Faculty Opinions recommendation of HIV inhibits CD4+ T-cell proliferation by inducing indoleamine 2,3-dioxygenase in plasmacytoid dendritic cells.

Author(s):  
Alan Landay
Blood ◽  
2006 ◽  
Vol 109 (8) ◽  
pp. 3351-3359 ◽  
Author(s):  
Adriano Boasso ◽  
Jean-Philippe Herbeuval ◽  
Andrew W. Hardy ◽  
Stephanie A. Anderson ◽  
Matthew J. Dolan ◽  
...  

AbstractInfection with the human immunodeficiency virus type-1 (HIV) results in acute and progressive numeric loss of CD4+ T-helper cells and functional impairment of T-cell responses. The mechanistic basis of the functional impairment of the surviving cells is not clear. Indoleamine 2,3-dioxygenase (IDO) is an immunosuppressive enzyme that inhibits T-cell proliferation by catabolizing the essential amino acid tryptophan (Trp) into the kynurenine (kyn) pathway. Here, we show that IDO mRNA expression is elevated in peripheral blood mononuclear cells (PBMCs) from HIV+ patients compared with uninfected healthy controls (HCs), and that in vitro inhibition of IDO with the competitive blocker 1-methyl tryptophan (1-mT) results in increased CD4+ T-cell proliferative response in PBMCs from HIV-infected patients. We developed an in vitro model in which exposure of PBMCs from HCs to either infectious or noninfectious, R5- or X4-tropic HIV induced IDO in plasmacytoid dendritic cells (pDCs). HIV-induced IDO was not inhibited by blocking antibodies against interferon type I or type II, which, however, induced IDO in pDCs when added to PBMC cultures. Blockade of gp120/CD4 interactions with anti-CD4 Ab inhibited HIV-mediated IDO induction. Thus, induction of IDO in pDCs by HIV may contribute to the T-cell functional impairment observed in HIV/AIDS by a non–interferon-dependent mechanism.


2017 ◽  
Vol 33 (1) ◽  
pp. 21-28
Author(s):  
Daniel Scott-Algara ◽  
Josiane Warszawski ◽  
Jérôme Le Chenadec ◽  
Céline Didier ◽  
Thomas Montange ◽  
...  

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1553-1553
Author(s):  
Davi d J. Chung ◽  
Marco Rossi ◽  
Emanuela Romano ◽  
Jennifer Pressley ◽  
Christophe Antczak ◽  
...  

Abstract Best characterized as initiators of immunity, dendritic cells (DCs) also play an integral role in immune modulation. Immature DCs, for example, process self-antigens to induce and maintain tolerance. The immunoregulatory effects of DCs, however, are not limited to immature subtypes. Immunogenic mature DCs can also induce T regs to curb immune responses. We have found that human monocyte-derived DCs (moDCs) upregulate the immunomodulatory enzyme indoleamine 2,3-dioxygenase (IDO) with maturation and expand functionally active, naturally occurring as well as inducible regulatory T cells (T regs) in an IDO-dependent manner. Priming of resting bulk T cells with autologous, IDO-expressing, mature moDCs in the absence of exogenous cytokines results in up to 10-fold expansion of CD4+CD25hiFoxp3+CD127neg T cells that mediate significant dose-dependent suppression of both allogeneic and autologous T cells stimulated de novo by DCs. The expansion of T regs by IDO-expressing moDCs involves cell-to-cell contact, CD80/CD86 ligation, and IL-2. Autologous priming in the presence of a competitive inhibitor of IDO, 1-methyl-tryptophan, diminishes T reg expansion. Candidate T regs were further characterized after cytofluorographic sorting primed bulk T cells into CD4+CD25hi, CD4+CD25int, and CD4+CD25neg subpopulations. Post-sort analysis showed that >60% of the CD4+CD25hi cells coexpressed Foxp3, which was not present in the CD4+CD25neg cells. CD4+CD25hi T regs exerted dose-dependent inhibition of DC-stimulated allogeneic T cell proliferation, with >90% inhibition at a suppressor to responder T cell ratio of 1:1 and ~50% inhibition at a ratio of 1:25. CD4+CD25int cells produced intermediate suppression depending on dose, and CD4+CD25neg cells were not inhibitory. CD4+CD25hi T regs mediated similar suppression of autologous T cell responses to stimulation de novo by DCs. CD4+CD25hi T regs also inhibited the generation of cytotoxic T lymphocytes (CTLs) specific for the Wilms’ tumor gene product (WT-1). The addition of CD4+CD25hi T regs to CTL-priming cultures resulted in a >80% decrease in specific target cell lysis of a WT-1-expressing cell line. Separate studies showed that T reg-mediated suppression is contact dependent and also requires TGF-beta, suggesting inhibition by naturally occurring and inducible T regs, respectively. Depletion of CD4+CD25hi T cells from bulk T cells by negative immunoselection with anti-CD25 magnetic beads at the outset of autologous priming significantly blunts T reg expansion, indicating a requirement for pre-existing T regs in the bulk T cell population. T reg expansion also occurs in priming cultures using cytofluorographically-sorted CD4+CD25neg T cells, indicating de novo generation of T regs from CD4+CD25neg precursors. In summary, our results demonstrate a mechanism by which mature, IDO-expressing, human moDCs expand autologous, naturally occurring as well as inducible T regs that functionally suppress the proliferation of both autologous and allogeneic T cells. Inhibition of this counter-regulatory pathway should result in more sustained benefit from active DC-based immunotherapy.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 3179-3179
Author(s):  
Haimeng Yan ◽  
Donghua He ◽  
Xi Huang ◽  
Zhang En Fan ◽  
He Huang ◽  
...  

