult
Collapse
|
45
|
Fried M, Duffy PE. Designing a VAR2CSA-based vaccine to prevent placental malaria. Vaccine 2015; 33:7483-8. [PMID: 26469717 PMCID: PMC5077158 DOI: 10.1016/j.vaccine.2015.10.011] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Revised: 09/23/2015] [Accepted: 10/02/2015] [Indexed: 11/29/2022]
Abstract
Placental malaria (PM) due to Plasmodium falciparum is a major cause of maternal, fetal and infant mortality, but the mechanisms of pathogenesis and protective immunity are relatively well-understood for this condition, providing a path for vaccine development. P. falciparum parasites bind to chondroitin sulfate A (CSA) to sequester in the placenta, and women become resistant over 1–2 pregnancies as they acquire antibodies that block adhesion to CSA. The protein VAR2CSA, a member of the PfEMP1 variant surface antigen family, mediates parasite adhesion to CSA, and is the leading target for a vaccine to prevent PM. Obstacles to PM vaccine development include the large size (~350 kD), high cysteine content, and sequence variation of VAR2CSA. A number of approaches have been taken to identify the combination of VAR2CSA domains and alleles that can induce broadly active antibodies that block adhesion of heterologous parasite isolates to CSA. This review summarizes these approaches, which have examined VAR2CSA fragments for binding activity, antigenicity with naturally acquired antibodies, and immunogenicity in animals for inducing anti-adhesion or surface-reactive antibodies. Two products are expected to enter human clinical studies in the near future based on N-terminal VAR2CSA fragments that have high binding affinity for CSA, and additional proteins preferentially expressed by placental parasites are also being examined for their potential contribution to a PM vaccine.
Collapse
Affiliation(s)
- Michal Fried
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, 5640 Fishers Lane, TWB1/Room 1111, Rockville, MD, USA.
| | - Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, 5640 Fishers Lane, TWB1/Room 1111, Rockville, MD, USA.
| |
Collapse
|
46
|
Gangnard S, Lewit-Bentley A, Dechavanne S, Srivastava A, Amirat F, Bentley GA, Gamain B. Structure of the DBL3X-DBL4ε region of the VAR2CSA placental malaria vaccine candidate: insight into DBL domain interactions. Sci Rep 2015; 5:14868. [PMID: 26450557 PMCID: PMC4598876 DOI: 10.1038/srep14868] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 09/09/2015] [Indexed: 11/25/2022] Open
Abstract
The human malaria parasite, Plasmodium falciparum, is able to evade spleen-mediated clearing from blood stream by sequestering in peripheral organs. This is due to the adhesive properties conferred by the P. falciparum Erythrocyte Membrane Protein 1 (PfEMP1) family exported by the parasite to the surface of infected erythrocytes. Expression of the VAR2CSA variant of PfEMP1 leads to pregnancy-associated malaria, which occurs when infected erythrocytes massively sequester in the placenta by binding to low-sulfated Chondroitin Sulfate A (CSA) present in the intervillous spaces. VAR2CSA is a 350 kDa protein that carries six Duffy-Binding Like (DBL) domains, one Cysteine-rich Inter-Domain Regions (CIDR) and several inter-domain regions. In the present paper, we report for the first time the crystal structure at 2.9 Å of a VAR2CSA double domain, DBL3X-DBL4ε, from the FCR3 strain. DBL3X and DBL4ε share a large contact interface formed by residues that are invariant or highly conserved in VAR2CSA variants, which suggests that these two central DBL domains (DBL3X-DBL4ε) contribute significantly to the structuring of the functional VAR2CSA extracellular region. We have also examined the antigenicity of peptides corresponding to exposed loop regions of the DBL4ε structure.
