Role Of Treg Cells Research Articles

The role of regulatory T-cells in the development of endometriosis.

Endometriosis is a benign disease of the female reproductive tract, characterized by the process of chronic inflammation and alterations in immune response. It is estimated to affect 2-19% of women in the general population and is commonly associated with symptoms of chronic pelvic pain and infertility. Regulatory T cells (Treg) are a subpopulation of T lymphocytes that are potent suppressors of inflammatory immune response, essential in preventing destructive immunity in all tissues. In endometriosis, several studies have investigated the possible role of Treg cells in the development of the disease. Most studies to date are heterogeneous in methodology and are based on a small number of cases, which means that it is impossible to define their exact role at present. Based on current knowledge, it seems that disturbed Treg homeostasis, leading to increased systemic and local inflammation within ectopic and eutopic endometrium, is present in women who eventually develop endometriosis. It is also evident that different subsets of human Treg cells have different roles in suppressing the immune response. Recent studies in patients with endometriosis have investigated naive/resting FOXP3lowCD45RA+ Treg cells, which upon T cell receptor stimulation, differentiate into activated/effector FOXP3highCD45RA- Treg cells, characterized by a strong immunosuppressive activity. In addition, critical factors controlling expression of Treg/effector genes, including reactive oxygen species and heme-responsive master transcription factor BACH2, were found to be upregulated in endometriotic lesions. As shown recently for cancer microenvironments, microbial inflammation may also contribute to the local composition of FOXP3+ subpopulations in endometriotic lesions. Furthermore, cytokines, such as IL-7, which control the homeostasis of Treg subsets through the tyrosine phosphorylation STAT5 signalling pathway, have also been shown to be dysregulated. To better understand the role of Treg in the development of endometriosis, future studies should use clear definitions of Tregs along with specific characterization of the non-Treg (FOXP3lowCD45RA-) fraction, which itself is a mixture of follicular Tregs and cells producing inflammatory cytokines.

Transcriptome profiling of regulatory T cells from children with transient hypogammaglobulinemia of infancy.

Transient hypogammaglobulinemia of infancy (THI) is one of the most common forms of hypogammaglobulinemia in the early childhood. THI is usually associated with chronic, recurrent bacterial and viral infections, life-threatening in some cases, yet its pathogenesis is still largely unknown. As our previous findings indicated the possible role of Treg cells in the pathomechanism of THI, the aim of the current study was to investigate gene expression profile of Treg cells isolated from THI patients. The transcriptome-wide gene profiling was performed using microarray technology on THI patients in two time-points: during (THI-1), and in resolution phase (THI-2) of hypogammaglobulinemia. As a result, a total of 1086 genes were differentially expressed in THI-1 patients, when compared to THI-2 as well as control group. Among them, 931 were up- and 155 downregulated, and part of them encodes genes important for Treg lymphocyte biology and function, i.e. transcription factors/cofactors that regulate FOXP3 expression. Thus, we postulate that Treg cells isolated from THI patients during hypogammaglobulinemia display enhanced suppressor transcriptome signature. Treg expression profile of THI children after normalization of Ig levels largely resembles the results obtained in healthy control group, suggesting THI Treg transcriptome seems to return to that observed in healthy children. Taken together, we suggest that THI pathomechanism is associated not only with transiently elevated Treg cell numbers, but also with their enhanced regulatory/inhibitory functions. These findings expand our knowledge of human Treg cells and may be useful for the future diagnosis or management of THI.

Role of t-regulatory cells as immuno-evader in tumor microenvironment - Strategies for the future

Role of t-regulatory cells as immuno-evader in tumor microenvironment - Strategies for the future

Mechanisms of Altered Immune Response in Skin Melanoma.

Melanoma, a deadly form of skin cancer, poses significant challenges to the host immune system, allowing tumor cells to evade immune surveillance and persist. This complex interplay between melanoma and the immune system involves a multitude of mechanisms that impair immune recognition and promote tumor progression. This review summarizes the intricate strategies employed by melanoma cells to evade the immune response, including defective immune recognition, immune checkpoint activation, and the role of regulatory T-cells, myeloid-derived suppressor cells, and exosomes in suppressing anti-tumor immunity. Additionally, we discuss potential therapeutic targets aimed at reversing immune evasion in melanoma, highlighting the importance of understanding these mechanisms for developing more effective immunotherapies. Improved insights into the interactions between melanoma and the immune system will aid in the development of novel treatment strategies to enhance anti-tumor immune responses and improve patient outcomes.

