Dendritic cells with TGF-beta1 differentiate naive CD4+CD25- T cells into islet-protective Foxp3+ regulatory T cells

CD4(+)CD25(+)Foxp3(+) regulatory T cells (T regs) are important for preventing autoimmune diabetes and are either thymic-derived (natural) or differentiated in the periphery outside the thymus (induced). Here we show that beta-cell peptide-pulsed dendritic cells (DCs) from nonobese diabetic (NOD) mice can effectively induce CD4(+)CD25(+)Foxp3(+) T cells from na?ve islet-specific CD4(+)CD25(-) T cells in the presence of TGF-beta1. These induced, antigen-specific T regs maintain high levels of clonotype-specific T cell receptor expression and exert islet-specific suppression in vitro. When cotransferred with diabetogenic cells into NOD scid recipients, T regs induced with DCs and TGF-beta1 prevent the development of diabetes. Furthermore, in overtly NOD mice, these cells are able to significantly protect syngeneic islet grafts from established destructive autoimmunity. These results indicate a role for DCs in the induction of antigen-specific CD4(+)CD25(+)Foxp3(+) T cells that can inhibit fully developed autoimmunity in a nonlymphopoenic host, providing an important potential strategy for immunotherapy in patients with autoimmune diabetes.     

CD70+ non-Hodgkin lymphoma B cells induce Foxp3 expression and regulatory function in intratumoral CD4+CD25 T cells

Foxp3 expression was initially thought to be restricted to the CD4(+)CD25(+) regulatory T-cell population. However, recent studies suggest that forkhead box P3 (Foxp3) is expressed in CD4(+)CD25(-) T cells in aged mice. In the present study in B-cell non-Hodgkin lymphoma (NHL), we found that a subset of intratumoral but not peripheral blood CD4(+)CD25(-) T cells, comprising about 15% of intratumoral CD4(+) T cells, express Foxp3 and are capable of suppressing the proliferation of autologous infiltrating CD8(+) T cells. In vitro activation with OKT3/anti-CD28 antibody (Ab) or dendritic cells (DCs) induced Foxp3 expression in a subset of these CD4(+)CD25(-)Foxp3(-) T cells. We found that the presence of lymphoma B cells during activation augmented activation-induced Foxp3 expression in CD4(+)CD25(-) T cells. We also found that CD70(+) lymphoma B cells significantly contributed to the activation-induced Foxp3 expression in intratumoral CD4(+)CD25(-) T cells. Furthermore, the blockade of CD27-CD70 interaction by anti-CD70 Ab abrogated lymphoma B-cell-mediated induction of Foxp3 expression in intratumoral CD4(+)CD25(-) T cells. Taken together, these studies reveal a novel role for NHL B cells in the development of intratumoral regulatory T cells.     

CD4+CD25+调节性T细胞与支气管哮喘

支气管哮喘是一种常见的慢性呼吸道疾病,其免疫发病机制尚不十分清楚。CD4 CD25 调节性T细胞是一种特殊的调节性T细胞,参与自身免疫调节,维持自身免疫耐受。本文就CD4 CD25 调节性T细胞的特性及与支气管哮喘的发病机制、治疗、预后的研究进展做一综述。     

地塞米松对哮喘小鼠CD4+CD25+调节性T细胞及IL-4、IL-10水平的影响

目的 探讨地塞米松对哮喘小鼠CD4+ CD25+调节性T细胞及IL-4、IL-10水平的影响.方法 30只雄性BALB/c小鼠随机分为三组:正常对照组、哮喘组和地塞米松组.利用卵清白蛋白腹腔注射和雾化吸入制备哮喘模型;通过流式细胞仪检测各组小鼠脾脏单个核细胞CD4+ CD25+调节性T细胞占CD4+T细胞的百分比;使用免疫组织化学方法分析各组IL-4在小鼠肺组织中的表达情况;用酶联免疫吸附试验检测各组小鼠血清IL-10的水平.结果 哮喘组脾脏单个核细胞CD4+CD25+调节性T细胞百分比及IL-10的表达水平较正常对照组和地塞米松组降低(P＜0.05),哮喘组IL-4水平较正常对照组和地塞米松组增高(P＜0.05).结论 地塞米松的抗炎作用可能通过上调CD4+ CD25+调节性T细胞、调节性T细胞亚群失衡的途径来实现.     

