Soluble factors in tolerance and contact sensitivity to 2,4-dinitro-fluorobenzene in mice. IX. A monoclonal T cell suppressor molecule is structurally and serologically related to the alpha/beta T cell receptor.
Ts cells from mice tolerized with dinitrobenzene sulfonate produce a DNP-specific, MHC-restricted soluble suppressor factor (SSF) which regulates contact sensitivity to 2,4-dinitro-fluorobenzene. Previous studies have shown that the SSF-producing T cells and the soluble factor have the same hapten/MHC specificity suggesting that SSF may represent a secreted form of the Ts membrane receptor. The relationship between TCR proteins and SSF was investigated by examining the structural and serologic properties of a monoclonal DNP/H-2Kd-specific suppressor molecule produced by a Ts hybridoma. Reduction followed by alkylation abrogated the ability of the 3-10 molecule to inhibit transfer of contact sensitivity to 2,4-dinitro-fluorobenzene, indicating that intact disulfide bonds were a required structural property for suppression. Reduction of the 3-10 molecule followed by affinity chromatography on DNP-coupled Sepharose beads indicated that the 3-10 suppressor molecule is a dimer and that one of its chains binds to cell-free DNP. Serologic properties of the 3-10 molecule were examined by determining the ability of pan-reactive rabbit anti-TCR antibodies and anti-V beta 8 mAb KJ16.133 and F23.1 to adsorb suppressor activity from 3-10 culture supernatant and affinity purified 3-10 ascites material. All three reagents adsorbed the suppressor activity whereas control antibodies had no effect. When 3-10 material was passed through a F23.1-conjugated Sepharose affinity column, suppressor activity was recovered in the column eluate but not in the effluent fraction. When the 3-10 molecule was reduced and separated into its two chains (i.e., DNP-binding and non-DNP-binding chains), it was found that the anti-V beta 8 antibody F23.1-bound to the non-DNP-binding chain of the suppressor molecule. Collectively, these results indicate that the monoclonal 3-10 suppressor molecule is structurally similar to the alpha/beta TCR and suggest that the 3-10 molecule expresses a determinant encoded by the V beta 8 family of TCR genes. These results are consistent with our hypothesis that these suppressor molecules represent a secreted form of the TCR expressed on the surface of the DNP-specific Ts.
Fairchild
R L
RL
Department of Microbiology/Immunology, University of Colorado School of Medicine, Denver 80262.
Kubo
R T
RT
Moorhead
J W
JW
D000818:Animals; D001666:Binding Sites, Antibody; D003877:Dermatitis, Contact / Q000276:immunology*; D004139:Dinitrofluorobenzene; D004220:Disulfides; D000939:Epitopes / Q000276:immunology; D007108:Immune Tolerance; D051379:Mice; D008807:Mice, Inbred BALB C; D009578:Nitrobenzenes; D011487:Protein Conformation; D011948:Receptors, Antigen, T-Cell / Q000032:analysis / Q000276:immunology; D013329:Structure-Activity Relationship; D013491:Suppressor Factors, Immunologic / Q000032:analysis / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000032:analysis*
D004220:Disulfides; D000939:Epitopes; D009578:Nitrobenzenes; D011948:Receptors, Antigen, T-Cell; D013491:Suppressor Factors, Immunologic; D004139:Dinitrofluorobenzene