Dendritic cells, indoleamine 2,3 dioxygenase and acquired immune privilege.
Dendritic cells (DCs) are specialized to stimulate T cell immunity. Paradoxically, some DCs suppress T cell responses and activate regulatory T cells. In this review, we focus on a potent counter-regulatory pathway mediated by plasmacytoid DCs (pDCs) expressing the immunosuppressive enzyme indoleamine 2,3 dioxygenase (IDO). IDO-expressing pDCs inhibit effector T cell responses, activate regulatory T cells, and attenuate pro-inflammatory responses in settings of chronic inflammation that manifest in clinical syndromes, such as infectious, allergic, and autoimmune diseases; cancer; and transplantation. Thus, IDO-expressing pDCs create immune privilege and provide novel opportunities to improve immunotherapy in multiple disease syndromes.
Huang
Lei
L
Immunotherapy Center and Department of Radiology, Medical College of Georgia, Augusta, GA, USA.
Baban
Babak
B
Johnson
Burles A
BA
Mellor
Andrew L
AL
D003713:Dendritic Cells / Q000201:enzymology / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular; D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase / Q000378:metabolism*
D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase