Comparative immunodiagnostic approach of toxocariasis in buffalo calves.

ABSTRACT

Five Toxocara vitulorum antigens were utilized to diagnose natural toxocariasis in buffalo calves by ELISA. Adult antigen was proved to be the most potent one. The second potent antigen was egg antigen followed by excretory secretory antigen of male worms then female worms. The coproantigen was the least potent one. The electrophoretic make-up of the antigens, examined by SDS-PAGE, revealed different patterns of separation. Common as well as specific component(s) to each antigen were identified. Employing naturally infected buffalo calf sera in immunoblot assay, five immunogenic components were detected in adult antigen of molecular weight 191 KD, 166 KD, 102 KD, 65 KD and 54 KD. The reactive polypeptides in egg antigen were 191 KD, 105 KD, 99 KD and 79 KD. In coproantigen, six bands were identified. These components were of molecular weight 191 KD, 178 KD, 166 KD, 124 KD, 96 KD and 65 KD. Five components of molecular weight 191 KD, 166 KD, 102 KD, 96 KD and 65 KD were immunogenic in excretory/secretory antigen of male worms. Only four polypeptide of 191 KD, 166 KD, 102 KD and 66 KD were identified in excretory/secretory female antigen. Of interest is the immunogenic component of 54 KD expressed only by adult extract in immunoblot assay. This component could be responsible for the immunodiagnostic advantage of adult worm antigen and it deserves further studies to evaluate its diagnostic value.