Comparative antigen analysis of different life stages of Schistosoma mansoni by crossed immunoelectrophoresis.

Two-dimensional (crossed) immunoelectrophoresis was used for analysis of soluble antigen extracts obtained from the three developmental stages, cercariae, adult worms and eggs, of Schistosoma mansoni by using homologous hyperimmune sera produced in sheep. The antigenic relationships between the three stages as well as the possible relationship to the intermediate snail host were studied. Seven antigen components were shown to be shared between all three life stages of S. mansoni. Furthermore, one antigen was common to adult worm and snail, and one other antigen was shared between cercaria and snail. By using an intermediate gel containing lectin in the antigen-antibody system or by enzyme staining of the immune precipitates it was possible to identify schistosome antigens possessing lectin reactivity or enzyme activity. Characterization of enzyme activities revealed three individual precipitating antigens in adult worm of S. mansoni possessing esterase, leucyl-glycyl-glycine peptidase and phenylalanyl-leucine peptidase activities, respectively. One further precipitinogen with malate dehydrogenase activity was identified for all three life stages.