TMA-specific first-order T-suppressor hybridoma. I. Characterization of the hybridoma-derived single-chain inducer suppressor factor, TsF₁

Experiments described in this report will characterize a monoclonal phenyltrimethylammonium (TMA) specific, first-order T-suppressor factor (TsF₁) produced by a T-cell hybridoma, 8A.3. The hybridoma expressed the Thy-1, Lyt-1, Lyt-2 antigens as well as cross-reactive idiotypic (CRI) determinants but did not express I-J encoded epitopes. It was also found to bear determinants recognized by a monoclonal antibody raised against single-chain GAT-specific TsF₁. The hybridoma-derived factor was capable of suppressing primary in vitro trinitrophenol (TNP)-specific responses induced with the Brucella abortus antigen, conjugated with TMA and TNP haptens (TMA-BA-TNP). In addition, in vivo administration of 8A.3 culture supernatant resulted in the specific suppression of TMA-specific delayed-type hypersensitivity (DTH) responses. Analysis of this factor revealed it to be an induction-phase, antigen-binding, CRI⁺, and I-J⁺ single chain polypeptide. Our results represent only the second such described single chain, antigen binding, I-J⁺ suppressor factor derived from a monoclonal T-cell hybridoma.