Ontogeny, function, and peripheral homeostasis of regulatory T cells in the absence of interleukin-7

Mice lacking interleukin-7 (IL-7-/- mice) have no signs of autoimmune disease, contrary to other models of lymphopenia. We investigated whether the absence of disease was due to the fact that IL-7 is dispensable for the ontogeny, function, and homeostasis of regulatory CD4+ T cells. We show here that the establishment of the peripheral pool of Foxp3-expressing regulatory cells is IL-7 independent, and the premature involution of the thymus in IL-7-/- mice does not change the representation of the CD4+CD25+ T-cell compartment. In addition, CD4+CD25+ T cells expand in the absence of IL-7, without losing Foxp3 expression. The frequency of activated peripheral CD4+ T cells increases with age in both the CD25- and CD25+ compartments, with the CD4+CD25+ T cells displaying signs of constant activation. IL-7-/- CD4+CD25+ T cells control inflammatory bowel disease induced by IL-7-/- T cells even in hosts lacking IL-7. Depletion of the CD25+ T-cell subset after thymic involution results in a mild form of inflammatory bowel disease (IBD), which resolves concomitantly with the regeneration of this subset. This study shows for the first time that IL-7-/- mice have a robust regulatory Foxp3-expressing CD4+ T-cell compartment that controls T-cell-mediated disease. It also highlights the potential of the regulatory Foxp3-expressing CD4+CD25- T-cell population to restore a functional CD4+CD25+ T-cell compartment through an IL-7-independent pathway.     

TGF-beta regulates in vivo expansion of Foxp3-expressing CD4+CD25+ regulatory T cells responsible for protection against diabetes

CD4+CD25+ regulatory T cells are essential in the protection from organ-specific autoimmune diseases. In the pancreas, they inhibit actions of autoreactive T cells and thereby prevent diabetes progression. The signals that control the generation, the maintenance, or the expansion of regulatory T cell pool in vivo remain poorly understood. Here we show that a transient pulse of transforming growth factor beta (TGF-beta) in the islets during the priming phase of diabetes is sufficient to inhibit disease onset by promoting the expansion of intraislet CD4+CD25+ T cell pool. Approximately 40-50% of intraislet CD4+ T cells expressed the CD25 marker and exhibited characteristics of regulatory T cells including small size, high level of intracellular CTLA-4, expression of Foxp3, and transfer of protection against diabetes. Results from in vivo incorporation of BrdUrd revealed that the generation of a high frequency of regulatory T cells in the islets is due to in situ expansion upon TGF-beta expression. Thus, these findings demonstrate a previously uncharacterized mechanism by which TGF-beta inhibits autoimmune diseases via regulation of the size of the CD4+CD25+ regulatory T cell pool in vivo.     

