title: CD4+ CD25+ regulatory T cells control T helper cell type 1 responses to foreign antigens induced by mature dendritic cells in vivo.
abstract: Recent evidence suggests that in addition to their well known stimulatory properties, dendritic cells (DCs) may play a major role in peripheral tolerance. It is still unclear whether a distinct subtype or activation status of DC exists that promotes the differentiation of suppressor rather than effector T cells from naive precursors. In this work, we tested whether the naturally occurring CD4+ CD25+ regulatory T cells (Treg) may control immune responses induced by DCs in vivo. We characterized the immune response induced by adoptive transfer of antigen-pulsed mature DCs into mice depleted or not of CD25+ cells. We found that the development of major histocompatibility complex class I and II-restricted interferon gamma-producing cells was consistently enhanced in the absence of Treg. By contrast, T helper cell (Th)2 priming was down-regulated in the same conditions. This regulation was independent of interleukin 10 production by DCs. Of note, splenic DCs incubated in vitro with Toll-like receptor ligands (lipopolysaccharide or CpG) activated immune responses that remained sensitive to Treg function. Our data further show that mature DCs induced higher cytotoxic activity in CD25-depleted recipients as compared with untreated hosts. We conclude that Treg naturally exert a negative feedback mechanism on Th1-type responses induced by mature DCs in vivo.
authors.affiliation: Laboratoire de Physiologie Animale, Université Libre de Bruxelles, Rue des Prof. Jeener et Brachet, 12, 6041 Gosselies, Belgium.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Oldenhove
authors.forename: Magali
authors.initials: M
authors.lastname: de Heusch
authors.forename: Georgette
authors.initials: G
authors.lastname: Urbain-Vansanten
authors.forename: Jacques
authors.initials: J
authors.lastname: Urbain
authors.forename: Charlie
authors.initials: C
authors.lastname: Maliszewski
authors.forename: Oberdan
authors.initials: O
authors.lastname: Leo
authors.forename: Muriel
authors.initials: M
authors.lastname: Moser
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology*; D005434:Flow Cytometry; D007108:Immune Tolerance / Q000276:immunology*; D007371:Interferon-gamma / Q000235:genetics; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D015375:Receptors, Interleukin-2 / Q000172:deficiency* / Q000235:genetics / Q000276:immunology*; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
chemical_list: D015375:Receptors, Interleukin-2; D007371:Interferon-gamma