Human CD4+CD25+ regulatory T Cells Exhibit Dual Mechanisms of Action in Suppressing in Vitro Alloreactivity

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2582-2582
Author(s):  
Rachel E Protheroe ◽  
Graziella Mazza ◽  
Kirsty S Nicolson ◽  
Colin G Steward ◽  
David C Wraith
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
Regulatory T Cells ◽  
Mechanisms Of Action ◽  
Cell Contact ◽  
Regulatory Cells ◽  
Responder Cell ◽  
Cytokine Responses ◽  
A Cell

Abstract There is extensive evidence from murine models supporting a role for CD4+CD25+ regulatory T cells in suppressing alloreactivity. However, clinical evidence regarding the role of regulatory T cells in human alloresponses is conflicting and may reflect the difficulty in defining and isolating naturally occurring human CD4+CD25+ regulatory T cells. Moreover, the mechanism of action of Foxp3+ regulatory T cells remains somewhat controversial with a number of proposed modes of suppression described, including cell contact-dependent inhibition, cytokine mediated suppression and cytokine consumption. We have previously used peripheral blood monocyte-derived dendritic cells (DCs) as antigen presenting cells (APCs) in allogeneic mixed lymphocyte reactions (MDCLRs), to assess the in vitro suppressive function of human CD4+CD25+ T cells. Healthy volunteer donor MACS isolated CD4+CD25+ regulatory T cells demonstrated anergy and significant dose-dependent suppression of responder cell proliferation, to physiological frequencies, in allogeneic MDCLRs (p<0.005). In this study we investigated the in vitro mechanism of action of human CD4+CD25+ T cells in suppressing alloreactivity in MDCLRs. Co-culture of CD4+CD25+ regulatory T cells with autologous CD4+ responder cells in allogeneic MDCLRs, at a ratio of 1:4, resulted in suppression of proliferation by 68%. Peak suppression of CD4+ responder cell proliferation, observed on day five of co-culture, was accompanied by significant suppression of co-culture supernatant IL-5 concentration (p<0.05), and preceded by inhibition of IL-2. Intracellular cytokine staining confirmed that CD4+ responder cell intracellular IL-2 was reduced by 60% on co-culturing with CD4+CD25+ regulatory T cells in the allogeneic MDCLR. CD4+CD25+ regulatory T cells mediated suppression of proliferation and cytokine responses across transwell membranes, demonstrating a cell contact-independent mechanism and a potential soluble factor in the mode of action of CD4+CD25+ regulatory T cells in suppressing human alloresponses. This was confirmed by suppression of responder cell proliferation and cytokine responses by supernatant transfer from DCs co-cultured with allogeneic CD4+CD25+ regulatory cells. We surveyed possible candidate molecules responsible for mediating the cell contact-independent suppression; in our hands, neither IL-10 nor TGF-β was identified as the soluble factor. Next, we examined the effect of CD4+CD25+ regulatory T cells on APCs in the allogeneic MDCLR. Immunophenotypic characterization of DCs recovered from MDCLRs in the presence of CD4+CD25+ regulatory T cells showed down-regulation of HLA-DR, CD83, and co-stimulatory molecules, CD80 and CD86, compared with DCs cultured with CD4+CD25− T cells or cytokines, IL-4 and GM-CSF, alone. The suppression of DC activation by CD4+CD25+ regulatory T cells was not mediated across transwell membranes, demonstrating a cell contact-requirement. Moreover, downregulation of DC activation markers was not accompanied by IL-12 suppression, implying no role for IL-10 in mediating the suppressive effect of the regulatory cells on the APCs. Our results demonstrate both a cell contact-independent mode of action in suppressing CD4+ responder cell proliferation, Th1 and Th2 cytokine responses, independent of IL-10 and TGF-β, and a cell contact-requirement in the suppression of allogeneic DC maturation and activation. In summary, our findings suggest that multiple mechanisms of action contribute to the in vitro suppressive effects of human CD4+CD25+ regulatory T cells on alloreactivity.

