title: HLA-A2.1-associated peptides from a mutant cell line: a second pathway of antigen presentation.
abstract: Peptides extracted from HLA-A2.1 class I major histocompatibility complex (MHC) molecules expressed on the antigen processing mutant CEMx721.174.T2 were characterized by electrospray ionization-tandem mass spectrometry. Only seven dominant peptides were found, in contrast to over 200 associated with HLA-A2.1 on normal cells. These peptides were derived from the signal peptide domains of normal cellular proteins, were usually larger than nine residues, and were also associated with HLA-A2.1 in normal cells. These results suggest that proteolysis of signal peptide domains in the endoplasmic reticulum is a second mechanism for processing and presentation of peptides for association with class I molecules.
authors.affiliation: Department of Microbiology, University of Virginia School of Medicine, Charlottesville 22908.
authors.forename: R A
authors.initials: RA
authors.lastname: Henderson
authors.forename: H
authors.initials: H
authors.lastname: Michel
authors.forename: K
authors.initials: K
authors.lastname: Sakaguchi
authors.forename: J
authors.initials: J
authors.lastname: Shabanowitz
authors.forename: E
authors.initials: E
authors.lastname: Appella
authors.forename: D F
authors.initials: DF
authors.lastname: Hunt
authors.forename: V H
authors.initials: VH
authors.lastname: Engelhard
mesh_terms: D000595:Amino Acid Sequence; D000938:Antigen-Presenting Cells / Q000276:immunology*; D000941:Antigens / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D015789:HLA-A2 Antigen / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009154:Mutation; D010455:Peptides / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D021382:Protein Sorting Signals / Q000737:chemistry; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000941:Antigens; D015789:HLA-A2 Antigen; D010455:Peptides; D021382:Protein Sorting Signals