Passive protection against Taenia saginata infection in cattle by a mouse monoclonal antibody reactive with the surface of the invasive oncosphere.

The surface, excretory/secretory and intracellular compartments of Taenia saginata oncospheres were analysed by a combination of immunochemical techniques and by the use of selected hybridoma antibodies. The surface proteins of the oncospheres were directly iodinated by the lactoperoxidase technique and the intracellular and excretory/secretory components were labelled biosynthetically by culture in vitro with 35S-methionine. Analysis of radiolabelled proteins by SDS-PAGE revealed a restricted number of components in all of these three compartments. Mouse derived monoclonal antibodies directed against the oncospheral stage of this parasite demonstrated both stage specific and common determinants on the surfaces of the oncospheres and the metacestodes. One monoclonal (IgM) antibody, reactive with the oncosphere surface, which had a half life of 4.1 days when injected into calves, conferred protection against oral infection with T. saginata eggs. A monoclonal antibody reactive with a major secreted component did not confer passive protection.