Collapse
Affiliation(s)
- Stéphane Gangnard
- Inserm UMR_1134, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, UMR_S1134 Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratory of excellence GR-Ex, Paris, France.,Unité d'Immunologie Structurale, Département de Biologie Structurale et Chimie, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris, France.,Centre National de la Recherche Scientifique URA2185, 25 rue du Docteur Roux, 75724 Paris, France
| | - Anita Lewit-Bentley
- Unité d'Immunologie Structurale, Département de Biologie Structurale et Chimie, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris, France.,Centre National de la Recherche Scientifique URA2185, 25 rue du Docteur Roux, 75724 Paris, France
| | - Sébastien Dechavanne
- Inserm UMR_1134, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, UMR_S1134 Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratory of excellence GR-Ex, Paris, France
| | - Anand Srivastava
- Inserm UMR_1134, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, UMR_S1134 Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratory of excellence GR-Ex, Paris, France
| | - Faroudja Amirat
- Unité d'Immunologie Structurale, Département de Biologie Structurale et Chimie, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris, France.,Centre National de la Recherche Scientifique URA2185, 25 rue du Docteur Roux, 75724 Paris, France
| | - Graham A Bentley
- Unité d'Immunologie Structurale, Département de Biologie Structurale et Chimie, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris, France.,Centre National de la Recherche Scientifique URA2185, 25 rue du Docteur Roux, 75724 Paris, France
| | - Benoît Gamain
- Inserm UMR_1134, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, UMR_S1134 Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratory of excellence GR-Ex, Paris, France
| |
Collapse
|
47
|
Birch CM, Hou HW, Han J, Niles JC. Identification of malaria parasite-infected red blood cell surface aptamers by inertial microfluidic SELEX (I-SELEX). Sci Rep 2015; 5:11347. [PMID: 26126714 PMCID: PMC4486934 DOI: 10.1038/srep11347] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 05/14/2015] [Indexed: 01/09/2023] Open
Abstract
Plasmodium falciparum malaria parasites invade and remodel human red blood cells (RBCs) by trafficking parasite-synthesized proteins to the RBC surface. While these proteins mediate interactions with host cells that contribute to disease pathogenesis, the infected RBC surface proteome remains poorly characterized. Here we use a novel strategy (I-SELEX) to discover high affinity aptamers that selectively recognize distinct epitopes uniquely present on parasite-infected RBCs. Based on inertial focusing in spiral microfluidic channels, I-SELEX enables stringent partitioning of cells (efficiency ≥ 106) from unbound oligonucleotides at high volume throughput (~2 × 106 cells min−1). Using an RBC model displaying a single, non-native antigen and live malaria parasite-infected RBCs as targets, we establish suitability of this strategy for de novo aptamer selections. We demonstrate recovery of a diverse set of aptamers that recognize distinct, surface-displayed epitopes on parasite-infected RBCs with nanomolar affinity, including an aptamer against the protein responsible for placental sequestration, var2CSA. These findings validate I-SELEX as a broadly applicable aptamer discovery platform that enables identification of new reagents for mapping the parasite-infected RBC surface proteome at higher molecular resolution to potentially contribute to malaria diagnostics, therapeutics and vaccine efforts.
Collapse
Affiliation(s)
- Christina M Birch
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Han Wei Hou
- 1] Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA [2] BioSystems and Micromechanics (BioSyM) IRG, Singapore-MIT Alliance for Research and Technology (SMART) Centre, 1 Create Way, #04-13/14 Enterprise Wing, Singapore 138602, SINGAPORE
| | - Jongyoon Han
- 1] Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA [2] Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA [3] BioSystems and Micromechanics (BioSyM) IRG, Singapore-MIT Alliance for Research and Technology (SMART) Centre, 1 Create Way, #04-13/14 Enterprise Wing, Singapore 138602, SINGAPORE
| | - Jacquin C Niles
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| |
Collapse
|
48
|
Abstract
INTRODUCTION Placental malaria (PM) is a major public health problem that constitutes a significant health concern for the mother, and especially for the developing fetus and offspring. Current means of prevention have limitations, including a restricted window of intervention that excludes the first trimester of pregnancy, and the fact that very few drugs can be used for this purpose. The identification of the VAR2CSA antigen, specific to PM parasites, offers an excellent opportunity to develop a vaccine against this disease. Proof of concept of a first-generation vaccine is nearing completion, and two clinical trials are underway. AREAS COVERED This review focuses on PM, which is mainly caused by Plasmodium falciparum. The review highlights recent advances and the key milestones that led to the identification of the optimal vaccine target within the large VAR2CSA protein. The paper also points out how future improvements can strengthen this process to achieve an effective vaccine in the field. EXPERT OPINION The approach taken to develop a P. falciparum erythrocyte membrane protein 1-based vaccine to protect pregnant women is very promising in view of the current difficulties of achieving a sterilizing vaccine against malaria parasite. This approach could help us to control the deleterious effect of malaria infections that characterize severe clinical forms.
