Identification and purification of Cooperia oncophora-specific antigens to improve serological diagnosis

Cooperia oncophora total adult extracts were examined by Western blotting with sera from C. oncophora- and O. ostertagi-infected calves to determine species-specific antigens. It was shown that two antigens with apparent molecular weights of 14.2 and 14.9 kDa were only recognized by calves which received a Cooperia infection and not by Ostertagia mono-infected calves or parasite-naive animals. The partial purification of these two antigens was achieved by gel filtration and ion-exchange chromatography. An enzyme-linked immunosorbent assay (ELISA) was developed based on the fractions containing these two antigens and no cross-reactivity could be noticed with serum from Ostertagia mono-infected calves. In contrast, the ELISA with total worm extracts showed strong cross-reactivity with heterologous serum. It was concluded that the 14.2 and 14.9 kDa Cooperia adult antigens have diagnostic potential, at least to differentiate C. oncophora and O. ostertagi.