Monoclonal antibody analysis of responder and stimulator cells in the human autologous mixed lymphocyte reaction

Responder and stimulator cell subpopulations in the autologous mixed lymphocyte reaction (AMLR) were determined with the OK series of monoclonal antibodies. Mitomycin-C-treated, monocyte-enriched cell populations were used as stimulator cells in the AMLR. Treatment of these monocytes with either OKM and/or OKI monoclonal antibodies and complement resulted in a marked loss of ability of these cells to act as stimulators in the AMLR. Removal of OKT3+ and OKT4+ cells diminished the proliferative responses of AMLR cultures. Interaction of T cells with autologous monocytes resulted in generation of cells capable of suppressing both MLR and AMLR cultures. The suppressor activity of these cells was diminished by treatment with OKI , OKT4 or OKT8 monoclonal antibodies. No cytotoxic activity to autologous or allogeneic monocytes was observed. Additional studies showed an increased number of OKT9 + and OKI + as well as OKT8+ T cells in the AMLR responder cell population. This study indicates that cultures of T lymphocytes with autologous monocytes yield T cell subset(s) which suppress MLR and AMLR reactivity.