CD4+CD25-Foxp3+T淋巴细胞的表型鉴定及其在初发系统性红斑狼疮中的意义

目的 对初发系统性红斑狼疮(SLE)患者外周血异常表达CD4+CD25-Foxp3+T淋巴细胞进行表型鉴定,并探讨其临床意义.方法 对初发SLE患者外周血CD4+T淋巴细胞进行细胞表面分子[CD25、CD127、CCR4、糖皮质激素诱导的肿瘤坏死因子受体(GITR)、细胞毒T淋巴细胞相关抗原4(CT-LA-4)]和胞内分子(Foxp3)标染,流式细胞仪检测,并研究CD4+各细胞亚群与狼疮肾炎和疾病活动度(SLEDAI)相关性.结果 SLE患者外周血CD4+CD25-Foxp3+T淋巴细胞表面 GITR、CTLA-4和CCR4表达率与活化T淋巴细胞(CD4+CD25+Foxp3-)相比差异无统计学意义(P均>0.05),而显著低于调节性T淋巴细胞(CD4+CD25+Foxp3+)(P均<0.01);CD4+Foxp3+CD25high,CD4+Foxp3+CD25low和CD4+Foxp3+CD25-细胞中CD127low-百分率分别为(93.8±,3.5)%,(93.7±2.3)%,(92.0±2.1)%,三者之间差异无统计学意义(P>0.05);在CD4+细胞亚群中,当CD127low-时,Foxp3+在CD25high,CD25low和CD25-中表达率分别为 (91.4±2.6)%,(71.9±3.3)%,(9.0±2.2)%,三者之间差异均有统计学意义(P<0.01);SLE患者外周血CD4+CCR4+CD25highT淋巴细胞百分率与SLEDAI呈显著负相关(r=-0.695,P<0.001),狼疮肾炎患者(1.10±0.17)%显著低于SLE无肾炎组[(1.61±0.23)%,P<0.01]和健康对照组[(1.75±0.10)%,P<0.01];狼疮肾炎患者外周血CD4+ CCR4+CD25low-T淋巴细胞百分率显著高于健康对照组[(11.5 ±2.3)%与(8.0±1.0)%,P<0.01)].结论 初发SLE中异常升高的CD4+CD25-Foxp3+T淋巴细胞的表型类似早期活化效应T淋巴细胞.可以用CD4+CD25highCD127low-T淋巴细胞替选CD4+CD25highFoxp3+调节性T淋巴细胞.CCR4+调节性T淋巴细胞可能参与狼疮肾炎发病.     

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.     

Regulatory potential and control of Foxp3 expression in newborn CD4+ T cells

Thymectomy at day 3 after birth leads to autoimmune disease in some genetic backgrounds. Disease is thought to be caused by the lack/paucity of regulatory T cells. We show that 3-day-old mice already contain a significant compartment of Foxp3-expressing CD25(+)CD4(+) splenocytes. Whereas, in adult spleen, the subsets of regulatory T cells (CD25(+) and/or CD103(+)) express high amounts of Foxp3 mRNA, in 3-day-old mice, both thymic and splenic CD25(+)CD4(+) T cell subsets express lower amounts of Foxp3 mRNA, and CD103(+) cells are barely detected. In adult day 3-thymectomized mice, the CD25(+)CD4(+) T cell subset is overrepresented (most of the cells being CD103(+)) and expresses high amounts of Foxp3 mRNA, independent of the development of autoimmune gastritis. These cells control inflammatory bowel disease and the homeostatic expansion of lymphocytes. This study demonstrates that the peripheral immune system of newborn mice is endowed of a remarkable regulatory potential, which develops considerably in the absence of thymic supply.     

调节性T淋巴细胞对成人乙型肝炎疫苗接种免疫应答的影响

目的 通过对乙型肝炎疫苗接种后不同免疫应答人群调节性T淋巴细胞(Treg细胞)Foxp3 mRNA的表达和细胞因子分泌的检测,探讨乙型肝炎疫苗接种后免疫应答与免疫调节细胞和细胞因子之间的内在联系.方法 采集不同反应人群全血,实时荧光定量PCR检测人外周血单个核细胞Foxp3 mRNA的表达;流式细胞术对外周血单核细胞的表面标志物CD4、CD25进行检测;酶联免疫法检测外周血单个核细胞植物血凝素(PHA)和HBsAg刺激后白细胞介素(IL)-4、IL-12、IL-18、干扰素(IFN)γ的产生水平.根据不同资料采用方差分析、q检验或相关分析进行统计学处理.结果 (1)PHA和HBsAg刺激前后,无应答组Foxp3的表达均高于应答组和对照组,差异有统计学意义(P＜0.05).(2)应答组外周血CD4+CD25+Treg细胞占CD4+T淋巴细胞的百分比(0.59%±0.46%)明显低于对照组(1.30%±1.44%),差异有统计学意义(F=2.990,P＜0.01).(3)各组外周血单个核细胞经PHA和HBsAg刺激后,无应答组的IFN γ浓度[(11.00±9.03)U/ml]明显低于应答组[(38.88±28.16)U/ml],差异有统计学意义(P＜0.01).(4)各组外周血单个核细胞经PHA和HBsAg刺激后,IL-18、IL-4、IL-12的浓度差异均无统计学意义.结论 CD4+CD25+Foxp3+Treg细胞在一定程度上参与了乙型肝炎疫苗接种应答的负性调控;乙型肝炎疫苗接种后无应答与IFN γ分泌不足有关;抗-HBs滴度水平与IFN γ和CD4+CD25+Foxp3表达无相关性.     

