title: Microbial colonization influences composition and T-cell receptor V beta repertoire of intraepithelial lymphocytes in rat intestine.
abstract: Studies in mice have shown that the composition of intestinal intraepithelial lymphocytes (IEL) may be markedly altered by gut microbial colonization. Such modulation was studied in a rat model by the use of germ-free and conventionalized animals from which IEL from the small intestine were isolated and analysed by flow cytometry. Conventionalization caused expansion as well as phenotypic alterations of T-cell receptor (TCR) alpha/beta + IEL in that the proportions of CD4+ and CD8 alpha beta + TCR alpha/beta + cells were increased, while the double negative (CD4- CD8-) fraction was reduced. microbial colonization also influenced the TCR V beta repertoire of CD8+ IEL in that the proportions of V beta 8.2+ and V beta 10+ cells were increased, whereas V beta 8.5+ and V beta 16+ cells were relatively decreased. Moreover, conventionalization influenced the levels of TCR cell surface expression in the same V beta subsets. Three-colour flow-cytometric analysis demonstrated that skewing of the V beta repertoire was most pronounced in the CD8 alpha alpha + subset, although the numerical increase of IEL mainly included the CD8 alpha beta + subset. In contrast to IEL, the TCR V beta repertoire in mesenteric lymph nodes was unchanged after intestinal colonization. These results confirm that TCR alpha/beta + IEL subpopulations respond dynamically to the microbial gut flora and suggest that their V beta repertoire can be shaped by luminal microbial antigens.
authors.affiliation: Laboratory for Immunohistochemistry and Immunopathology (LIIPAT), University of Oslo, Norway.
authors.forename: L
authors.initials: L
authors.lastname: Helgeland
authors.forename: J T
authors.initials: JT
authors.lastname: Vaage
authors.forename: B
authors.initials: B
authors.lastname: Rolstad
authors.forename: T
authors.initials: T
authors.lastname: Midtvedt
authors.forename: P
authors.initials: P
authors.lastname: Brandtzaeg
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D005434:Flow Cytometry; D005856:Germ-Free Life; D018928:Immunity, Mucosal; D007413:Intestinal Mucosa / Q000276:immunology* / Q000382:microbiology*; D008213:Lymphocyte Activation; D008297:Male; D008643:Mesentery / Q000276:immunology; D051381:Rats; D011919:Rats, Inbred Strains; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D016693:Receptors, Antigen, T-Cell, alpha-beta