Protective immunization of mice against Schistosoma mansoni with purified adult worm surface membranes.

Immunity to Schistosoma mansoni in the mouse was induced by vaccination with adult worm surface membrane (mb-S). Of several adjuvants tested, including Freund's, BCG and alum, 50 micrograms of saponin per mouse given subcutaneously with the antigen was the easiest to administer, and gave consistent protection, approaching levels usually seen in our mouse model after exposure to irradiated cercariae. An antibody response to the schistosomular surface was detected in mice immunized with mb-S plus saponin which was predominantly anti-polypeptide, not anti-carbohydrate, and thus similar to the antibody response of mice exposed to irradiated cercariae. The level of antibodies to Mr 90,000 and 38,000 schistosomular surface antigens as well as to Mr 25,000 adult surface membrane antigen was significantly correlated with the presence of protection.