Natural indoleamine-2,3-dioxygenase (IDO)-reactive CD4(+) T cells have been shown to release interferonγ (IFNγ), tumor necrosis factor α (TNFα), as well as interleukin 17 (IL-17). In some individuals, these cells also demonstrated the ability to suppress IL-10 production. IDO-specific CD4(+) helper T cells among peripheral blood lymphocytes may participate in immunoregulatory networks by delayi...

Induction of the heme-containing indoleamine 2,3-dioxygenase (IDO) by IFN-gamma is implicated in anti-microbial and pro-inflammatory activities of human macrophages. Antioxidants can modulate the expression of immune and inflammatory genes, and pyrrolidine dithiocarbamate (PDTC) is a frequently used antioxidant to inhibit the transcription factor NF-kappaB. Here we show that IFN-gamma treatment...

BACKGROUND Indoleamine 2,3-dioxygenase (IDO) is an enzyme with immune-suppressive properties that is commonly exploited by tumors to evade immune destruction. Anti-tumor T cell responses can be initiated in solid tumors, but are immediately suppressed by compensatory upregulation of immunological checkpoints, including IDO. In addition to these known effects on the adaptive immune system, we pr...

IDO converts tryptophan to l-kynurenine, and it is noted as a relevant molecule in promoting tolerance and suppressing adaptive immunity. In this study, we examined the effect of IDO in α-galactosylceramide (α-GalCer)-induced hepatitis. The increase in IDO expression in the liver of wild-type (WT) mice administered α-GalCer was confirmed by real-time PCR, Western blotting, and IDO immunohistoch...

Indoleamine 2,3-dioxygenase (IDO) is overexpressed in many human cancers and is believed to play a role in tumor immune evasion, but a requirement for IDO in tumor progression has not been formally shown. The study by Smith and colleagues in this issue of Cancer Discovery provides genetic evidence for the importance of IDO in tumorigenesis, which supports the use of IDO inhibitors in clinical t...

Indoleamine 2,3-dioxygenase (IDO) can locally suppress T cell-mediated immune responses. It has been shown that defective self-tolerance in early prediabetic female non-obese diabetic (NOD) mice can be attributed to the impaired interferon-gamma (IFN-γ)- induced IDO expression in dendritic cells of these animals. As IFN-γ can induce IDO in both dendritic cells and fibroblasts, we asked the ques...

The cytotoxic T lymphocyte antigen-4 (CTLA-4)-blocking antibody ipilimumab results in durable responses in metastatic melanoma, though therapeutic benefit has been limited to a fraction of patients. This calls for identification of resistance mechanisms and development of combinatorial strategies. Here, we examine the inhibitory role of indoleamine 2,3-dioxygenase (IDO) on the antitumor efficac...

Costimulatory blockade of CD28-B7 interaction with CTLA4Ig is a well-established strategy to induce transplantation tolerance. Although previous in vitro studies suggest that CTLA4Ig upregulates expression of the immunoregulatory enzyme IDO in dendritic cells, the relationship of CTLA4Ig and IDO in in vivo organ transplantation remains unclear. In this study, we studied whether concerted immuno...

We aimed to investigate the expression of suppressors cytokine signaling (SOCS)-3, transforming growth factor (TGF)-β and indoleamine 2,3-dioxygense (IDO) and to analyse the relationship of SOCS3 and TGF-β with IDO expression in early pregnancy chorionic villi and decidua in the maternal-fetal interface. Western blot analysis and immunohistochemical method were used to detect the expression of ...

BACKGROUND Indoleamine 2,3-dioxygenase (IDO), which is mainly expressed in activated dendritic cells, catabolizes tryptophan to kynurenine and other downstream catabolites. It is known to be an immune mediator in HIV pathogenesis. The impact of anti-retroviral therapy on its activity has not been well established. METHODS We measured systemic IDO activity (the ratio of plasma kynurenine to tr...