[Evidence for receptors of the specific T-suppressor cells immune to the H-2 antigens, and enrichment of these cells by fractionation on target cell monolayer].

Specific T-suppressor cells induced by an intravenous injection of mice with a large number of gamma-irradiated allogeneic spleen cells are shown to inhibit the DNA synthesis activation and the killer generation in mixed lymphocyte culture (MLC). These suppressors can be removed from the population as a result of their adherence to the macrophage monolayer of the corresponding donor strain, whereas only a small part of specific suppresors gets adherent to the syngeneic macrophage monolayer. Subsequent elution of the lymphocytes adherent to the specific monolayer gives rise to the enrichment of the cell population in specific T-suppressors by a factor of 30 and 2.6, judging by the reduction of lymphocyte number required for 50% inhibition of the DNA synthesis and the killer generation, respectively. The gain in suppressor activity appears to be specific, as it is not observed when either the elution is performed from the syngeneic monolayer, or the third-party stimulator cells are used in the test-MLC. The faint non-specific suppression of the reactions to thirdparty stimulator cells in the test-MCL which intact immune lymphocytes are responsible for, does not decrease after their absorption but almost disappears after their elution from the specific monolayer. The findings are indicative of the existence of antigen-binding receptors on T-suppressors which allow to remove and concentrate specific T-suppressor cells.