Regulatory T cell-like activity of Foxp3+ adult T cell leukemia cells

Adult T cell leukemia (ATL) is an aggressive neoplastic disease, in which a quarter of the patients develop opportunistic infections due to cellular immunodeficiency. However, the underlying mechanism responsible for the immunosuppression has remained unclear. Recent studies have demonstrated that the leukemia cells from a subset of patients with ATL express Foxp3, a specific marker for CD25+CD4+ regulatory T (Treg) cells, which regulate the immune response by suppressing CD4+ T cell functions. However, whether there is a functional resemblance between ATL cells that have Foxp3 expression and Treg cells is still unknown. In this report, we confirmed the high expression of Foxp3 in leukemia cells from 5 of 12 ATL patients and demonstrated that ATL cells from 3 patients suppressed the proliferation of CD4+ T cells. Similarly, one of six HTLV-I-infected cell lines showed both high Foxp3 expression and suppressive activity. Like Treg cells, the suppression induced by the ATL cells from two patients and the HTLV-infected cell line appeared to be mediated by a cell-cell contact-dependent mechanism. Nevertheless, among the ATL cells that strongly expressed Foxp3, those from two of the five patients showed no apparent suppressive activity. Furthermore, retroviral transfection of Foxp3 did not confer any suppressive function on low Foxp3-expressing HTLV-I-infected cell lines. These results indicate that Foxp3 may be essential but is not sufficient for the Treg-cell-like suppressive activity of ATL cells and HTLV-I-infected cell lines.     

CD4+CD25+Foxp3+ Regulatory T Cells Contribute in Liver Fibrosis Improvement with Interferon Alpha

The aim of this study is to investigate the optimal dose, treatment time, and possible immunologic mechanisms of interferon alpha (IFN-α) in the treatment of liver fibrosis. Mice were injected intraperitoneally with 10 % carbon tetrachloride to induce liver fibrosis, except in the normal control group. The experimental mice were randomly divided into four groups: physiological saline group, 20 U/gb wt IFN-α group, 40 U/gb wt IFN-α group, and 60 U/gb wt IFN-α group. After 3 and 6 weeks, type I collagen was detected in liver by hematoxylin and eosin (HE) stain, Masson’s trichrome stain, and immunohistochemical staining. The number of CD8⁺ T cells, the number of CD4⁺CD25⁺Foxp3⁺ Tregs and the activation of CD4⁺ T cells were detected in liver and spleen. Beneficial effects were observed in the 40 U/gb wt IFN-α group by pathological analysis. The number of CD8⁺ T cells in the liver was significantly lower in mice receiving middle-dose IFN-α therapy as compared to mice receiving physiological saline (P?<?0.05), while CD4⁺CD25⁺Foxp3⁺ Tregs and activation of CD4⁺ T cells in the liver were significantly higher in the therapeutic group than in the physiological saline group (P?<?0.05). CD8⁺ T cells (r?=?0.3796) and activated CD4⁺ T cells (r?=?0.2437) were found to be positively correlated with the degree of liver fibrosis. CD4⁺CD25⁺Foxp3⁺ Tregs (r?=??0.7932) was found to be negatively correlated with the degree of liver fibrosis. IFN-α can inhibit liver fibrosis following 6 weeks of middle-dose IFN-α therapy by upregulating CD4⁺CD25⁺Foxp3⁺ Tregs and suppressing CD8⁺ T cells.     

Prevalence of Foxp3 Positive T Regulatory Cells is Increased during Progression of Cutaneous Squamous Tumors

Purpose

Forkhead box p3 (Foxp3) positive T regulatory cells (Tregs) have a functionally immunosuppressive property that prevents effector cells from acting against self in autoimmune diseases or a tumor. It is known that Tregs may be highly relevant in cancer progression. Dendritic cells (DCs) induce cutaneous immune response, however several studies have suggested that DCs are involved in immunosuppression. The aim of this study is to evaluate the prevalence of Tregs and DCs infiltration in cutaneous premalignant and malignant squamous lesions.

Materials and Methods

We evaluated Tregs and DCs in skin tissue samples obtained from 83 patients with actinic keratosis, Bowen''s disease or squamous cell carcinoma by immunohistochemistry.

Results

The prevalence of Tregs and DCs was significantly higher in squamous cell carcinoma and Bowen''s disease than in actinic keratosis. In addition, the number of DCs was closely correlated with the prevalence of Tregs, and DCs were also located in direct proximity to Tregs.

Conclusion

Tregs is related to cutaneous squamous tumor progression.     

