Characterization of prominent protein antigens from mycobacteria.

Detailed analysis of mycobacterial proteins originally identified by their prominent interaction with the host immune system reveals a number of interesting biochemical characteristics. M. tuberculosis antigens with molecular weights of 71, 65 and 12 kilodaltons (kD) belong to highly conserved heat shock protein families. A group of closely related antigens with molecular weights around 30 kD are major secreted antigens which share the ability to bind to fibronectin. Antigens with molecular weights of 38 kD and 19 kD are probably lipoproteins with a role in nutrient transport, while the 23 kD antigen is the superoxide dismutase enzyme of M. tuberculosis. It is anticipated that further studies along these lines will generate information of importance to the understanding of the lifestyle of mycobacteria in vivo and also to the elucidation of immune mechanisms in mycobacterial disease.