Idiotype expression and fine specificity of Glu60Ala30Tyr10-specific T proliferating cells

The fine specificity of anti-Glu 60 Ala 30 Tyr 10 (GAT) and anti-Glu 60 Ala 40 (GA) proliferating cells was studied. T cells primed with GAT proliferate both to GAT and GA and GA-primed T cells proliferate also to GA and GAT. This cross-reactivity was unexpected given the results previously reported on the fine specificity of anti-GAT antibodies. The effect on the proliferation of BALB/c lymph node cells (LNC) of a syngeneic anti-idiotypic serum, prepared in BALB/c against anti-GAT antibodies, was studied. Two major points are made in this paper: ( i ) the in vitro addition of the anti-idiotypic serum in cultures containing GAT-primed LNC and GAT enhances the proliferation of GAT-specific T cells; ( ii ) the anti-idiotypic serum is effective in priming in vivo LNC which then acquire the capacity to proliferate specifically with GAT in vitro . These results further confirm the existence of idiotype-like determinants on T cells.