Production and characterization of monoclonal antibodies specific for the murine T cell receptor zeta chain.

The T cell receptor (TCR) comprises an antigen-specific alpha beta heterodimer non-covalently associated with the CD3 gamma delta epsilon and TCR zeta subunits. Both the CD3 and TCR zeta subunits are proposed to be responsible 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 chain comprising the last 29 COOH-terminal residues. Thus, this region of TCR theta may encode an immunodominant epitope. Furthermore, one of these mAbs, G3, is capable of precipitating both non-phosphorylated and tyrosine phosphorylated TCR zeta. The G3 mAb should be useful for elucidating the structural and signalling characteristics of the TCR zeta chain.