The identification of antigenic determinants on Mycobacterium bovis using monoclonal antibodies.

Murine hybridomas secreting monoclonal antibodies to Mycobacterium bovis were produced and three soluble antigens were identified using radioimmunoassays and immunoblotting from polyacrylamide electrophoresis gels. Antibody MB3 (IgM, k chain) reacted with 20-100 kDal antigens produced by all mycobacterial strains examined while antibody MB5 (IgG2a, k chain) identified a 29.8 kDal antigen detected in field isolates of M. bovis and M. bovis strains Vallée and AN5. There was insignificant binding to M. bovis BCG, M. tuberculosis, M. microti, M. africanum, M. avium or M. paratuberculosis. Monoclonal antibody MB17 (IgA, k chain) reacted with a 17.4 kDal antigen present in M. bovis, M. tuberculosis and M. microti. Absorption of monoclonal antibodies with antigens from different species of Mycobacterium confirmed the specificities of MB3 and MB5 but the binding of MB17 was inhibited to some extent by all the extracts examined. The antigen identified by MB3 was present in purified protein derivative (PPD) from M. bovis, M. paratuberculosis and M. avium but antigens identified by MB5 and MB17 were not detected in these reagents.