Comparison of 22 species of Mycobacteria by immunodiffusion against an absorbed reference leprosy serum.

Lithium acetate antigenic extracts of 22 species of acetone-treated mycobacteria were tested by immunodiffusion precipitation for reactivity with a pool of sera from treated lepromatous leprosy patients (ARLS). This ARLS had been adsorbed with M. bovis (BCG, M. vaccae, cardiolipin, and lecithin to make it specific for M. leprae when used in an indirect immunofluorescence test. The ARLS produced two precipitin lines with M. leprae extract, one of which formed a line of identity with extracts of M. lepraemurium and M. bovis (BCG). Aso, recognition without reactions of identity was produced between ARLS and M. flavecens, M. gastri, M. gordonae, and M. nonchromogenicum. The ARLS did not recognize the 15 other species including the human pathogens, M. tuberculosis, M. intracellulare, M. kansasii, M. scrofulaceum, and M. marinum. These data suggest that serologic tests for M. leprae infection might be affected by antibodies to antigens shared by M. leprae and other mycobacteria. The significance of these shared antigens will depend upon the prevalence of human immune responses to mycobacteria containing the shared antigens in any given community.