Behavior of Circulating CD4+CD25+Foxp3+ Regulatory T Cells in Colon Cancer Patients Undergoing Surgery

CD4+CD25+Foxp3+ regulatory T cells (Treg) specialize in suppressing immune responses. In this study, 47 consecutive colon cancer patients were subjected to circulating Treg frequency assessment by flow cytometry before and after cancer resection. Thirty-two healthy subjects served as controls. Circulating Treg frequencies were significantly higher in colon cancer patients with respect to healthy controls. When patients were subgrouped according to Dukes stages, a linear relationship was observed between Dukes stages and Treg frequencies. In radically resected patients, Treg frequencies were shown to have significantly dropped down. Patients with advanced colon cancer were more likely to have significantly higher proportions of circulating Treg frequencies than Dukes A and B patients when compared to healthy subjects. Of note, nonradically resected patients were found to display reductions in—but not normalization of—Treg frequencies. These results suggest that cancer itself may be able to drive Treg recruitment as a strategy of immunoevasion.     

Decreased Levels of Circulating CD4+CD25+Foxp3+ Regulatory T Cells in Patients with Primary Antiphospholipid Syndrome

Introduction

CD4⁺CD25⁺Foxp3⁺ regulatory T (Treg) cell dysfunction has been documented in various autoimmune disorders, but not in antiphospholipid syndrome (APS) so far.

Methods

In this cross-sectional study, we aim to investigate CD4⁺CD25⁺Foxp3⁺ Treg cells, CD3⁺CD19^? T cells and CD3^?CD19⁺ B cells in patients with primary APS and healthy controls. Cell subtypes were immunophenotyped using specific monoclonal antibodies (anti-CD3 CY5, anti-CD4 FITC, anti-CD25, anti-Foxp3, anti-CD19 PE) and flow cytometry.

Results

Twenty patients with APS and 20 age- and sex-matched controls were studied. The percentage of total lymphocytes, activated Th cells (CD4+CD25+), Treg cells and CD3^?CD19⁺ B cells were found significantly lower in APS patients as compared to controls (all p?<?0.05).

Conclusion

A dysfunction in CD4⁺CD25⁺Foxp3⁺ Treg cells may represent one of the mechanisms leading to autoimmunity in APS patients. The decreased number of CD3^?CD19⁺ B cells of APS patients warrants further elucidation.     

Radiofrequency Ablation Does Not Induce the Significant Increase of CD4+CD25+Foxp3+ Regulatory T Cells Compared with Surgical Resection in Hepal-6 Tumor Model

Surgical resection (SR) and radiofrequency ablation (RFA) are all currently recognized as important and effective treatment in solid tumors. This study aimed to investigate change in level of CD4⁺CD25⁺Foxp3⁺ regulatory T (Treg) cells in tumor-bearing mice after SR vs. RFA and the relationship of this level with tumor progression. Hepa1-6 tumor cells were inoculated subcutaneously into C57BL/6J mice. The population of Treg cells was measured by flow cytometry at selected post-SR or post-RFA times. Tumor growth was measured by rechallenge in the contralateral flank. The tumor volume was calculated and compared with that of a control group. The correlation between the population of Treg cells and tumor volume was analyzed. A significant increase in Treg cells was observed after SR compared with the preoperative level, while the level after RFA was relatively stable. A significant difference in tumor growth between the SR and RFA groups was observed in the initial postoperative phase but not in the later phase. A correlation was found between tumor volume and level of Treg cells. Our study revealed that RFA stabilizes the level of Treg during postoperative recovery, whereas SR activates the immunosuppressive reaction by upregulating the level of such cells, promoting tumor growth.     

Localization of IL-17+Foxp3+ T Cells in Esophageal Cancer

The etiology of cancer is unclear. Recent studies indicate that some cytokines, such as interleukin (IL)-17, and regulatory T cells are involved in the development of cancer. This study aims to detect a subset of T cell, IL17+Foxp3+ T cell, in the pathogenesis of esophageal cancer (Eca). Twelve patients with squamous Eca were recruited in this study. The surgically removed Eca tissue was collected. Cells isolated from Eca tissue were analyzed by flow cytometry. The results showed that 2–10% Eca tissue-derived CD4⁺ T cells expressed Foxp3; only 0.2–0.8% non-ca tissue-derived CD4⁺ T cells expressed Foxp3. Further analysis showed that 3–15% Eca-isolated CD4⁺ T cells were also IL-17 positive whereas only 0.4–1.5% non-ca tissue-isolated CD4⁺ T cells were IL-17 positive. We also found that about 4.8–11.2% Foxp3⁺ IL-17⁺ T cells in isolated CD4⁺ T cells from Eca tissue that were significantly less than in non-ca tissue derived CD4⁺ T cells. Less than 1% Foxp3⁺ IL-17⁺ T cells in isolated CD4⁺ T cells in both Eca patients and healthy controls. Treatment with hypoxia markedly increased the expression of IL-6 in peripheral CD68+ cells. Coculturing CD68+ cells and Foxp3+ T cells under hypoxic environment resulted in abundant expression of IL-17 in Foxp3+ T cells that could be blocked by pretreatment with either anti-IL-17 or anti-transforming growth factor beta antibodies. We conclude that IL-17+Foxp3+ T cells may contribute to the development of Eca.     

