Diabetes is not prevented by Foxp3-transduced CD4(+)T cells under the IL-12Rbeta2 promoter control

Our previous studies have shown that Foxp3 under the control of IFN-gamma promoter (IgammaP-Foxp3) converts pathogenic CD4(+)Th1 cells into regulatory T cells (Tregs), which control diabetes in non-obese diabetic (NOD) mice. Here, we tested the other hypothesis that transient expression of Foxp3 as controlled by the transient expression of IL-12Rbeta2 during Th1 cell derivation is sufficient to convert cells to Tregs. Foxp3, under the control of IL-12Rbeta2 promoter (Ibeta2P), was lentivirally transduced into na?ve CD4(+)T cells from NOD mice. Ibeta2P-Foxp3-transduced CD4(+)T cells could not effectively suppress the incidence of diabetes when transferred into NOD mice. Furthermore, we found that Ibeta2P-Foxp3-transduced CD4(+)T cells, stimulated by a high dose of autoantigen, did not suppress CD4(+)T cell activation, produce CD4(+)Foxp3(+)Tregs, and up-regulate CTLA4 expression. These results suggest that Ibeta2P cannot mediate Foxp3 to convert pathogenic CD4(+)Th1 cells into Tregs which control diabetes in NOD mice.     

High antigen dose and activated dendritic cells enable Th cells to escape regulatory T cell-mediated suppression in vitro

CD4+CD25+ regulatory T cells (Tregs) are critical for peripheral tolerance and prevention of autoimmunity. In vitro coculture studies have revealed that increased costimulation breaks Treg-mediated suppression in response to anti-CD3 or antigen. However, it was unclear whether loss of suppression arose from inactivation of Tregs or whether increased stimulation caused Th cells to escape suppression. We have investigated conditions that allow or override Treg-mediated suppression using DO11.10 TCR-transgenic T cells and chicken ovalbumin peptide 323-339-pulsed antigen-presenting cells. Treg suppression of Th proliferation is broken with potent stimulation, using activated spleen cells and high antigen dose, but is intact at low antigen dose. Costimulation with CD80 and CD86 expressed on activated dendritic cells was essential for Th cell escape from suppression at a high antigen dose. Potently stimulated Tregs were functional since they reduced levels of IL-2, IFN-gamma, IL-4 and Th CD25 expression in cocultures. Furthermore, Tregs responding to high antigen dose and activated splenocytes retained the ability to suppress proliferation, but only of Th cells responding to a sub-optimal dose of independent antigen. Together, our results demonstrate that under conditions of strong antigen-specific stimulation, Tregs remain functional, but Th cells escape Treg-mediated suppression.     

Adoptive transfer of all-trans-retinal-induced regulatory T cells ameliorates experimental autoimmune arthritis in an interferon-gamma knockout model

Maintaining an appropriate balance between subsets of CD4(+) helper T cells and T regulatory cells (Tregs) is a critical process in immune homeostasis and a protective mechanism against autoimmunity and inflammation. To identify the role of vitamin A-related compounds, we investigated the regulation of interleukin (IL)-17-producing helper T cells (Th17 cells) and Tregs treated with all-trans-retinal (retinal). CD4(+)T cells or total cells from the spleens of C57BL/6 mice were stimulated under Treg-polarizing (anti-CD3/CD28 and TGF-β) or Th17-polarizing (anti-CD3/CD28, TGF-β, and IL-6) conditions in the presence or absence of retinal. To analyze their suppressive abilities, retinal-induced Tregs or TGF-β-induced Tregs were co-cultured with responder T cells. Collagen-induced arthritis (CIA) was established in interferon (IFN)-γ knockout mice. On day 13, retinal-induced Tregs were adoptively transferred to mice with established CIA after second immunizations. Compared with TGF-β-induced Treg cells, retinal-induced Tregs showed increased Foxp3 expression and mediated stronger suppressive activity. Under Th17-polarizing conditions, retinal inhibited the production of IL-17 and increased the expression of Foxp3.Retinal-induced Tregs showed therapeutic effects in IFN-γ knockout CIA mice. Thus, we demonstrated that retinal reciprocally regulates Foxp3(+) Tregs and Th17 cells. These findings suggest that retinal, a vitamin A metabolite, can regulate the balance between pro- and anti-inflammatory immunity. A better understanding of the manipulation of Foxp3 and Tregs may enable the application of this tremendous therapeutic potential in various autoimmune diseases.     

