Functional characteristics of TG and TnonG cells in a three party MLR.

Human peripheral blood T lymphocytes were separated into highly purified Fc gamma receptor-positive (TG) and negative (TnonG) populations. These subgroups were compared with unseparated T cells for their ability to proliferate in response to concanavalin A or allogeneic cells, and to suppress a mixed leukocyte culture reaction (MLR). TG cells fail to vigorously proliferate in response to Con A or irradiated allogeneic cells. Moreover, the response of TnonG populations to Con A and allogeneic cells is enhanced compared with unseparated T cells, suggesting active suppression by TG cells. The suppressive effects of TG cells was confirmed in a 3-party MLR. In contrast, TnonG cells failed to suppress the MLR. However, Con A-activated TnonG cells did suppress the MLR and were as effective as TG cells.