Characterization of in vitro antimurine thymocyte globulin–induced regulatory T cells that inhibit graft-versus-host disease in vivo

Blood ◽  
2008 ◽  
Vol 111 (3) ◽  
pp. 1726-1734 ◽  
Author(s):  
Melanie C. Ruzek ◽  
James S. Waire ◽  
Deborah Hopkins ◽  
Gina LaCorcia ◽  
Jennifer Sullivan ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Graft Versus Host Disease ◽  
Antithymocyte Globulin ◽  
Mrna Level ◽  
Regulatory Cells ◽  
Host Disease ◽  
Graft Versus Host

Abstract Antithymocyte/antilymphocyte globulins are polyclonal antihuman T-cell antibodies used clinically to treat acute transplant rejection. These reagents deplete T cells, but a rabbit antihuman thymocyte globulin has also been shown to induce regulatory T cells in vitro. To examine whether antithymocyte globulin–induced regulatory cells might be functional in vivo, we generated a corresponding rabbit antimurine thymocyte globulin (mATG) and tested its ability to induce regulatory cells in vitro and whether those cells can inhibit acute graft-versus-host disease (GVHD) in vivo upon adoptive transfer. In vitro, mATG induces a population of CD4+CD25+ T cells that express several cell surface molecules representative of regulatory T cells. These cells do not express Foxp3 at either the protein or mRNA level, but do show suppressive function both in vitro and in vivo when adoptively transferred into a model of GVHD. These results demonstrate that in a murine system, antithymocyte globulin induces cells with suppressive activity that also function in vivo to protect against acute GVHD. Thus, in both murine and human systems, antithymocyte globulins not only deplete T cells, but also appear to generate regulatory cells. The in vitro generation of regulatory cells by anti-thymocyte globulins could provide ad-ditional therapeutic modalities for immune-mediated disease.

scholarly journals Mechanisms of Immunosuppression By FVIII-Specific TCR Engineered Human Regulatory T Cells

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3514-3514
Author(s):  
Yong Chan Kim ◽  
Ai-Hong Zhang ◽  
Jeong Heon Yoon ◽  
David William Scott
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Immune Responses ◽  
Immune Tolerance ◽  
Hemophilia A ◽  
Culture Media ◽  
Cell Contact ◽  
Suppressive Function

Abstract Expanded antigen-specific engineered regulatory T cells (Tregs) have been proposed for potential clinical application for the treatment of undesirable immune responses, such as inhibitor responses in hemophilia A patients and autoimmune diseases. By providing an antigen-specific T-cell receptor (TCR) to polyclonal natural Tregs, we suggested that antigen-specific engineered Tregs would migrate specifically to particular target tissues and induce antigen-specific immune tolerance in the local milieu. Previously, we developed FVIII C2-specific Tregs using a long-term stabilization protocol in vitro and demonstrated that these stabilized engineered Tregs successfully modulated FVIII-specific T-cell- and B-cell immune responses. Herein, we examined the mechanism of suppression by antigen-specific engineered Tregs compared to polyclonal normal natural Tregs. Initially, we tested whether these FVIII-specific engineered Tregs were able to suppress neighboring activated T-cell effectors locally. We found that FVIII C2-specific Tregs strongly suppressed myelin basic protein (MBP)-specific T effectors by presentation of both specific antigens in same APC population. However, we also observed that C2-specific Tregs could suppress MBP-specific T effectors presented on different APCs. These results imply contactless suppressive function of C2-specific engineered Tregs. Using a modified trans-well suppression assay, in which physical distance and clear separation between Tregs and a set of T effectors was created, we found that C2-specific activated Tregs showed significant contactless suppression only when T effectors were also present. In addition, and confirming previous studies with polyclonal Tregs, suppression by FVIII-specific engineered Tregs could be overcome by increasing the dose of IL-2 in co-culture media. This suggests that Tregs act, in part, by usurping IL-2 needed by T effectors to proliferate. Surprisingly, neutralization of CTLA-4 did not interfere with FVIII C2-specific suppression of engineered Tregs in contrast to the reversal seen with anti-CD3e-driven non-specific immunosuppression. Our data strongly suggest that suppressive function of FVIII-specific engineered Tregs is not restricted to cell-to-cell contact. Rather cross-talk of engineered Tregs and T effectors potentially generate a contactless suppressive mechanism to suppress other FVIII-specific multiple effector cells in the local milieu for effective immune tolerance. Understanding the mechanism of contactless suppression mechanism should provide critical clues to develop more effective engineered Tregs as a therapeutic tool in hemophilia A. (Supported by NIH grants HL061883 and HL126727) Disclosures Kim: Henry Jackson Foundation: Other: patent filed. Zhang:Henry Jackson Foundation: Other: patent filed. Scott:Henry Jackson Foundation: Other: patent filed.

