Antigen- and receptor-driven regulatory mechanisms. VII. H-2-restricted anti-idiotypic suppressor factor from efferent suppressor T cells.

Abstract

Azobenzenearsonate (ABA)-specific [murine] T cell-derived suppressor factor (TsF1) from A/J mice was used to induce 2nd-order suppressor T cells (Ts2). Comparison of suppressor T cells induced by antigen (Ts1), with Ts2 induced by TsF1, revealed that Ts1 were afferent suppressor active only when given at the antigen priming timing and not thereafter; Ts2 however, could act when transferred at any time up to 1 day before antigen challenge for a delayed-type hypersensitivity response. This was true even when the recipient could be shown to be fully immune before Ts2 transfer, thus defining these cells as efferent suppressors. The anti-idiotypic specificity of the Ts2 was demonstrated by the ability of Ts2 to bind to idiotype (cross-reactive idiotype [CRI])-coated Petri dishes. A soluble extract from Ts2 (TsF2) was also capable of mediating efferent suppression that was functionally antigen- (ABA) specific. Comparison of TsF1 with this new factor, TsF2, revealed that both lack Ig-constant-region determinants, possess H-2-coded determinants, and show specific binding (to ABA and to CRI+-Ig, respectively). TsF1 acts in strains that differ with respect to H-2 and background genes, whereas TsF2 shows H-2- and non-H-2-linked genetic restrictions. This existence of H-2 restriction of TsF2 activity suggests that the apparent discrepancies in studies on H-2 restriction of TsF may be a result of the analysis of 2 separate classes of TsF, only 1 of which shows genetically restricted activity; thus this unifies several suppressor cell activity models.