Abstract Background: The interaction of multiple myeloma (MM) cells with macrophages (MΦs) in the bone marrow microenvironment contributes to the pathophysiology of MM. In addition to promoting angiogenesis through vasculogenic mimicry, MM-associated MΦs (mMΦs) protect MM cells from spontaneous and chemotherapy-induced apoptosis. mMΦs therefore represent a potential target for myeloma treatment and it is essential to explore the mechanisms underlying normal MΦ polarization to mMΦs. We previously showed that IL-32 is overexpressed in MM patients and is mainly derived from MM cells. The present study was designed to explore the clinical significance of IL-32 in MM and to further elucidate the molecular mechanisms underlying the IL-32-mediated immune function of MΦs. Methods: We examined the expression of IL-32 in bone marrow biopsy samples using immunohistochemistry. Quantitative real-time PCR, western blot analysis and immunofluorescence were applied to measure the expression of IL-32, IDO and proteinase 3 (PR3). We obtained the global transcriptional profile of the IL-32γ-treated MΦs by RNA sequencing (RNA-Seq). Immunoprecipitation (IP) and GST pulldown experiments was applied to confirm the binding affinity of PR3 for IL-32. We created IL-32-knockdown MM cells by transfection of IL-32 shRNA and silenced PR3 expression in MΦs using siRNA targeting PR3. CD4+ T cell proliferation and IL-2, IFN-γ and TNF-α production were measured by flow cytometry. Results: We found that high IL-32 expression in MM patients was associated with advanced clinical stage and high serum β2-microglobulin levels. Several isoforms of IL-32 were detected in MM cells and IL-32γ was the most active subtype. RNA sequencing revealed that IL-32γ significantly induced the production of the immunosuppressive molecule indoleamine 2,3-dioxygenase (IDO) in MΦs and this effect was verified at the protein level. Furthermore, IL-32-knockdown MM cells showed less ability than control MM cells to promote IDO expression. As a binding protein for IL-32, PR3 was universally expressed on the surface of MΦs and knockdown of PR3 or inhibition of the STAT3 and nuclear factor κB (NF-κB) pathways hindered the IL-32γ-mediated stimulation of IDO expression. Finally, IDO-positive IL-32γ-educated MΦs inhibited CD4+ T cell proliferation and IL-2, IFN-γ and TNF-α production in response to activation. Conclusion: Our study showed that MM cell-derived IL-32γ induced IDO production in MΦs through PR3 and the downstream STAT3 and NF-κB pathways, resulting in the suppression of the proliferation and effector function of CD4+ T cells. High IL-32 expression in MM may contribute to an immunosuppressive microenvironment by upregulating IDO production in MΦs and promote MM progression. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 4298-4298
Author(s):  
Sara Trabanelli ◽  
Antonio Curti ◽  
Darina Očadlíková ◽  
Cecilia Evangelisti ◽  
Valentina Salvestrini ◽  
...  

