Suppression of the mixed lymphocyte reaction by alloantigen-primed and -stimulated human spleen lymphocytes.

This communication examines the ability of T cell-enriched preparations from human spleen to suppress lymphocyte proliferation following activation in the mixed lymphocyte reaction (MLR). To enable the generation of a subsequent responding MLR between identical partners to those employed in the initial (stimulating) MLR, spleen T cells were frozen at the time of the first culture. Spleen T cells, stimulated in this way, showed a marked ability to suppress human MLR responses, but HLA-D identity was required for the full expression of suppressor activity. The characteristics of the spleen MLR-induced suppressor T cell resemble closely those described for MLR-generated suppressor T cells in human peripheral blood.