title: T cell epitope definition by differential mass spectrometry: identification of a novel, immunogenic HLA-B8 ligand directly from renal cancer tissue.
abstract: In this study, we describe a differential mass spectrometric technique for the immuno-proteomic analysis of the major histocompatibility complex (MHC) peptides of a renal cell carcinoma (RCC) biopsy compared with the healthy kidney tissue of the same patient after nephrectomy. Using a stable isotope labeling approach, we could directly compare and relatively quantify 43 MHC-peptide pairs, most of which were present in similar proportions on both normal kidney and tumor. Significantly, two dominant peptides of monoisotopic masses ([M+H](+)) 973.43 u and 967.59 u, respectively, were found exclusively in the tumor sample. One of these was identified as originating from heme oxygenase-1 (HO-1), a protein involved in induction of apoptosis resistance, immuno-suppression and neoangiogenesis and reported to be up-regulated in various cancer types. Moreover, the corresponding synthetic HO-1-derived peptide was shown to be immunogenic in vitro by generation of CD8+ T cell lines with peptide-specific cytolytic activity. Thus, this peptide is an example of a differentially identified T cell epitope that could be considered as a target for immunotherapy.
authors.affiliation: Section for Transplantation Immunology and Immunohematology, University of Tuebingen, Waldhoernlestrasse 22, 72072 Tuebingen, Germany. thomas.flad@gmx.de
authors.forename: Thomas
authors.initials: T
authors.lastname: Flad
authors.forename: Ludmila
authors.initials: L
authors.lastname: Mueller
authors.forename: Hassan
authors.initials: H
authors.lastname: Dihazi
authors.forename: Veneta
authors.initials: V
authors.lastname: Grigorova
authors.forename: Ralf
authors.initials: R
authors.lastname: Bogumil
authors.forename: Alexander
authors.initials: A
authors.lastname: Beck
authors.forename: Cornelia
authors.initials: C
authors.lastname: Thedieck
authors.forename: Gerhard A
authors.initials: GA
authors.lastname: Mueller
authors.forename: Hubert
authors.initials: H
authors.lastname: Kalbacher
authors.forename: Claudia A
authors.initials: CA
authors.lastname: Mueller
mesh_terms: D000368:Aged; D002851:Chromatography, High Pressure Liquid; D000939:Epitopes / Q000737:chemistry*; D005260:Female; D015795:HLA-B8 Antigen / Q000276:immunology*; D006801:Humans; D007150:Immunohistochemistry; D007371:Interferon-gamma / Q000032:analysis; D007680:Kidney Neoplasms / Q000737:chemistry*; D008024:Ligands; D013058:Mass Spectrometry / Q000379:methods*; D036103:Nanotechnology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000939:Epitopes; D015795:HLA-B8 Antigen; D008024:Ligands; D007371:Interferon-gamma