SPECIFIC BINDING OF ANTIGENIC PEPTIDES TO CELL-ASSOCIATED MHC CLASS-I MOLECULES

T LYMPHOCYTES recognize antigen in the form of peptides that associate with specific alleles of class I or class II major histocompatibility (MHC) molecules 1,2. By contrast with the clear MHC allele-specific binding of peptides to purified class II molecules 3-6 purified solubilized class I molecules either bind relatively poorly 7 or show degenerate specificity 8-11. Using photoaffinity labelling, we demonstrate here the specific interaction of peptides with cell-associated MHC class I molecules and show that this involves metabolically active processes.