美沙拉嗪对DSS诱导小鼠溃疡性结肠炎模型Th1、Th17及Treg细胞亚群的影响

 目的:观察葡聚糖硫酸钠（DSS）诱导小鼠溃疡性结肠炎（UC）模型中辅助性T细胞（Th1、Th17亚群）及调节性T细胞（Treg）细胞亚群的变化,探讨美沙拉嗪（MSLZ）治疗UC的免疫学机制。方法: 采用流式细胞分析术检测DSS诱导的小鼠UC模型结肠组织及外周血单个核细胞中白细胞介素17（IL-17）、γ-干扰素（IFN-γ）及核转录因子Foxp3的表达,并检测MSLZ预治疗对小鼠UC 模型Th1、Th17和Treg亚群的影响。结果: 在DSS诱导的小鼠UC模型中,其外周血单个核细胞（PBMC）中CD3+T细胞高表达IL-17、IFN-γ及Foxp3,肠黏膜单个核细胞（LPMC）中CD3+T细胞高表达IFN-γ和Foxp3,但IL-17的表达与对照组无差异。进一步发现UC模型小鼠LPMC中Th17、Th1和Treg均显著高于对照组,但PBMC中只有Treg高于对照组。MSLZ预治疗能显著下调UC 模型小鼠PBMC和LPMC中Th17、Th1和Treg细胞亚群。结论: DSS诱导的小鼠 UC模型中CD4+T细胞亚群Th1、Th17及Treg细胞显著升高,提示CD4+T细胞亚群在UC发病中起重要作用,美沙拉嗪可能通过调节Th1、Th17及Treg细胞亚群发挥抗炎及治疗UC作用。     

The opposite-direction modulation of CD4+CD25+ Tregs and T helper 1 cells in acute coronary syndromes

Different subsets of T lymphocytes have different functions in atherosclerosis advancement. T helper 1 cells and T regulatory 1 cells have been demonstrated to play opposite roles in rupture of atherosclerotic lesion. However, the role of novel subset of T regulatory cells, known as CD4+CD25+Foxp3+ T cells, remains largely unknown in coronary artery disease (CAD). In this study, we investigated the peripheral CD4+CD25+Foxp3+ T cells of patients with CAD and controls. The patients submitted were divided into three groups: stable angina pectoris (SA) group, unstable angina pectoris (UA) group and acute myocardial infarction (AMI) group. We analyzed the frequencies of peripheral CD4+CD25+Foxp3+ T cells and T helper 1/T helper 2 cells, expression of Foxp3 in CD4+CD25+ T subsets and cytokines pattern in patients and controls. We found that the reduction of CD4+CD25+Foxp3+ T lymphocytes was consistent with the expansion of Th1 cells in patients with unstable CAD. The reversed development between CD4+CD25+ Tregs and Th1 cells might contribute to plaque destabilization.     

Adoptive transfer of all-trans-retinal-induced regulatory T cells ameliorates experimental autoimmune arthritis in an interferon-gamma knockout model

Maintaining an appropriate balance between subsets of CD4⁺ helper T cells and T regulatory cells (Tregs) is a critical process in immune homeostasis and a protective mechanism against autoimmunity and inflammation. To identify the role of vitamin A-related compounds, we investigated the regulation of interleukin (IL)-17-producing helper T cells (Th17 cells) and Tregs treated with all-trans-retinal (retinal). CD4⁺T cells or total cells from the spleens of C57BL/6 mice were stimulated under Treg-polarizing (anti-CD3/CD28 and TGF-β) or Th17-polarizing (anti-CD3/CD28, TGF-β, and IL-6) conditions in the presence or absence of retinal. To analyze their suppressive abilities, retinal-induced Tregs or TGF-β-induced Tregs were co-cultured with responder T cells. Collagen-induced arthritis (CIA) was established in interferon (IFN)-γ knockout mice. On day 13, retinal-induced Tregs were adoptively transferred to mice with established CIA after second immunizations. Compared with TGF-β-induced Treg cells, retinal-induced Tregs showed increased Foxp3 expression and mediated stronger suppressive activity. Under Th17-polarizing conditions, retinal inhibited the production of IL-17 and increased the expression of Foxp3.Retinal-induced Tregs showed therapeutic effects in IFN-γ knockout CIA mice. Thus, we demonstrated that retinal reciprocally regulates Foxp3⁺ Tregs and Th17 cells. These findings suggest that retinal, a vitamin A metabolite, can regulate the balance between pro- and anti-inflammatory immunity. A better understanding of the manipulation of Foxp3 and Tregs may enable the application of this tremendous therapeutic potential in various autoimmune diseases.     

