EXPRESSION OF IA ANTIGENS ON IMMUNOCOMPETENT CELLS IN GUINEA-PIG .1. DIFFERENTIAL EXPRESSION OF IA ANTIGENS ON T-CELL SUBPOPULATIONS

Abstract

The effect of negative selection with anti-Ia [immune response-associated] antigen serum and C [complement] serum and C on a number of T [thymus-derived] cell functions was examined; 2 subpopulations of guinea pig T lymphocytes were defined. One subpopulation is susceptible to the lytic effects of anti-Ia serum and C, and includes the majority of the primed T cells which proliferate and which produce migration inhibition factor in response to specific antigen stimulation in vitro. The lytic effects of anti-Ia serum were directed against the antigen-specific T cell and not an accessory cell such as a macrophage or nonantigen-specific T cell. No evidence for allelic exclusion of the Ia antigens of the antigen-responsive cell could be demonstrated. The susceptiblity of the mitogen-responsive T cell to lysis by anti-Ia serum and C varied with the mitogen used, anatomic origin of the T cell and the strain of animals studied. A 2nd subpopulation of T cells is completely resistant to the lytic effects of anti-Ia serum and C, and includes the primed T helper cell and the T cell that proliferates in response to alloantigenic stimulation in the MLR [mixed lymphocyte reaction].