Dissection of binding vs. recognition functions of H-2 class-I synthetic peptides which are recognized by alloreactive cytotoxic T lymphocytes.

Cytotoxic T lymphocytes (CTLs) cause specific destruction of allografts and viral-infected cells. While viral-restricted CTLs recognize viral peptides in association with class-I molecules encoded in the major histocompatibility complex, the role which peptides play during allorecognition remains obscure. We have shown previously that Ld-specific alloreactive CTLs can recognize the peptide Ld61-80 (or Ld61-85) in association with the dmI class-I molecule. We have now developed an assay, based on inhibition of cytotoxicity, in which we can monitor peptide binding to the dmI molecule in the absence of CTL recognition. In this report we have used this assay to differentiate those amino acids of the peptide Ld61-80 which contribute to class-I binding from those involved with T-cell-receptor (TCR) interactions.