Role of normal adherent cells in the regulation of the autologous mixed lymphocyte reactions in humans

The effect of normal adherent suppressor cells on the blastogenesis of human T lymphocytes in the mixed lymphocyte reaction (MLR) was studied in both allogeneic and autologous combinations. Non-T cells and Ia⁺ T lymphocytes were used as stimulator cells in both allogeneic and autologous MLR. The addition of adherent cells to the stimulators inhibited blastogenesis of T lymphocytes in both types of MLR when the stimulator population was made up of non-T lymphocytes but did not interfere with blastogenesis when Ia⁺ T lymphocytes were used as stimulator cells. The present data indicate that the T lymphocytes able to respond to Ia⁺ T cells (in the MLR, autologous or allogeneic) may be different from those which respond to non-T lymphocytes or may be less sensitive to the regulatory function of normal adherent cells.