IgG response of rats and humans to the released products of schistosomula of Schistosoma mansoni.

The participation of products released from Schistosoma mansoni schistosomula (SRP-A) in the IgG antibody response of infected Brown-Norway rats and infected humans has been studied using immunoprecipitation with various antigenic preparations and in in vitro cytotoxicity assays. A large number of SRP-A molecules with a wide range of molecular weights was recognized by infected rat and human sera. Anti-SRP-A antibodies appeared in rat sera from day 28 after infection. In infected humans, a variable pattern of SRP-A recognition was observed between individuals. IgG antibodies obtained by immunization of rats with SRP-A without addition of adjuvants reacted with 3 major schistosomula surface proteins with molecular weights of 38, 32 and 21 kDa. These latter molecules were also revealed strongly by infected rat sera. Moreover, these antibodies were able to kill schistosomula in vitro in the presence of complement or eosinophils.