Monoclonal antibody analysis of human T lymphocyte subpopulations exhibiting autologous mixed lymphocyte reaction.

Abstract

In autologous mixed lymphocyte reaction (MLR), T cells proliferate in response to the stimulation by autologous non-T cells. Human T cell subpopulations, defined by murine monoclonal antibodies OKT4, OKT8 or 9.3, were examined for their capacity to proliferate in autologous and allogeneic MLR. Treatment of responder T cells with OKT4 or 9.3 antibody (both defining helper/inducer T cells) and complement (C'') ablated their proliferative response in autologous MLR and markedly reduced their allogeneic MLR proliferative response. Treatment of T cells with OKT8 antibody (defining suppressor/cytotoxic T cells) and C'' had no or minimal effect on their proliferative response in autologous MLR. OKT4, 9.3, 9.6 (PAN) or 7.2 anti-human Ia (framework specific) but not OKT8 antibody, when present during the entire culture period, in the absence of C'' inhibited in a dose-dependent manner the proliferative response in both autologous and allogeneic MLR. Inhibition of proliferation was also observed when the responder T cells were pretreated with OKT4 or 9.3 antibody, washed and then stimulated with irradiated autologous or allogeneic non-T cells. Pretreatment of T cells with OKT8 or 7.2 anti-Ia antibody in the absence of C'' did not influence their proliferative response in autologous MLR. Thus, T cells containing cells with helper/inducer activity defined by OKT4 or 9.3 antibody appear to be the major responder T-cell subpopulation in autologous MLR.