Delayed-type hypersensitivity to allogeneic mouse epidermal cell antigens. III. Analysis of suppressor cells

The specificity of suppressor T cells (Ts cells) induced by intravenous administration of allogeneic spleen cells was studied in mice using a delayed-type hypersensitivity (DTH) assay. The DTH responses were induced by subcutaneous injection of allogeneic epidermal cells (ECs) and were assayed by footpad swelling. Afferent-phase Ts cells (Ts-aff cells) were transferred into the recipient mice before ECs immunization. Treatment with monoclonal anti-Thy-1.2 antibody and complement abolished the suppression by Ts-aff cells in the DTH response. The suppression induced by Ts-aff cells, however, was resistant to the treatment with monoclonal anti-I-A or anti-Lyt-2.2 antibody and complement. These results showed that Ts-aff cells were Lyt-2-, Ia- T cells. Efferent-phase Ts cells (Ts-eff cells) were transferred before challenge of the DTH assay. Phenotypic analysis of these Ts-eff cells showed them to be Lyt-2+, Ia- T cells. Studies using several strains of congenic mice revealed the antigen specificity of both Ts cell subsets. Adoptive transfer of Ts-eff cells required H-2 restriction, but Ts-aff cells did not. We also induced cognate suppression of the DTH responses to the alloantigens mediated by Ts-eff cells.