Immunity to leprosy. IV. Murine T-cell proliferative responses to mycobacteria.

The nature of antigens shared between Mycobacterium leprae and other species of mycobacteria has been examined using a murine T-cell proliferation assay. Mice were immunized with different mycobacteria, and lymph node cultures were prepared one week later and challenged with M. leprae antigen. The 13 species of mycobacteria tested as antigens in this assay revealed that several species shared antigens in common with M. leprae as recognized by T-cell responses. C57BL/10J mice and congenic strains exhibit differences in T-cell responsiveness to M. leprae. B10.M and B10.Q mice are high responders and C57BL/10J are low responders, while F1 (C57BL/10J X B10.M) and (C57BL/10J X B10.Q) hybrid progeny are also low responders. These genetic differences were not observed when six other mycobacterial species were used as T-cell antigens. An unexpected finding was that the genetic pattern of T-cell responsiveness to M. marinum was identical to that observed for M. leprae using these strains of mice. Helper T cells may recognize antigenic determinants shared by M. leprae and M. marinum. These antigens may initiate the induction of T-cell responses to these two species of mycobacteria.