The effect of ionizing radiation on the homeostasis and functional integrity of murine splenic regulatory T cells

Objective

Radiotherapy affects antitumor immune responses; therefore, it is important to study radiation effects on various compartments of the immune system. Here we report radiation effects on the homeostasis and function of regulatory T (Treg) cells, which are important in down-regulating antitumor immune responses.

Methods

C57Bl/6 mice were irradiated with 2 Gy and alterations in splenic lymphocyte fractions analyzed at different intervals.

Results

Total CD4+ numbers showed stronger decrease after irradiation than CD4+Foxp3+ Tregs. Tregs were less prone to radiation-induced apoptosis than CD4+Foxp3? T cells. The ratio of CD4+Foxp3? and CD4+Foxp3+ fractions within the proliferating CD4+ pool progressively changed from 74:26 in control animals to 59:41 eleven days after irradiation, demonstrating a more dynamic increase in the proliferation and regeneration of the Treg pool. The CD4+Foxp3+ fraction expressing cell-surface CTLA4, an antigen associated with Treg cell activation increased from 5.3 % in unirradiated mice to 10.5 % three days after irradiation. The expression of IL-10 mRNA was moderately upregulated, while TGF-β expression was not affected. On the other hand, irradiation reduced Treg capacity to suppress effector T cell proliferation by 2.5-fold.

Conclusion

Tregs are more radioresistant, less prone to radiation-induced apoptosis, and have faster repopulation kinetics than CD4+Foxp3? cells, but irradiated Tregs are functionally compromised, having a reduced suppressive capacity.     

Progressive divergent shifts in natural and induced T-regulatory cells signify the transition from undifferentiated to definitive connective tissue disease

The objectives of the study is to determine clinical signs and distribution of peripheral T-cell subsets, B cells and T regulatory cells in patients with undifferentiated connective tissue disease (UCTD) and during the development toward well-established connective tissue diseases (CTD). The methods include 46 patients with UCTD were followed and investigated for differentiation into defined CTDs for 2 years. Cell subsets were determined on the basis of cell surface markers, intracellular cytokine production by flow cytometry and serum cytokine levels by ELISA. The results are as follows: 45.6% of UCTD patients developed into a defined CTD. The number and percentage of activated T cells, memory T cells and NKT cells were increased in patients compared with controls. In addition, in patients with UCTD, the percentage of CD4+/IFN gamma+ T(h)1 was significantly higher compared with controls and further increased in patients that developed CTDs. The percentage and absolute number of CD4+CD25+Foxp3+ regulatory T cells (Tregs) were diminished in UCTD patients compared with healthy controls, while the number of CD4+/IL-10+ Tregs increased. The conclusions are Overproduction of IFN gamma and the decrease of natural (Foxp3+) Tregs seem to be characteristic features of UCTD patients. The increased IL-10 production of CD4+ T cells might be a compensatory suppressive mechanism; however, it is probably not able to balance the overproduction of IFN gamma and the observed decrease of Foxp3+ Tregs. The shift toward T(h)1 with increased IFN gamma production in patients with UCTD combined with the degree of immunoregulatory disturbances characterized by the progressive divergent shifts in natural and induced T-regulatory cell populations signify the transition from undifferentiated to definitive CTD.     

