title: Nonspecific inhibitor of contact sensitivity made by T-acceptor cells: triggering of T cells armed with antigen-specific T-suppressor factor (TsF) requires both occupancy of the major histocompatibility complex recognition site by soluble I-J product and cross-linking of the antigen recognition sites of the TsF.
abstract: The phenomenon of associative recognition, i.e., the recognition of antigen together with major histocompatibility complex products (MHC) was studied in a model system. T-acceptor cells armed with antigen-specific T-suppressor factor (TsF) released a nonspecific inhibitor of the transfer of contact sensitivity when exposed to antigen together with MHC. The MHC product occurred in a KCl extract of cells and behaved genetically and serologically as I-J. Cells armed with anti-picryl or anti-"oxazolone" TsF could be triggered by the corresponding "bis-picryl-L-lysine" and "bis-oxazolone-L-lysine" together with MHC. This suggested that cross-linking of antigen recognition sites on separate molecules of TsF might be required. To investigate this possibility the bifunctional "mixed" hapten "N alpha-picryl-N epsilon-oxazolone-L-lysine," which is univalent with respect to the picryl and oxazolone haptenic groups, was synthesized. This triggered cells armed with a mixture of anti-picryl and anti-oxazolone TsF but not cells armed with either TsF alone. It was concluded that both occupancy of the I-J recognition site and the cross-linking of separate molecules of TsF was required for triggering. Moreover the hapten and the KCl extract could be given sequentially and in either order. This finding suggested that the triggering of the release of nonspecific inhibitor was due to the separate recognition of I-J and antigen and not to new antigenic determinants produced by their interaction.
mesh_terms: D000818:Animals; D002457:Cell Extracts; D003432:Cross-Linking Reagents / Q000494:pharmacology; D003877:Dermatitis, Contact / Q000517:prevention & control*; D000939:Epitopes; D006241:Haptens; D008222:Lymphokines / Q000276:immunology*; D008285:Major Histocompatibility Complex; D051379:Mice; D012995:Solubility; D013491:Suppressor Factors, Immunologic; D013601:T-Lymphocytes / Q000276:immunology*; D014301:Trinitrobenzenes / Q000276:immunology
chemical_list: D002457:Cell Extracts; D003432:Cross-Linking Reagents; D000939:Epitopes; D006241:Haptens; D008222:Lymphokines; D013491:Suppressor Factors, Immunologic; D014301:Trinitrobenzenes