Analysis of perchloric-acid-soluble Mycobacterium bovis Bacille bilié de Calmette-Guerin antigen

The perchloric-acid-soluble Bacille bilie de Calmette-Guerin (BCG) antigen (BCG-P) was investigated for the diagnosis of tuberculosis. Monoclonal antibodies against BCG-P were produced. After SDS-PAGE. silver staining and immunoblotting were done. Pathological specimens of pulmonary tuberculosis. BCG organism itself and atypical mycobactcrium were stained using the indirect immunofluorescent technique with the strongest one among these monoclonal antibodies. Intradermal skin test and ELISA were also done with BCG-P. BCG-P was composed of a major 65-kD protein and a minor 61-kD protein. Fourteen monoclonal antibodies were produced which were all IgM. These antibodies reacted with the 65-kD protein which also showed cross-reactivity with Mycobacterium tuberculosis in pathologic tissues and atypical mycobactcrium. BCG-P did not react with the sera of patients with active pulmonary tuberculosis. However, intradermal skin test with BCG-P showed positive reactions in the patients with a positive purified protein derivative of tuberculin skin test. This antigen could be a good antigen to evaluate the success of BCG vaccination.