J. Biol. Chem., Vol. 265, Issue 15, 8842-8846, 05, 1990
Amino acid substitutions in the first complementarity-determining region of a murine T-cell receptor alpha chain affect antigen-major histocompatibility complex recognition
EA Nalefski, JG Wong and A Rao
Division of Tumor Virology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115.
The T-cell antigen receptor mediates recognition of foreign antigens
physically associated with major histocompatibility complex (MHC) proteins.
The tertiary structure of the T-cell receptor is thought to resemble that
of immunoglobulin Fab fragments and to possess corresponding
complementarity-determining regions (CDRs) that contact antigen-MHC. To
test such a model for the T-cell receptor, we have generated T-cell
hybridomas that express a wild-type or mutant form of the T-cell receptor
present on the p-azobenzenearsonate-specific T-cell clone D5. Mutation of 2
amino acids (Tyr26 to serine, Gly28 to valine) in the predicted CDR1 of the
D5 T-cell receptor alpha chain caused a markedly diminished response to
antigen without affecting the response to anti-CD3 and anti-T-cell receptor
antibodies. These results constitute the first test of the prediction that
CDR1 in the T-cell receptor alpha chain is important for antigen-MHC
recognition, thus providing strong evidence for the structural model of the
T-cell antigen receptor based upon immunoglobulin.