Identification and preliminary purification of a protein antigen apparently specific to mycobacterium kansasii

A highly anodal protein antigen of molecular weight approximately 10,000 daltons has been identified in culture filtrates of Mycobacterium kansasii and not in culture filtrates of 9 other mycobacterial species. Using immunoabsorbent affinity chromatography, this antigen has been purified and used to skin test guinea pigs sensitized with Mycobacterium kansasii and Mycobacterium tuberculosis. In these animals it was found to be tuberculin active and to have partial species specificity.