Analysis of hapten-specific T suppressor factors: genetic restriction of TsF1 activity analyzed with synthetic hybrid suppressor molecules.
We have analyzed the first-order suppressor factor secreted by an azobenzenearsonate (ABA)-specific T suppressor cell (Ts) hybridoma. Treatment of the factor with 5 mM dithiothreitol (DTT) yields two fragments with distinct phenotypes and functional capabilities. One fragment is bound by a monoclonal anti-I-J antibody, the other is not. Further, although neither molecular fragment by itself is sufficient to suppress an ABA response, a mixture of the two reconstitutes the suppressive activity. The I-J- portion of the first-order suppressor factor (TsF1) presumably guides the antigen specificity; activity of the ABA-specific Ts I-J- TsF1 factor can be reconstituted with an I-J+ subunit of a TsF molecule of either sheep red blood cell (SRBC) or ABA specificity. The genetic restriction for Igh-linked determinants of the ABA/SRBC hybrid TsF molecules is influenced by the I-J+ portion, regardless of the original antigen specificity of that molecule. The data support a two-subunit TsF model. Polyclonal ABA-specific TsF1 molecules appear to resemble the monoclonal factor in structure.
D000818:Animals; D000950:Antigens, Ly / Q000235:genetics; D000939:Epitopes / Q000235:genetics*; D005802:Genes, MHC Class II; D006241:Haptens / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D006825:Hybridomas / Q000032:analysis / Q000276:immunology*; D008222:Lymphokines / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D051379:Mice; D008805:Mice, Inbred A; D008809:Mice, Inbred C3H; D013154:Spleen / Q000166:cytology; D013491:Suppressor Factors, Immunologic; D010132:p-Azobenzenearsonate / Q000276:immunology
D000950:Antigens, Ly; D000939:Epitopes; D006241:Haptens; D000949:Histocompatibility Antigens Class II; D008222:Lymphokines; D013491:Suppressor Factors, Immunologic; D010132:p-Azobenzenearsonate