Collapse
|
49
|
Merrick CJ, Jiang RHY, Skillman KM, Samarakoon U, Moore RM, Dzikowski R, Ferdig MT, Duraisingh MT. Functional analysis of sirtuin genes in multiple Plasmodium falciparum strains. PLoS One 2015; 10:e0118865. [PMID: 25780929 PMCID: PMC4364008 DOI: 10.1371/journal.pone.0118865] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 01/07/2015] [Indexed: 12/22/2022] Open
Abstract
Plasmodium falciparum, the causative agent of severe human malaria, employs antigenic variation to avoid host immunity. Antigenic variation is achieved by transcriptional switching amongst polymorphic var genes, enforced by epigenetic modification of chromatin. The histone-modifying 'sirtuin' enzymes PfSir2a and PfSir2b have been implicated in this process. Disparate patterns of var expression have been reported in patient isolates as well as in cultured strains. We examined var expression in three commonly used laboratory strains (3D7, NF54 and FCR-3) in parallel. NF54 parasites express significantly lower levels of var genes compared to 3D7, despite the fact that 3D7 was originally a clone of the NF54 strain. To investigate whether this was linked to the expression of sirtuins, genetic disruption of both sirtuins was attempted in all three strains. No dramatic changes in var gene expression occurred in NF54 or FCR-3 following PfSir2b disruption, contrasting with previous observations in 3D7. In 3D7, complementation of the PfSir2a genetic disruption resulted in a significant decrease in previously-elevated var gene expression levels, but with the continued expression of multiple var genes. Finally, rearranged chromosomes were observed in the 3D7 PfSir2a knockout line. Our results focus on the potential for parasite genetic background to contribute to sirtuin function in regulating virulence gene expression and suggest a potential role for sirtuins in maintaining genome integrity.
Collapse
Affiliation(s)
- Catherine J. Merrick
- Department of Immunology & Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Rays H. Y. Jiang
- Department of Immunology & Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Kristen M. Skillman
- Department of Immunology & Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Upeka Samarakoon
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Rachel M. Moore
- Department of Immunology & Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Ron Dzikowski
- Department of Microbiology & Molecular Genetics, The Kuvin Center for the Study of Infectious and Tropical Diseases, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Michael T. Ferdig
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Manoj T. Duraisingh
- Department of Immunology & Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
- * E-mail:
| |
Collapse
|
50
|
Nacer A, Claes A, Roberts A, Scheidig-Benatar C, Sakamoto H, Ghorbal M, Lopez-Rubio JJ, Mattei D. Discovery of a novel and conserved Plasmodium falciparum exported protein that is important for adhesion of PfEMP1 at the surface of infected erythrocytes. Cell Microbiol 2015; 17:1205-16. [PMID: 25703704 PMCID: PMC4654329 DOI: 10.1111/cmi.12430] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 02/17/2015] [Accepted: 02/18/2015] [Indexed: 11/27/2022]
Abstract
Plasmodium falciparum virulence is linked to its ability to sequester in post-capillary venules in the human host. Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is the main variant surface antigen implicated in this process. Complete loss of parasite adhesion is linked to a large subtelomeric deletion on chromosome 9 in a number of laboratory strains such as D10 and T9-96. Similar to the cytoadherent reference line FCR3, D10 strain expresses PfEMP1 on the surface of parasitized erythrocytes, however without any detectable cytoadhesion. To investigate which of the deleted subtelomeric genes may be implicated in parasite adhesion, we selected 12 genes for D10 complementation studies that are predicted to code for proteins exported to the red blood cell. We identified a novel single copy gene (PF3D7_0936500) restricted to P. falciparum that restores adhesion to CD36, termed here virulence-associated protein 1 (Pfvap1). Protein knockdown and gene knockout experiments confirmed a role of PfVAP1 in the adhesion process in FCR3 parasites. PfVAP1 is co-exported with PfEMP1 into the host cell via vesicle-like structures called Maurer's clefts. This study identifies a novel highly conserved parasite molecule that contributes to parasite virulence possibly by assisting PfEMP1 to establish functional adhesion at the host cell surface.
