PEPTIDE SPECIFICITY IN THE RECOGNITION OF MHC CLASS-I BY NATURAL-KILLER-CELL CLONES

Recognition by natural killer (NK) cells of major histocompatibility c omplex (MHC) class I molecules on target cells inhibits NK-mediated ly sis. Here, inhibition of NK clones by HLA-B2705 molecules mutated at single amino acids in the peptide binding site varied among HLA-B2705 -specific NK clones. In addition, a subset of such NK clones was inhib ited by only one of several self peptides loaded onto HLA-B2705 molec ules expressed in peptide transporter-deficient cells, showing that re cognition was peptide-specific. These data demonstrate that specific s elf peptides, complexed with MHC class I, provide protection from NK-m ediated lysis.