scholarly journals Regulatory T-cell: Regulator of Host Defense in Infection

2017 ◽  
Vol 7 (1) ◽  
pp. 9 ◽  
Author(s):  
Mousa Mohammadnia-Afrouzi ◽  
Mehdi Shahbazi ◽  
Sedigheh Baleghi Damavandi ◽  
Ghasem Faghanzadeh Ganji ◽  
Soheil Ebrahimpour
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Immune Responses ◽  
Regulatory T Cell ◽  
Critical Role ◽  
The Body ◽  
Cell Contact ◽  
Infectious Agents ◽  
Activated T Cells

Based on diverse activities and production of several cytokines, T lymphocytes and T helper cells are divided into Th1, Th2, Th17 and regulatory T-cell (T regs) subsets based on diverse activities and production of several cytokines. Infectious agents can escape from host by modulation of immune responses as effector T-cells and Tregs. Thus, regulatory T-cells play a critical role in suppression of immune responses to infectious agents such as viruses, bacteria, parasites and fungi and as well as preserving immune homeostasis. However, regulatory T-cell responses can advantageous for the body by minimizing the tissue-damaging effects. The following subsets of regulatory T-cells have been recognized: natural regulatory Tcells, Th3, Tr1, CD8+ Treg, natural killer like Treg (NKTreg) cells. Among various markers of Treg cells, Forkhead family transcription factor (FOXP3) as an intracellular protein is used for discrimination between activated T reg cells and activated T-cells. FOXP3 has a central role in production, thymocyte differentiation and function of regulatory Tcells. Several mechanisms have been indicated in regulation of T reg cells. As, the suppression of T-cells via regulatory T-cells is either mediated by Cell-cell contact and Immunosuppressive cytokines (TGF-Beta, IL-10) mediated.

scholarly journals Regulatory T-cell therapy in Crohn’s disease: challenges and advances

Gut ◽  
2020 ◽  
Vol 69 (5) ◽  
pp. 942-952 ◽  
Author(s):  
Jennie N Clough ◽  
Omer S Omer ◽  
Scott Tasker ◽  
Graham M Lord ◽  
Peter M Irving
Keyword(s):  
T Cells ◽  
Crohn’S Disease ◽  
T Cell ◽  
Crohn's Disease ◽  
Regulatory T Cells ◽  
Cell Therapy ◽  
Regulatory T Cell ◽  
Critical Role ◽  
Significant Proportion ◽  
T Cell Therapy

The prevalence of IBD is rising in the Western world. Despite an increasing repertoire of therapeutic targets, a significant proportion of patients suffer chronic morbidity. Studies in mice and humans have highlighted the critical role of regulatory T cells in immune homeostasis, with defects in number and suppressive function of regulatory T cells seen in patients with Crohn’s disease. We review the function of regulatory T cells and the pathways by which they exert immune tolerance in the intestinal mucosa. We explore the principles and challenges of manufacturing a cell therapy, and discuss clinical trial evidence to date for their safety and efficacy in human disease, with particular focus on the development of a regulatory T-cell therapy for Crohn’s 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.

CD4+ Regulatory T Cells Specific for the WT1 Antigen Are Present in Acute Myeloid Leukemia Patients: Implication for Immunotherapy.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1933-1933
Author(s):  
Said Dermime ◽  
Cynthia Lehe ◽  
Hazem Ghebeh ◽  
Abdullah Al-Sulaiman ◽  
Ghofran Al Qudaihi ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Cytotoxic Activity ◽  
Cd8 T Cells ◽  
Ex Vivo ◽  
Granzyme B ◽  
Critical Role ◽  
Leukemic Cells ◽  
Cell Contact

