scholarly journals Involvement of Regulatory T Cells in the Immunosuppression Characteristic of Patients with Paracoccidioidomycosis

2010 ◽  
Vol 78 (10) ◽  
pp. 4392-4401 ◽  
Author(s):  
Maria Carolina Ferreira ◽  
Rômulo Tadeu Dias de Oliveira ◽  
Rosiane Maria da Silva ◽  
Maria Heloisa Souza Lima Blotta ◽  
Ronei Luciano Mamoni
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Neutralizing Antibodies ◽  
Transforming Growth Factor ◽  
Paracoccidioides Brasiliensis ◽  
Treg Cells ◽  
Delayed Type Hypersensitivity ◽  
Cell Contact ◽  
Regulatory Activity ◽  
Cell Cell

ABSTRACT Patients with paracoccidioidomycosis (PCM) exhibit a suppression of the cellular immune response characterized by negative delayed-type hypersensitivity (DTH) to Paracoccidioides brasiliensis antigens, the apoptosis of lymphocytes, and high levels of expression of cytotoxic-T-lymphocyte-associated antigen 4 (CTLA-4), interleukin-10 (IL-10), and transforming growth factor β (TGF-β). The aim of this study was to investigate whether and how regulatory T cells (Treg cells) are involved in this immunosuppression by analyzing the number, phenotype, and activity of these cells in patients with active disease (AD group) and patients who had received treatment (TD group). Our results showed that the AD patients had more Treg cells than the TD patients or controls (C group) and also had elevated levels of expression of regulatory markers (glucocorticoid-induced tumor necrosis factor [TNF] receptor-related protein [GITR], CTLA-4, CD95L, LAP-1, and CD38). An analysis of regulatory activity showed that Treg cells from the AD group had greater activity than did cells from the other groups and that cell-cell contact is mandatory for this activity in the C group but was only partially involved in the regulatory activity of cells from AD patients. The addition of anti-IL-10 and anti-TGF-β neutralizing antibodies to the cultures showed that the production of cytokines may be another mechanism used by Treg cells. In conclusion, the elevated numbers of these cells with an increased regulatory phenotype and strong suppressive activity suggest a potential role for them in the immunosuppression characteristic of paracoccidioidomycosis. In addition, our results indicate that while Treg cells act by cell-cell contact, cytokine production also plays an important role.

scholarly journals IL-15 and dermal fibroblasts induce proliferation of natural regulatory T cells isolated from human skin

Blood ◽  
2006 ◽  
Vol 109 (1) ◽  
pp. 194-202 ◽  
Author(s):  
Rachael A. Clark ◽  
Thomas S. Kupper
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Human Skin ◽  
Neutralizing Antibodies ◽  
Transforming Growth Factor ◽  
Dermal Fibroblasts ◽  
Cell Contact ◽  
Skin Sample ◽  
Peripheral Tissues ◽  
Treg Population

Abstract Regulatory T cells (Tregs) are crucial for the induction and maintenance of self-tolerance and are present in peripheral tissues such as skin and gut under normal, noninflamed conditions. We report isolation and expansion of the Treg population resident in normal human skin. Cutaneous Tregs expressed high levels of CD25, L-selectin, GITR, FOXP3, and intracellular CTLA-4, low levels of CD69, and high levels of the skin-homing addressins CLA, CCR4, and CCR6. Skin Tregs suppressed the proliferation of CD25lo T cells from the same skin sample in response to CD3 and CD28 antibodies. Suppression was dependent on cell contact and not affected by neutralizing antibodies to interleukin-10 (IL-10) and transforming growth factor-β (TGF-β). Surprisingly, cutaneous Tregs proliferated in an antigen-independent manner when cultured in contact with dermal fibroblasts and IL-15, conditions similar to those found in chronically inflamed skin. We hypothesize that local proliferation of Tregs may occur within inflamed skin and could serve as a brake for cutaneous inflammation as well as a mechanism for the homeostatic proliferation of natural Tregs that has been observed within intact organisms.

