Production and characterization of a monoclonal antibody against 28.5 kDa tegument antigen of Fasciola gigantica.

A monoclonal antibody (MoAb) against the 28.5 kDa tegumental antigen of Fasciola gigantica was produced by the hybridoma technique using spleen cells from BALB/c mice immunized with the tegumental extract from adult F. gigantica. This MoAb was found to be of the isotype IgG(1), kappa-light chain, and shown by immunoblotting to specifically react with the 28.5 kDa antigen present in the tegument, excretion-secretion material of the adult, whole-body extracts of newly excysted juveniles, 5-week-old juvenile and adult parasites. It did not cross-react with antigens from other trematode parasites, including Schistosoma mansoni, Eurytrema pancreaticum and Paramphistomum spp. Immunolocalization of this antigen by indirect immunofluorescence indicated that it was present as a major component of the adult tegument, particularly in its outer rim, tegumental cells, and their processes. Furthermore, the epithelium linings of the oral sucker, buccal tube, pharynx, caecal bifurcation, both male and female genital canals, which were the continuation of the tegumental-type epithelium, were also positively stained with this MoAb. A similar pattern of immunolocalization, but with weaker staining intensity, was observed in newly excysted, 5- and 7-week-old juveniles. Thus this antigen is expressed in all developmental stages of the parasite, and it could be a strong candidate for immunodiagnosis and vaccine development.