Regulatory Tcells as metabolic sensors.

Compelling experimental evidence links immunity and metabolism. In this perspective, we propose forkhead-box-P3 (FoxP3)+CD4+CD25+ regulatory T (Treg) cells as key metabolic sensors controlling the immunological state in response to their intrinsic capacity to perceive nutritional changes. Treg cell high anabolic state invivo, residency in metabolically crucial districts, and recirculation between lymphoid and non-lymphoid sites enable them to recognize the metabolic cues and adapt their intracellular metabolism and anti-inflammatory function at the paracrine and systemic levels. As privileged regulators at the interface between neuroendocrine and immune systems, the role of Treg cells in maintaining metabolic homeostasis makes these cells promising targets of therapeutic strategies aimed at restoring organismal homeostasis not only in autoimmune but also metabolic disorders.

Role and Function of Regulatory T Cell in Chronic Rhinosinusitis with Nasal Polyposis.

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a subtype of chronic rhinosinusitis characterized by high edema in the stroma, albumin deposition, and formation of pseudocysts. The pathogenesis of CRSwNP is not yet fully understood. Regulatory T (Treg) cells are a subset of CD4+ T cells that play a suppressive immunoregulatory role in the process of CRSwNP. Recent studies have found that there was a significant reduction in Treg cells in polyp tissues, which leads to the onset of CRSwNP. An imbalance between Th17 and Treg cells can also aggravate inflammation toward the Th2 type. This review focuses on our understanding of the function and role of Treg cells and their regulatory factors and clinical significance in CRSwNP. We also summarize the current drug treatments for CRSwNP with Tregs as the potential therapeutic target, which will provide new ideas for the treatment of CRSwNP in the future.

Regulatory T cell-exosomal miR-142-3p promotes angiogenesis and osteogenesis via TGFBR1/SMAD2 inhibition to accelerate fracture repair

Although the immune system is well recognized as a key player in fracture repair, the exact mechanisms, particularly the role of regulatory T-cells (Tregs), have not yet been established. Our increased understanding of the Tregs and exosomes involved in organ repair creates opportunity of application of Tregs derived Exosomes (TregD-Exos) in the modulation of fracture repair. In the present study, we report that TregD-Exos containing miR-142-3p can be shuttled into bone mesenchymal stem cells (BMSCs) and Human umbilical vein endothelial cells (HUVECs) promoting osteogenesis and angiogenesis. Overexpression of miR-142-3p remarkedly promoted BMSC osteoblastic differentiation, and enhanced HUVEC function, including proliferation, migration and angiogenesis. Furthermore, TGFBR1/SMAD2 was shown to be involved in the TregD-Exos’ promotive effect on bone healing. Moreover, both TregD-Exos and miR-142-3p administration restored bone repair in vivo. Taken together, our results indicate that TregD-Exos containing miR-142-3p can be transferred to BMSCs and HUVECs with robust effects on osteogenesis and angiogenesis. These findings shed a new light for the use of Tregs in facilitating bone repair, suggesting that both TregD-Exos and miR-142-3p are promising effective therapeutic agents for bone remodeling.

Atopic dermatitis in West Highland white terriers – Part III: early life peripheral blood regulatory T cells are reduced in atopic dermatitis

Regulatory T (Treg) cells are involved in homeostasis of immune regulation and suppression of inflammation and T-cell polarisation. Current knowledge regarding the role of Treg cells in the initiation of allergic disease is limited for both people and dogs. To explore the role of circulating Treg cells and their possible influencing factors, on the development of atopic dermatitis (AD). This study followed part of a birth cohort of West Highland white terrier dogs and classified them according to eventual clinical signs of AD (i.e. allergic versus healthy). The Treg phenotypes were assessed longitudinally by flow cytometry at 3, 3-12 and 12-36months of age, and associated with development of AD. Different early life antigenic factors [endotoxins and allergens in house dust, Toxocara canis-specific immunoglobulin (Ig)E/IgG, allergen-specific and total IgE, skin microbiota] were measured at three months of age, and a possible association with Treg cell levels was assessed. The percentages of CD4+ CD25+ Foxp3+ Treg cells in healthy dogs were significantly higher at in 3-month-old (mean 4.5% healthy versus 3.3% allergic; P=0.021) and <1-year-old (4.0% healthy versus 2.9% allergic; P=0.028) dogs when compared to percentages of Treg cells in dogs that developed AD. There was a significantly positive correlation between the relative abundance of Lachnospiraceae on the skin and CD4+ CD25+ Foxp3+ Treg cells in puppies that became allergic (r=0.568, P=0.017). Further large-scale studies are needed to identify the practical value of these findings in AD diagnosis, treatment and prevention.

