Antigen-Specific T Cell-Mediated Suppression

Abstract

Previous studies demonstrated that nonresponder (DBA/1)-derived suppressor factor specific for the random copolymer L-glutamic acid⁶⁰-L-alanine³⁰-L-tyrosine¹⁰ (GAT-T_sF) failed to suppress responder strain mice when administred at the same time as antigen (GAT) challenge. The present study demonstrates that if responder (BALB/c or A/J) spleen cells are preincubated with nonresponder GAT-T_sF for 2 days in vitro, suppressor T cells (T_s2) are induced that can suppress syngeneic GAT plaque-forming cell responses in vivo or in vitro. This finding is in accord with T_s2 induction in nonresponder mice with the same GAT-T_sF. Further, administration of nonresponder GAT-T_sF to responder mice 7 days before in vivo antigen challenge suppressed subsequent GAT-PFC responses in these mice. Finally, the T_s2 induced in the same strain of mice (BALB/c) by GAT-T_sF and by L-glutamic acid⁵⁰-L-tyrosine⁵⁰ (GT)-specific T_sF were shown to be able to suppress only the response to the inducing antigen, demonstrating the fine specificity of these T_s2. The implications of this demonstration of nonresponder T_sF activity in responder mice for an antigen under strict Ir gene control are discussed.