Idiotypic receptors for soluble antigens on human T lymphocyte clones.

T lymphoblasts sensitized in vitro to tetanus toxoid (TT) in 6 day cultures, acquire the capacity of stimulating the blastogenic response of "resting" autologous T lymphocytes in primary AMLC reactions. The response of lymphocytes primed against autologous-TT-sensitized-lymphoblasts (ATTSL) seems to be specific for idiotypic receptors for TT, expressed by ATTSL. Evidence to this effect derive from restimulation experiments in which anti-ATTSL primed lymphocytes (PL) were shown to display memory responses only when challenged with ATTSL, and not when exposed to the antigen alone, or to autologous lymphoblasts that had been sensitized to other antigens. Memory responses were induced, however, by allogeneic lymphoblasts primed to TT, even when the latter shared no HLA-DR antigen with the responding anti-ATTSL-PL. This indicated that the recognition of idiotypic receptors for TT is not DR-restricted. By generating T cell clones reacting to PPD and anti-idiotypic T cell clones which respond to anti-PPD sensitized blasts, we have been able to analyze the idiotype-anti-idiotype T cell interreaction at the clonal level. We found that anti-idiotypic T cell clones discriminate between determinants expressed by various autologous anti-PPD clones. Certain idiotypic determinants seem to prevail, however, as they were recognized in concert by the same cluster of anti-idiotypic clones.