Immunity to leprosy. 1. The proliferative response of murine T lymphocytes to Mycobacterium leprae.

A microculture assay is described for measuring the response of murine T lymphocytes to Mycobacterium leprae antigens. Mice were immunized with M. leprae in Freund's incomplete adjuvant at the base of the tail, and after five days lymphocytes from draining lymph nodes were harvested and cultured with M. leprae antigens. Radioactive thymidine uptake was used to quantitate the antigen-induced proliferation of the lymphocytes. The effects of cell density and antigen concentration on the kinetics of the proliferative response were determined. We present evidence that it is the T lymphocytes that proliferate in response to antigen in microcultures, and that the lymphocyte response varies with the mouse strain used. This assay system can be used to identify the antigens of M. leprae that elicit T cell responses and the effector function of the M. leprae-specific T cell involved.