乙肝病毒感染者外周血中CD4~+Foxp3~+T细胞亚群的表达及临床意义

目的研究外周血中3个CD4~+Foxp3~+T细胞亚群在乙肝病毒感染者外周血中频率及其可能的临床意义。方法分离来自无症状携带者(AsC)、慢性乙型肝炎患者(CHB)以及健康对照(Health)的外周血单个核细胞(PBMC),用流式细胞术分析PBMC中3个CD4~+Foxp3~+T细胞亚群占CD4~+T细胞的比例,并分析其与临床参数间的相关性,同时将CD4~+CD25~+Foxp3~+Treg作对比分析。结果CD4~+CD45RA~+Foxp3~(lo)(静息态Treg)频率在各实验组间无显著差别;CD4~+CD45RA~-Foxp3~(lo)(非Treg)频率在CHB组和AsC组间无明显差别,但两组相对Health组明显升高;CHB组CD4~+CD45RA~-Foxp3~(hi)(活动态Treg)明显高于AsC组和Health组。在CHB和AsC病例中活动态Treg与HBV病毒载量,HBeAg状态均无显著相关性。在CHB病例中活动态Treg与ALT水平不相关。结论相当比例的不具抑制功能的Foxp3~+T细胞可能混杂在CD4~+CD25~+Foxp3~+Treg的分析中,因此活动态Treg比CD4~+CD25~...     

B7H1-Ig诱导Tr1细胞向CD4~+CD25~+Foxp3~+Treg细胞转化的研究

为探讨Ⅰ型调节性T细胞(Tr1)与CD4+CD25+Foxp3+Treg之间的转化和相互关系,以预包被而固相化的B7H1-Ig融合蛋白加抗CD3单抗刺激初始CD4+CD62L+T细胞,分析细胞因子及Foxp3表达水平的变化,检测细胞功能;在B7H1-Ig开始刺激时或诱导细胞分化结束后加入重组人TGF-β,观察其对细胞分化的影响。结果显示,B7H1-Ig激活的CD4+T细胞产生高水平IL-10、IFN-γ和IL-5,极低水平的IL-2和IL-4,不表达Foxp3,通过分泌抑制性细胞因子IL-10发挥免疫抑制功能,证实B7H1-Ig可诱导Tr1细胞的产生。同时发现TGF-β不影响B7H1-Ig刺激的初始CD4+T的分化,却可促进B7H1-Ig诱导的已分化Tr1细胞向CD4+CD25+Foxp3+Treg转化,提示在特定条件下,Tr1细胞可转化的CD4+CD25+Foxp3+Treg。研究结果为将来临床应用CD4+Treg治疗免疫失调性疾病奠定了基础。     

Reciprocal generation of Th1/Th17 and T(reg) cells by B1 and B2 B cells

Regulatory T (T(reg)) cells are indispensable for maintaining peripheral tolerance, whereas T helper (Th)1 and Th17 cells induce inflammation and tissue destruction. Using Foxp3-GFP knock-in mice, we report a novel regulatory role for B cell subsets in influencing the differentiation of T(reg) versus Th1/Th17 cells. Peritoneal B1 cells strongly promoted T cell proliferation and cytokine secretion when presenting nominal or allogeneic antigens, as compared to conventional follicular B (B2) cells. However, peritoneal B1 cells largely failed to convert naive Foxp3(-)CD4(+) T cells into Foxp3(+) T(reg) cells in the presence of TGF-beta and IL-2, in marked contrast to conventional B2 cells, which excelled in T(reg) conversion. Interestingly, under the same T(reg) conversion conditions, peritoneal B1 cells preferentially promoted Th1 and Th17 cell differentiation. Blockade of CD86 but not CD80 costimulation markedly enhanced T(reg) cell induction by B1 cells. Thus, B cell antigen presentation function is inversely correlated with de novo T(reg) cell induction for these B cell subsets. Our findings suggest that B1 and B2 cell subsets play distinct roles in immune regulation by promoting reciprocal differentiation of T cell lineages.     

