The proposed research will focus on the isolation and characterization of the immunologically reactive portions of the currently used soluble egg antigenic preparation (SEA) of S. mansoni. The number of antigenic and immunogenic moieties in SEA will be determined and active fractions will be characterized in relationship to their physicochemical characteristics and biological and immunological activities. SEA will be subjected to salting-out, molecular sieve and ion-exchange column chromatography, and electrophoretic and isoelectric-focusing separations. Following the above procedures, fractions will be identified by straining and absorption methods specific for proteins, carbohydrates, lipids and nucleic acids. They will then be analyzed for their antigenic and immunogenic properties. These studies will utilize the following techniques: in vitro lymphocyte blastogenesis; intradermal skin-testing; immunoprecipitation in gels (Ouchterlony and immunoelectrophoresis); passive (indirect) hemagglutination; and sensitization followed by the above immunoassays and granuloma formation determinations. The studies should yield information which allows more precise immunologic information regarding the anti-SEA response which leads to schistosomal egg granuloma formation and point to specific means of immunosuppressing this pathogenic response.