Variable species and stage specificity of schistosomulum surface epitopes recognized by mice vaccinated with highly irradiated cercariae.

Antibodies from mice vaccinated with highly irradiated Schistosoma mansoni or S. haematobium cercariae were used to characterize schistosomulum surface epitopes which were found to be diverse in their species and stage specificities. The epitopes recognized on the Mr greater than 200,000 and 15,000 schistosomulum surface antigens of S. mansoni and the Mr greater than 200,000 schistosomulum surface antigen of S. haematobium were found to be cross-specific whereas those on the Mr 38,000, 32,000 and 20,000 schistosomulum surface antigens of S. mansoni and the Mr 35,000, 30,000 and 24,000 schistosomulum surface antigens of S. haematobium were only immunoprecipitated by homologous antibody and are thus possible targets of the protective species-specific immunity stimulated by highly irradiated cercariae. The epitopes recognized on the Mr greater than 200,000 and 38,000 antigens of S. mansoni were shown to cross-react with both the egg and the adult worm whereas those on the Mr 32,000 and 20,000 antigens only cross-reacted with the adult worm, and those on the Mr 15,000 antigen cross-reacted with neither the adult worm nor the egg. In addition the epitopes on the Mr 38,000 and 32,000 antigens were demonstrated to be polypeptide in nature. Those on the Mr greater than 200,000, 20,000 and 15,000 antigens, on the other hand, could not be conclusively defined.