Charles Hannum

The major histocompatibility complex-restricted antigen receptor on T cells in mouse and man: Identification of constant and variable peptides

The variability of the MHC restricted receptor on murine T cells was examined by comparing tryptic peptide fingerprints of the receptor isolated fom three T cell hybridomas and a T cell tumor. Both variable and constant peptides were seen. Constant peptides were most apparent when comparing receptors from the same mouse strain. Peptide fingerprints of receptors from two independent T cell hybridomas with the same idiotype and specificity were identical. We also describe a molecule detected on the surface of a human T cell leukemia whose properties were identical to those reported for the MHC receptor on normal human T cells. The molecule was a dimer of 85,000-90,000 MW containing a 46,000 MW acidic alpha-chain and an unrelated 40,000 MW neutral beta-chain.

The Murine T Cell Receptor

In the past two years, the major histocompatibility complex (MHC)-restricted receptor for antigen on T cells has been identified by several laboratories through the use of clone-specific antibodies which recognize idiotypic determinants on T cell antigen receptors. Studies with these antibodies, summarized in a recent review (1) have established that the antigen/MHC recognition structures on T cells (a) are idiotypic molecules as indicated by the highly specific nature of their binding to the anti-receptor antibodies; (b) can be functionally inhibited or stimulated through interaction with clone-specific antibodies, suggesting that the specific recognition of antigen and MHC involves a single binding site; (c) are 85–90,000 dalton glycoproteins consisting of two heterodimeric disulfide-linked subunits; and (d) contain variable and constant peptide regions in both the alpha and the beta chains. The biochemical characterization of the receptor with the clone-specific antibodies has since been confirmed and extended by recent reports on the genomic organization of the receptor β chain (2–6).