[Antigen proteins specific to mycobacteria].

More than 10 mycobacterial proteins (MPB or MPT) have been isolated from the nutrient fluids after cultivation of Mycobacterium bovis BCG (Japanese substrain) or M. tuberculosis H37Rv on Sauton medium. The genes for 4 antigens, MPB70, MPB64, alpha-antigen (MPB59), and MPB57, were cloned so far and the complete nucleotide and amino acid sequences were determined. MPB70 is a quite unique protein in 3 points; a highly species-specific antigen for M. bovis, a large amount of secretion more than 10% of the total protein amount in the culture fluid when the cells are actively growing, and a composition with hydrophobic amino acids in a high rate. MPB64 was also a unique antigen specific to M. bovis and M. tuberculosis with a strong reactivity in delayed-type hypersensitivity. MPB59, corresponds to alpha-antigen, was a protein of a group of several similar configurations and was commonly found in the mycobacterial species. These 3 antigens are synthesized in the cells binding with each signal peptide which is characteristic of secreted proteins. A heat stable protein, MPB57, a dominant component of PPD, corresponded to BCG-a or 10kD protein and is supposed to be one of the heat shock proteins.