scholarly journals Targeting Antigen Presenting   Cells to Treat Autoimmune  Inflammation

2021 ◽  
Author(s):  
◽  
Aras Toker
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Mhc Class Ii ◽  
T Cell Proliferation ◽  
Target Cells ◽  
Antigen Presenting

<p>Glatiramer acetate (GA) is approved for the treatment of relapsing-remitting multiple sclerosis (MS), and can suppress experimental autoimmune encephalomyelitis (EAE), a murine model of human MS. GA treatment is associated with the induction of anti-inflammatory TH2 responses and with the antigen specific expansion of regulatory T cells that counteract or inhibit pathogenic events in MS and EAE. These T cell mediated mechanisms of protection are considered to be a result of modulation of antigen presenting cells (APCs) by GA, rather than direct effects on T cells. However, it is unknown if GA preferentially targets a specific APC subset or can act through multiple APCs in vivo. In addition, GA-modulated innate cells may also exhibit direct antigen non-specific suppression of autoreactive cells. One objective of this study was to identify the in vivo target cell population of GA and to assess the potential of the target cells to antigen non-specifically suppress immune responses. Fluorophor-labelled GA bound to monocytes after intravenous injections, suggesting that monocytes may be the primary target of GA in vivo. In addition, intravenous GA treatment enhanced the intrinsic ability of monocytes to suppress T cell proliferation, both in vitro and in vivo. The findings of this study therefore suggest that GA-induced monocytes may contribute to GA therapy through direct mechanisms of antigen non-specific T cell immunosuppression. A further objective of this work was to investigate the potential of an in vivo drug targeting approach. This approach was hypothesised to increase the uptake of GA by the target cells and substantially improve GA treatment through antigen specific mechanisms such as induction of TH2 or regulatory T cells. Targeting antigens to professional APCs with an anti-MHC class II antibody resulted in significantly enhanced T cell proliferation in vitro. However, no EAE suppression occurred when GA was targeted to MHC class II in vivo. In addition, targeting GA specifically to monocytes also failed to suppress EAE. These findings suggest that GA treatment may selectively modulate monocytes to enhance their ability to inhibit autoreactive T cells, which could be part of the mechanism by which GA ameliorates MS. Targeting GA to a specific cell type may not be a powerful approach to improve treatment, because increased proliferation of GA specific T cells is not sufficient for disease suppression, and conjugation to antibodies may functionally reduce GA to a mere antigen devoid of immunomodulatory capacity.</p>

scholarly journals The Outcome of Neutrophil-T Cell Contact Differs Depending on Activation Status of Both Cell Types

2021 ◽  
Vol 12 ◽  
Author(s):  
Danielle Minns ◽  
Katie J. Smith ◽  
Gareth Hardisty ◽  
Adriano G. Rossi ◽  
Emily Gwyer Findlay
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
Full Range ◽  
T Cell Proliferation ◽  
Cell Contact ◽  
Activation Process ◽  
Naive T Cells ◽  
Naïve T Cells

