Regulatory T Cells Expanded by Autologous Mature Human Dendritic Cells Expressing Indoleamine 2,3-Dioxygenase Are Potent Suppressors of T Cell Proliferation.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1553-1553
Author(s):  
Davi d J. Chung ◽  
Marco Rossi ◽  
Emanuela Romano ◽  
Jennifer Pressley ◽  
Christophe Antczak ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
De Novo ◽  
T Cell Proliferation ◽  
Indoleamine 2,3 Dioxygenase ◽  
Naturally Occurring ◽  
Dose Dependent

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.

scholarly journals Regulatory T Cells Target Chemokine Secretion by Dendritic Cells Independently of Their Capacity To Regulate T Cell Proliferation

2011 ◽  
Vol 186 (12) ◽  
pp. 6807-6814 ◽  
Author(s):  
Sara Morlacchi ◽  
Valentina Dal Secco ◽  
Cristiana Soldani ◽  
Nicolas Glaichenhaus ◽  
Antonella Viola ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
T Cell Proliferation

Mature Conventional Human Dendritic Cells Express Indoleamine 2,3-Dioxygenase and Support the Relative Expansion of Autologous Regulatory T Cells.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1804-1804
Author(s):  
David J. Chung ◽  
Marco Rossi ◽  
Jennifer Pressley ◽  
David H. Munn ◽  
James W. Young
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
Tumor Antigens ◽  
De Novo ◽  
T Cell Proliferation ◽  
Dependent Manner ◽  
Suppressor T Cells ◽  
Cell Ratio ◽  
Dose Dependent

Abstract Effective immunotherapy must overcome tolerance toward tumor antigens and avoid subsequent inhibition of stimulated antitumor immunity. The specific contribution of immune regulatory mechanisms intrinsic to dendritic cells (DCs), especially with regard to regulatory T cells (T regs), is of emerging importance. We have found that all conventional, immunogenic human DCs express the immunomodulatory enzyme indoleamine 2,3-dioxygenase (IDO) and that IDO protein expression and activity are markedly increased in mature compared with immature DCs. Priming of resting T cells with mature IDO+ DCs in an autologous mixed leukocyte reaction (MLR) increases the proportion of CD4+CD25+ T cells capable of suppressing allogeneic T cell proliferation in secondary MLRs as much as 10-fold above baseline (Figure 1A). Conversely, 1-methyl-tryptophan, a competitive inhibitor of IDO, dampens the inhibitory activity (Figure 1A). Further characterization of the suppressor T cells was performed after cytofluorographic sorting into CD4+CD25hi, CD4+CD25int, and CD4+CD25low/− subpopulations. Post-sort analysis revealed that the majority (>60%) of the CD4+CD25hi cells coexpressed Foxp3, which was absent in the CD4+CD25low/− cells. Separate studies showed that these Foxp3+ cells express little or no CD127 (IL-7R-alpha). Candidate CD4+CD25hi T regs inhibited DC-stimulated allogeneic T cell proliferation in a dose dependent manner, with >90% inhibition at a suppressor to responder T cell ratio of 1:1 and ∼50% inhibition at a ratio as low as 1:25 (Figure 1B). CD4+CD25low/− cells were not inhibitory, and CD4+CD25int cells exerted intermediate suppression depending on dose (Figure 1B). CD4+CD25hi T regs exert similar inhibition of autologous T cell responses to stimulation de novo by DCs. Both the priming and effector phases of T reg suppression were contact dependent. Moreover, depletion of the trace population of CD4+CD25hi T cells at the outset of autologous priming largely abolished the relative expansion of this population. These results clearly demonstrate that mature conventional human DCs support relative but significant expansion of autologous, constitutive CD4+CD25hi T cells, which coexpress Foxp3, express little or no CD127, and exert significant suppression of both allogeneic and autologous T cells stimulated de novo by DCs. Although contrary to the anticipated enrichment of IDO in immature DCs because of their expected tolerogenicity, these findings underscore the importance of regulatory mechanisms exerted by immunogenic cells like mature conventional DCs. While this may provide a physiologic means of turning off an otherwise unchecked immune response, this IDO-mediated pathway in DCs provides a rational target for optimizing host immune responses against tumor antigens. This should result in more sustained benefit from active immunotherapy with DC-based vaccines. FIGURE 1: A) T cell mediated suppression of secondary allogeneic MLR. Autologous T eels primed in the presence of the IDO inhibitor. 1-metnyl-D-tryptophan (1-MT), do not develop as much suppressor activity as T cells primed in the absence of 1-MT, resulting in loss inhibition of the secondary MLR Data presented are representative of 6 experiments. B) CD4−CD25***** T cells art potent inhibitors of T cell proliferation. FACS-sorted CD4−CD25******, CD4−CD25*****, and CD4−CD25***** T cells (‘suppressor T cells’) were added to allogeneic MLRs composed of autologous DCs + allogeneic T cells. DC to T cell ratio was 1:30. Suppressor T cell to responder T cell ratios were 1:25, 1:5, and 1:1. After 4–5 days in culture, responder T cell proliferation was assessed by measuring 3HTdR incorporation and comparing with controls containing no suppressor cells (black bar). CD4−CD25***** cells inhibited T cell proliferation in a dose-dependent manner. CD4−CD25***** cells inhibited proliferation to a lesser degree, and CD4-CD25***** cells showed no inhibition. While the CD4−CD25***** cells and to a lesser extent the CD4−CD25***** cells suppressed the proliferative response of alloreactive T cells in the MLRs, they were themselves anergic to the allogeneic DCs in proportion to CD25 and FOXP3 expression (data not shown). Values are pooled from 3 independent experiments (N=4 for each condition), and error bars indicate standard deviation of the mean. FIGURE 1:. A) T cell mediated suppression of secondary allogeneic MLR. Autologous T eels primed in the presence of the IDO inhibitor. 1-metnyl-D-tryptophan (1-MT), do not develop as much suppressor activity as T cells primed in the absence of 1-MT, resulting in loss inhibition of the secondary MLR Data presented are representative of 6 experiments. B) CD4−CD25***** T cells art potent inhibitors of T cell proliferation. FACS-sorted CD4−CD25******, CD4−CD25*****, and CD4−CD25***** T cells (‘suppressor T cells’) were added to allogeneic MLRs composed of autologous DCs + allogeneic T cells. DC to T cell ratio was 1:30. Suppressor T cell to responder T cell ratios were 1:25, 1:5, and 1:1. After 4–5 days in culture, responder T cell proliferation was assessed by measuring 3HTdR incorporation and comparing with controls containing no suppressor cells (black bar). CD4−CD25***** cells inhibited T cell proliferation in a dose-dependent manner. CD4−CD25***** cells inhibited proliferation to a lesser degree, and CD4-CD25***** cells showed no inhibition. While the CD4−CD25***** cells and to a lesser extent the CD4−CD25***** cells suppressed the proliferative response of alloreactive T cells in the MLRs, they were themselves anergic to the allogeneic DCs in proportion to CD25 and FOXP3 expression (data not shown). Values are pooled from 3 independent experiments (N=4 for each condition), and error bars indicate standard deviation of the mean.

