Minimal alterations in the HLA-B27-bound peptide repertoire induced upon infection of lymphoid cells with Salmonella typhimurium.
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.
Ramos
M
M
Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Spain.
Alvarez
I
I
García-del-Portillo
F
F
López de Castro
J A
JA
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
D015796:HLA-B27 Antigen