title: Plasmodium falciparum sexual stage antigens: immunogenicity and cell-mediated responses.
abstract: Antibody and cell-mediated immune responses to the transmission-blocking target antigens of Plasmodium falciparum, Pfs 48/45, were determined in infected non-immune patients and in immune individuals from an endemic area. Characterization of the B cell epitopes with monoclonal antibodies showed that there were five regions identifiable but there could be interactions between them causing either competitive or enhancing effects. Sera from infected non-immune patients contained antibodies that would compete with one or more of the mAbs to the different epitopes. Immune responsiveness to purified Pfs 48/45 in P. falciparum-immune adults measured as lymphoproliferation, production of interferon-gamma, or as Pfs 48/45-specific antibody was very limited. This did not appear to be due to MHC class II restriction, to diversity in structure of the parasite antigens or to a failure of immunological memory. The antibody-response data were more consistent with down-regulation of immunity as a result of prolonged exposure to infection.
authors.affiliation: Department of Medical Parasitology, London School of Hygiene and Tropical Medicine, U.K.
authors.forename: G A
authors.initials: GA
authors.lastname: Targett
authors.forename: P G
authors.initials: PG
authors.lastname: Harte
authors.forename: S
authors.initials: S
authors.lastname: Eida
authors.forename: N C
authors.initials: NC
authors.lastname: Rogers
authors.forename: C S
authors.initials: CS
authors.lastname: Ong
mesh_terms: D000328:Adult; D000818:Animals; D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan / Q000032:analysis; D000953:Antigens, Protozoan / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D002648:Child; D015536:Down-Regulation; D000939:Epitopes / Q000276:immunology; D005854:Germ Cells / Q000276:immunology; D006801:Humans; D007111:Immunity, Cellular; D007156:Immunologic Memory; D008285:Major Histocompatibility Complex / Q000276:immunology; D008288:Malaria / Q000276:immunology; D010963:Plasmodium falciparum / Q000276:immunology*; D015800:Protozoan Proteins / Q000276:immunology*; D012008:Recurrence
chemical_list: D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D000939:Epitopes; D015800:Protozoan Proteins; C064783:sexual stage specific protein, Plasmodium