CHARACTERIZATION OF THE ANTIGEN-85 COMPLEX FIBRONECTIN-BINDING PROTEINS DERIVED FROM AGED CULTURE FILTRATES OF MYCOBACTERIUM-BOVIS BCG, TICE(R) SUBSTRAIN

The antigen 85 complex are major T-cell and B-cell antigens and fibron ectin-binding proteins secreted by Mycobacterium tuberculosis, M. lepr ae and attenuated M. bovis (BCG vaccine). The Ag 85 complex was found to comprise a high proportion of the extracellular protein in filtrate s of surface-pellicle cultures of Tice(R)-substrain BCG vaccine, attai ning a maximum of 25%. This proportion began to decrease prior to the end of the logarithmic growth phase, about 3 weeks after the start of the culture, mainly due to apparent degradation of the Ag 85 complex. Isolation of the main Ag 85 protein and determination of the first 36 residues of the NH2-terminus showed identity with the 85A protein isol ated by others from various mycobacteria. Both the Ag 85A and B compon ents were secreted in nearly constant proportions over a 6-week period . No Ag 85C protein was detected.