Neutrophils and T cells exist in close proximity in lymph nodes and inflamed tissues during health and disease. They are able to form stable interactions, with profound effects on the phenotype and function of the T cells. However, the outcome of these effects are frequently contradictory; in some systems neutrophils suppress T cell proliferation, in others they are activatory or present antigen directly. Published protocols modelling these interactions in vitro do not reflect the full range of interactions found in vivo; they do not examine how activated and naïve T cells differentially respond to neutrophils, or whether de-granulating or resting neutrophils induce different outcomes. Here, we established a culture protocol to ask these questions with human T cells and autologous neutrophils. We find that resting neutrophils suppress T cell proliferation, activation and cytokine production but that de-granulating neutrophils do not, and neutrophil-released intracellular contents enhance proliferation. Strikingly, we also demonstrate that T cells early in the activation process are susceptible to suppression by neutrophils, while later-stage T cells are not, and naïve T cells do not respond at all. Our protocol therefore allows nuanced analysis of the outcome of interaction of these cells and may explain the contradictory results observed previously.

Sirolimus Inhibits Proliferation but Enhances Suppressive Activity of Rhesus Macaque Natural CD4 Regulatory T Cells

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1008-1008
Author(s):  
Karnail Singh ◽  
Natalia Kozyr ◽  
Linda Stempora ◽  
Allan D Kirk ◽  
Christian P Larsen ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Ex Vivo ◽  
Cd8 T Cell ◽  
T Cell Proliferation ◽  
Suppressive Activity ◽  
Suppressive Capacity

Abstract Abstract 1008 Regulatory T cells (Tregs) have been shown to be potent inhibitors of autoimmunity, and to be capable of suppressing alloimmune responses that occur during both allograft rejection and graft-versus host disease. However, they have yet to gain widespread use clinically, due in part to the fact that it remains extremely costly and difficult to produce them in sufficient numbers and with sufficient suppressive capacity to significantly impact the alloimmune response. Here we have used our established non-human primate model to demonstrate that significant Treg expansion (up to 600-fold in 21 days) can be maintained, and suppressive capacity enhanced by exposing Treg cultures to a short burst of sirolimus at the end of the culture period. Using a highly sensitive and specific in vitro CFSE-MLR assay we show that Tregs significantly inhibit allo-proliferation of multiple T cell subpopulations including both CD4+ and CD8+ T cells (3.2 and 2.7-fold inhibition of proliferation, respectively), as well as their CD28+CD95+ and CD28-CD95+ subpopulations (2.2 and 2.1 and 1.9 and 2.7-fold inhibition of CD4+ and CD8+ subpopulation proliferation, respectively). Tregs were able to combine in vitro with the newly FDA-approved CTLA4-Ig analog belatacept to enhance the inhibition of alloproliferation that occurred with either agent alone (4.8-fold inhibition of CD8 T cell proliferation with Tregs + belatacept, compared to 3.0-fold or 1.9-fold inhibition of CD8 T cell proliferation with Tregs or belatacept alone, respectively). Importantly, we have found that the suppressive activity of ex-vivo expanded Tregs could be further enhanced by pulsing with sirolimus. Thus, while long-term culture of Tregs in the presence of sirolimus (1–1000 nM) profoundly inhibited Treg expansion (50–800 fold inhibition of expansion when cultured in the presence of 1–1000 nM sirolimus), a 48 hour pulse of sirolimus (100 nM) on days 20–21 of culture completely preserved Treg yields while doubling their suppressive function against CD8 proliferation when compared to unpulsed Tregs, p<0.01) A mechanistic evaluation of the increase potency observed with sirolimus pulsed Tregs (SPTs) has revealed several key differences that distinguish these cells from the less-potent unpulsed Tregs: SPTs were found to undergo fewer rounds of proliferation in an MLR when compared with unpulsed Tregs (14% proliferation in SPTs versus 37% proliferation in un-pulsed Tregs, p= 0.015), suggesting that the suppressive capability of Tregs may be inversely related to their proliferative capacity. SPTs were also shown to have significantly increased expression of CD25 (p=0.04) and total CTLA4 (p= 0.009) compared to unpulsed Tregs, implicating signaling through both of these molecules in their enhanced function. Our results suggest that the creation of SPTs may provide a novel avenue by which to achieve enhanced Treg-based suppression of alloimmunity, in a manner that is amenable to large-scale ex-vivo expansion and to combinatorial therapy with novel, costimulation-blockade-based immunosuppression strategies. Disclosures: No relevant conflicts of interest to declare.