Mechanisms of Suppression Used by Regulatory T Cells in Patients Newly Diagnosed with Acute Myeloid Leukemia

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2938-2938 ◽  
Author(s):  
Miroslaw J Szczepanski ◽  
Marta Szajnik ◽  
Malgorzata Czystowska ◽  
Magis Mandapathil ◽  
Ann Welsh ◽  
...  
Keyword(s):  
T Cells ◽  
Acute Myeloid Leukemia ◽  
Regulatory T Cells ◽  
Myeloid Leukemia ◽  
Neutralizing Antibodies ◽  
Hematologic Malignancies ◽  
Cell Contact ◽  
Newly Diagnosed ◽  
Acute Myeloid

Abstract An elevated frequency of CD4+CD25high regulatory T cells (Treg) has been reported in the peripheral blood in patients with various solid tumors and hematologic malignancies. Although the increase in Treg seems to be a characteristic feature of most tumors, the functional role of Treg and the mechanisms of suppression, especially in patients with hematologic malignancies, have been less well defined. We investigated Treg-mediated suppression and the responsible mechanisms in thirty newly diagnosed acute myeloid leukemia (AML) patients prior to any treatment and twenty five healthy donors (NC). The percentage of circulating CD4+ CD25high Treg was higher (p <0.0001) in the AML patients (4.5 ±0.2%, range 1.7–8.2%) compared to NC (1.5 ± 0.08%, range 0.9–3.1 %). To evaluate the suppressive function, CD4+CD25high T cells (S) were co-cultured with sorted, CFSE-labeled autologous CD4+CD25high T cells (R) at different S/R ratios. Suppression mediated by Treg co-incubated with proliferating autologous responders was significantly higher (p<0.001) in AML than that mediated by control Treg. To evaluate the role of cytokines produced by Treg in suppression and a need for cell-to- cell contact, transwell analysis of S/R co-cultures was performed. Co-incubation in the presence of transwell inserts (TRI) resulted in significant reduction of suppression (p<0.05), and the addition of neutralizing antibodies to IL-10 and TGF-β1 in the presence of TRI further decreased suppression mediated by Treg. These data suggest that both immunoinhibitory cytokine production and cell-to-cell contact are necessary for suppression. To explore other potential mechanisms of Treg suppression, we evaluated the expression by Treg of ectonucleotidases CD39 and CD73 and the capability of Treg to produce adenosine. CD4+CD25high T cells of AML patients had higher expression (p<0.01) of CD39 and more efficiently hydrolyzed ATP to adenosine relative to Treg in NC. These data indicate that various mechanisms of suppression may be utilized by Treg in patients with AML. The increase frequency of Treg mediating potent suppression by various mechanisms is likely to play a role in host anti-tumor immune responses. Therefore, modulation of the frequency and functions of Treg might provide new immunotherapeutic approaches in AML.

scholarly journals Infectious Tolerance

2002 ◽  
Vol 196 (2) ◽  
pp. 255-260 ◽  
Author(s):  
Helmut Jonuleit ◽  
Edgar Schmitt ◽  
Hacer Kakirman ◽  
Michael Stassen ◽  
Jürgen Knop ◽  
...  
Keyword(s):  
T Cells ◽  
Treg Cell ◽  
Cd4 T Cells ◽  
Transforming Growth Factor ◽  
Treg Cells ◽  
Cell Contact ◽  
Th Cells ◽  
Self Tolerance ◽  
Infectious Tolerance ◽  
Membrane Bound

Regulatory CD4+CD25+ T cells (Treg) are mandatory for maintaining immunologic self-tolerance. We demonstrate that the cell-cell contact–mediated suppression of conventional CD4+ T cells by human CD25+ Treg cells is fixation resistant, independent from membrane-bound TGF-β but requires activation and protein synthesis of CD25+ Treg cells. Coactivation of CD25+ Treg cells with Treg cell–depleted CD4+ T cells results in anergized CD4+ T cells that in turn inhibit the activation of conventional, freshly isolated CD4+ T helper (Th) cells. This infectious suppressive activity, transferred from CD25+ Treg cells via cell contact, is cell contact–independent and partially mediated by soluble transforming growth factor (TGF)-β. The induction of suppressive properties in conventional CD4+ Th cells represents a mechanism underlying the phenomenon of infectious tolerance. This explains previously published conflicting data on the role of TGF-β in CD25+ Treg cell–induced immunosuppression.

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.

scholarly journals Donor-derived exosomes induce specific regulatory T cells to suppress immune inflammation in the allograft heart

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Jiangping Song ◽  
Jie Huang ◽  
Xiao Chen ◽  
Xiao Teng ◽  
Zhizhao Song ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
Regulatory T Cells ◽  
Cardiac Transplantation ◽  
Transforming Growth Factor ◽  
Treg Cells ◽  
Mouse Serum ◽  
T Helper ◽  
Immune Inflammation ◽  
Head Protein

