title: T cell regulatory plasmacytoid dendritic cells expressing indoleamine 2,3 dioxygenase.
abstract: Mature dendritic cells (DCs) are potent stimulators of T cells that recognize antigens presented by the DCs. In this chapter we describe mature DCs that suppress T cell responses to antigens they present due to expression of the intracellular enzyme indoleamine 2,3 dioxygenase (IDO). IDO-competent DCs are a subset of plasmacytoid DCs that can be induced to express IDO under certain inflammatory conditions in humans and mice. Though rare, IDO-expressing DCs acquire potent T cell suppressor activity that may predominate over the T cell stimulatory functions of all other antigen-presenting cells in physiologic environments due in part, to cooperation with regulatory T cells. Thus, IDO-expressing DCs are critical regulators of adaptive immunity that contribute to a wide range of inflammatory disease processes. As such, manipulating IDO expression in DCs using IDO inhibitors or IDO inducers offers considerable opportunities to improve immunotherapies in a range of clinically-significant disease syndromes.
authors.affiliation: Department of Medicine, Program in Molecular Immunology, Institute of Molecular Medicine and Genetics, Medical College of Georgia 1120, 15th Street, Augusta, GA 30912-2600, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Kahler
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Mellor
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D002454:Cell Differentiation; D003713:Dendritic Cells / Q000201:enzymology* / Q000276:immunology; D004790:Enzyme Induction; D006801:Humans; D007121:Immunocompetence; D007167:Immunotherapy / Q000379:methods; D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D007249:Inflammation / Q000201:enzymology* / Q000276:immunology / Q000628:therapy; D008213:Lymphocyte Activation; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase