IDO expression by dendritic cells: tolerance and tryptophan catabolism.
Indoleamine 2,3-dioxygenase (IDO) is an enzyme that degrades the essential amino acid tryptophan. The concept that cells expressing IDO can suppress T-cell responses and promote tolerance is a relatively new paradigm in immunology. Considerable evidence now supports this hypothesis, including studies of mammalian pregnancy, tumour resistance, chronic infections and autoimmune diseases. In this review, we summarize key recent developments and propose a unifying model for the role of IDO in tolerance induction.
Mellor
Andrew L
AL
Program in Molecular Immunology, Institute of Molecular Medicine and Genetics, Department of Medicine, Medical College of Georgia, Augusta, Georgia 30912, USA. amellor@mail.mcg.edu
Munn
David H
DH
D000818:Animals; D003713:Dendritic Cells / Q000378:metabolism*; D006801:Humans; D007108:Immune Tolerance; D007165:Immunosuppression Therapy; D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase; D018448:Models, Immunological; D014364:Tryptophan / Q000378:metabolism*; D014366:Tryptophan Oxygenase / Q000096:biosynthesis*
D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase; D014364:Tryptophan; D014366:Tryptophan Oxygenase