title: Antigen-specific helper factor reacts with antibody to the T-cell receptor.
abstract: Antigen-specific helper factor (ASHF), a soluble product of T helper (Th) cells, binds antigen and can induce B-cell and cytotoxic T-lymphocyte (CTL) differentiation. Its relationship to the T-cell surface antigen receptor (TcR) is unknown. Both have MHC-restricted recognition of nominal antigen, thus they may share very similar combining sites. Using monoclonal anti-TcR to immunoprecipitate partially purified ASHF, we have obtained evidence for shared determinants between ASHF and the TcR. Antigen affinity-enriched supernatants of a Th clone, LB19, are functionally active in antigen-specific, help-dependent CTL assays. FPLC anion exchange salt fractions of these supernatants were 125I-labelled and immunoprecipitated with KJ16.133 monoclonal anti-TcR coupled to Sepharose 4B. Precipitates were analysed by SDS-PAGE. We have obtained clear evidence that functionally active Th culture supernatants contain molecules specifically precipitable by anti-TcR antibody.
mesh_terms: D000818:Animals; D000937:Antigen-Antibody Reactions; D000939:Epitopes / Q000276:immunology* / Q000302:isolation & purification; D008222:Lymphokines / Q000276:immunology* / Q000302:isolation & purification; D051379:Mice; D008970:Molecular Weight; D051381:Rats; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000032:analysis / Q000276:immunology*
chemical_list: D000939:Epitopes; D008222:Lymphokines; D011948:Receptors, Antigen, T-Cell