scholarly journals CD4+CD25+ Regulatory T Cells Can Mediate Suppressor Function in the Absence of Transforming Growth Factor β1 Production and Responsiveness

2002 ◽  
Vol 196 (2) ◽  
pp. 237-246 ◽  
Author(s):  
Ciriaco A. Piccirillo ◽  
John J. Letterio ◽  
Angela M. Thornton ◽  
Rebecca S. McHugh ◽  
Mizuko Mamura ◽  
...  
Keyword(s):  
T Cells ◽  
Growth Factor ◽  
Regulatory T Cells ◽  
T Cell Activation ◽  
Transforming Growth Factor ◽  
Cell Contact ◽  
Suppressor Function ◽  
Tgf Β1

CD4+CD25+ regulatory T cells inhibit organ-specific autoimmune diseases induced by CD4+CD25−T cells and are potent suppressors of T cell activation in vitro. Their mechanism of suppression remains unknown, but most in vitro studies suggest that it is cell contact–dependent and cytokine independent. The role of TGF-β1 in CD4+CD25+ suppressor function remains unclear. While most studies have failed to reverse suppression with anti–transforming growth factor (TGF)-β1 in vitro, one recent study has reported that CD4+CD25+ T cells express cell surface TGF-β1 and that suppression can be completely abrogated by high concentrations of anti–TGF-β suggesting that cell-associated TGF-β1 was the primary effector of CD4+CD25+-mediated suppression. Here, we have reevaluated the role of TGF-β1 in CD4+CD25+-mediated suppression. Neutralization of TGF-β1 with either monoclonal antibody (mAb) or soluble TGF-βRII-Fc did not reverse in vitro suppression mediated by resting or activated CD4+CD25+ T cells. Responder T cells from Smad3−/− or dominant-negative TGF-β type RII transgenic (DNRIITg) mice, that are both unresponsive to TGF-β1–induced growth arrest, were as susceptible to CD4+CD25+-mediated suppression as T cells from wild-type mice. Furthermore, CD4+CD25+ T cells from neonatal TGF-β1−/− mice were as suppressive as CD4+CD25+ from TGF-β1+/+ mice. Collectively, these results demonstrate that CD4+CD25+ suppressor function can occur independently of TGF-β1.

Induction of CD8+ regulatory T cells in the intestine by Heligmosomoides polygyrus infection

2006 ◽  
Vol 291 (2) ◽  
pp. G253-G259 ◽  
Author(s):  
Ahmed Metwali ◽  
Tommy Setiawan ◽  
Arthur M. Blum ◽  
Joseph Urban ◽  
David E. Elliott ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Lamina Propria ◽  
T Cell Proliferation ◽  
Cell Contact ◽  
Heligmosomoides Polygyrus ◽  
Histocompatibility Complex ◽  
Antigen Presenting

This study determined whether Heligmosomoides polygyrus induces intestinal regulatory T cells. Splenic T cells proliferate strongly when cultured with anti-CD3 and antigen-presenting cells (APC). Lamina propria T cells from mice with H. polygyrus mixed with normal splenic T cells from uninfected mice inhibited proliferation over 90%. Lamina propria T cells from mice without H. polygyrus only modestly affected T cell proliferation. The worm-induced regulatory T cell was CD8+ and required splenic T cell contact to inhibit proliferation. The regulation also was IL-10 independent, but TAP-dependent, suggesting that it requires major histocompatibility complex (MHC) class I interaction. Additional studies employed mice with transgenic T cells that did not express functional TGF-β receptors. The lamina propria T regulator inhibited proliferation of these transgenic T cells nearly 100%, suggesting that TGF-β signaling via the T cell was not required. CD8+ T cells were needed for worms to reverse piroxicam-induced colitis in Rag mice (T and B cell deficient) reconstituted with IL-10−/− T cells. Thus H. polygyrus induces a regulatory CD8+ lamina propria T cell that inhibits T cell proliferation and that appears to have a role in control of colitis.

