105,597 research outputs found
IDO-1 mRNA expression and kynurenine production following cortisol challenges.
No full textThe white bars represent the mean ± SEM of three values performed in triplicate in female PBMCs; the striped bars represent the mean ± SEM of three values performed in triplicate in male PBMCs. *** p<0.001 or ** p<0.01 vs female cells (t-test); § p<0.05 vs non-stimulated female cells (One-Way Anova, Newman-Keuls post-test); # p<0.05 or ## p<0.01 or ### p<0.001 vs non-stimulated male cells (One-Way Anova, Newman-Keuls post-test); çç p<0.01 or ççç p<0.001 vs 0.2 microg/ml cortisol treated female cells (t-test); °° p<0.01 vs 0.2 microg/ml cortisol treated male cells (t-test). For IDO-1, Two-way ANOVA test (sex, treatment): interaction P value < 0.0001; F = 14.35; DFn = 2. For Kyn, Two-way ANOVA test (sex, treatment): interaction p value = 0.0005; F = 14.35; DFn = 2.</p
Suppression of T cell proliferation by rfNSCs expressing IDO.
No full text<p>(A) The result of mixed leukocyte reaction showed that T cell proliferation was significantly suppressed by both rfNSCs-Cont and rfNSCs-IDO groups. Moreover, the T cell number in the rfNSCs-IDO group was significantly reduced compared to that in the rfNSCs-Cont group. (B) With the treatment of IDO inhibitor, 1-MT (1-methyl-DL-tryptophan) at a 0.5 mM concentration, the T cell number in the rfNSCs-IDO group became similar to that in the rfNSCs-Cont group. (n = 3, *** p < 0.001).</p
Influence of IDO-mediated immunosuppression on T lymphocytes
No full textDas tryptophanabbauende Enzym Indolamin-2,3-Dioxygenase (IDO) wurde ursprünglich im Zusammenhang mit der Proliferationshemmung fakultativ intrazellulärer Mikroorganismen beschrieben. Mittlerweile ist bekannt, dass IDO eine Vielzahl weiterer Funktionen ausübt, die noch nicht alle bekannt sind. Durch den Abbau der essentiellen Aminosäure Tryptophan hat IDO eine proliferationshemmende Wirkung auf T-Lymphozyten. Das Enzym spielt eine Rolle bei einer Vielzahl von Krankheiten. So exprimiert eine Reihe von Tumoren IDO als möglichen Mechanismus der Immunantwort des Wirts zu entkommen. Auch in der Pathogenese des Humanen Immundefizienz Virus (HIV) soll das Enzym beteiligt sein, beispielsweise führt eine in vitro HIV-Infektion menschlicher Makrophagen zu einer hohen IDO-Expression. Durch die Fähigkeit der Toleranzinduktion ist IDO ein interessanter Angriffspunkt zukünftiger Therapien. In der vorliegenden Arbeit gebe ich einen Überblick über den aktuellen Forschungsstand bezüglich der Funktion, Regulation und Wirkung auf T-Lymphozyten von IDO.This thesis deals with the enzyme Indoleamine 2,3-Dioxygenase (IDO) which was originally described as an inhibitory mechanism of facultatively intracellular pathogens. By now, it is known that IDO also has a lot of other functions. Not all of them are clearly established at the moment. IDO inhibits the proliferation of T lymphocytes through the degradation of the essential amino acid tryptophan. Furthermore, IDO is associated with a series of diseases. Thus it is known, that some tumors express IDO as a mechanism to overcome the immune defense of the host. The enzyme also seems to be involved in the pathogenesis of Human Immundeficiency Virus (HIV). For example, an in vitro infection of human macrophages with HIV leads to a high expression of IDO. Because of its potential for immune-tolerance induction, IDO is an interesting target for future therapies. In this thesis I am giving an overview of the current state of research about regulation, function and effects on T lymphocytes of IDO
Metabolic regulation of regulatory T cell development and function
No full textIt is now well established that the effector T cell (Teff) response is regulated by a series of metabolic switches. Quiescent T cells predominantly require ATP-generating processes, whereas proliferating Teff require high metabolic flux through growth-promoting pathways, such as glycolysis. Pathways that control metabolism and immune cell function are intimately linked, and changes in cell metabolism at both the cell and system levels have been shown to enhance or suppress specific T cell effector functions. Furthermore, functionally distinct T cell subsets have been shown to require distinct energetic and biosynthetic pathways to support their specific functional needs. In particular, naturally occurring regulatory T cells (Treg) are characterized by a unique metabolic signature distinct to that of conventional Teff cells. We here briefly review the signaling pathways that control Treg metabolism and how this metabolic phenotype integrates their differentiation and function. Ultimately, these metabolic features may provide new opportunities for the therapeutic modulation of unwanted immune responses
Transect-rapport 1690: Archeologisch bureauonderzoek en inventariserend veldonderzoek, verkennende fase. Hendrik-Ido-Ambacht, Vrouwgelenweg 80, gemeente Hendrik-Ido-Ambacht (ZH).
