The subset of T lymphocytes mediating delayed-type hypersensitivity in the rat.

Populations enriched in each of the major rat T-cell subsets recognized by mouse monoclonal antibodies were prepared from thoracic-duct lymphocytes by affinity chromatography. Such enriched populations obtained from donor rats immunized with BCG were tested for their capacity to mediate delayed-type hypersensitivity (DTH) against purified protein derivative by adoptive transfer to recipient rats. The mediator activity was found in the populations enriched in T cells recognized by the monoclonal antibody W3/25. Thus, the results formally demonstrate that mediating DTH is another function of W3/25-positive T lymphocytes. In addition, the studies show that affinity chromatography is an effective method for preparing bulk quantities of functional lymphocyte populations enriched in the major rat T-cell subsets.