title: Glucocorticoids down-regulate dendritic cell function in vitro and in vivo.
abstract: Exogenous glucocorticoid hormones are widely used as therapeutical agents, whereas endogenous glucocorticoids may act as physiological immunosuppressants involved in the control of immune and inflammatory responses. The optimal activation of T lymphocytes requires two distinct signals: the major histocompatibility complex-restricted presentation of the antigen and an additional co-stimulatory signal provided by the antigen-presenting cells. There is ample evidence that, among the cells able to present the antigen, the dendritic cells (DC) have the unique property to activate antigen-specific, naive T cells in vitro and in vivo, and are therefore required for the induction of primary immune responses. In this work, we tested whether glucocorticoids affected the capacity of DC to sensitize naive T cells. Our data show that, in vitro, the steroid hormone analog dexamethasone (Dex) affects the viability of DC, selectively down-regulates the expression of co-stimulatory molecules on viable DC, and strongly reduces their immunostimulatory properties. In vivo, a single injection of Dex results in impaired antigen presenting function, a finding which correlates with reduced numbers of splenic DC. These results show that glucocorticoids regulate DC maturation and immune function in vitro and in vivo and suggest that this mechanism may play a role in preventing overstimulation of the immune system.
authors.affiliation: Département de Biologie Moléculaire, Université Libre de Bruxelles, Rhode-Saint-Genèse, Belgium.
authors.forename: M
authors.initials: M
authors.lastname: Moser
authors.forename: T
authors.initials: T
authors.lastname: De Smedt
authors.forename: T
authors.initials: T
authors.lastname: Sornasse
authors.forename: F
authors.initials: F
authors.lastname: Tielemans
authors.forename: A A
authors.initials: AA
authors.lastname: Chentoufi
authors.forename: E
authors.initials: E
authors.lastname: Muraille
authors.forename: M
authors.initials: M
authors.lastname: Van Mechelen
authors.forename: J
authors.initials: J
authors.lastname: Urbain
authors.forename: O
authors.initials: O
authors.lastname: Leo
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000187:drug effects*; D018122:B7-1 Antigen / Q000096:biosynthesis / Q000235:genetics; D006224:Cricetinae; D003713:Dendritic Cells / Q000187:drug effects*; D003907:Dexamethasone / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D016131:Lymphocyte Subsets / Q000187:drug effects / Q000276:immunology; D051379:Mice; D008808:Mice, Inbred CBA; D008811:Mice, Inbred DBA; D015735:Mifepristone / Q000494:pharmacology; D013047:Specific Pathogen-Free Organisms; D013154:Spleen / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D018122:B7-1 Antigen; D007166:Immunosuppressive Agents; D015735:Mifepristone; D003907:Dexamethasone; D016178:Granulocyte-Macrophage Colony-Stimulating Factor