De novo generation of antigen-specific CD4+CD25+ regulatory T cells from human CD4+CD25- cells

Antigen-specificity is a hallmark of adaptive T cell-mediated immune responses. CD4+CD25+FOXP3+ regulatory T cells (T(R)) also require activation through the T cell receptor for function. Although these cells require antigen-specific activation, they are generally able to suppress bystander T cell responses once activated. This raises the possibility that antigen-specific T(R) may be useful therapeutically by localizing generalized suppressive activity to tissues expressing select target antigens. Here, we demonstrate that T(R) specific for particular peptide-MHC complexes can be generated from human CD4+CD25- T cells in vitro and isolated by using HLA class II tetramers. Influenza hemagglutinin epitopes were used to generate hemagglutinin-specific T(R), which required cognate antigen for activation but which subsequently suppressed noncognate bystander T cell responses as well. These findings have implications for the generation of therapeutic regulatory T cells in disease, and also suggest an important mechanism by which T cells may be regulated at the site of inflammation.     

CD4+ CD25+调节性T细胞在哮喘患者体内的功能变化及其意义

目的探讨CD_4~ CD_(25)~ 调节性T细胞在哮喘患者体内的功能变化。进一步探讨哮喘的发病机制。方法使用免疫磁珠分选正常对照组和哮喘患者的CD_4~ CD_(25)~ 调节性T细胞;流式细胞仪分析其纯度;分别用变应原或联合应用抗CD3单抗和抗CD28单抗,刺激两种来源的CD_4~ CD_(25)~ 调节性T细胞和CD_4~ CD_(25)~-5T细胞,ELISA、3H-TdR等检测CD_4~ CD_(25)~ 调节性T细胞功能。结果:来源于哮喘患者的CD4 CD2 5调节性T细胞不能抑制变应原对CD_4~ CD_(25)~-T细胞的活化增殖,而能抑制抗CD3和抗CD28单抗对CD_4~ CD_(25)~-T细胞的刺激作用。结论哮喘患者体内CD_4~ CD_(25)~ 调节性T细胞存在功能缺陷。     

CD4+ CD25+ 调节性T细胞与自身免疫性甲状腺疾病

CD4+ CD25+ 调节性T细胞为新近发现的一群功能成熟的T细胞亚群.其特征性表达叉头盒蛋白3(Foxp3)分子,专职免疫无能和免疫抑制,在维持外周免疫耐受,防止自身免疫性疾病发病中起着极为关键的作用.CD4+ CD25+ 调节性T细胞在自身免疫性甲状腺疾病(AITD)发病中的作用引起了人们的关注.动物实验发现CD4+ CD25+ 调节性T细胞存在与否决定了实验动物是否发生实验性自身免疫性甲状腺炎(EAT)和Graves病.人体研究发现CD4+ CD25+ 调节性T细胞数目和功能异常与人AITD发生密切相关.这些研究结果提示,CD4+ CD25+ 调节性T细胞可能在AITD发病中起重要作用.     