Increased Bronchial Density of CD25+Foxp3+ Regulatory T Cells in Occupational Asthma: Relationship to Current Smoking

To identify activated T cell subset in the asthmatic bronchia, we developed a triple‐colour immunohistofluorescence labelling technique on cryo‐section to discriminate activated CD4+CD25+ T cells, (effector T cells) from Foxp3+ regulatory T cells (Treg). Additional coexpression of activation and proliferation markers was also examined in situ. Bronchial biopsies were taken from 20 aluminium potroom workers (12 smokers) with asthma (>12% reversibility), 15 non‐asthmatic potroom workers (7 smokers) and 10 non‐smoking, non‐exposed controls. Non‐smoking asthmatics had significantly higher subepithelial density of both Tregs, effector T cells, activated (HLA‐DR+) CD8+ and activated CD4+ T cells. Moreover, both Tregs, effector T cells and CD8+ T cells proliferated in the non‐smoking asthmatics, only. Although smoking asthmatics had no asthma‐associated increase in bronchial T cell, both had a significantly increase in effector T cell to Treg ratios. The significantly increased bronchial density of Tregs, effector T cells, proliferative T cells and activated CD8+ T cells in non‐smoking asthmatics clearly showed that both the effector T cells and the inhibitory Treg system were activated in asthma.     

CD4+ T Cell Hyporesponsiveness after Repeated Exposure to Schistosoma mansoni Larvae Is Dependent upon Interleukin-10

The effect that multiple percutaneous exposures to Schistosoma larvae has on the development of early CD4⁺ lymphocyte reactivity is unclear, yet it is important in the context of humans living in areas where schistosomiasis is endemic. In a murine model of multiple infections, we show that exposure of mice to repeated doses (4×) of Schistosoma mansoni cercariae, compared to a single dose (1×), results in CD4⁺ T cell hyporesponsiveness within the skin-draining lymph nodes (sdLN), manifested as reduced CD4⁺ cell proliferation and cytokine production. FoxP3⁺ CD4⁺ regulatory T cells were present in similar numbers in the sdLN of 4× and 1× mice and thus are unlikely to have a role in effecting hyporesponsiveness. Moreover, anergy of the CD4⁺ cell population from 4× mice was slight, as proliferation was only partly circumvented through the in vitro addition of exogenous interleukin-2 (IL-2), and the in vivo blockade of the regulatory molecule PD1 had a minimal effect on restoring responsiveness. In contrast, IL-10 was observed to be critical in mediating hyporesponsiveness, as CD4⁺ cells from the sdLN of 4× mice deficient for IL-10 were readily able to proliferate, unlike those from 4× wild-type cohorts. CD4⁺ cells from the sdLN of 4× mice exhibited higher levels of apoptosis and cell death, but in the absence of IL-10, there was significantly less cell death. Combined, our data show that IL-10 is a key factor in the development of CD4⁺ T cell hyporesponsiveness after repeated parasite exposure involving CD4⁺ cell apoptosis.     

A Mutation in the Transcription Factor Foxp3 Drives T Helper 2 Effector Function in Regulatory T Cells

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Suppression of CD4+ Effector Responses by Naturally Occurring CD4+ CD25+ Foxp3+ Regulatory T Cells Contributes to Experimental Cerebral Malaria

The role of naturally occurring CD4⁺ CD25⁺ Foxp3⁺ regulatory T cells (nTreg) in the pathogenesis of cerebral malaria (CM), which involves both pathogenic T cell responses and parasite sequestration in the brain, is still unclear. To assess the contribution and dynamics of nTreg during the neuropathogenesis, we unbalanced the ratio between nTreg and naive CD4⁺ T cells in an attenuated model of Plasmodium berghei ANKA-induced experimental CM (ECM) by using a selective cell enrichment strategy. We found that nTreg adoptive transfer accelerated the onset and increased the severity of CM in syngeneic C57BL/6 (B6) P. berghei ANKA-infected mice without affecting the level of parasitemia. In contrast, naive CD4⁺ T cell enrichment prevented CM and promoted parasite clearance. Furthermore, early during the infection nTreg expanded in the spleen but did not efficiently migrate to the site of neuroinflammation, suggesting that nTreg exert their pathogenic action early in the spleen by suppressing the protective naive CD4⁺ T cell response to P. berghei ANKA infection in vivo in both CM-susceptible (B6) and CM-resistant (B6-CD4^−/−) mice. However, their sole transfer was not sufficient to restore CM susceptibility in two CM-resistant congenic strains tested. Altogether, these results demonstrate that nTreg are activated and functional during P. berghei ANKA infection and that they contribute to the pathogenesis of CM. They further suggest that nTreg may represent an early target for the modulation of the immune response to malaria.     

