Specificity and distribution of alpha antigens of Mycobacterium kansasii and Mycobacterium marinum.

Specificity of antigenic determinants in alpha antigens of Mycobacterium kansasii and Mycobacterium marinum was investigated in 170 strains classified into 16 species of slowly growing mycobacteria by the agar gel diffusion technique using the respective absorbed anti-alpha serum. The specific antigenic determinants in alpha antigen of M. kansasii were detected in all of the 20 strains classified as M. kansasii, and not in strains belonging to other species. The specific antigenic determinants in alpha antigen of M. marinum were only detected in all of the 13 strains classified as M. marinum. These results suggest that the absorbed anti-alpha-M. kansasii and -M. marinum serums are useful for serologic identification of these species of slowly growing mycobacteria.