Schistosoma mansoni: reactivity with infected human sera and monoclonal antibody characterization of a glycoprotein in different developmental stages

Cercarial glycoproteins of Schistosoma mansoni were purified by concanavalin A affinity chromatography. The purified fraction consisted of at least 15 polypeptides when analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Sera of infected humans specifically immunoprecipitated all of these polypeptides. These purified glycoproteins were used as antigen for preparing monoclonal antibodies. One of these monoclonal antibodies immunoprecipitated cercarial polypeptides that were identical to polypeptides immunoprecipitated with sera of infected humans as analyzed by two-dimensional gel electrophoresis. Direct binding assays with ¹²⁵I-labeled monoclonal antibody showed that proteins sharing antigenic determinants recognized by this monoclonal antibody were present not only in cercariae (the source of the immunogen) but also in adult male and female worms and in eggs. The protein molecules expressing these antigenic determinants were glycosylated in each of the developmental stages of the larvae, but differed with respect to molecular weight. These findings indicate a role for this monoclonal antibody in serodiagnosis and immunoprophylaxis.