Cellular interactions in the human T-T autologous mixed lymphocyte reaction

Human peripheral blood T cells and T cell subsets were studied for the proliferative response in the autologous mixed lymphocyte reaction (AMLR) upon stimulation with mitogen- or AMLR-activated T cells and T cell subsets. T cells exhibited a vigorous proliferative response when stimulated with autologous activated T cells but not with unactivated T cells. The stimulatory capacity of activated T cells in the T-T AMLR was inhibited by prior treatment with 7.2 anti-DR monoclonal antibody in the absence of complement A BUdR and light experiment clearly demonstrated that T cells responding to activated T cells in the AMLR were distinct from those responding in allogeneic MLR. Further analysis with OKT4+ and OKT8+ T cell subsets demonstrated that OKT8+ T cells were the major responder upon stimulation with PHA-activated T cells. In contrast, OKT4+ T cells were the major responder in the T-T AMLR, when AMLR-activated T-cells were used as stimulators. T cells activated in T-T AMLR (PHA-activated T cells as stimulators) demonstrated suppressor activity against the proliferative response of autologous responder T cells. This study demonstrates that distinct subsets of T cells respond in the T-T AMLR and express suppressor activity.