系统性红斑狼疮患者CD4~+CD25~+CD127~(low/-)调节性T细胞中Foxp3的表达及免疫抑制功能研究

目的 研究系统性红斑狼疮(SEE)外周血中调节性T细胞不同标志以及调节性T细胞在SLE发病中的作用;探讨CD127与Foxp3的相关性,明确CD127定义调节性T细胞的特异性;鉴定CD4~+CD25~+CD127~(low/-)T淋巴细胞免疫抑制功能.方法 ①采用四色直接荧光素标记法和多参数流式细胞术检测40例SLE患者(19例初发和21例缓解)及15名健康对照外周血CD4~+CD25~+T淋巴细胞、CD4~+CD25~+CD127~(low-)T淋巴细胞、CD4~+CD25~+Foxp3~+T淋巴细胞、CD4~+CD25~(high)T淋巴细胞、CD4~+CD25~(high)CD127~(low/-)T淋巴细胞、CD4~+CD25~(high)Foxp3~+T淋巴细胞以及CD4~+CD127~(low/-)Foxp3~+T淋巴细胞占CD4~+T淋巴细胞的比率,并且将7种调节性T细胞比率与外周血抗双链DNA(dsDNA)等抗体及SLE疾病活动指数(SLEDA1)评分等进行相关性分析.②以流式细胞分选术结合细胞培养技术,检测和分析3例SLE患者和4名健康人外周血中CD4~+CD25~+CD127~(low/-)调节性T细胞对CD4~+CD25~-效应性T细胞增殖的抑制作用.采用两样本均数的t检验,重复测量的方差分析,Pearson相关与Spearman相关分析进行统计学处理.结果 ①SLE患者组7种调节性T细胞比率分别为(6.1±1.7)%,(3.1±1.3)%,(2.1±1.0)%,(1.6±0.3)%,(0.97±0.28)%,(0.69±0.23)%和(0.71±0.35)%.与健康对照组比较:SLE患者组前6种调节性T细胞比率均低于健康对照组(P<0.05).②SLE患者组:CD4~+CD25~+Foxp3~+、CD4~+CD25~(high)Foxp3~+T淋巴细胞比率与IgA呈正相关;CD4~+CD25~(high)CD127~(low/-)T淋巴细胞比率与抗SSB抗体呈正相关.③SLE患者初发组和缓解组比较:SLE患者初发组7种调节性T细胞中除CD4~+CD127~(low/-)Foxp3~+T淋巴细胞比率外,其余均低于缓解组(P<0.05).④SLE患者初发组治疗前后比较:激素治疗前6种调节性T细胞比率均低于激素治疗后(P<0.05).⑤SLE患者初发组、缓解组和对照组中,CD4~+CD25~+T淋巴细胞及CD4~+CD25~(high)T淋巴细胞中Foxp3的表达与CD127低表达均呈正相关.⑥SLE患者、健康人CD4+CD25-效应性T细胞的体外增殖都可以被自身CD4~+CD25~+CD127~(low/-)调节性T细胞所抑制,但SLE患者的抑制率明显低于健康对照.结论 SLE的免疫异常可能与调节性T细胞的数量和功能缺陷有关;CD127可能代替Foxp3作为调节性T细胞特异性的表面标记物.     

