title: Minimal alterations in the HLA-B27-bound peptide repertoire induced upon infection of lymphoid cells with Salmonella typhimurium.
abstract: OBJECTIVE
  To characterize putative changes in the HLA-B27-bound peptide repertoire following infection of lymphoid cells with Salmonella typhimurium, a bacterium known to trigger reactive arthritis in HLA-B27-positive individuals.
  
  
  METHODS
  A protocol was developed for efficient large-scale infection of lymphoblastoid cell transfectants expressing HLA-B*2705. HLA-B27-bound peptide pools were isolated from noninfected and infected B*2705+ cells and comparatively analyzed by high-performance liquid chromatography. Peptide-containing chromatographic fractions from noninfected and infected cells were systematically compared by mass spectrometry (MS) to look for putative differences at the level of individual peptides.
  
  
  RESULTS
  The presence of B*2705 did not influence S typhimurium invasion, since this was equally efficient in nontransfected or B27-transfected cells. The chromatographic profiles of B*2705-bound peptides from noninfected and infected cells were virtually identical. A total of 808 molecular species were compared by MS. Of these, 807 were present in both infected and noninfected cells. Only one molecular species from infected cells lacked a detectable counterpart in noninfected cells.
  
  
  CONCLUSIONS
  Intracellular infection of lymphoid cells by S typhimurium induces minimal alterations in the HLA-B27-bound peptide repertoire. Minor changes detectable by cytotoxic T lymphocytes, but not easily amenable to direct biochemical analysis, are not ruled out.
authors.affiliation: Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Ramos
authors.forename: I
authors.initials: I
authors.lastname: Alvarez
authors.forename: F
authors.initials: F
authors.lastname: García-del-Portillo
authors.forename: J A
authors.initials: JA
authors.lastname: López de Castro
mesh_terms: D016918:Arthritis, Reactive / Q000276:immunology*; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D015796:HLA-B27 Antigen / Q000032:analysis / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D010950:Plasma Cells / Q000166:cytology / Q000382:microbiology; D012480:Salmonella Infections / Q000276:immunology*; D012486:Salmonella typhimurium; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D015796:HLA-B27 Antigen