Comparison of hemocyte components from Schistosoma mansoni (Trematoda)-susceptible and resistant Biomphalaria glabrata (Gastropoda) that cross-react with larval schistosome surface proteins.

1. Cross-reactive antigens between larval Schistosoma mansoni and hemocytes from schistosome-resistant and susceptible strains of Biomphalaria glabrata were identified and compared using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), immunoblotting and surface radioiodination. 2. Four sporocyst (larval S. mansoni) surface antigens (27, 39, 40 and 70 kDa) reacted with antibodies to hemocytes from resistant snails whereas only one surface antigen (70 kDa) was recognized by antibodies to hemocytes from susceptible B. glabrata. 3. The wider distribution and greater frequency of cross-reactive antigens between resistant hemocytes and sporocysts suggests that such cross-reactivity may be involved in the hemocyte-mediated killing of larval schistosomes that occurs in this host-parasite system.