Abstract Abstract 4298 Indoleamine 2,3-dioxygenase (IDO1) and indoleamine 2,3-dioxygenase-like (IDO2) are enzymes involved in the tryptophan catabolism along the kynurenine pathway. While it is established that IDO1-expressing dendritic cells (DCs) contribute to tolerance in a number of biological settings, little is known about the expression and function of IDO2 in DCs. Human DCs can be generated in vitro to obtain immunogenic antigen-presenting cells (APC), used as cellular vaccines. In the clinical setting, DCs are commonly matured with a cytokine cocktail (CC) which includes TNF-a, IL-1b, IL-6 and PGE2. In particular, PGE2 enhances APC function of DCs by increasing IL-12 production and facilitating DC migration to lymph nodes. However, PGE2 is also a strong IDO1 inducer, which by this route can also limit the anti-tumor activity of DC-based immunotherapies. Thus, understanding the roles of IDO1 and IDO2 in DCs may impact the development of vaccines or DC-based immunotherapies. In the present study, we fully characterized IDO1 and IDO2 expression and function in human monocyte-derived dendritic cells (Mo-DCs). Mo-DCs were generated from purified CD14+ monocytes after culture with GM-CSF and IL-4 and then matured with CD40L, LPS alone, LPS plus IFN-g and the CC. We observed that immature Mo-DCs had little if any expression of both IDO1 and IDO2, whereas mature Mo-DCs exhibited upregulation of both enzymes. Among the different maturation stimuli, CC was the most effective in upregulating IDO1 and IDO2, both at the message and protein levels. This effect was associated also with the highest kynurenine production. By means of IDO1 and IDO2 expression, mature Mo-DCs were inhibited in stimulating allogeneic T cell proliferation and generated a population of CD4+CD25+FOXP3+ Tregs which highly suppressed allogeneic and autologous T-cell proliferation. On the basis of evidence that IDO1 is preferentially inhibited by the L-isoform of 1 methyl-tryptophan (1-MT) and IDO2 by the D-isoform, we performed functional enzyme tests in presence of both isoforms. Notably, both isoforms exhibited inhibitory effects, although we observed a stronger effect of L-1-MT than with D-1-MT suggesting a greater contribution of IDO1 than IDO2. These results offer direct evidence that Mo-DCs express functional IDO1 and IDO2 proteins. During the maturation phase, Mo-DCs enhance their tolerogenic qualities, and in particular the capacity to induce Tregs, through the upregulation of both IDO1 and IDO2. Beside the critical role of IDO1 in enhancing the immunosuppressive capacity of DCs, we show, for the first time, that IDO2 is involved also. Our findings imply that, from a clinical standpoint, to improve the efficacy of DC-based vaccines mature DCs should be combined with molecules that can inhibit the activity of both IDO1 and IDO2. Disclosures: Metz: NewLink Genetics: Employment. Prendergast:New Link Genetics Corp: Consultancy, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties.


2005 ◽  
Vol 174 (3) ◽  
pp. 1433-1437 ◽  
Author(s):  
Mi-Yeon Kim ◽  
Vasilios Bekiaris ◽  
Fiona M. McConnell ◽  
Fabrina M. C. Gaspal ◽  
Chandra Raykundalia ◽  
...  

2007 ◽  
Vol 13 (1) ◽  
pp. 33-40 ◽  
Author(s):  
W-H Zhu ◽  
C-Z Lu ◽  
Y-M Huang ◽  
H Link ◽  
B-G Xiao

The basis for the reduced relapse rate of multiple sclerosis (MS) during pregnancy remains unexplained but, if defined, could create novel treatment options. Estrogen constitutes one candidate molecule, but the mechanism by which estrogen may affect MS during pregnancy is unclear. In this study, we used monocyte-derived dendritic cells (DCs) from MS patients to explore the estrogen (17-b-estradiol)-related pathway of immune modulation. Estrogen induced the expression of indoleamine 2,3-dioxygenase (IDO) on DCs, limiting T-cell proliferation and both Th1 and Th2 cytokine production. The suppression of T-cell proliferation mediated by estrogenexposed DCs was partly abolished by the IDO-inhibitor, 1-methyl-dl-tryptophan, indicating that estrogen-exposed DCs induced IDO-dependent T-cell suppression. Our data support the hypothesis that the change in the clinical course of MS observed in pregnancy may be related to the estrogen DC-IDO axis, which could represent a novel target for MS therapy.


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