Prolactin down-regulates CD4+CD25hiCD127low/- regulatory T cell function in humans

Among its many functions, prolactin (PRL) participates in immune responses and promotes the activation, differentiation and proliferation of T cells. However, the mechanisms by which PRL regulates regulatory T (T(reg)) cells are still unknown. Our goal was to determine whether PRL plays a role in T(reg) function. We measured the expression of PRL and its receptor in T(reg) and effector T (T(eff)) cells from 15 healthy individuals. We also evaluated the functional activity of T(reg) cells by examining proliferation and cytokine secretion in cells activated with anti-CD3/CD28 in the presence or absence of PRL. We report that T(reg) cells constitutively expressed PRL receptor, whereas T(eff) cells required stimulation with anti-CD3/CD28 to induce PRL receptor expression. Expression of PRL was constitutive in both populations. We found that the addition of PRL inhibited the suppressor effect (proliferation) mediated by T(reg) cells in vitro, reducing suppression from 37.4 to 13% when PRL was added to co-cultures of T(reg) and T(eff) cells (P<0.05). Cultures treated with PRL favoured a Th1 cytokine profile, with increased production of TNF and IFNγ. We report for the first time that PRL receptor expression was constitutive in T(reg) cells but not in T(eff) cells, which require stimulation to induce PRL receptor expression. PRL inhibited the suppressive function of T(reg) cells, apparently through the induced secretion of Th1 cytokines.     

IL-5 promotes induction of antigen-specific CD4+CD25+ T regulatory cells that suppress autoimmunity

Immune responses to foreign and self-Ags can be controlled by regulatory T cells (Tregs) expressing CD4 and IL-2Rα chain (CD25). Defects in Tregs lead to autoimmunity, whereas induction of Ag-specific CD4+CD25+ Tregs restores tolerance. Ag-specific CD4+CD25+ FOXP3+Tregs activated by the T helper type 2 (Th2) cytokine, IL-4, and specific alloantigen promote allograft tolerance. These Tregs expressed the specific IL-5Rα and in the presence of IL-5 proliferate to specific but not third-party Ag. These findings suggest that recombinant IL-5 (rIL-5) therapy may promote Ag-specific Tregs to mediate tolerance. This study showed normal CD4+CD25+ Tregs cultured with IL-4 and an autoantigen expressed Il-5rα. Treatment of experimental autoimmune neuritis with rIL-5 markedly reduced clinical paralysis, weight loss, demyelination, and infiltration of CD4+ (Th1 and Th17) CD8+ T cells and macrophages in nerves. Clinical improvement was associated with expansion of CD4+CD25+FOXP3+ Tregs that expressed Il-5rα and proliferated only to specific autoantigen that was enhanced by rIL-5. Depletion of CD25+ Tregs or blocking of IL-4 abolished the benefits of rIL-5. Thus, rIL-5 promoted Ag-specific Tregs, activated by autoantigen and IL-4, to control autoimmunity. These findings may explain how Th2 responses, especially to parasitic infestation, induce immune tolerance. rIL-5 therapy may be able to induce Ag-specific tolerance in autoimmunity.     

CD4+CD25+Foxp3+ regulatory T cells induce alternative activation of human monocytes/macrophages

CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) are potent suppressors of the adaptive immune system, but their effects on innate immune cells are less well known. Here we demonstrate a previously uncharacterized function of Tregs, namely their ability to steer monocyte differentiation toward alternatively activated macrophages (AAM). AAM are cells with strong antiinflammatory potential involved in immune regulation, tissue remodeling, parasite killing, and tumor promotion. We show that, after coculture with Tregs, monocytes/macrophages display typical features of AAM, including up-regulated expression of CD206 (macrophage mannose receptor) and CD163 (hemoglobin scavenger receptor), an increased production of CCL18, and an enhanced phagocytic capacity. In addition, the monocytes/macrophages have reduced expression of HLA-DR and a strongly reduced capacity to respond to LPS in terms of proinflammatory mediator production (IL-1beta, IL-6, IL-8, MIP-1alpha, TNF-alpha), NFkappaB activation, and tyrosine phosphorylation. Mechanistic studies reveal that CD4(+)CD25(+)CD127(low)Foxp3(+) Tregs produce IL-10, IL-4, and IL-13 and that these cytokines are the critical factors involved in the suppression of the proinflammatory cytokine response. In contrast, the Treg-mediated induction of CD206 is entirely cytokine-independent, whereas the up-regulation of CD163, CCL18, and phagocytosis are (partly) dependent on IL-10 but not on IL-4/IL-13. Together these data demonstrate a previously unrecognized function of CD4(+)CD25(+)Foxp3(+) Tregs, namely their ability to induce alternative activation of monocytes/macrophages. Moreover, the data suggest that the Treg-mediated induction of AAM partly involves a novel, cytokine-independent pathway.     