Abstract Compelling evidences indicate a key role for regulatory T cells (Tregs) on the host response to cancer and recent studies indicated that the generation of effective WT1-specific cytotoxic T cells can be largely affected by the presence of Tregs. This is the first study to describe human Tregs generated specifically against the WT1 antigen which is overexpressed in several human leukemias and provide the mechanism by which these anti-WT1 Tregs inhibit the immune response in leukemia patients. We have generated T cell lines and clones that specifically recognized a WT1-84 peptide in an HLA DRB1*0402/TCR-Vb8-restricted manner. Importantly, they recognized HLADRB1* 04-matched fresh leukemic cells expressing the WT1 antigen. These clones exerted a Th2 cytokine profile, had a CD4+CD25+Foxp3+GITR+CD127− Tregs phenotype, and significantly inhibited the proliferative activity of allogeneic T cells independently of cell-contact. Priming of allo-reactive T cells in the presence of Tregs strongly inhibited the expansion of NK; NK-T and CD8+ T cells, had an inhibitory effect on NK/NK-T cytotoxic activity but not on CD8+ T cells. Furthermore, priming of T cells with the WT1- 126 HLA-A0201-restricted peptide in the presence of Tregs strongly inhibited the induction of anti-WT1-126 CD8+ CTL responses as evidenced by both very low cytotoxic activity and IFN-g production. Moreover, these Tregs clones specifically produced Granzyme-B and selectively induced apoptosis in WT1-84 pulsed-autologous APCs but not in apoptoticresistant DR4-matched leukemic cells. Importantly, we have also detected anti-WT1-84 IL-5+/Granzyme-B+/Foxp3+ CD4+ Tregs in 5 out of 8 HLA-DR4+ AML patients. These findings suggest a critical role for anti-WT1 Tregs in the inhibition of T cell responses against leukemia. This study may have important implications for the clinical manipulation of Tregs such as immuno-targeting of TCR-Vb-8 with mAbs to eliminate anti-WT1 Tregs in leukemia patients in order to enhance GVL before vaccination with the WT1 antigen. On the other hand, leukemia patients with GVHD should be clinically-tried for vaccination with the current WT1-84 peptide or adoptively-treated with ex-vivo anti-WT1 Treg cells to specifically enhance their frequency, which is known to be very low in these patients.

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.

scholarly journals FVIII-Specific TCR Engineered Human Regulatory T Cells Suppress the Production of FVIII-Specific Responses Vitro and In Vivo

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2586-2586
Author(s):  
Yong Chan Kim ◽  
Aihong Zhang ◽  
Jeong-Heon Yoon ◽  
David W. Scott
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Immune Responses ◽  
Hemophilia A ◽  
Cell Receptor ◽  
Cell Contact ◽  
Therapeutic Trial

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 in vitro. Furthermore, these engineered Tregs could suppress T-effectors specific for additional epitopes in local milieu in both a cell contact and contactless manner. From these data, we hypothesized that IL-2 and related signaling pathways are major regulatory mechanisms of the suppression. To further investigate how IL-2R signaling is engaged to control T effectors and Tregs, we followed the phospho-STAT5 status of these cells kinetically. Our results showed clearly that IL-2 from activated T effectors is a key requirement for Treg activation, inducing subsequent blockage of STAT5 signal in T effectors by activated Tregs. As further evidence of the efficacy of these specific Tregs, we then determined whether FVIII C2-specific Tregs could suppress the induction of FVIII inhibitor antibody in vivo. Thus, we transferred FVIII C2-specific human Tregs into HLA DR1 hemophilic mice and challenged them with FVIII in vivo. Our results showed that induction of FVIII-specific antibodies was inhibited for over 8 weeks. Taken together, our results suggest a potential therapeutic trial of FVIII-specific engineered Tregs in hemophilia A. Disclosures Kim: Henry Jackson Foundation: Patents & Royalties: Provisional submitted.

scholarly journals The Effect of Age on the Immunogenicity of the Live Attenuated Zoster Vaccine Is Predicted by Baseline Regulatory T Cells and Varicella-Zoster Virus-Specific T Cell Immunity

2019 ◽  
Vol 93 (15) ◽  
Author(s):  
Adriana Weinberg ◽  
Lei Pang ◽  
Michael J. Johnson ◽  
Yupanqui Caldas ◽  
Alice Cho ◽  
...  
Keyword(s):  
Older Adults ◽  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Immune Responses ◽  
Varicella Zoster Virus ◽  
Regulatory T Cell ◽  
Zoster Vaccine ◽  
Varicella Zoster ◽  
Effect Of Age

ABSTRACT Older age is associated with increased infectious morbidity and decreased immune responses to vaccines, but the mechanisms that mediate this effect are incompletely understood. The efficacy and immunogenicity of the live attenuated zoster vaccine (ZVL) have a very-well-described negative association with the age of the vaccinee. In a study of 600 ZVL recipients 50 to >80 years of age, we investigated immunological factors that might explain the effect of age on the immunogenicity of ZVL. Using FluoroSpot assays and flow cytometry, we determined that varicella-zoster virus (VZV)-specific peak T helper 1 (VZV-Th1) responses to ZVL were independently predicted by prevaccination VZV-Th1 responses, regulatory T cells (Treg), and PD1-expressing immune checkpoint T cells (Tcheck) but not by the age of the vaccinee. Persistence of VZV-Th1 1 year after vaccination was independently predicted by the factors mentioned above, by peak VZV-Th1 responses to ZVL, and by the age of the vaccinee. We further demonstrated by ex vivo blocking experiments the mechanistic role of PD1 and CTLA4 as modulators of decreased VZV-Th1 responses in the study participants. VZV-specific cytotoxic T cell (VZV-CTL) and T follicular helper responses to ZVL did not correlate with age, but similar to other Th1 responses, VZV-CTL peak and baseline responses were independently correlated. These data expand our understanding of the factors affecting the magnitude and kinetics of T cell responses to ZVL in older adults and show the importance of prevaccination Treg and Tcheck in modulating the immunogenicity of ZVL. This presents new potential interventions to increase vaccine responses in older adults. IMPORTANCE Vaccination is the most effective method to protect older adults against viral infections. However, the immunogenicity of viral vaccines in older adults is notoriously poor. The live attenuated zoster vaccine (ZVL) provides the best example of a gradual decrease of vaccine immunogenicity with every 10-year age increase above 50 years. Here we show that the abundance of regulatory T cells before vaccine administration to older adults has a significant inhibitory effect on immune responses to ZVL and, together with baseline immunity to varicella-zoster virus, explains the effect of age on the immunogenicity of ZVL. Moreover, in vitro blockade of regulatory T cell mechanisms of action with biologic modulators restores immune responses to varicella-zoster virus in vaccinees. Collectively, these observations suggest that immune modulators that block regulatory T cell activity may increase responses to viral attenuated vaccines in older adults.