Evidence revealing the role of T cell regulators (Tregs) in periodontal diseases: A review.

Periodontitis is an inflammatory disease of the periodontium, which is a reflection of the overgrowth of oral commensals. This alteration in the oral microbiota initiates inflammation of the gingiva, which when left untreated, terminates with the resorption of the alveolar bone that may lead to a poor and hopeless prognosis. With upcoming trends in modulating the host's immunity, the role of regulatory T-cells has gained importance. These T-cells defend against inflammation and autoimmunity as they suppress both. However, in both the conditions, the regulatory cells are invariably reduced in number. Novel methods to enhance the function of Tregs have made their way in dentistry, as a promising approach to cure periodontitis. This article discusses various significant tests and trials of Tregs in the recent years.

Modulation of T-cell Regulators Associated with Advanced Stage of Prostate Cancer.

Background:Benign prostatic hyperplasia (BPH) and prostate cancer are the most common prostate diseases. The possible role of the immune system in the pathogenesis of BPH and prostate cancer in recent years has begun to be widely studied. Although many studies have focused on T lymphocytes on the development of BPH and prostate cancer, the role of regulatory T-cells in the pathogenesis of BPH and prostate cancer is still not well known.Objective:To determine the amount of regulatory T-cells in prostate cancer and BPH so that it can contribute to the concept of understanding the pathogenesis of prostate cancer and BPH.Methods:This study used cross-sectional design study. Total samples were 24 patients, with 13 subjects prostate cancer group, and 11 subjects BPH group. Furthermore, peripheral blood samples are taken and then the amount of regulatory T-cells is calculated. After obtaining data on the amount of CD4+ CD25+ Foxp3+ regulatory T-cells in the blood, data analysis was performed between groups of patients diagnosed with prostate cancer and benign prostatic hyperplasia.Results:The average amount of regulatory T-cells in the CRPC group was 53.44±29.43, prostate cancer group was 57.02±22.49 and the BPH group 89.71±9.31. One Way ANOVA test results showed that the average amount of regulatory T-cells between treatment groups gave a significant difference in regulatory T-cells with a p-value (0,003) <0.05. It can be concluded that there are differences in the average amount of regulatory T-cells, so we continued the testing with Tukey test. We continue to Pearson correlation study and resulted in significantly correlated with p value = 0.011 (P<0.05) and r = 0.414.Conclusions:It can be concluded there was significant difference between the average number of regulator T-cells in the BPH group compared with prostate cancer and CRPC patient. Further research is needed regarding the number of regulator T-cells CD4 + CD25 + FOXP3 + in prostate cancer patients (grouped according to Gleason score) and benign prostatic hyperplasia before and after therapy with bigger samples.

Abstract 3289: The status of the tumor microenvironment changes dynamics of the balance of CD8+ T cells and Treg cells in renal cell carcinoma

