title: Characterization of anti-var2CSA-PfEMP1 cytoadhesion inhibitory mouse monoclonal antibodies.
abstract: Pregnancy-associated malaria (PAM) is associated with the massive sequestration of erythrocytes infected with CSA-binding parasites in the placenta. Natural protective immunity against PAM is acquired during the course of pregnancies, with the development of anti-PfEMP1 antibodies recognizing placental infected erythrocytes (IEs) from different geographical regions. Mouse monoclonal antibodies (mabs) were raised against Plasmodium falciparum variant surface proteins expressed by CSA-binding parasites. These mabs blocked 0-60% of CSA-binding parasite adhesion and immunoprecipitated a 350 kDa 125I-labeled PfEMP1(CSA). Two var2CSA domains expressed on the surface of CHO cells (DBL5epsilon and DBL6epsilon) were identified as the targets of three of four antibodies inhibiting CSA binding. Two of these antibodies also recognized either DBL2x or DBL3x, suggesting that some epitopes may be common to several var2CSA domains. These mabs also specifically selected CSA-binding IEs and facilitated the purification from IE extracts of the native var2CSA ligand. This purified ligand elicited antibodies in immunized mice inhibiting efficiently IE(CSA) cytoadhesion. Based on our findings, we provide the first demonstration that the parasite var2CSA surface protein can elicit inhibitory antibodies and define here the subunits of the var2CSA ligand suitable for use in vaccine development.
authors.affiliation: Unité de Parasitologie Expérimentale, URA Institut Pasteur, Univ Med. EA 3282, IFR 48 Université de la Méditerranée 27, Bd. Jean Moulin, 13385, Marseille Cedex 05, France.
authors.forename: Marion
authors.initials: M
authors.lastname: Avril
authors.forename: Benoit
authors.initials: B
authors.lastname: Gamain
authors.forename: Catherine
authors.initials: C
authors.lastname: Lépolard
authors.forename: Nicolas
authors.initials: N
authors.lastname: Viaud
authors.forename: Artur
authors.initials: A
authors.lastname: Scherf
authors.forename: Jürg
authors.initials: J
authors.lastname: Gysin
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000913:Antibodies, Protozoan / Q000276:immunology*; D000918:Antibody Specificity; D000953:Antigens, Protozoan / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D016466:CHO Cells / Q000378:metabolism; D002809:Chondroitin Sulfates / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D004912:Erythrocytes / Q000469:parasitology; D006801:Humans; D051379:Mice; D010920:Placenta / Q000469:parasitology; D010963:Plasmodium falciparum / Q000737:chemistry / Q000502:physiology; D011485:Protein Binding / Q000276:immunology; D017434:Protein Structure, Tertiary
chemical_list: D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; C512601:VAR2CSA protein, Plasmodium falciparum; D002809:Chondroitin Sulfates