CD4+CD25+Foxp3+T细胞在子痫前期中作用机制的研究

目的 探讨子痫前期(PE)患者外周血中CD4+CD25+Foxp3+T细胞及胎盘组织Foxp3的表达水平.方法 73例PE患者分为MPE组(轻度PE,38例)和SPE组(重度PE,35例),以正常的孕妇作为对照组;采用流式细胞术(FCM)检测外周血中CD4+CD25+Foxp3+T细胞的表达水平,采用免疫组化法(IHC)检测胎盘组织Foxp3的表达水平;将Foxp3与CD4+CD25+Foxp3+T、胎盘重量和阿氏(Apgar)评分进行Spearman相关性分析.结果 SPE组、MPE组外周血中CD4+CD25+Foxp3+T细胞表达水平分别为4.23±0.74％、6.58±0.8％,均低于对照组的7.01±0.95 ％(P＜0.05),SPE组外周血中CD4+CD25+Foxp3+T细胞表达水平低于MPE组(P ＜0.05);SPE组、MPE组胎盘组织中Foxp3的阳性表达率分别为28.57％、47.37％,均低于对照组的82.76％(P ＜0.05),SPE组胎盘组织中Foxp3的阳性表达率显著低于MPE组(P＜0.05);胎盘组织中Foxp3的阳性表达率与CD4+CD25+Foxp3+T细胞表达水平、胎盘重量及Apgar评分均呈正相关(P＜0.01).结论 PE与外周血中CD4+CD25+Foxp3+T细胞表达水平下降密切相关.     

Combined CD4+ Donor Lymphocyte Infusion and Low-Dose Recombinant IL-2 Expand FOXP3+ Regulatory T Cells following Allogeneic Hematopoietic Stem Cell Transplantation

CD4⁺CD25⁺FOXP3⁺ regulatory T cells (Treg) successfully control graft-versus-host-disease (GVHD) in animal models. In humans, incomplete reconstitution of Treg after allogeneic hematopoietic stem cell transplantation (HSCT) has been associated with chronic GVHD (cGVHD). Recent studies have demonstrated that interleukin (IL)-2 infusions expand Treg in vivo. However, the effectiveness of this therapy depends on the number of cells capable of responding to IL-2. We examined the effect of low-dose IL-2 infusions on Treg populations after HSCT in patients who also received infusions of donor CD4⁺ lymphocytes. Utilizing FOXP3 as a Treg marker, we found that patients who received CD4+DLI concomitantly with IL-2 had greater expansion of Treg compared to patients who received IL-2 (P = .03) or CD4⁺DLI alone (P = .001). FOXP3 expression correlated with absolute CD4⁺CD25⁺ cell counts. Moreover, expanded CD4⁺CD25⁺ T cells displayed normal suppressive function and treatment with CD4⁺DLI and IL-2 was not associated with GVHD. This study suggests that administration of low-dose IL-2 combined with adoptive CD4⁺ cellular therapy may provide a mechanism to expand Treg in vivo.     

Schistosoma mansoni antigens modulate experimental allergic asthma in a murine model: a major role for CD4+ CD25+ Foxp3+ T cells independent of interleukin-10

In areas where schistosomiasis is endemic, a negative correlation is observed between atopy and helminth infection, associated with a low prevalence of asthma. We investigated whether Schistosoma mansoni infection or injection of parasite eggs can modulate airway allergic inflammation in mice, examining the mechanisms of such regulation. We infected BALB/c mice with 30 S. mansoni cercariae or intraperitoneally injected 2,500 schistosome eggs, and experimental asthma was induced by ovalbumin (OVA). The number of eosinophils in bronchoalveolar lavage fluid was higher in the asthmatic group than in asthmatic mice infected with S. mansoni or treated with parasite eggs. Reduced Th2 cytokine production, characterized by lower levels of interleukin-4 (IL-4), IL-5, and immunoglobulin E, was observed in both S. mansoni-treated groups compared to the asthmatic group. There was a reduction in the number of inflammatory cells in lungs of S. mansoni-infected and egg-treated mice, demonstrating that both S. mansoni infection and the egg treatment modulated the lung inflammatory response to OVA. Only allergic animals that were treated with parasite eggs had increased numbers of CD4(+) CD25(+) Foxp3(+) T cells and increased levels of IL-10 and decreased production of CCL2, CCL3, and CCL5 in the lungs compared to the asthmatic group. Neutralization of IL-10 receptor or depletion of CD25(+) T cells in vivo confirmed the critical role of CD4(+) CD25(+) Foxp3(+) regulatory T cells in experimental asthma modulation independent of IL-10.