Monoclonal antibodies against Opisthorchis viverrini antigens

Monoclonal antibodies (MoAb) were produced against somatic antigens of adult human liver fluke Opisthorchis viverrini. Earlier studies attached diagnostic potential to an 89-90 kD antigen present in both somatic extracts and in vitro culture supernatants as well as to the abundant 16-17 kD tegumental protein doublet. Mice made excellent immune responses to low dose somatic extract adsorbed onto nitrocellulose or to the 80-95 kD region of SDS gel Western blots. The antigen specificities of hybridomas reactive with somatic antigen by ELISA were determined by radioimmunoprecipitation or immunoblotting. Six MoAb reacted with the desired 16 kD tegumental protein. A 90 kD somatic protein was identified by 9 clones. By indirect immunofluorescence, monoclonals reactive with the 16 kD polypeptide identified the outermost surface of the tegument. The 90 kD antigen was associated with all major muscle systems, most strikingly the crossed subtegumental layers, oral and ventral suckers, pharynx and a thin layer surrounding caeca. The biochemical identity of this muscle-associated antigen is unknown, but it is clearly distinct from the previously identified species-specific 89 kD exoantigen. The 16 kD tegumental protein shares epitopes with a number of related flukes. However, 2 MoAb which react with this protein show no crossreaction.