title: Effect of intestinal microbiota on the induction of regulatory CD25+ CD4+ T cells.
abstract: When oral tolerance was induced in either specific pathogen-free (SPF) or germ-free (GF) mice, ovalbumin (OVA) feeding before immunization induced oral tolerance successfully in SPF mice. On the other hand, OVA-specific immunoglobulin G1 (IgG1) and IgE titres in OVA-fed GF mice were comparable to those in phosphate-buffered saline-fed GF mice, thus demonstrating that oral tolerance could not be induced in GF mice. The frequencies of CD25(+) CD4(+)/CD4(+) cells in the mesenteric lymph node (MLN) and the absolute number of CD25(+) CD4(+) cells in the Peyer's patches and MLN of naive GF mice were significantly lower than those in naive SPF mice. In an in vitro assay, the CD25(+) CD4(+) cells from the naive SPF mice suppressed more effectively the proliferation of responder cells in a dose-dependent manner than those from the GF mice. In addition, the CD25(+) CD4(+) regulatory T (T(reg)) cells from the naive SPF mice produced higher amounts of interleukin (IL)-10 and transforming growth factor (TGF)-beta than those from the GF mice. When anti-TGF-beta neutralizing antibody, but not anti-IL-10 neutralizing antibody, was added to the in vitro proliferation assay, the suppressive effect of the CD25(+) CD4(+) T(reg) cells from the SPF mice was attenuated to the same level as that of the CD25(+) CD4(+) cells from the GF mice. In conclusion, the TGF-beta-producing CD25(+) CD4(+) T(reg) cells from the MLN of SPF mice played a major role in oral tolerance induction. In addition, as the regulatory function of the CD25(+) CD4(+) cells from the naive GF mice was much lower than that of the CD25(+) CD4(+) T(reg) cells from the SPF mice, indigenous microbiota are thus considered to contribute to the induction and maintenance of CD25(+) CD4(+) T(reg) cells.
authors.affiliation: Department of Microbiology, Tokyo Medical University, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ishikawa
authors.forename: K
authors.initials: K
authors.lastname: Tanaka
authors.forename: Y
authors.initials: Y
authors.lastname: Maeda
authors.forename: Y
authors.initials: Y
authors.lastname: Aiba
authors.forename: A
authors.initials: A
authors.lastname: Hata
authors.forename: N M
authors.initials: NM
authors.lastname: Tsuji
authors.forename: Y
authors.initials: Y
authors.lastname: Koga
authors.forename: T
authors.initials: T
authors.lastname: Matsumoto
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000032:analysis; D005856:Germ-Free Life; D007108:Immune Tolerance; D016753:Interleukin-10 / Q000032:analysis; D007376:Interleukin-2 / Q000032:analysis; D007422:Intestines / Q000276:immunology / Q000382:microbiology*; D008198:Lymph Nodes / Q000276:immunology*; D008643:Mesentery; D051379:Mice; D008807:Mice, Inbred BALB C; D010047:Ovalbumin; D013047:Specific Pathogen-Free Organisms; D013154:Spleen / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D016212:Transforming Growth Factor beta / Q000032:analysis
chemical_list: D051858:Forkhead Transcription Factors; C498833:Foxp3 protein, mouse; D007376:Interleukin-2; D016212:Transforming Growth Factor beta; D016753:Interleukin-10; D010047:Ovalbumin