SEROLOGICAL SPECIFICITY OF A MONOCLONAL-ANTIBODY TO MYCOPLASMA-CAPRICOLUM STRAIN-F38, THE AGENT OF CONTAGIOUS CAPRINE PLEUROPNEUMONIA

A previously described mouse monoclonal antibody (WM25), directed agai nst the caprine pathogenic mycoplasma strain F38 (Mycoplasma capricolu m subspecies capripneumoniae), was further examined for its diagnostic efficacy in serological tests against various isolates of this group and of each of the five other 'M mycoides cluster' groups (M mycoides subspecies mycoides, small colony (SC) and large colony (LC) biotypes, M mycoides subspecies capri, M capricolum subspecies capricolum and b ovine group 7) and M agalactiae. The methods used were the conventiona l disc-growth inhibition and colony-immunofluorescence techniques. The same strains were also tested against polyclonal rabbit antisera for each mycoplasmal group. With the polyclonal antisera, many cross react ions occurred between members of the different groups. The two F38-pol yclonals gave cross reactions only against various M capricolum subspe cies capricolum and bovine group 7 strains, apart from one of M mycoid es sc in the immunofluorescence test only. The F38 monoclonal antibody gave more specific results, in that only the F38-type strains (M capr icolum subspecies capripneumoniae) and three of the four bovine group 7 strains reacted positively in growth inhibition tests; the only hete rologous reaction by colony immunofluorescence was with one M capricol um subspecies capricolum strain. The F38 monoclonal antibody, WM25, ma y therefore be useful for the specific serological identification of c aprine F38-type isolates by the disc-growth inhibition method, which w ill exclude M agalactiae, M capricolum subspecies capricolum and the o ther members of the 'M mycoides cluster' associated with goats, but no t bovine group 7 (which is not found in goats), which can be excluded by colony immunofluorescence tests.