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

The T cell receptor (TCR) comprises an antigen-specific αβ heterodimer non-covalently associated with the CD3 γδε{lunate} and TCR ζ subunits. Both the CD3 and TCR ζ 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 ζ. Western blot analysis of anti-CD8 precipitates of lysates of transfectants expressing chimeric CD8/ζ constructs encoding increasing COOH-terminal truncations of TCR ζ indicates that four of these mAbs recognized the region of TCR ζ chain comprising the last 29 COOH-terminal residues. Thus, this region of TCR ζ may encode an immunodominant epitope. Furthermore, one of these mAbs, G3, is capable of precipitating both non-phosphorylated and tyrosine phosphorylated TCR ζ. The G3 mAb should be useful for elucidiating the structural and signalling characteristics of the TCR ζ chain.