scholarly journals Formaldehyde exposure induces regulatory T cell-mediated immunosuppression via calcineurin-NFAT signalling pathway

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jeongsik Park ◽  
Hyo-Seon Yang ◽  
Mi-Kyung Song ◽  
Dong Im Kim ◽  
Kyuhong Lee
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Immune Responses ◽  
Mrna Expression ◽  
Regulatory T Cell ◽  
Cell Activity ◽  
Helper T Cells ◽  
Dependent Manner ◽  
Dose Dependent

Abstract In this study, we investigated the effects of Formaldehyde (FA) exposure on splenic immune responses wherein helper T cells become activated and differentiate into effector T and regulatory T cells. BALB/c mice were exposed to two FA concentrations (1.38 mg/m3 and 5.36 mg/m3) for 4 h/day and 5 days/week for 2 weeks. FA-induced immune responses were examined by the production of cytokines, expression of mRNAs, and distributions of helper T cells and regulatory T cells. Moreover, expression of calcineurin and NFATs, regulatory T cell-related signalling proteins, were evaluated. FA exposure suppressed Th2-, Th1-, and Th17-related splenic cytokines in a dose-dependent manner. mRNA expression of splenic cytokines was also decreased by FA exposure, which correlated with decreased cytokine expression. In parallel, FA exposure promoted T cell differentiation into regulatory T cells in a dose-dependent manner supported by the expression of calcineurin and NFAT1. Taken together, our results indicated that FA exposure increases the number of regulatory T cells via calcineurin-NFAT signalling, thereby leading to effector T cell activity suppression with decreased T cell-related cytokine secretion and mRNA expression. These findings provide insight into the mechanisms underlying the adverse effects of FA and accordingly have general implications for human health, particularly in occupational settings.

Anti-CD20 therapy corrects a CD8 regulatory T cell deficit in multiple sclerosis

2021 ◽  
pp. 135245852110033
Author(s):  
Quentin Howlett-Prieto ◽  
Xuan Feng ◽  
John F Kramer ◽  
Kevin J Kramer ◽  
Timothy W Houston ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
B Cell ◽  
Regulatory T Cell ◽  
Healthy Controls ◽  
Regulatory Cells ◽  
Long Term Treatment ◽  
Anti Cd20

Objective: To determine the effect of long-term anti-CD20 B-cell-depleting treatment on regulatory T cell immune subsets that are subnormal in untreated MS patients. Methods: 30 clinically stable MS patients, before and over 38 months of ocrelizumab treatment, were compared to 13 healthy controls, 29 therapy-naïve MS, 9 interferon-β-treated MS, 3 rituximab-treated MS, and 3 rituximab-treated patients with other autoimmune inflammatory diseases. CD8, CD28, CD4, and FOXP3 expression in peripheral blood mononuclear cells was quantitated with flow cytometry. Results: CD8+ CD28− regulatory cells rose from one-third of healthy control levels before ocrelizumab treatment (2.68% vs 7.98%), normalized by 12 months (13.5%), and rose to 2.4-fold above healthy controls after 18 months of ocrelizumab therapy (19.0%). CD4+ FOXP3+ regulatory cells were lower in MS than in healthy controls (7.98%) and showed slight long-term decreases with ocrelizumab. CD8+ CD28− and CD4+ FOXP3+ regulatory T cell percentages in IFN-β-treated MS patients were between those of untreated MS and healthy controls. Interpretation: Long-term treatment with ocrelizumab markedly enriches CD8+ CD28− regulatory T cells and corrects the low levels seen in MS before treatment, while slightly decreasing CD4+ FOXP3+ regulatory T cells. Homeostatic enrichment of regulatory CD8 T cells provides a mechanism, in addition to B cell depletion, for the benefits of anti-CD20 treatment in MS.

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