Production and Characterization of Monoclonal Antibodies Against the Excretory-secretory Antigen of the Liver Fluke (Opisthorchis Viverrini)

Monoclonal antibodies (MoAb) were produced against a major soluble metabolic product (excretory-secretory, ES) of Opisthorchis viverrini. The latter was obtained in a form of spent culture medium in which the adult flukes had been maintained in vitro. The MoAb produced were exclusively associated with either IgG or IgM isotypes. When screened against a panel of parasite antigens by indirect ELISA, these MoAb exhibited three patterns of reactivity. Approximately 50% of the MoAb were highly specific for O. viverrini and another 25% cross-reacted only with Clonorchis sinensis. The remaining 25% cross-reacted extensively with other parasites. Results from radioimmunoprecipitation and immunoblotting experiments showed all MoAb to react with the 89-kDa glycoprotein. By indirect immunofluorescence, these MoAb reacted almost exclusively with the tegumental surface, tegumental cells, cecum and developing miracidium. Different lines of evidence suggest that these MoAb reacted with different epitopes on the same 89-kDa polypeptide carrier.