Indoleamine 2,3-dioxygenase (IDO) is an ancestral enzyme that, initially confined to the regulation of tryptophan availability in local tissue microenvironments, is now considered to play a wider role that extends to homeostasis and plasticity of the immune system. Thus, IDO biology has many implications for many aspects of immunopathology, including viral infections, neoplasia, autoimmunity, and chronic inflammation. Its immunoregulatory effects arc mainly mediated by dendritic cells (DCs) and involve not only tryptophan deprivation but also production of kynurenines that act on IDO- DCs - thus rendering an otherwise stimulatory DC capable of regulatory effects as well as on T cells. As a result, IDO+ DCs mediate multiple effects on T lymphocytes, including inhibition of proliferation, apoptosis, and differentiation toward a regulatory phenotype.
Indoleamine 2,3-Dioxygenase and RegulatoryFunction: Tryptophan Starvation and Beyond
ORABONA, Ciriana;GROHMANN, Ursula
2011
Abstract
Indoleamine 2,3-dioxygenase (IDO) is an ancestral enzyme that, initially confined to the regulation of tryptophan availability in local tissue microenvironments, is now considered to play a wider role that extends to homeostasis and plasticity of the immune system. Thus, IDO biology has many implications for many aspects of immunopathology, including viral infections, neoplasia, autoimmunity, and chronic inflammation. Its immunoregulatory effects arc mainly mediated by dendritic cells (DCs) and involve not only tryptophan deprivation but also production of kynurenines that act on IDO- DCs - thus rendering an otherwise stimulatory DC capable of regulatory effects as well as on T cells. As a result, IDO+ DCs mediate multiple effects on T lymphocytes, including inhibition of proliferation, apoptosis, and differentiation toward a regulatory phenotype.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