Stability of human rapamycin-expanded CD4+CD25+ T regulatory cells

Background

The clinical use of ex vivo-expanded T-regulatory cells for the treatment of T-cell-mediated diseases has gained increasing momentum. However, the recent demonstration that FOXP3⁺ T-regulatory cells may contain interleukin-17–producing cells and that they can convert into effector cells once transferred in vivo raises significant doubts about their safety. We previously showed that rapamycin permits the ex vivo expansion of FOXP3⁺ T-regulatory cells while impairing the proliferation of non-T-regulatory cells. Here we investigated the Th17-cell content and the in vivo stability of rapamycin-expanded T-regulatory cells as pertinent aspects of cell-based therapy.

Design and Methods

T-regulatory-enriched cells were isolated from healthy volunteers and were expanded ex vivo with rapamycin with a pre-clinical applicable protocol. T-regulatory cells cultured with and without rapamycin were compared for their regulatory activity, content of pro-inflammatory cells and stability.

Results

We found that CD4⁺CCR6⁺CD161⁺ T cells (i.e., precursor/committed Th17 cells) contaminate the T-regulatory cells cultured ex vivo in the absence of rapamycin. In addition, Th17 cells do not expand when rapamycin-treated T-regulatory cells are exposed to a “Th17-favorable” environment. Rapamycin-expanded T-regulatory cells maintain their in vitro regulatory phenotype even after in vivo transfer into immunodeficient NOD-SCID mice despite being exposed to the irradiation-induced pro-inflammatory environment. Importantly, no additional rapamycin treatment, either in vitro or in vivo, is required to keep their phenotype fixed.

Conclusions

These data demonstrate that rapamycin secures ex vivo-expanded human T-regulatory cells and provide additional justification for their clinical use in future cell therapy-based trials.     

Therapeutic vaccination using CD4+CD25+ antigen-specific regulatory T cells

Autoimmune disease results from the dysregulation of basic tolerogenic processes designed to control self/non-self-discrimination. Approaches to treat autoimmunity have focused historically on potent immunosuppressives that block the activation and expansion of antigen-specific T cells before they differentiate into pathogenic T cell responses. These therapies are very efficient in reducing clonal expansion and altering early signaling pathways. However, once the pathogenic responses are established (i.e., autoimmunity), the interventions are less effective on activated and differentiated T cell subsets (including memory T cells) or acting in the presence of an inflammatory milieu to abort immune responses at the target tissue and systemically. Moreover, the current immunotherapies require continuous use because they do not redirect the immune system to a state of tolerance. The continuous treatment leads to long-term toxicities and can profoundly suppress protective immune responses targeted at viruses, bacteria, and other pathogens. Over the past decade, there have been tremendous advances in our understanding of the basic processes that control immune tolerance. Among the most exciting has been the identification of a professional regulatory T cell subset that has shown enormous potential in suppressing pathologic immune responses in autoimmune diseases, transplantation, and graft vs. host disease. In this review, we summarize current efforts to induce and maintain tolerance in the autoimmune diabetes setting by using therapeutic vaccination with CD4(+)CD25(+) regulatory T cells. Emphasis will be placed on approaches to exploit regulatory T cells either directly or through the use of anti-CD3 immunotherapy.     

CD4+CD25+T细胞延长同种异体胰岛移植物存活

探讨CD4+ CD25+调节性T细胞作为细胞疫苗抑制小鼠同种异体胰岛移植物排斥反应的作用,采用免疫磁珠分离技术分选CD4+ CD25+调节性T细胞联合BALB/cByJ小鼠同种异体胰岛移植.结果 显示,CD4+ CD25+调节性T细胞可明显延长同种异体移植物的存活时间.     

