PARTIAL CHARACTERIZATION OF THE EPITOPE ON EXCRETORY-SECRETORY PRODUCTS OF FASCIOLA-HEPATICA RECOGNIZED BY MONOCLONAL-ANTIBODY ES78

This report contains a partial characterization of the epitope recogni zed by monoclonal antibody (MAb) ES78 produced against excretory-secre tory (ES) antigens of Fasciola hepatica. ES78 is currently used for th e detection of ES antigens in serum and stool samples of cattle and hu mans with fasciolosis, using a highly sensitive and specific sandwich enzyme-linked immunosorbent assay (ELISA). The epitope was characteriz ed by periodate oxidation, alkaline borohydride reduction, trichloroac etic acid precipitation beta-mercaptoethanol treatment, and enzymatic proteolysis. These results, together with those of the 2-site ELISA, l ectin immunoassays, and beta-galactosidase digestion, showed that MAb ES78 reacts with a partly protein/partly carbohydrate antigenic determ inant that is found on several ES molecules of adult specimens of F. h epatica and contains at least 1 disulfide bond and beta-galactose prob ably as galactose-beta(1-3)-N-acetylgalactosamine disaccharide.