Identification of a CD4+ T cell line with Treg-like activity

Regulatory T cells (Tregs) suppress adaptive immunity and inflammation. Although they play a role in suppressing anti-tumor responses, development of therapeutics that target Tregs is limited by their low abundance, heterogeneity, and lack of specific cell surface markers. We isolated human PBMC-derived CD4⁺ CD25^high Foxp3⁺ Tregs and demonstrate they suppress stimulated CD4⁺ PBMCs in a cell contact-dependent manner. Because it is not possible to functionally characterize cells after intracellular Foxp3 staining, we identified a human T cell line, MoT, as a model of human Foxp3⁺ Tregs. Unlike Jurkat T cells, MoT cells share common surface markers consistent with human PBMC-derived Tregs such as: CD4, CD25, GITR, LAG-3, PD-L1, CCR4. PBMC-derived Tregs and MoT cells, but not Jurkat cells, inhibited proliferation of human CD4⁺ PBMCs in a ratio-dependent manner. Transwell membrane separation prevented suppression of stimulated CD4⁺ PBMC proliferation by MoT cells and Tregs, suggesting cell–cell contact is required for suppressive activity. Blocking antibodies against PD-L1, LAG-3, GITR, CCR4, HLA-DR, or CTLA-4 did not reverse the suppressive activity. We show that human PBMC-derived Tregs and MoT cells suppress stimulated CD4⁺ PBMCs in a cell contact-dependent manner, suggesting that a Foxp3⁺ Treg population suppresses immune responses by an uncharacterized cell contact-dependent mechanism.     

Expansion and activation of CD4(+)CD25(+) regulatory T cells in Heligmosomoides polygyrus infection

Regulatory T cell responses to infectious organisms influence not only immunity and immunopathology, but also responses to bystander antigens. Mice infected with the gastrointestinal nematode parasite Heligmosomoides polygyrus show an early Th2-dominated immune response (days 7-14), but by day 28 a strongly regulatory profile is evident with antigen-specific IL-10 release and elevated frequency of CD4(+) T cells bearing surface TGF-beta. CD4(+)CD25(+) T cells from infected mice show enhanced capacity to block in vitro effector T cell proliferation. CD4(+)CD25(+) cell numbers expand dramatically during infection, with parallel growth of both CD25(+)Foxp3(+) and CD25(+)Foxp3(-) subsets. CTLA-4 and glucocorticoid-induced tolerance-associated receptor, also associated with regulatory T cell function, become more prominent, due to both expanded CD25(+) cell numbers and increased expression among the CD25(-) population. Both intensity and frequency of CD103 expression by CD4(+) T cells rise significantly, with greatest expansion among CD25(+)Foxp3(+) cells. While TGF-beta expression is observed among both CD25(+)Foxp3(+) and CD25(+)Foxp3(-) subsets, it is the latter population which shows higher TGF-beta staining following infection. These data demonstrate in a chronic helminth infection that Foxp3(+) regulatory T cells are stimulated, increasing CD103 expression in particular, but that significant changes occur to other populations including expansion of CD25(+)TGF-beta(+)Foxp3(-) cells, and induction of CTLA-4 on CD25(-) non-regulatory lymphocytes.     

Der p2重组BCG诱导适应性CD4+CD25+ Treg产生并下调小鼠变应性气道炎症反应

目的： 卡介苗（BCG）是广泛应用的Th1应答诱导疫苗。近年来的几项研究认为分支杆菌疫苗可作为免疫佐剂诱导生成调节性T细胞并抑制哮喘气道炎症。我们前期构建了胞壁表达屋尘螨抗原Der p2的重组BCG疫苗（Der p2 rBCG）。本研究的目的是阐明Der p2 rBCG的免疫调节机制。方法：小鼠分别给予生理盐水、BCG、Der p2 rBCG免疫后,观察脾细胞中相关调节性T细胞亚群的相对比例和绝对数量。体外及在体观察Der p2 rBCG诱导产生的CD4+CD25+ Treg的抑制功能。结果：(1)Der p2 rBCG可以诱导CD4+CD25+ Treg的产生;(2)Der p2 rBCG诱导产生的CD4+CD25+ T细胞可以在体外以变应原特异的方式抑制效应CD4+T细胞的增殖;(3)Der p2 rBCG诱导产生的CD4+CD25+ T细胞可以在体内下调Der p2诱导的小鼠变应性气道炎症。结论：Der p2 rBCG可以诱导适应性CD4+CD25+ Treg的产生,并通过其介导的免疫抑制作用下调小鼠变应性气道炎症反应。     

