Insoluble immune complexes suppress mitogen-induced proliferation of human T lymphocytes bearing Fc gamma receptors.

Human peripheral blood lymphocytes were mixed with erythrocyte-antibody (EA) complexes and separated into EA-rosette forming cell (EA-RFC)-enriched and EA-RFC-depleted suspensions. Thymidine incorporation of EA-RFC-enriched population in the presence of T cell mitogens (PHA, Con A, PWM) was about half of that of EA-RFC-depleted or of unseparated cells. The dose-response curves and kinetics of proliferation were found to be very similar in the three populations. Proliferative response of EA-RFC-enriched lymphocytes was strictly T cell dependent, although non-T cells were later recruited to incorporate thymidine. The interaction of T lymphocytes bearing surface receptors for IgG (T_G) with insoluble complexes followed by a post-binding temperature sensitive event, resulted in the modulation of Fc receptors associated with an impaired proliferative response to PHA, Con A, and PWM, without significant change in metabolic cell activity as shown by cell viability, sponaneous leucine incorporation, or β₂ microglobulin release.