title: Presentation of antigenic peptides by products of the major histocompatibility complex.
abstract: Molecules encoded by the major histocompatibility complex (MHC) are polymorphic integral membrane proteins adapted to the presentation of peptide fragments of foreign antigens to antigen-specific T-cells. The diversity of infectious agents to which an immune response must be mounted poses a unique problem for receptor-ligand interactions; how can proteins whose polymorphism is necessarily limited bind an array of peptides almost infinite in its complexity? Both MHC class I and class II determinants have achieved this goal by harnessing a limited number of peptide side chains to anchor the epitope in place while exploiting conserved features of peptide structure, independent of their primary sequence. While class I molecules interact predominantly with the N- and C-termini of peptides, class II determinants form an extensive hydrogen bonding network along the length of the peptide backbone. Such a strategy ensures high-affinity binding, while selectively exposing the unique features of each ligand for recognition by the T-cell receptor.
authors.affiliation: Sir William Dunn School of Pathology, University of Oxford, UK.
authors.forename: P J
authors.initials: PJ
authors.lastname: Fairchild
mesh_terms: D000818:Animals; D000939:Epitopes / Q000737:chemistry; D015395:Histocompatibility Antigens Class I / Q000737:chemistry*; D000949:Histocompatibility Antigens Class II / Q000737:chemistry*; D006801:Humans; D008285:Major Histocompatibility Complex / Q000276:immunology*; D010455:Peptides / Q000737:chemistry / Q000276:immunology*; D011948:Receptors, Antigen, T-Cell / Q000737:chemistry
chemical_list: D000939:Epitopes; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D010455:Peptides; D011948:Receptors, Antigen, T-Cell