Abstract Immune checkpoint inhibitors (ICIs) are widely applied into the clinic based on their remarkable clinical effectiveness. Tumor mutation burden (TMB) and PD-L1 expression in the tumor microenvironment (TME) have been shown to be correlated with clinical responses of ICIs. In contrast, immunosuppressive cells, especially regulatory T (Treg) cells, in the TME are thought to be associated with the resistance to ICI therapy. In this study, we investigated the role of Treg cells in the TME in renal cancer (RCC). We have previously reported that the RCCs can be classified into three groups based on the frequency of CD3+CD4+CD45RA+FoxP3highcells; effector/activated Treg (eTreg) cells: high: &amp;gt; 10%, moderate: &amp;gt; 5%, and low: &amp;gt; 0%, and high frequency of eTreg cells were correlated with the higher expression of PD-1, LAG-3, TIM-3 by CD8+ T cells. Based on the findings, we further investigated the frequency and phenotypes of Treg cells in the TME. We first compared flow cytometry analysis with immunohistochemistry analysis in the frequency of Treg cells. The frequency of Treg cells in the TME was well-correlated with FCM and IHC analyses. Then, the detailed phenotypes of tumor-infiltrating eTreg cells was examined. eTreg cells harbored high expression of activation markers such as TIGIT and CTLA-4, but low-moderate expression of exhausted molecules such as PD-1 and LAG-3. These data implicate that CD8+ T cells are exhausted, whereas Treg cells are activated in the TME. The clinical benefits by ICI therapy for RCC could be associated with the balance of CD8+ T cells and Treg cells. We are now analyzing the detailed mechanism controlling the balance to identify biomarkers of ICI therapy and to develop novel effective cancer immunotherapies. Citation Format: Daisuke Sugiyama, Tomoaki Muramatsu, Yoichi Kobayashi, Naoto Sassa, Shoichi Maruyama, Momokazu Goto, Yoshiki Akatsuka, Hiroyoshi Nishikawa. The status of the tumor microenvironment changes dynamics of the balance of CD8+ T cells and Treg cells in renal cell carcinoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3289.

Abstract LB-087: Blockade of β-catenin-induced CCL28 suppresses gastric cancer progression via inhibition of Treg cell infiltration

Abstract Dysregulation of Wnt/β-catenin signaling is frequently observed in human gastric cancer. Elucidation of tumor immune microenvironment is essential for the understanding of tumorigenesis and the development of immunotherapeutic strategies. However, it remains unclear how β-catenin signaling regulates stomach tumor immune microenvironment. Our in vitro study unraveled CCL28 as a direct transcriptional target gene of β-catenin/T cell factor (TCF). Protein levels of β-catenin and CCL28 were positively correlated in human gastric adenocarcinoma. β-Catenin-activated CCL28 was able to recruit Regulatory T (Treg) cells in transwell migration assay. In a clinically relevant mouse gastric cancer model established by Helicobacter (H.) felis infection and MNU treatment, inhibition of β-catenin/TCF activity by a pharmacological inhibitor iCRT14 suppressed CCL28 expression and Treg cell infiltration in the stomach. Moreover, anti-CCL28 antibody attenuated Treg cell infiltration and tumor progression in H. felis/MNU mouse models. Diphtheria toxin (DT)-induced Treg cell ablation restrained gastric cancer progression in H. felis/MNU-treated DEREG (Foxp3-DTR) mice, clarifying the tumor-promoting role of Treg cells. Thus, the β-catenin-CCL28-Treg cell axis may serve as an important mechanism for immunosuppression of the stomach tumor microenvironment. Our findings highlighted an immunoregulatory role of β-catenin signaling in stomach tumors and the therapeutic potentials of CCL28 blockade for the treatment of gastric cancer. Citation Format: Lu Ji, Helen He Zhu, Bin Ma, Wei-Qiang Gao. Blockade of β-catenin-induced CCL28 suppresses gastric cancer progression via inhibition of Treg cell infiltration [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-087.

Role of regulatory T-cells in the systemic inflammatory response syndrome

Systemic inflammatory response syndrome is a complex multisyndromic, phase-specific pathological process that develops with systemic damage. Outcomes largely depend on the balance of multidirectional sequential stages: hyperinflammatory reaction and compensatory anti-inflammatory response syndrome (CARS). Regulatory T-cells (Tregs) are able to regulate adaptive and innate immune responses and contribute to the various stages ofthe systemic inflammatory response syndrome. At the initial hyperinflammatory stage, Tregs are able to limit self-inflicted damage. At the same time, Tregs contribute to CARS and the formation of induced immunosuppression, predisposing to a high susceptibility to nosocomial and opportunistic infections, with subsequent transition to multiple organ dysfunction syndrome. Regulatory T-cells and their functional changes are considered as predictors and prognostic markers of critical illness.

Expansion of Host Regulatory T Cells by Secreted Products of the Tapeworm Echinococcus multilocularis.