scholarly journals Inhibition of Allogeneic T Cell Proliferation by Indoleamine 2,3-Dioxygenase–expressing Dendritic Cells

2002 ◽  
Vol 196 (4) ◽  
pp. 447-457 ◽  
Author(s):  
Peter Terness ◽  
Thomas M. Bauer ◽  
Lars Röse ◽  
Christoph Dufter ◽  
Andrea Watzlik ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
Cell Death ◽  
Dendritic Cells ◽  
T Cell ◽  
Antigen Presenting Cells ◽  
T Cell Proliferation ◽  
Inhibition Of Proliferation ◽  
Indoleamine 2,3 Dioxygenase ◽  
Antigen Presenting

Indoleamine 2,3-dioxygenase (IDO), an enzyme involved in the catabolism of tryptophan, is expressed in certain cells and tissues, particularly in antigen-presenting cells of lymphoid organs and in the placenta. It was shown that IDO prevents rejection of the fetus during pregnancy, probably by inhibiting alloreactive T cells, and it was suggested that IDO-expression in antigen-presenting cells may control autoreactive immune responses. Degradation of tryptophan, an essential amino acid required for cell proliferation, was reported to be the mechanism of IDO-induced T cell suppression. Because we wanted to study the action of IDO-expressing dendritic cells (DCs) on allogeneic T cells, the human IDO gene was inserted into an adenoviral vector and expressed in DCs. Transgenic DCs decreased the concentration of tryptophan, increased the concentration of kynurenine, the main tryptophan metabolite, and suppressed allogeneic T cell proliferation in vitro. Kynurenine, 3-hydroxykynurenine, and 3-hydroxyanthranilic acid, but no other IDO-induced tryptophan metabolites, suppressed the T cell response, the suppressive effects being additive. T cells, once stopped in their proliferation, could not be restimulated. Inhibition of proliferation was likely due to T cell death because suppressive tryptophan catabolites exerted a cytotoxic action on CD3+ cells. This action preferentially affected activated T cells and increased gradually with exposure time. In addition to T cells, B and natural killer (NK) cells were also killed, whereas DCs were not affected. Our findings shed light on suppressive mechanisms mediated by DCs and provide an explanation for important biological processes in which IDO activity apparently is increased, such as protection of the fetus from rejection during pregnancy and possibly T cell death in HIV-infected patients.

Relative impact of CD4+CD25+ regulatory T cells and tacrolimus on inhibition of T-cell proliferation in patients with atopic dermatitis

2005 ◽  
Vol 153 (4) ◽  
pp. 750-757 ◽  
Author(s):  
M. Vukmanovic-Stejic ◽  
A. McQuaid ◽  
K.E. Birch ◽  
J.R. Reed ◽  
C. Macgregor ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
Atopic Dermatitis ◽  
T Cell ◽  
Regulatory T Cells ◽  
T Cell Proliferation ◽  
Relative Impact

scholarly journals HIV inhibits CD4+ T-cell proliferation by inducing indoleamine 2,3-dioxygenase in plasmacytoid dendritic cells

Blood ◽  
2006 ◽  
Vol 109 (8) ◽  
pp. 3351-3359 ◽  
Author(s):  
Adriano Boasso ◽  
Jean-Philippe Herbeuval ◽  
Andrew W. Hardy ◽  
Stephanie A. Anderson ◽  
Matthew J. Dolan ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Dendritic Cells ◽  
T Cell ◽  
Functional Impairment ◽  
Plasmacytoid Dendritic Cells ◽  
Cd4 T Cell ◽  
T Cell Proliferation ◽  
Type I ◽  
Indoleamine 2,3 Dioxygenase

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.

scholarly journals Cutting Edge: Regulatory T Cells from Lung Cancer Patients Directly Inhibit Autologous T Cell Proliferation

2002 ◽  
Vol 168 (9) ◽  
pp. 4272-4276 ◽  
Author(s):  
Edward Y. Woo ◽  
Heidi Yeh ◽  
Christina S. Chu ◽  
Katia Schlienger ◽  
Richard G. Carroll ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Cancer Patients ◽  
Cutting Edge ◽  
T Cell Proliferation ◽  
Lung Cancer Patients
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