title: Naturally occurring antibodies to an epitope on Plasmodium falciparum gametes detected by monoclonal antibody-based competitive enzyme-linked immunosorbent assay.
abstract: The antibody response to an epitope on gamete antigens of Plasmodium falciparum in persons naturally exposed to malaria has been investigated by competitive enzyme-linked immunosorbent assay. The assay detects antibodies to an epitope on the 48/45-kilodalton (kDa) gamete surface antigen by competition with horseradish peroxidase-labeled monoclonal antibody IIC5-B10. Five sera previously shown to immunoprecipitate the 230- and 48/45-kDa antigens significantly inhibited IIC5-B10 binding to an average of 24.2% of control. The one serum which precipitated only the 48/45-kDa antigen did not inhibit IIC5-B10 binding. For 26 sera which were negative by immunoprecipitation, mean binding in the assay was 112.7% of control (pooled London nonimmune sera). Recognition of both 230-kDa and 48/45-kDa antigens was associated with a titer of 1:9 or greater (reciprocal geometric mean titer, 27.6) for inhibition to more than 2 standard deviations from the mean of the negative sera. The results show that the IIC5-B10 binding site is a naturally immunogenic epitope recognized by the majority of persons who had antibodies to the 48/45-kDa protein. An additional finding was enhancement of binding of IIC5-B10 to an average of 154.4% of control by five sera which recognized only the 230-kDa antigen, presumably due to conformational alteration of the gamete antigen complex.
authors: London School of Hygiene and Tropical Medicine, England.
authors: P M
authors: PM
authors: Graves
authors: R A
authors: RA
authors: Wirtz
authors: R
authors: R
authors: Carter
authors: T R
authors: TR
authors: Burkot
authors: M
authors: M
authors: Looker
authors: G A
authors: GA
authors: Targett
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000913:Antibodies, Protozoan / Q000032:analysis*; D000953:Antigens, Protozoan / Q000032:analysis*; D001667:Binding, Competitive; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes; D005854:Germ Cells / Q000276:immunology; D006801:Humans; D010963:Plasmodium falciparum / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D000939:Epitopes