BackgroundAlveolar echinococcosis (AE), caused by the metacestode larval stage of the fox-tapeworm Echinococcus multilocularis, is a chronic zoonosis associated with significant modulation of the host immune response. A role of regulatory T-cells (Treg) in generating an immunosuppressive environment around the metacestode during chronic disease has been reported, but the molecular mechanisms of Treg induction by E. multilocularis, particularly parasite immunoregulatory factors involved, remain elusive so far.Methodology/Principal FindingsWe herein demonstrate that excretory/secretory (E/S) products of the E. multilocularis metacestode promote the formation of Foxp3+ Treg from CD4+ T-cells in vitro in a TGF-β-dependent manner, given that this effect was abrogated by treatment with antibody to mammalian TGF-β. We also show that host T-cells secrete elevated levels of the immunosuppressive cytokine IL-10 in response to metacestode E/S products. Within the E/S fraction of the metacestode we identified an E. multilocularis activin A homolog (EmACT) that displays significant similarities to mammalian Transforming Growth Factor-β (TGF-β/activin subfamily members. EmACT obtained from heterologous expression failed to directly induce Treg expansion from naïve T cells but required addition of recombinant host TGF-β to promote CD4+ Foxp3+ Treg conversion in vitro. Furthermore, like in the case of metacestode E/S products, EmACT-treated CD4+ T-cells secreted higher levels of IL-10. These observations suggest a contribution of EmACT to in vitro expansion of Foxp3+ Treg by the E. multilocularis metacestode. Using infection experiments we show that intraperitoneally injected metacestode tissue expands host Foxp3+ Treg, confirming the expansion of this cell type in vivo during parasite establishment.Conclusion/SignificanceIn conclusion, we herein demonstrate that E. multilocularis larvae secrete factors that induce the secretion of IL-10 by T-cells and contribute to the expansion of TGF-b-driven Foxp3+ Treg, a cell type that has been reported crucial for generating a tolerogenic environment to support parasite establishment and proliferation. Among the E/S factors of the parasite we identified a factor with structural and functional homologies to mammalian activin A which might play an important role in these activities.

New Insights about Regulatory T Cells Distribution and Function with Exercise: The Role of Immunometabolism.

A lack of physical activity is linked to the development of many chronic diseases through a chronic low-grade inflammation state. It is now well accepted that the immune system plays a central role in the development of several chronic diseases, including insulin resistance, type 2 diabetes, atherosclerosis, heart failure and certain types of cancer. Exercise elicits a strong anti-inflammatory response independently of weight loss and can be a useful non-pharmacologic strategy to counteract the low-grade inflammation. The CD4+CD25+CD127- FoxP3+ Regulatory T (Treg) cells are a unique subset of helper T-cells, which regulate immune response and establish self-tolerance through the secretion of immunoregulatory cytokines, such as IL-10 and TGF-β, and the suppression of the function and activity of many immune effector cells (including monocytes/macrophages, dendritic cells, CD4+ and CD8+ T cells, and Natural Killers). The metabolic phenotype of Tregs are regulated by the transcription factor Foxp3, providing flexibility in fuel choice, but a preference for higher fatty acid oxidation. In this review, we focus on the mechanisms by which exercise - both acute and chronic - exerts its antiinflammatory effects through Treg cells mobilization. Furthermore, we discuss the implications of immunometabolic changes during exercise for the modulation of Treg phenotype and its immunosuppressive function. This narrative review focuses on the current knowledge regarding the role of Treg cells in the context of acute and chronic exercise using data from observational and experimental studies. Emerging evidence suggests that the immunomodulatory effects of exercise are mediated by the ability of exercise to adjust and improve Tregs number and function.

Regulatory T cells and IL-17A levels in noninfectious uveitis.

