title: VAR2CSA Domain-Specific Analysis of Naturally Acquired Functional Antibodies to Plasmodium falciparum Placental Malaria.
abstract: 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.
  
  
  
  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.
  
  
  
  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.
  
  
  
  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.
authors.affiliation: Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Disease, National Institute of Health, Rockville, Maryland.
authors.forename: Justin Yai Alamou
authors.initials: JY
authors.lastname: Doritchamou
authors.affiliation: Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Disease, National Institute of Health, Rockville, Maryland.
authors.forename: Raul
authors.initials: R
authors.lastname: Herrera
authors.affiliation: Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Disease, National Institute of Health, Rockville, Maryland.
authors.forename: Joan A
authors.initials: JA
authors.lastname: Aebig
authors.affiliation: 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.
authors.forename: Robert
authors.initials: R
authors.lastname: Morrison
authors.affiliation: Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Disease, National Institute of Health, Rockville, Maryland.
authors.forename: Vu
authors.initials: V
authors.lastname: Nguyen
authors.affiliation: Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Disease, National Institute of Health, Rockville, Maryland.
authors.forename: Karine
authors.initials: K
authors.lastname: Reiter
authors.affiliation: Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Disease, National Institute of Health, Rockville, Maryland.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Shimp
authors.affiliation: Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Disease, National Institute of Health, Rockville, Maryland.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: MacDonald
authors.affiliation: Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Disease, National Institute of Health, Rockville, Maryland.
authors.forename: David L
authors.initials: DL
authors.lastname: Narum
authors.affiliation: Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Disease, National Institute of Health, Rockville, Maryland.
authors.forename: Michal
authors.initials: M
authors.lastname: Fried
authors.affiliation: Laboratory of Malaria Immunology & Vaccinology, National Institute of Allergy and Infectious Disease, National Institute of Health, Rockville, Maryland.
authors.forename: Patrick E
authors.initials: PE
authors.lastname: Duffy
mesh_terms: D057134:Antibodies, Neutralizing / Q000097:blood*; D000913:Antibodies, Protozoan / Q000097:blood*; D000953:Antigens, Protozoan / Q000276:immunology*; D002448:Cell Adhesion; D004797:Enzyme-Linked Immunosorbent Assay; D018604:Epitope Mapping; D018985:Epitopes, B-Lymphocyte; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D017780:Malaria Vaccines / Q000276:immunology; D016778:Malaria, Falciparum / Q000276:immunology*; D010922:Placenta Diseases / Q000276:immunology*; D010963:Plasmodium falciparum / Q000276:immunology*; D011247:Pregnancy
chemical_list: D057134:Antibodies, Neutralizing; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D018985:Epitopes, B-Lymphocyte; D017780:Malaria Vaccines; C512601:VAR2CSA protein, Plasmodium falciparum
keywords: DBL domains; VAR2CSA; functional antibody; malaria; multigravidae; pregnancy; vaccine