Regulatory T cells and asthma

Airway inflammation in asthma is characterized by activation of T helper type-2 (Th2) T cells, IgE production and eosinophilia. In many cases, this process is related to an inappropriate T cell response to environmental allergens, and other T cell-dependent pathways may also be involved (such as Th17). Regulatory T cells (Tregs) are T cells that suppress potentially harmful immune responses. Two major subsets of Treg are CD25^hi, Foxp3⁺Tregs and IL-10-producing Tregs. There is evidence that the numbers or function of both subsets may be deficient in patients with atopic allergic disease. Recent work has extended these findings into the airway in asthma where Foxp3 expression was reduced and CD25^hi Treg-suppressive function was deficient. In animal models of allergic airways disease, Tregs can suppress established airway inflammation and airway hyperresponsiveness, and protocols to enhance the development, recruitment and function of Tregs have been described. Together with studies of patients and in vitro studies of human T cells, these investigations are defining potential interventions to enhance Treg function in the airway in asthma. Existing therapies including corticosteroids and allergen immunotherapy act on Tregs, in part to increase IL-10 production, while vitamin D3 and long-acting β-agonists enhance IL-10 Treg function. Other possibilities may be enhancement of Treg function via histamine or prostanoid receptors, or by blocking pro-inflammatory pathways that prevent suppression by Tregs (activation of Toll-like receptors, or production of cytokines such as IL-6 and TNF-α). As Tregs can also suppress the potentially beneficial immune response important for controlling infections and cancer, a therapeutic intervention should target allergen- or site-specific regulation.     

De novo induction of antigen-specific CD4+CD25+Foxp3+ regulatory T cells in vivo following systemic antigen administration accompanied by blockade of mTOR

Although regulatory CD4+CD25+ forkhead box p3+ (Foxp3+) T cells (Tregs) are generally thought to arise in the thymus as a separate lineage of CD4 T cells, they can also be induced de novo in the periphery. Peripheral development of Tregs from na?ve T cells is favored by low-intensity activation and absence of inflammation. We show here that absence of CD28 costimulation results in a modest decrease in activation of na?ve, antigen-specific CD4 T cells under noninflammatory conditions and benefits their initial Foxp3 induction. However, expression of Foxp3 following T cell activation without CD28 costimulation remains sensitive to the antigen dose. Furthermore, basal CD28 costimulation is critical for survival of the induced Foxp3+ CD4 T cells, and their accumulation is abrogated in the absence of CD28. In contrast, pharmacologic blockade of mammalian target of rapamycin enhances lasting induction of Tregs, irrespective of the initial antigen dose used to activate the antigen-specific T cells. This finding may have important practical, clinical implication in development of tolerance protocols.     

Costimulatory effects of IL-1 on the expansion/differentiation of CD4+CD25+Foxp3+ and CD4+CD25+Foxp3- T cells

CD4+CD25+forkhead box p3 (Foxp3)+ regulatory T cells (Treg) control peripheral tolerance. Although Treg are anergic when stimulated through the TCR, mature bone marrow-derived, but not splenic, dendritic cells (DC) can induce their proliferation after TCR stimulation in the absence of IL-2. One possibility is that the DC produce proinflammatory cytokines such as IL-1 or IL-6 that function as growth factors for Treg. We have analyzed the costimulatory effects of IL-1 on the expansion of Foxp3+ Treg in vitro. When CD4+CD25+ T cells were cultured in the presence of splenic DC and IL-1, marked expansion of the Foxp3+ T cells was observed. The effects of IL-1 were mediated on CD4+CD25+Foxp3(-) T cells present in the starting population rather than on the DC or on the CD4+CD25+Foxp3+ T cells. In contrast, stimulation of CD4+CD25+ T cells with plate-bound anti-CD3 and IL-1 in the absence of DC resulted in the outgrowth of a CD4+CD25+Foxp3(-) T cell population composed of NKT cells and non-NKT, IL-17-producing cells. Foxp3+ Treg purified from mice expressing the reporter gene enhanced GFP in the Foxp3 locus failed to proliferate when costimulated with IL-1. These findings have important implications for the design of protocols for the expansion of CD4+CD25+ T cells for cellular biotherapy.     

