The interaction of antigenic peptides with the H-2Kd MHC class I molecule

Abstract An important event in the recognition of antigen by T cells is the selective interaction of peptides with major histocompatibility complex (MHC) molecules. We have defined several critical structural features that promote the efficient interaction of antigenic peptides with the MHC class I molecule, H-2K d . For four unrelated antigens, we found that optimal synthetic peptides were short, only 9 or 10 amino acids long. These and other H-2K d -restricted peptides were found to share a distinct 2-residue binding motif. Two regions in the H-2K d antigen binding site that might accommodate the motif residues were identified by analysis of Ala-substituted H-2K d molecules. A molecular model showing the possible interaction of one antigenic peptide with the H-2K d molecule is presented.