No full textIn april 2018 is een archeologisch vooronderzoek uitgevoerd in een plangebied aan de Vrouwgelenweg 80 in Hendrik-Ido-Ambacht (gemeente Hendrik-Ido-Ambacht). De aanleiding voor het onderzoek is een bestemmingsplanwijziging en de aanvraag van een omgevingsvergunning die de realisatie van een drietal woningen in het plangebied mogelijk moet maken. Bij de voorgenomen werkzaamheden zal grondverzet plaatsvinden, waardoor de
oorspronkelijke bodem en daarmee eventueel aanwezige archeologische resten in het gebied kunnen worden verstoord.
In het plangebied geldt in het vigerende bestemmingsplan een dubbelbestemming Waarde Archeologie. Een archeologisch onderzoek is verplicht bij bodemingrepen met een oppervlakte groter dan 100 m2. Dit betekent dat gezien de omvang van de voorgenomen bodemingrepen archeologisch vooronderzoek nodig is
Blockade of IDO inhibits nasal tolerance induction
No full textThe amino acid tryptophan is essential for the proliferation and survival of cells. Modulation of tryptophan metabolism has been described as an important regulatory mechanism for the control of immune responses. The enzyme IDO degrades the indole moiety of tryptophan, not only depleting tryptophan but also producing immunomodulatory metabolites called kynurenines, which have apoptosis-inducing capabilities. In this study, we show that IDO is more highly expressed in nonplasmacytoid dendritic cells of the nose draining lymph nodes (LNs), which form a unique environment to induce tolerance to inhaled Ags, when compared with other peripheral LNs. Upon blockade of IDO during intranasal OVA administration, Ag-specific immune tolerance was abrogated. Analysis of Ag-specific T cells in the LNs revealed that inhibition of IDO resulted in enhanced survival at 48 h after antigenic stimulation, although this result was not mediated through alterations in apoptosis or cell proliferation. Furthermore, no differences were found in CD4(+) T cells expressing FoxP3. Our data suggest that the level of IDO expression in dendritic cells, present in nose draining LNs, allows for the generation of a sufficient number of regulatory T cells to control and balance effector T cells in such a way that immune tolerance is induced, whereas upon IDO blockade, effector T cells will outnumber regulatory T cells, leading to immunity
Invited lecture: Expression of IDO in human mature dendritic cells in vivo
No full textIndoleamine dioxygenase (IDO) is a tryptophan-degrading enzyme that contributes to peripheral tolerance by inducing a local tryptophan shortage that prevents T cell proliferation. We studied the expression of IDO in human normal tissues by immunohistochemistry using a novel monoclonal antibody we raised against human IDO. Most normal tissues were completely negative, with the exception of lymphoid tissues, which contained scattered IDO-positive cells located in T cell areas of normal lymph nodes, in the spleen, the gut lamina propria and the thymus. Their morphology corresponded to that of interdigitating dendritic cells.
Using a novel virtual double staining technique, we identified those IDO-positive cells in lymph nodes as mature dendritic cells (DC), based on their expression of CD83 and DC-Lamp and their lack of expression of macrophage marker CD163. Surprisingly, they did not express CD123, a marker of plasmacytoid dendritic cells, which have been claimed to express IDO. IDO-expressing DC represented about 50% of mature DC in the lymph nodes.
Tumor-draining lymph nodes were reported to been enriched in IDO-positive dendritic cells. Since the published data were obtained using polyclonal antibodies that were cross-reactive, we evaluated the expression of IDO in tumor-draining lymph nodes, using our specific monoclonal antibody on a similar series of clinical samples from breast carcinomas and melanomas. We found IDO-positive dendritic cells in those tumor-draining lymph nodes. However, their frequency and phenotype were identical to those observed in normal lymph nodes.