Regulatory T cells (Tregs) have been intensively studied in a myriad of autoimmune diseases. As for noninfectious uveitis (NIU), results have been contradictory, and studies have failed to demonstrate a consistent reduction in Treg cell frequency in patients with active disease. The present study aims to characterize T lymphocyte subsets, including naïve and memory Tregs as well as their respective CD39 expression, in the peripheral blood of NIU patients. Inflammatory as well as suppressive cytokine profiles were also evaluated. T cell subpopulations were evaluated by multiparametric flow cytometry using anti-CD3, anti-CD4, anti-CD45, anti-CD45RA, anti-CD197, anti-CD25, anti-CD127, and anti-CD39. Treg cells were defined as CD3 + CD4+CD25hiCD127low. A multiplex bead-based immunoassay was used to determine TNF-α, IFN-ɣ, IL-17A, IL-10, and TGF-β levels. Twenty-nine patients with active NIU were included as well as 15 sex- and age-matched controls. There were no significant differences in T lymphocyte subsets, including Tregs, between patients and controls. However, patients with a lower grade of anterior chamber or vitreous inflammatory cellular reaction showed higher memory Treg counts than controls, with no respective increase in CD39+ expression, and a tendency for higher IL-17A levels (p = 0.06). This IL-17A elevation was present in the total NIU group (p = 0.08) as well as a positive correlation between IL-17A levels and the absolute counts of memory Tregs (p = 0.013; R = 0.465). Patients with higher IL-17A levels also showed higher serum concentrations of memory (p = 0.001) and naïve (p = 0.003) Tregs as well as elevated TNF-α (p < 0.0001) and IFN-ɣ (p = 0.016) levels. Negative correlations were observed between IL-10 and TGF-β levels and the percentages of memory (p = 0.030; R = - 0.411) and total CD39+ Tregs (p = 0.051; R = - 0.373) in the peripheral blood of NIU patients. Our results showed that total Treg levels were not reduced in patients with NIU. Further characterization of Treg subsets, including memory Tregs and respective CD39 expression, may provide additional insight on the role of Treg cells in NIU. Consistent high levels of circulating IL-17A in NIU patients are in accordance with previous studies and reinforce this cytokine's vital role in uveitis pathogenesis and its possible use as a therapeutic target.

Getting to the Heart of the Matter: The Role of Regulatory T-Cells (Tregs) in Cardiovascular Disease (CVD) and Atherosclerosis

Cardiovascular diseases (CVD) are the leading cause of mortality worldwide. Atherosclerosis is directly associated with CVD and is characterized by slow progressing inflammation which results in the deposition and accumulation of lipids beneath the endothelial layer in conductance and resistance arteries. Both chronic inflammation and disease progression have been associated with several risk factors, including but not limited to smoking, obesity, diabetes, genetic predisposition, hyperlipidemia, and hypertension. Currently, despite increasing incidence and significant expense on the healthcare system in both western and developing countries, there is no curative therapy for atherosclerosis. Instead patients rely on surgical intervention to avoid or revert vessel occlusion, and pharmacological management of the aforementioned risk factors. However, neither of these approaches completely resolve the underlying inflammatory environment which perpetuates the disease, nor do they result in plaque regression. As such, immunomodulation could provide a novel therapeutic option for atherosclerosis; shifting the balance from proatherogenic to athero-protective. Indeed, regulatory T-cells (Tregs), which constitute 5-10% of all CD4+ T lymphocytes in the peripheral blood, have been shown to be athero-protective and could function as new targets in both CVD and atherosclerosis. This review aims to give a comprehensive overview about the roles of Tregs in CVD, focusing on atherosclerosis.

Therapeutic effect of regulatory T cells on mice with experimental autoimmune encephalomyelitis

Objective To study the role of Treg cells in the development of mouse experimental autoimmune encephalomyelitis (EAE) through depleting or transplanting Treg cells. Methods C57BL/6 mice were injected with anti-CD25 monoclonal antibody to deplete natural CD25-expressing Treg cells in vivo, and then treated with MOG35-55/CFA to induce EAE. Their EAE scores were compared with those of the mice without Treg cell deletion (control group). The numbers and percentages of CD4+ Foxp3+ cells in mouse blood samples on 6 d, 10 d, 20 d and 35 d were quantified using flow cytometry. To evaluate the therapeutic effect of Treg cells transplantation on EAE, magnetic activated cell sorting (MACS) combined with fluorescence-activated cell sorting (FACS) was used to isolate Treg cells from spleen and lymph nodes of Foxp3GFP+ transgenic mice on 6 d after EAE induction. Then the cells were injected through tail vein into wild-type mice on 6 d after EAE induction. The EAE scores of both recipient and control mice were recorded and compared. Results The efficiency of natural Treg cells depletion with anti-CD25 antibody was above 95%. The mice with Treg cell depletion developed significantly more severe EAE than the control mice after MOG35-55/CFA induction. FACS analysis of Treg cells during the development of EAE demonstrated that the lowest Treg cell percentage was detected on 6 d after EAE induction, hence it was the time point for the transplantation of Treg cells. CD4+ GFP+ Treg cells were isolated from Foxp3GFP+ transgenic mice on 6 d after EAE induction and immediately transplanted into wild-type mice on 6 d after EAE induction. The transplantation of isolated Treg cells significantly alleviated the EAE in mice as compared with the control group. Conclusions Mice with Treg cell depletion developed severer EAE than the control mice after induction, but the EAE score could be significantly reduced with the transplantation of Treg cells. This study showed that the transplanted Treg cells had protective effect on mice during the course of EAE development. Thus, Treg cell transplantation could be used as an effective therapeutic approach for the treatment of multiple sclerosis (MS). Key words: Multiple sclerosis; Experimental autoimmune encephalomyelitis; Regulatory T cell