scholarly journals Coexpression of CD25 and CD27 identifies FoxP3+ regulatory T cells in inflamed synovia

2005 ◽  
Vol 201 (11) ◽  
pp. 1793-1803 ◽  
Author(s):  
Claudia R. Ruprecht ◽  
Marco Gattorno ◽  
Francesca Ferlito ◽  
Andrea Gregorio ◽  
Alberto Martini ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
Synovial Fluid ◽  
Regulatory T Cells ◽  
Cell Function ◽  
Effector T Cells ◽  
T Cell Proliferation ◽  
Activated T Cells

A better understanding of the role of CD4+CD25+ regulatory T cells in disease pathogenesis should follow from the discovery of reliable markers capable of discriminating regulatory from activated T cells. We report that the CD4+CD25+ population in synovial fluid of juvenile idiopathic arthritis (JIA) patients comprises both regulatory and effector T cells that can be distinguished by expression of CD27. CD4+CD25+CD27+ cells expressed high amounts of FoxP3 (43% of them being FoxP3+), did not produce interleukin (IL)-2, interferon-γ, or tumor necrosis factor, and suppressed T cell proliferation in vitro, being, on a per cell basis, fourfold more potent than the corresponding peripheral blood population. In contrast, CD4+CD25+CD27− cells expressed low amounts of FoxP3, produced effector cytokines and did not suppress T cell proliferation. After in vitro activation and expansion, regulatory but not conventional T cells maintained high expression of CD27. IL-7 and IL-15 were found to be present in synovial fluid of JIA patients and, when added in vitro, abrogated the suppressive activity of regulatory T cells. Together, these results demonstrate that, when used in conjunction with CD25, CD27 is a useful marker to distinguish regulatory from effector T cells in inflamed tissues and suggest that at these sites IL-7 and IL-15 may interfere with regulatory T cell function.

scholarly journals CD25+CD4+ Regulatory T Cells from the Peripheral Blood of Asymptomatic HIV-infected Individuals Regulate CD4+ and CD8+ HIV-specific T Cell Immune Responses In Vitro and Are Associated with Favorable Clinical Markers of Disease Status

2004 ◽  
Vol 200 (3) ◽  
pp. 331-343 ◽  
Author(s):  
Audrey L. Kinter ◽  
Margaret Hennessey ◽  
Alicia Bell ◽  
Sarah Kern ◽  
Yin Lin ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Immune Responses ◽  
Cd4 T Cells ◽  
Cellular Proliferation ◽  
Cell Contact ◽  
Hiv Disease ◽  
T Cell Immune Responses

Human immunodeficiency virus (HIV) disease is associated with loss of CD4+ T cells, chronic immune activation, and progressive immune dysfunction. HIV-specific responses, particularly those of CD4+ T cells, become impaired early after infection, before the loss of responses directed against other antigens; the basis for this diminution has not been elucidated fully. The potential role of CD25+CD4+ regulatory T cells (T reg cells), previously shown to inhibit immune responses directed against numerous pathogens, as suppressors of HIV-specific T cell responses was investigated. In the majority of healthy HIV-infected individuals, CD25+CD4+ T cells significantly suppressed cellular proliferation and cytokine production by CD4+ and CD8+ T cells in response to HIV antigens/peptides in vitro; these effects were cell contact dependent and IL-10 and TGF-β independent. Individuals with strong HIV-specific CD25+ T reg cell function in vitro had significantly lower levels of plasma viremia and higher CD4+: CD8+ T cell ratios than did those individuals in whom this activity could not be detected. These in vitro data suggest that CD25+CD4+ T reg cells may contribute to the diminution of HIV-specific T cell immune responses in vivo in the early stages of HIV disease.

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