CD4+CD25+调节性T细胞在肿瘤免疫逃逸机制中的作用研究进展

CD4+CD25+调节性T细胞是一类具有免疫抑制功能的T细胞亚群,能阻止肿瘤免疫和逃避肿瘤对抗原的有效识别.Foxp3是近年来发现的一种转录因子,是CD4+CD25+调节性T细胞表面特异性标志,检测其表达可以作为判定CD4+CD25+调节性T细胞的方法.最近,大量研究已经证实CD4+CD25+调节性T细胞与各种肿瘤生存期和不良预后密切相关.目前,CD4+CD25+调节性T细胞的靶向治疗和选择性清除成为新的免疫治疗方法.     

慢性乙型肝炎患者血清转化生长因子β1与CD4~+CD25~+Foxp3~+调节性T淋巴细胞的关系

目的 调查慢性乙型肝炎患者转化生长因子β1(TGF β1)与CD4~+CD25~+Foxp3~+调节性T淋巴细胞异常的关系.方法 将实验对象分为慢性乙型肝炎(CHB)患者、无症状HBV携带者(AsC)、乙型肝炎恢复者、正常人对照4组.通过流式细胞术分析外周CD4~+CD25~+Foxp3~+调节性T淋巴细胞的表型和频率以及实时荧光定量PCR分析Foxp3表达水平;并通过酶联免疫吸附法检测血清中TGF β1水平.根据数据不同采用方差分析或秩和检验进行统计学分析.结果 CHB或AsC组外周CD4~+T淋巴细胞中CD4~+CD25~+Foxp3~+T淋巴细胞频率以及CD4~+CD25~+T淋巴细胞中Foxp3 mRNA表达水平显著高于正常人对照组,差异有统计学意义(P<0.05).CHB患者和AsC血清中TGF β1水平显著高于正常人和乙型肝炎恢复者,并与CD4~+CD25~+Foxp3~+T淋巴细胞频率存在显著正相关(r=0.78,P<0.01).结论 CHB和AsC患者TGF β1与CD4~+CD25~+Foxp3~+调节性T淋巴细胞增高有密切关系.     

Induction of allopeptide-specific human CD4+CD25+ regulatory T cells ex vivo

Although CD4+CD25+ regulatory T cells are pivotal in the prevention of autoimmunity and appear to mediate transplantation tolerance, little is known concerning their antigen specificity. Here we describe the induction of a human CD4+CD25+ regulatory T-cell line specific for a defined peptide alloantigen (human leukocyte antigen A2 [HLA-A2] 138-170) by priming purified CD4+CD25+ cells ex vivo. The regulatory cells were anergic and retained their ability to suppress antigen-driven responses of CD4+CD25- cells. They inhibited not only interleukin 2 (IL-2) secretion by CD4+CD25- T cells specific for the same peptide but also direct alloresponse of naive CD4+CD25- T cells stimulated by semiallogeneic dendritic cells (DCs) in the presence of the peptide ("linked suppression"). They also suppressed the response of CD4+ T cells specific for viral and bacterial antigens. The suppressive T-cell line showed sustained high CD25 expression. These findings suggest that peripheral CD4+CD25+ regulatory cells are a precommitted cell lineage from which cells with specificity for non-self-peptides can be selected. This may pave the way for inducing and expanding peptide antigen-specific regulatory T cells ex vivo for cell therapy in transplantation, allergy, and autoimmune disease.     

