Interferons and indoleamine 2,3-dioxygenase: Role in antimicrobial and antitumor effects
ABSTRACT Indoleamine 2,3-dioxygenase (IDO) is an interferon (IFN)-induced protein that initiates the metabolism of tryptophan along the kynurenine pathway. Although IDO can be induced by IFN-gamma in many cell types, only mononuclear phagocytes have been shown to be induced to decyclize tryptophan by all three IFN classes. Since tryptophan is an essential amino acid necessary for a variety of metabolic processes, depletion of available tryptophan may be an important mechanism for control of rapidly-dividing microbial pathogens and tumors. The purpose of this review is to present evidence that documents the effects of IFN-induced IDO on prokaryotic and eukaryotic pathogens, as well as on a variety of tumor cell lines.
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- "The cumulative proportions of the first, second and third PCs (PC1, PC2, and PC3) were 44.8, 57.6 and 67.0%. The same analyses presented for all datasets are shown in Supplementary Fig. S2 In addition to polyamines, the level of tryptophan (Carlin et al. 1989), which is increased in oral and pancreatic cancer, is a direct marker for tumor development. In terms of an indirect connection between the detected metabolites and human cancer, the repeat peptide "
ABSTRACT: Saliva is a readily accessible and informative biofluid, making it ideal for the early detection of a wide range of diseases including cardiovascular, renal, and autoimmune diseases, viral and bacterial infections and, importantly, cancers. Saliva-based diagnostics, particularly those based on metabolomics technology, are emerging and offer a promising clinical strategy, characterizing the association between salivary analytes and a particular disease. Here, we conducted a comprehensive metabolite analysis of saliva samples obtained from 215 individuals (69 oral, 18 pancreatic and 30 breast cancer patients, 11 periodontal disease patients and 87 healthy controls) using capillary electrophoresis time-of-flight mass spectrometry (CE-TOF-MS). We identified 57 principal metabolites that can be used to accurately predict the probability of being affected by each individual disease. Although small but significant correlations were found between the known patient characteristics and the quantified metabolites, the profiles manifested relatively higher concentrations of most of the metabolites detected in all three cancers in comparison with those in people with periodontal disease and control subjects. This suggests that cancer-specific signatures are embedded in saliva metabolites. Multiple logistic regression models yielded high area under the receiver-operating characteristic curves (AUCs) to discriminate healthy controls from each disease. The AUCs were 0.865 for oral cancer, 0.973 for breast cancer, 0.993 for pancreatic cancer, and 0.969 for periodontal diseases. The accuracy of the models was also high, with cross-validation AUCs of 0.810, 0.881, 0.994, and 0.954, respectively. Quantitative information for these 57 metabolites and their combinations enable us to predict disease susceptibility. These metabolites are promising biomarkers for medical screening.Metabolomics 03/2010; 6(1):78-95. DOI:10.1007/s11306-009-0178-y · 3.86 Impact Factor
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- "-g-responsive gene in W/K mice during chronic TB and that epithelial and endothelial cells were the major source of this enzyme at that time. IDO catalyzes the first step of the degradation of tryptophan and is induced by IFN-g in a wide variety of cells (Carlin et al., 1989 "
ABSTRACT: Immunity to Mycobacterium tuberculosis in humans and in mice requires interferon gamma (IFN-gamma). Whereas IFN-gamma has been studied extensively for its effects on macrophages in tuberculosis, we determined that protective immunity to tuberculosis also requires IFN-gamma-responsive nonhematopoietic cells. Bone marrow chimeric mice with IFN-gamma-unresponsive lung epithelial and endothelial cells exhibited earlier mortality and higher bacterial burdens than control mice, underexpressed indoleamine-2,3-dioxygenase (Ido1) in lung endothelium and epithelium, and overexpressed interleukin-17 (IL-17) with massive neutrophilic inflammation in the lungs. We also found that the products of IDO catabolism of tryptophan selectively inhibit IL-17 production by Th17 cells, by inhibiting the action of IL-23. These results reveal a previously unsuspected role for IFN-gamma responsiveness in nonhematopoietic cells in regulation of immunity to M. tuberculosis and illustrate the role of IDO in the inhibition of Th17 cell responses.Immunity 12/2009; 31(6):974-85. DOI:10.1016/j.immuni.2009.10.007 · 21.56 Impact Factor
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- "Cancer Letters 223 (2005) 323–329 www.elsevier.com/locate/canlet reduced availability and is considered as an immune defence mechanism, which suppresses the growth of intracellular bacteria, viruses and parasites like toxoplasma   and of malignant tumor cells . But also T-cell proliferation can be inhibited by IDO activity , immune response may be suppressed when tryptophan is diminished due to activated IDO. "
ABSTRACT: Tryptophan degradation by the enzyme indoleamine-(2,3)-dioxy genase (IDO) and neopterin production are induced within cellular immune activation by stimulation of monocyte-derived macrophages and dendritic cells with cytokine interferon-gamma. Deprivation of tryptophan represents an important antimicrobial and antitumoral immune defence mechanism but it also suppresses T-cell proliferation. Recently tryptophan degradation by tumor cells was proposed as strategy to escape immune response. In this study the relationship between tryptophan degradation and immune activation was examined in 20 patients with gynecological cancer. Concentrations of tryptophan and kynurenine were measured by HPLC in sera of patients, and to estimate IDO activity, the kynurenine to tryptophan ratio was calculated. In parallel, neopterin concentrations were measured by ELISA. Tryptophan concentrations (median, interquartile range: 43.5, 31.2-56.3 microM) were lower in patients with gynecological cancer compared to healthy individuals of similar age (53.5, 47.0-64.2 microM; P<0.05). Kynurenine concentrations (median: 1.91 vs. 1.73 microM in controls) and kyn/trp (median: 41 vs. 35 micromol/mmol in controls) were slightly higher in patients, but not significantly different. Neopterin concentrations were significantly higher in patients (median: 10.8 vs. 7.0 nM in controls; P<0.05) and correlated with the kynurenine per tryptophan ratio (r(s)=0.555; P<0.02). In conclusion, tryptophan degradation is detectable in patients with gynecological cancer. The relationship between kyn/trp and neopterin concentrations indicates that cellular immune activation rather than tumor-mediated IDO-activity is responsible (228 words).Cancer Letters 07/2005; 223(2):323-9. DOI:10.1016/j.canlet.2004.10.033 · 5.62 Impact Factor