Autologous mixed lymphocyte reaction in man. III. Regulation of autologous MLR by theophylline-resistant and -sensitive human T-lymphocyte subpopulations.

Abstract

Human peripheral blood T lymphocytes were separated into theophylline-resistant (TR) and -sensitive (TS) subpopulations. Proliferative responses TR, TS and unfractionated T cells were studied, using irradiated autologous or allogeneic non-T cells as stimulators. TR cells proliferated vigorously in both autologous and allogeneic mixed lymphocyte cultures (MLC). TS cells. which constitute about 20% of unfractionated T cells, exhibited poor proliferative responses to autologous and allogeneic stimulation. The magnitude of proliferation in autologous and in allogeneic MLC was found to be directly dependent on the number of TR cells in the culture. Mitomycin-C (MMC)-treated TR cells augmented and MMC-treated TS cells suppressed (P less than 0.05) the autologous and allogeneic MLC responses of unfractionated T cells. However, the response of TS cells did not increase in autologous or allogeneic MLC when co-cultured with MMC-treated TR cells. MMC-treated TS cells, when co-cultured with TR cells, suppressed the responses of TR cells (P less than 0.05). The enhancing effect of TR cells was radiation-resistant. Suppressor influence of TS cells, in contrast, was abolished by irradiation (P less than 0.05). These findings demonstrate that TR cells are the responding cell in autologous MLR and augment the MLC responses of unfractionated T cells. TS cells, on the other hand, respond poorly in autologous or allogeneic MLC and suppress the response of TR cells.