title: Studies on Pf155/RESA and other soluble antigens from in vitro cultured Plasmodium falciparum.
abstract: Spent culture medium from in vitro cultures of Plasmodium falciparum was used as the source for immunoadsorbent enrichment of soluble parasite antigens. IgG obtained from P. falciparum-hyperimmune Liberian serum was used as the ligand in the immunoadsorbent. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of the immunoadsorbent isolated material revealed the presence of at least 15 antigenic and parasite-derived polypeptides. Immunoblotting after SDS-PAGE showed greater than 20 antigenic polypeptides in the molecular weight range of 15-250 kDa. Several of these were heat-stable (100 degrees C for 5 min), and six of them were detected even after heating for 60 min. Among the latter antigens was Pf155/RESA, a merozoite antigen deposited in the erythrocyte membrane at invasion. Pf155/RESA can be detected using a modified erythrocyte membrane immunofluorescence (EMIF) assay. Inhibition of EMIF with heated parasite material showed that the antigenic activity was intact after heating for up to 30 min. The immunofluorescence-inhibitory activity was separated into two fractions, one containing Pf155/RESA and one containing polypeptides with molecular weights of 135 and 120 kDa. All three of these antigenic polypeptides bound selectively, albeit nonspecifically, to aminoethyl-BioGel resins.
authors.affiliation: Dept. of Immunology, Stockholm University, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Carlsson
authors.forename: K
authors.initials: K
authors.lastname: Berzins
authors.forename: H
authors.initials: H
authors.lastname: Perlmann
authors.forename: P
authors.initials: P
authors.lastname: Perlmann
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000032:analysis*; D000954:Antigens, Surface / Q000032:analysis; D001345:Autoradiography; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D005455:Fluorescent Antibody Technique; D006801:Humans; D015151:Immunoblotting; D007163:Immunosorbent Techniques; D010963:Plasmodium falciparum / Q000276:immunology*; D015800:Protozoan Proteins / Q000032:analysis*
chemical_list: D000953:Antigens, Protozoan; D000954:Antigens, Surface; D015800:Protozoan Proteins; C050256:ring-infected erythrocyte surface antigen (RESA), Plasmodium falciparum