Specificity and distribution of alpha antigens of Mycobacterium avium-intracellulare, Mycobacterium scrofulaceum, and related species of mycobacteria.

Specificity of antigenic determinants in alpha antigens of Mycobacterium avium, M. intracellulare, M. scrofulaceum, M. gordonae, and M. szulgai was investigated by the agar gel diffusion technique using the respective absorbed antialpha serum on a total of 225 strains classified into 13 species of slowly growing mycobacteria. The specific antigenic determinants in alpha antigen of M. scrofulaceum, M. gordonae, and M. szulgai were species specific, whereas those of M. avium and M. intracellulare were M. avium-M. intracellulare complex specific. Alpha antigens were found to be stable. These results suggest that the absorbed serums of antialpha- M. avium-intracellulare, -M. scrofulaceum, -M. gordonae, and -M. szulgai are useful for serologic identification of these species of slowly growing mycobacteria.