Indoleamine 2, 3-dioxygenase (IDO) is a rate-limiting enzyme for the tryptophan catabolism. In human and murine cells, IDO inhibits antigen-specific T cell proliferation in vitro and suppresses T cell responses to fet...Indoleamine 2, 3-dioxygenase (IDO) is a rate-limiting enzyme for the tryptophan catabolism. In human and murine cells, IDO inhibits antigen-specific T cell proliferation in vitro and suppresses T cell responses to fetal alloantigens during murine pregnancy. In mice, IDO expression is an inducible feature of specific subsets of dendritic cells (DCs), and is important for T cell regulatory properties. However, the effect of IDO and tryptophan deprivation on DC func- tions remains unknown. We report here that when tryptophan utilization was prevented by a pharmacological inhibitor of IDO, 1-methyl tryptophan (1MT), DC activation induced by pathogenic stimulus lipopolysaccharide (LPS) or inflam- matory cytokine TNF-α was inhibited both phenotypically and functionally. Such an effect was less remarkable when DC was stimulated by a physiological stimulus, CD40 ligand. Tryptophan deprivation during DC activation also regu- lated the expression of CCR5 and CXCR4, as well as DC responsiveness to chemokines. These results suggest that tryptophan usage in the microenvironment is essential for DC maturation, and may also play a role in the regulation of DC migratory behaviors.展开更多
肿瘤可以通过多种方式逃逸机体免疫系统的监控。吲哚胺-2,3双加氧酶(indoleamine-2,3-dioxygenase,IDO)和CD4+CD25+调节性T细胞(CD4+ CD25+ regulatory T cells,Tregs)是近些年在肿瘤免疫逃逸领域中备受关注的两个重要因素。两者相互作...肿瘤可以通过多种方式逃逸机体免疫系统的监控。吲哚胺-2,3双加氧酶(indoleamine-2,3-dioxygenase,IDO)和CD4+CD25+调节性T细胞(CD4+ CD25+ regulatory T cells,Tregs)是近些年在肿瘤免疫逃逸领域中备受关注的两个重要因素。两者相互作用在肿瘤免疫逃逸机制中起着尤为关键的作用,已引起众多研究者的关注。本文就IDO及Tregs在肿瘤免疫逃逸中的作用以及两者之间的相互关系等方面的研究进展作一综述。展开更多
文摘Indoleamine 2, 3-dioxygenase (IDO) is a rate-limiting enzyme for the tryptophan catabolism. In human and murine cells, IDO inhibits antigen-specific T cell proliferation in vitro and suppresses T cell responses to fetal alloantigens during murine pregnancy. In mice, IDO expression is an inducible feature of specific subsets of dendritic cells (DCs), and is important for T cell regulatory properties. However, the effect of IDO and tryptophan deprivation on DC func- tions remains unknown. We report here that when tryptophan utilization was prevented by a pharmacological inhibitor of IDO, 1-methyl tryptophan (1MT), DC activation induced by pathogenic stimulus lipopolysaccharide (LPS) or inflam- matory cytokine TNF-α was inhibited both phenotypically and functionally. Such an effect was less remarkable when DC was stimulated by a physiological stimulus, CD40 ligand. Tryptophan deprivation during DC activation also regu- lated the expression of CCR5 and CXCR4, as well as DC responsiveness to chemokines. These results suggest that tryptophan usage in the microenvironment is essential for DC maturation, and may also play a role in the regulation of DC migratory behaviors.
文摘肿瘤可以通过多种方式逃逸机体免疫系统的监控。吲哚胺-2,3双加氧酶(indoleamine-2,3-dioxygenase,IDO)和CD4+CD25+调节性T细胞(CD4+ CD25+ regulatory T cells,Tregs)是近些年在肿瘤免疫逃逸领域中备受关注的两个重要因素。两者相互作用在肿瘤免疫逃逸机制中起着尤为关键的作用,已引起众多研究者的关注。本文就IDO及Tregs在肿瘤免疫逃逸中的作用以及两者之间的相互关系等方面的研究进展作一综述。
