PRODUCTION AND CHARACTERIZATION OF MONOCLONAL-ANTIBODIES SPECIFIC FORTHE MURINE T-CELL RECEPTOR ZETA-CHAIN

The T cell receptor (TCR) comprises an antigen-specific cup heterodime r non-covalently associated with the CD3 gamma delta epsilon and TCR z eta subunits. Both the CD3 and TCR zeta subunits are proposed to be re sponsible for the intracellular signal-transduction events. We report here the production of eight monoclonal antibodies (mAbs) that bind in an ELISA assay to a 113 amino acid synthetic peptide corresponding to the cytoplasmic domain of TCR zeta. Western blot analysis of anti-CD8 precipitates of lysates of transfectants expressing chimeric CD8/zeta constructs encoding increasing COOH-terminal truncations of TCR zeta indicates that four of these mAbs recognized the region of TCR zeta ch ain comprising the last 29 COOH-terminal residues. Thus, this region o f TCR zeta may encode an immunodominant epitope. Furthermore, one of t hese mAbs, G3, is capable of precipitating both non-phosphorylated and tyrosine phosphorylated TCR zeta. The G3 mAb should be useful for elu cidiating the structural and signalling characteristics of the TCR zet a chain.