Conformational changes in MHC class I moleculesAntibody, T-cell receptor, and NK cell recognition in an HLA-B7 model system

In this article we review the role of MHC conformation, including peptide-induced MHC conformation, in forming antibody (Ab), T-cell receptor (TCR), and natural killer (NK) cell receptor epitopes. Abs recognize conformational major histocompatibility (MHC) epitopes that often are influenced by the identity of MHC-bound peptide. Diverse TCRs recognize a common docking site on peptide/MHC complexes and directly contact peptide. Human NK cell inhibitory receptors (KIR) appear to recognize limited regions of the HLA α1 helix. DX9+ KIR specifically focus on HLA-B residues 82 and 83. However, NK cells recognize much broader regions of HLA class I molecules and are sensitive to bound peptides. Thus, several classes of lymphocyte receptors are peptidespecific. Peptide specificity could be the result of direct contact with the receptor, or to conformational shifts in MHC residues that interact with both receptor and bound peptide.