Isolation and characterization of surface antigens from Schistosoma mansoni. II. Antigenicity of radiolabeled proteins from adult worms.

Adult Schistosoma mansoni were radiolabeled in vitro with 125I Bolton-Hunter reagent. Surface membrane antigens were solubilized with non-ionic detergent, then reacted with infection or normal serum. The antigen-antibody complexes were then precipitated with staphylococcal protein A immunoadsorbent, eluted with urea and SDS, and fractionated by SDS-PAGE. The results indicated the presence of 6 to 8 tegument antigens, depending on the type of antisera used. Human antisera to S. japonicum and S. haematobium reacted with some but not all of the antigens identified with human S. mansoni infection serum; this implies the presence of species-specific tegument antigens. The molecular weights of the radiolabeled antigens ranged from 10,000 to 100,000. A large (greater than 100,000) molecular weight glycoprotein and an uncharacterized lipid fraction appeared to be precipitated nonspecifically. Immunoprecipitation methods with anti-mouse IgG and anti-mouse whole serum failed to detect the presence of hostlike antigens in the labeled extracts. Several of the labeled proteins from S. mansoni were found to react with serum from patients infected with either S. haematobium or with S. japonicum.