title: Peptides naturally presented by MHC class I molecules.
abstract: MHC class I molecules are peptide receptors of stringent specificity which however still allow millions of different ligands. This is achieved by the following specificity characteristics summarized as allele specific peptide motifs: Peptides are of defined length, depending on the class I allele (either 8 or 9 residues; exceptions have been observed). Typically, 2 of the 8 or 9 positions are anchors that can only be occupied by a single amino acid residue, or by residues with closely related side chains. Location and characteristics of anchors vary with class I alleles. The C terminus of the peptide ligands is frequently an aliphatic or charged residue. Such allele-specific class I peptide ligand motifs, known so far for H-2Kd, Kb, Kk, Kkm1, Db, HLA-A*0201, A*0205, and B*2705, are useful to predict natural T cell epitopes. The latter can be determined by extraction from cells recognized by the T cell of interest. It is not known how the class I ligands are produced in the cell, although speculative models exist. The peptide specificity of class I molecules and experimental evidence indicate that T cells are tolerant to only a small fraction of the expressed genomic sequences and are not tolerant to the remainder. The function of class I molecules is to present a collection of self-peptide samples at the cell surface for surveillance by T cells.
authors: Max-Planck-Institut für Biologie, Abteilung Immungenetik, Tübingen, Germany.
authors: H G
authors: HG
authors: Rammensee
authors: K
authors: K
authors: Falk
authors: O
authors: O
authors: Rötzschke
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015395:Histocompatibility Antigens Class I / Q000235:genetics; D006801:Humans; D007108:Immune Tolerance; D051379:Mice; D008969:Molecular Sequence Data; D010455:Peptides / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D011499:Protein Processing, Post-Translational / Q000276:immunology
chemical_list: D015395:Histocompatibility Antigens Class I; D010455:Peptides