Alopecia areata patients show deficiency of FOXP3+CD39+ T regulatory cells and clonotypic restriction of Treg TCRβ-chain, which highlights the immunopathological aspect of the disease.

Alopecia areata (AA) is a hair loss disorder resulting from an autoimmune reaction against hair follicles. T-helper 1 cells are a major contributor to this disorder, but little is known about the role of T-regulatory cells (Tregs) in AA. Here, we analysed the distribution of circulating Treg subsets in twenty AA patients with active hair loss and fifteen healthy subjects by flow cytometry. The Treg suppressor HLA-DR+ subpopulation was significantly reduced in the patients (P<0.001) and there were significantly fewer cells expressing CD39 among the CD4+CD25+Foxp3+ Treg subpopulation in patients (P = 0.001). FOXP3 CD39 Treg cells were also reduced in hair follicles; by 75% in non-lesional skin and 90% in lesional skin, when compared to control healthy skin. To further characterise Treg cells in AA; Tregs (CD4+CD25+FOXP3+) were investigated for their TCRβ sequence. PCR products analysed by Next Generation Sequencing techniques, showed that all frequent public clonotypes in AA Tregs were also present in controls at relatively similar frequencies, excepting two public clonotypes: CATSRDEGGLDEKLFF (V15 D1 J1-4) and CASRDGTGPSNYGYTF (V2 D1 J1-2), which were exclusively present in controls. This suggests that these Treg clonotypes may have a protective effect and that they may be an exciting subject for future therapeutic applications.

Abstract 5031: Regulatory T cell ablation accelerates early stage breast cancer progression

Abstract Breast cancer is the most common malignancy in women worldwide. Early detection of pre-invasive breast tumor has dramatically improved due to the routine screening for women. Ductal carcinoma in situ is a non-obligate precursor of breast cancer, and it only progresses to invasive breast cancer in about 40% of patients. We have previously shown that transient ablation of regulatory T (Treg) cells in established breast tumors results in significant reduction of primary and lung metastatic tumor growth. In this study, we aim to investigate the specific role of Treg cells at the pre-malignant stages. Using a spontaneous, stage-wise MMTV-driven polyoma middle T (PyMT) model of murine mammary carcinogenesis, crossed to Foxp3DTR knock-in mice where injection of diphtheria toxin leads to a complete ablation of Treg cells for around 7 days, we found that ablation of Treg cells at the pre-invasive tumor stage resulted in a significant increase in the number of mammary glands developing tumors, as well as tumor growth compared to control mice. Histological examination of tissues revealed that the area of the incipient tumors was larger in Treg cell-ablated mice, and presented a more advanced tumor stage. In addition, Treg cell ablation resulted in a pronounced mammary inflammatory infiltrate, including an increase in tumor-associated macrophages and a soluble cytokine network conducive to tumor progression. Interestingly, Treg cell ablation increased the percentage of cancer stem/progenitor cells in the mammary compartment. Overall, our study demonstrates that unlike their role in established cancers, Treg cells ablation promotes breast cancer progression at early stages. Citation Format: Wei Du, Leandro Martinez, Valentina Robila, Nicholas Clark, Michael Idowu, Paula Bos, Paula Bos. Regulatory T cell ablation accelerates early stage breast cancer progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5031.