Abstract To inhibit the immune inflammation in the allografts can be beneficial to organ transplantation. This study aims to induce the donor antigen specific regulatory T cells (Treg cell) inhibit the immune inflammation in the allograft heart. In this study, peripheral exosomes were purified from the mouse serum. A heart transplantation mouse model was developed. The immune inflammation of the allograft heart was assessed by histology and flow cytometry. The results showed that the donor antigen-specific T helper (Th)2 pattern inflammation was observed in the allograft hearts; the inflammation was inhibited by immunizing the recipient mice with the donor-derived exosomes. Purified peripheral exosomes contained integrin MMP1a; the latter induced CD4+ T cells to express Fork head protein-3 and transforming growth factor (TGF)-β via inhibiting the Th2 transcription factor, GATA binding protein 3, in CD4+ T cells. Administration with the donor-derived exosomes significantly prolonged the allograft heart survival. We conclude that the donor-derived peripheral exosomes have the capacity to inhibit the immune inflammation in the allograft heart via inducing specific Treg cells, implicating that administration with the donor-derived exosomes may be beneficial to cardiac transplantation.

scholarly journals Cas9-directed immune tolerance in humans—a model to evaluate regulatory T cells in gene therapy?

Gene Therapy ◽  
2021 ◽  
Author(s):  
Dimitrios Laurin Wagner ◽  
Lena Peter ◽  
Michael Schmueck-Henneresse
Keyword(s):  
Gene Therapy ◽  
T Cells ◽  
Regulatory T Cells ◽  
Immune Tolerance ◽  
Neutralizing Antibodies ◽  
Treg Cells ◽  
Gene Therapies ◽  
Early Results ◽  
Cell Immunity

AbstractThe dichotomic nature of the adaptive immune response governs the outcome of clinical gene therapy. On the one hand, neutralizing antibodies and cytotoxic T cells can have a dramatic impact on the efficacy and safety of human gene therapies. On the other hand, regulatory T cells (Treg) can promote tolerance toward transgenes thereby enabling long-term benefits of in vivo gene therapy after a single administration. Pre-existing antibodies and T cell immunity has been a major obstacle for in vivo gene therapies with viral vectors. As CRISPR-Cas9 gene editing advances toward the clinics, the technology’s inherent immunogenicity must be addressed in order to guide clinical treatment decisions. This review summarizes the recent evidence on Cas9-specific immunity in humans—including early results from clinical trials—and discusses the risks for in vivo gene therapies. Finally, we focus on solutions and highlight the potential role of Cas9-specific Treg cells to promote immune tolerance. As a “beneficial alliance” beyond Cas9-immunity, antigen-specific Treg cells may serve as a living and targeted immunosuppressant to increase safety and efficacy of gene therapy.

scholarly journals Cell Contact–Dependent Immunosuppression by Cd4+Cd25+Regulatory T Cells Is Mediated by Cell Surface–Bound Transforming Growth Factor β

2001 ◽  
Vol 194 (5) ◽  
pp. 629-644 ◽  
Author(s):  
Kazuhiko Nakamura ◽  
Atsushi Kitani ◽  
Warren Strober
Keyword(s):  
T Cells ◽  
Growth Factor ◽  
Cell Surface ◽  
Transforming Growth Factor ◽  
Cytotoxic T Lymphocyte ◽  
Transforming Growth Factor Β ◽  
Cell Interaction ◽  
Cell Contact ◽  
Tgf Β1 ◽  
Cell Cell

CD4+CD25+ T cells have been identified as a population of immunoregulatory T cells, which mediate suppression of CD4+CD25− T cells by cell–cell contact and not secretion of suppressor cytokines. In this study, we demonstrated that CD4+CD25+ T cells do produce high levels of transforming growth factor (TGF)-β1 and interleukin (IL)-10 compared with CD4+CD25− T cells when stimulated by plate-bound anti-CD3 and soluble anti-CD28 and/or IL-2, and secretion of TGF-β1 (but not other cytokines), is further enhanced by costimulation via cytotoxic T lymphocyte–associated antigen (CTLA)-4. As in prior studies, we found that CD4+CD25+ T cells suppress proliferation of CD4+CD25− T cells; however, we observed here that such suppression is abolished by the presence of anti–TGF-β. In addition, we found that CD4+CD25+ T cells suppress B cell immunoglobulin production and that anti–TGF-β again abolishes such suppression. Finally, we found that stimulated CD4+CD25+ T cells but not CD4+CD25− T cells express high and persistent levels of TGF-β1 on the cell surface. This, plus the fact that we could find no evidence that a soluble factor mediates suppression, strongly suggests that CD4+CD25+ T cells exert immunosuppression by a cell–cell interaction involving cell surface TGF-β1.

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