Immunodiffusion analyses of some diphtheroid organisms isolated from patients with leprosy.

Eight strains of diphtheroid bacteria isolated from patients with leprosy were analyzed by immunodiffusion, using precipitation systems representing various species of Corynebacterium, Mycobacterium, Nocardia, Rhodococcus, and related organisms. The analyses showed that six of the eight strains shared several antigens with representatives of these four genera. The largest number of shared precipitinogens was revealed when the corynebacterial precipitation systems were used, thus indicating that these organisms either belong to, or are closely related to the genus Corynebacterium. This assumption was further supported by the fact that the ribosomal precipitinogen beta--earlier demonstrated in mycobacteria but not in corynebacteria--was not found in the diphtheroid strains. Other ribosomal antigens were, however, revealed to be common to the diphtheroid organisms and mycobacteria. Further, the reaction between sera from patients with lepromatous leprosy and the diphtheroid strains was analyzed, very few and faint precipitates being demonstrated. It is concluded that the presence of anti-beta antibodies in leprosy sera is, most likely, not a result of the presence of diphtheroid organisms in the patients.