A T helper cell hybridoma produces an antigen-specific regulatory activity. Relationship to the T cell receptor by serology and antigenic fine specificity.
We have previously shown that a T cell hybridoma, A1.1, constitutively produces an Ag-specific regulatory factor with specificity for poly-18, a synthetic polypeptide. This cell also responds to poly-18 plus I-Ad by producing lymphokines. The antigenic specificity of the factor and the T cell appeared to be the same. This suggested the possibility that some part of the TCR, responsible for antigenic specificity of the cell, also imparts specificity to the A1.1-derived factor. This was supported by the observation that the factor was bound and eluted from a monospecific anti-TCR antiserum. Further, we demonstrated that antisense oligodeoxynucleotides corresponding to the TCR V alpha of A1.1 (but not TCR V beta) block production of the Ag-specific factor. Herein, we report recent findings that strengthen the proposed relationship between the TCR and the A1.1-derived factor. The factor was bound and eluted from a monoclonal anti-TCR C alpha antibody, but not from anti-TCR beta, anti-V beta 6, nor anti-CD3 epsilon. The anti-TCR C alpha antibody bound a Mr 46-kDa protein from A1.1 supernatants, which is the same apparent size at which activity could be eluted from an SDS-PAGE gel separation of concentrated factor. Antigenic fine-specificity analysis revealed that two amino acids in poly-18 are critical for the recognition of the antigen by the Ag-specific factor. These two amino acids appear to be those recognized by the TCR. The factor that was bound and eluted from the monoclonal anti-TCR C alpha showed this fine-specificity as well. This, combined with our earlier studies, supports the view that the A1.1-derived factor is encoded, at least in part, by TCR-alpha.
Bissonnette
R
R
Department of Immunology, University of Alberta, Edmonton, Canada.
Zheng
H G
HG
Kubo
R T
RT
Singh
B
B
Green
D R
DR
D000595:Amino Acid Sequence; D000818:Animals; D000917:Antibody Formation; D002846:Chromatography, Affinity; D000939:Epitopes; D006825:Hybridomas; D066298:In Vitro Techniques; D051379:Mice; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D016693:Receptors, Antigen, T-Cell, alpha-beta; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
D000939:Epitopes; D010455:Peptides; D011948:Receptors, Antigen, T-Cell; D016693:Receptors, Antigen, T-Cell, alpha-beta