title: Naturally arising CD4+CD25+ regulatory T cells suppress the expansion of colitogenic CD4+CD44highCD62L- effector memory T cells.
abstract: Naturally arising CD4+CD25+ regulatory T (T(R)) cells have been shown to prevent and cure murine T cell-mediated colitis. However, their exact mechanism of controlling colitogenic memory CD4+ T cells in in vivo systems excluding the initial process of naive T cell activation and differentiation has not been examined to date. Using the colitogenic effector memory (T(EM)) CD4+ cell-mediated colitis model induced by adoptive transfer of colitogenic CD4+CD44(high)CD62L(-) lamina propria (LP) T cells obtained from colitic CD4+CD45RB(high) T cell-transferred mice, we have shown in the present study that CD4+CD25+ T(R) cells are able not only to suppress the development of colitis, Th1 cytokine production, and the expansion of colitogenic LP CD4+ T(EM) cells but also to expand these cells by themselves extensively in vivo. An in vitro coculture assay revealed that CD4+CD25+ T(R) cells proliferated in the presence of IL-2-producing colitogenic LP CD4+ T(EM) cells at the early time point (48 h after culture), followed by the acquisition of suppressive activity at the late time point (96 h after culture). Collectively, these data suggest the distinct timing of the IL-2-dependent expansion of CD4+CD25+ T(R) cells and the their suppressive activity on colitogenic LP CD4+ T(EM) cells.
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan. taka.gast@tmd.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Kanai
authors.forename: K
authors.initials: K
authors.lastname: Tanimoto
authors.forename: Y
authors.initials: Y
authors.lastname: Nemoto
authors.forename: R
authors.initials: R
authors.lastname: Fujii
authors.forename: S
authors.initials: S
authors.lastname: Makita
authors.forename: T
authors.initials: T
authors.lastname: Totsuka
authors.forename: M
authors.initials: M
authors.lastname: Watanabe
mesh_terms: D019264:Adoptive Transfer / Q000379:methods; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000502:physiology*; D049109:Cell Proliferation; D018920:Coculture Techniques; D003092:Colitis / Q000139:chemically induced / Q000378:metabolism*; D005260:Female; D007156:Immunologic Memory; D007376:Interleukin-2 / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D016513:Mice, SCID; D023421:Models, Animal; D009092:Mucous Membrane / Q000378:metabolism; D013601:T-Lymphocytes / Q000502:physiology*; D050378:T-Lymphocytes, Regulatory / Q000502:physiology*
chemical_list: D007376:Interleukin-2