Collapse
Affiliation(s)
- Adéla Nacer
- Biology of Parasite-Host Interactions Unit, Department of Parasites and Insect Vectors, Institut Pasteur, 25, Rue du Dr. Roux, Paris, F-75015, France.,INSERM U1201, 25, Rue du Dr. Roux, Paris, F-75015, France.,CNRS ERL9195, 25, Rue du Dr. Roux, Paris, F-75015, France
| | - Aurélie Claes
- Biology of Parasite-Host Interactions Unit, Department of Parasites and Insect Vectors, Institut Pasteur, 25, Rue du Dr. Roux, Paris, F-75015, France.,INSERM U1201, 25, Rue du Dr. Roux, Paris, F-75015, France.,CNRS ERL9195, 25, Rue du Dr. Roux, Paris, F-75015, France
| | - Amy Roberts
- Biology of Parasite-Host Interactions Unit, Department of Parasites and Insect Vectors, Institut Pasteur, 25, Rue du Dr. Roux, Paris, F-75015, France.,INSERM U1201, 25, Rue du Dr. Roux, Paris, F-75015, France.,CNRS ERL9195, 25, Rue du Dr. Roux, Paris, F-75015, France
| | - Christine Scheidig-Benatar
- Biology of Parasite-Host Interactions Unit, Department of Parasites and Insect Vectors, Institut Pasteur, 25, Rue du Dr. Roux, Paris, F-75015, France.,INSERM U1201, 25, Rue du Dr. Roux, Paris, F-75015, France.,CNRS ERL9195, 25, Rue du Dr. Roux, Paris, F-75015, France
| | - Hiroshi Sakamoto
- Biology of Parasite-Host Interactions Unit, Department of Parasites and Insect Vectors, Institut Pasteur, 25, Rue du Dr. Roux, Paris, F-75015, France.,INSERM U1201, 25, Rue du Dr. Roux, Paris, F-75015, France.,CNRS ERL9195, 25, Rue du Dr. Roux, Paris, F-75015, France
| | - Mehdi Ghorbal
- Biology of Parasite-Host Interactions Unit, Department of Parasites and Insect Vectors, Institut Pasteur, 25, Rue du Dr. Roux, Paris, F-75015, France.,INSERM U1201, 25, Rue du Dr. Roux, Paris, F-75015, France
| | - Jose-Juan Lopez-Rubio
- Biology of Parasite-Host Interactions Unit, Department of Parasites and Insect Vectors, Institut Pasteur, 25, Rue du Dr. Roux, Paris, F-75015, France.,INSERM U1201, 25, Rue du Dr. Roux, Paris, F-75015, France
| | - Denise Mattei
- Biology of Parasite-Host Interactions Unit, Department of Parasites and Insect Vectors, Institut Pasteur, 25, Rue du Dr. Roux, Paris, F-75015, France.,INSERM U1201, 25, Rue du Dr. Roux, Paris, F-75015, France.,CNRS ERL9195, 25, Rue du Dr. Roux, Paris, F-75015, France
| |
Collapse
|