CD4+CD25+ regulatory T cells inhibit immune-mediated transgene rejection

Like cellular transplantation, gene therapy is often limited by immune rejection of the newly expressed antigen. In a model of gene transfer in muscle, delivery of the influenza hemagglutinin (HA) membrane protein by adeno-associated virus (AAV) is impaired by a strong immune response that leads to a rapid rejection of the transduced fibers. We show here that injection of HA-specific CD4+CD25+ T cells from T-cell receptor (TCR)-transgenic animals, concomitant with gene transfer, down-regulates the anti-HA cytotoxic and B-lymphocyte responses and enables persistent HA expression in muscle. This demonstrates for the first time that adoptive transfer of antigen-specific CD4+CD25+ regulatory T cells can be used to induce sustained transgene engraftment in solid tissues.     

乙型肝炎患者外周血CD4+ CD25+调节性T细胞表型与功能分析

目的 观察急、慢性乙型肝炎(AHB、CHB)患者外周血CD4+CD25 high调节性T细胞(Treg)的频率、表型和功能特点.方法 采集16例AHB急性发病期(发病后第1周)患者、72例CHB患者和32例健康人的外周血,检测Treg频率,并分析其表面CD45RO、CD45RA、HLA-DR、CD95和细胞内细胞毒T淋巴细胞相关抗原4(CTLA-4)的表达水平.应用实时荧光定量RT-PCR检测CD4+ CD25+、CD4+ CD25-、CD4+和CD4-等细胞亚群和外周血单个核细胞(PBMC)的FoxP3 mRNA表达量.通过MACS免疫磁珠分选Treg,并应用[3H]掺入法检测Treg抑制抗-CD3抗体和HBV抗原刺激的PBMC增殖能力,并观察Treg对HBV抗原或抗-CD3抗体刺激自体PBMC分泌IFNγ的影响.结果 CD4+CD25 high Treg高表达CD45RO、HLA-DR、CD95和细胞内CTLA-4,低表达CD45RA,并且较特异的高表达FoxP3 mRNA.乙型肝炎病人外周血Treg频率与健康对照(3.50±0.72)%比较无统计学差异,但CHB组(3.90±1.44)%显著高于AHB组(3.10±0.87)%,P＜0.05.Treg本身对于HBV抗原或抗-CD3抗体刺激没有明显的增殖反应和IFNγ分泌,但可抑制自体PBMC增殖和IFNγ分泌,其中对HBV抗原刺激引起的细胞反应抑制作用较强.结论 HBV感染者外周血Treg较特异地表达FoxP3分子,能抑制HBV抗原特异性细胞免疫反应,这对于深入阐明CHB发病机制具有重要意义.     

CD4+CD25+ regulatory T cells control CD8+ T-cell effector differentiation by modulating IL-2 homeostasis

CD4(+)CD25(+) regulatory T cells (Treg) play a crucial role in the regulation of immune responses. Although many mechanisms of Treg suppression in vitro have been described, the mechanisms by which Treg modulate CD8(+) T cell differentiation and effector function in vivo are more poorly defined. It has been proposed, in many instances, that modulation of cytokine homeostasis could be an important mechanism by which Treg regulate adaptive immunity; however, direct experimental evidence is sparse. Here we demonstrate that CD4(+)CD25(+) Treg, by critically regulating IL-2 homeostasis, modulate CD8(+) T-cell effector differentiation. Expansion and effector differentiation of CD8(+) T cells is promoted by autocrine IL-2 but, by competing for IL-2, Treg limit CD8(+) effector differentiation. Furthermore, a regulatory loop exists between Treg and CD8(+) effector T cells, where IL-2 produced during CD8(+) T-cell effector differentiation promotes Treg expansion.