Antibody and circulating antigen profiles before and after chemotherapy in goats infected with Fasciola gigantica.

The profiles of antibody response and circulating antigen levels in goats infected with Fasciola gigantica were studied by enzyme-linked immunoelectrotransfer blot (EITB) and enzyme-linked immunosorbent assay (ELISA). In the antibody assay, sera from goats experimentally infected with F. gigantica were reacted with whole worm antigen of the worm before and after chemotherapy with oxyclozanide. In ELISA, there was a significant increase in antibody level 2 weeks after infection. After chemotherapy, there was a gradual decrease in antibody within 3 weeks followed by a rapid decline by the 4th week after treatment. By EITB, the infected goat sera recognized three polypeptides in the range of 42-80 kDa as early as 2 weeks after infection. Recognition of the complete components of F. gigantica antigen repertoire occurred as early as the 4th week after infection. By the 8th week after chemotherapy, distinct polypeptide band recognition was no longer possible. Comparative immunoblotting with goat anti-Paramphistomum, anti-Dicrocoelium and anti-Fasciola sera revealed that the 14 kDa, 17 kDa, 21 kDa, 28 kDa and 30 kDa proteins are specific to F. gigantica. In the antigen assay, circulating antigen was detectable by the direct ELISA method one week after infection and negative absorbance values were observed 4 weeks after chemotherapy.