Tregs调节小鼠肝癌局部引流淋巴结内免疫效应细胞的功能

目的:探讨肿瘤引流淋巴结(TDLNs)内调节性T细胞(Tregs)对局部免疫效应细胞的调节作用。方法:建立小鼠肝癌TDLNs模型,通过免疫组织化学染色和流式细胞仪检测TDLNs内Foxp3+Tregs和CD4+及CD8+T细胞的数量。实时定量PCR测定Foxp3mRNA表达水平。应用酶联免疫斑点法(ELISPOT)检测TDLNs内CD8+T细胞分泌IFN-γ的功能。结果:TDLNs内Tregs和效应性T细胞均明显扩增,Tregs弥散分布于CD8+T细胞聚居区。TDLNs内Foxp3mRNA表达水平显著高于同一接种肿瘤小鼠腹股沟淋巴结(P0.01)和脾脏(P0.01)。Tregs趋向于在TDLNs内聚集,而非其它外周淋巴结位点。荷瘤小鼠的脾脏Foxp3mRNA表达明显高于注射LPS小鼠脾脏。Tregs抑制TDLNs内已初始化的CD8+T细胞分泌IFN-γ的功能,经anti-CD3刺激激活后,CD8+T细胞分泌IFN-γ的功能可恢复。结论:TDLNs内Tregs通过调控CD8+T细胞功能而发挥重要作用,清除Tregs是发挥特异性肿瘤免疫治疗的关键。     

Interleukin-6 is essential for Staphylococcal exotoxin B-induced T regulatory cell insufficiency in nasal polyps

Background The pathogenesis of nasal polyps is still unclear. There is increasing evidence indicating that Staphylococcal aureus (S. aureus) is associated with the formation of nasal polyps, but the mechanism has not been well documented to date.
Methods We stimulated cultured nasal polyps and turbinate tissues with Staphylococcal exotoxin B (SEB), detected the expression of pro-inflammatory cytokines (IL-2, IL-6, and IL-8) and T cell cytokines (IFN-γ, IL-4, IL-5, IL-10, and IL-17) in the supernatants, and evaluated mRNA expression (T-bet, GATA-3, Foxp3, and RORγt) and frequencies of CD4⁺CD25⁺ T regulatory cells (Tregs) in nasal tissues. We also evaluated the effects of blocking IL-6 with monoclonal antibodies to T cell profiles in cultured nasal tissues stimulated by SEB.
Results Levels of IL-6, IFN-γ and IL-4 increased significantly in SEB-stimulated nasal polyps. Meanwhile, mRNA expressions of T-bet and GATA-3 were significantly up-regulated, while Foxp3 was inhibited and the frequencies of CD4⁺CD25⁺ Tregs were decreased after SEB stimulation. After blocking IL-6, the levels of IL-10 and Foxp3 mRNA, as well as the frequencies of CD4⁺CD25⁺ Tregs, were significantly increased, while IFN-γ and IL-4 production and the mRNA expression of T-bet and GATA-3 were significantly inhibited.
Conclusions SEB is able to modulate pro-inflammatory factors, T-helper type 1/Th2 profiles and suppress Treg activity in cultured nasal polyps, which were rescued by blocking IL-6 activity. Therefore, IL-6 is essential for SEB-induced Treg insufficiency in nasal polyps.     

CD4+VEGFR1HIGH T cell as a novel Treg subset regulates inflammatory bowel disease in lymphopenic mice

Regulatory T cells (Tregs) are a specialized subpopulation of T cells that control the immune response and thereby maintain immune system homeostasis and tolerance to self-antigens. Many subsets of CD4⁺ Tregs have been identified, including Foxp3⁺, Tr1, Th3, and Foxp3neg iT(R)35 cells. In this study, we identified a new subset of CD4⁺VEGFR1^high Tregs that have immunosuppressive capacity. CD4⁺VEGFR1high T cells, which constitute approximately 1.0% of CD4⁺ T cells, are hyporesponsive to T-cell antigen receptor stimulation. Surface marker and FoxP3 expression analysis revealed that CD4⁺VEGFR1^high T cells are distinct from known Tregs. CD4⁺VEGFR1^high T cells suppressed the proliferation of CD4⁺CD25⁻ T cell as efficiently as CD4⁺CD25^high natural Tregs in a contact-independent manner. Furthermore, adoptive transfer of CD4⁺VEGFR1⁺ T cells from wild type to RAG-2-deficient C57BL/6 mice inhibited effector T-cell-mediated inflammatory bowel disease. Thus, we report CD4⁺ VEGFR1^high T cells as a novel subset of Tregs that regulate the inflammatory response in the intestinal tract.