Crossreactivity between Mycobacterium leprae and various actinomycetes and related organisms.

Serological crossreactivity was analyzed between M. leprae and strains of various species of Corynebacterium, Mycobacterium, Nocardia, Rhodococcus, Streptomyces, and related organisms. M. leprae shares antigens with most of these organisms, and sera from patients with lepromatous leprosy contain antibodies against them. The results demonstrate that M. leprae shares more antigens with the mycobacteria than with strains of the other tested genera, thus supporting the view that the leprosy organism belongs to the genus Mycobacterium. One precipitinogen (designated p beta) was found to be common to M. leprae and the streptomycetes, and sera from patients with lepromatous leprosy contain antibodies against this antigen.