Ookinete antigens of Plasmodium berghei. Appearance on the zygote surface of an Mr 21 kD determinant identified by transmission-blocking monoclonal antibodies.
Zygotes and ookinetes of the rodent malaria Plasmodium berghei can be enriched 50-fold, from whole blood cultures by ammonium chloride lysis. Three monoclonal antibodies (MoAbs) raised against such enriched preparations specifically bind to a determinant of Mr 21 kD as assessed by 125I-labelled goat anti-mouse IgG probed immunoblots of Western transfers of SDS-PAGE gels. Indirect immunofluorescence indicates that the 21 kD determinant bound by specific MoAbs, whilst not detectable on gametocytes or gametes, appears on the parasite surface within 2 h of exflagellation/fertilization and increases thereafter. The three MoAbs specifically binding the 21 kD determinant block oocyst development in mosquitoes by at least 90%, as assessed either by in-vitro membrane feeds or by live feeds on passively immunized mice. These MoAbs reduce ookinete formation in vitro by between 52 and 100%. Possible mechanisms of action of these MoAbs are discussed.
D000818:Animals; D000852:Anopheles; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000913:Antibodies, Protozoan / Q000276:immunology*; D000953:Antigens, Protozoan / Q000032:analysis* / Q000276:immunology; D001667:Binding, Competitive; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes / Q000032:analysis / Q000276:immunology; D005260:Female; D005455:Fluorescent Antibody Technique; D006825:Hybridomas; D007116:Immunization, Passive; D007118:Immunoassay; D007700:Kinetics; D051379:Mice; D010962:Plasmodium berghei / Q000276:immunology*; D015053:Zygote / Q000276:immunology
D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D000939:Epitopes