Experimental murine leprosy. IX. Antibodies against Mycobacterium lepraemurium in C3H and C57BL mice with murine leprosy and in patients with lepromatous leprosy.

Sera from C3H and C57BL mice infected with Mycobacterium lepraemurium (MLM) and from human leprosy patients were examined for antibodies against MLM by a crossed immunoelectrophoresis (CIE) technique. Altogether antibodies against six or seven MLM antigens were found in the mouse sera. After a small inoculum of MLM, C3H mice produced more antibodies than C57BL mice. After a large inoculum both strains produced about the same amount of antibodies but showed qualitative differences in their response patterns. A serum pool from patients with lepromatous leprosy contained antibodies against six MLM antigens; five of these were identical with the antigens against which antibodies were found in infected mice. C57BL mice that had lost their delayed-type hypersensitivity to MLM during the course of a disseminated infection showed a fairly strong antibody response to three antigens and a weak response to three others. Since almost the same spectrum of antibodies, although in lower titres, could be demonstrated in C57BL mice with intact delayed-type hypersensitivity to the bacilli, these antibodies did not seem to interfere with the expression of cell-mediated immunity.