We then evaluated the expression of IDO in monocyte-derived dendritic cells obtained in vitro with GM-CSF and IL-4. Immature dendritic cells did not express IDO, while IDO expression was induced upon maturation. The strongest maturation stimuli also induced the strongest IDO expression. This IDO was enzymatically active, and caused a reduction of allogeneic T cell proliferation observed in medium conditioned by mature DCs
Uncovering molecular actors of IDO-mediated T cell dysfunction with genome-wide CRISPR/Cas9 knockout screens
No full textIntroduction: Despite tremendous progress in cancer immunotherapy, most patients fail to benefit because of poorly characterized immune resistance mechanisms. Among these, expression of the tryptophan-catabolizing enzyme Indoleamine 2,3-dioxygenase (IDO) has been found in several tumors and associated with local immune suppression, notably by inhibiting T cell functions. However, the exact molecular pathways making T cells sensitive to IDO are still unclear. We propose to exploit the power of whole-genome single-guide RNA (sgRNA) CRISPR screens to uncover novel mechanisms of IDO-mediated T cell dysfunction. Methods: Cas9-expressing transgenic mice were crossed with mice expressing a transgenic T cell receptor (TCR) specifically recognizing a tumor antigen called P1A. Primary Cas9xTCRP1A CD8+ T cells were isolated from these mice and stimulated with P1A-expressing tumor cells. Cells were then transduced with the Teichmann retroviral genome wide CRISPR knockout library. Seven days after the first stimulation, CD8+ T cells were re-stimulated in a control (Tryptophanhigh, kynureninelow) or selective (Tryptophanlow, kynureninehigh) medium, mimicking the function of IDO in vitro. After four days of screening selection, genomic DNA was extracted from remaining living cells and sequencing libraries were prepared. sgRNA representation was then assessed by next-generation sequencing. Results: In vitro CRISPR knockout screening pipeline was successfully set up and validated. This includes: (1.) Successful transduction of the CRISPR knockout library, as well as efficient gene knockout in Cas9xTCRP1A primary CD8+ T cells. (2.) Confirming the strong inhibition of T cell proliferation and survival in the selective medium as compared to the control medium, thereby validating the screening selection strategy. (3.) Optimizing genomic DNA extraction procedure, as well as sequencing library preparation. Finally, the proposed in vitro CRISPR knockout screening was successfully launched, and analysis of potential candidate genes is ongoing. Conclusions and perspectives: Our study proposes to perform genome wide CRISPR knockout screens in T cells exposed to conditions mimicking IDO activity in vitro. Enriched sgRNA at the end of the selection should reveal genes whose inhibition improved T cell survival in Tryptophanlow/kynureninehigh medium. Resulting potential candidate targets will then be validated by knocking them out in T cells and assessing T cell functions under conditions mimicking IDO-mediated immune suppression in vitro. Similar validation of top candidate genes will also be performed in vivo in a model of adoptive cell transfer of target-knockout T cells in mice bearing IDO-expressing tumors. The identified genes/pathways involved in T cell sensitivity to Tryptophan shortage/Kynurenine enrichment should reveal new relevant mechanisms of IDO-mediated immune suppression in the tumor microenvironment
Letter, [Author unclear] to Paulina T. Merritt
No full textHandwritten letter to Paulina Merritt from an unknown author, October 1, 1876.
Reduced number of infiltrating activated T lymphocytes by transplantation of rfNSCs-IDO.
No full text<p>The EAE model exhibited the abnormal infiltration of lymphocytes into the brain. (A) Immunofluorescent staining was performed against CD3<sup>+</sup> T lymphocytes, CD25<sup>+</sup> activated T cells, and FoxP3<sup>+</sup> regulatory T cells in cerebral cortex. Scale bars, 100 μm. (B) The number of lymphocytes present in the cerebral cortex was quantified. The number of CD3<sup>+</sup> T cells was not different among experimental groups whereas the number of CD25<sup>+</sup> activated T cells was significantly reduced in both the rfNSCs-Cont and the rfNSCs-IDO groups compared to the HBSS group. The number of FoxP3<sup>+</sup> regulatory T cell was greatly increased in the rfNSCs-Cont and the rfNSCs-IDO groups, and the rfNSCs-IDO group showed a significantly increased level compared to the rfNSCs-Cont group (n = 4, * <i>p</i> < 0.05, ** <i>p</i> < 0.001).</p
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