CD4+CD25+Foxp3+调节性T细胞在慢性乙型肝炎患者中的作用

目的 探讨CD4+CD25+Foxp3+调节性T细胞与乙型肝炎慢性化和病毒清除之间的关系.方法 收集慢性活动性乙型肝炎(CAH)患者19例、HBV携带者(AsC)21例、HBV感染恢复者12例和健康对照者15例.通过流式细胞术分析外周血CD4+CD25+Foxp3+T细胞的表型和频率,磁珠分选(MACS)CD4+CD25+T细胞,实时荧光定量PCR方法 分析Foxp3 mRNA基因在CD4+CD25+T细胞的表达水平.统计学处理采用单因素方差分析或非参数检验.结果CAH或AsC组外周血CD4+CD25+Foxp3+T细胞频率以及CD4+CD25+T细胞中Foxp3 mRNA的表达水平显著高于健康对照组或HBV感染恢复者(F=6.8,F=3.72,均P<0.05).免疫组织化学染色发现,CAH患者肝组织Foxp3'T细胞浸润累积较对照组明显增高,但AsC较CAH减少.HBeAg阳性患者(包括CAH和AsC)CD4'CD25'T细胞频率显著高于HBeAg阴性患者(t=2.3,P<0.05),抗-HBe阴性患者显著高于抗-HBe阳性患者(t=2.4,P<0.05).CD4+CD25+Foxp3+T细胞频率与慢性乙型肝炎患者血清中HBV病毒载量存在正相关(r=0.56,P<0.01).结论 慢性乙型肝炎患者CD4+CD25+Foxp3+调节性T细胞异常与乙型肝炎慢性化和病毒清除有关.     

尖锐湿疣患者外周血Foxp3+CD4+CD25+调节性T细胞的检测及意义

目的 了解尖锐湿疣患者外周血Foxp3+CD4+CD25+调节性T细胞的表达水平,探讨其在尖锐湿疣发生发展机制中的作用.方法 分别收集30例尖锐湿疣患者(复发15例,初发15例)及20例健康者外周抗凝静脉血,分离出外周血单个核细胞.藻红蛋白(PE)标记抗CD4单抗,异硫氰酸荧光素(FITC)标记抗CD25单抗,细胞破膜后PE标记的抗Foxp3单抗行细胞内染色,三色流式细胞术分析Foxp3+CD4+CD25+调节性T细胞比例.组间比较采用ANOVA检验.结果外周血中Foxp3+CD4+CD25+调节性T细胞水平在尖锐湿疣患者组为(3.4±1.0)%,在复发组为(4.7±1.2)%,均显著高于健康对照组的(1.2±0.5)%(P<0.01).外周血Foxp3+CD4+CD25+调节性T细胞水平在初发组为(2.1±1.0)%,高于健康对照组,但差异无统计学意义,而在复发组明显高于初发组(P<0.05).结论 尖锐湿疣患者外周血Foxp3+CD4<"+>CD25+调节性T细胞数量增加,这种细胞免疫功能失调可能与其免疫学发病机制有关.     

扩张型心肌病患者CD4~+CD25~+Foxp3~+ T细胞的检测及意义

目的:探讨扩张型心肌病(DCM)患者外周血CD4+CD25+Foxp3+T细胞的水平及意义。方法:采用流式细胞术检测DCM患者30例及健康对照组20例外周血CD4+CD25+T细胞和CD4+CD25+Foxp3+T细胞的比例。结果:DCM患者外周血CD4+CD25+T细胞占CD4+T细胞的比例为(8.53±1.64)%,显著低于健康对照组的(11.4±2.17)%,P0.01;DCM患者CD4+CD25+Foxp3+T细胞占CD4+T细胞比例为(0.99±0.54)%,显著低于健康对照组的(1.55±0.55)%,P0.01;且DCM患者心功能越差,CD4+CD25+Foxp3+T细胞占CD4+T细胞的比例越低。结论:DCM患者调节性T细胞比例的减少,可能打破了自身免疫耐受,发生了针对心肌抗原的自身免疫反应,参与了DCM的发病。     

Large-scale in vitro expansion of polyclonal human CD4(+)CD25high regulatory T cells

CD4(+)CD25+ regulatory T (Treg) cells are pivotal for the maintenance of self-tolerance, and their adoptive transfer gives protection from autoimmune diseases and pathogenic alloresponses after solid organ or bone marrow transplantation in murine model systems. In vitro, human CD4(+)CD25+ Treg cells display phenotypic and functional characteristics similar to those of murine CD4(+)CD25+ Treg cells: namely, hyporesponsiveness to T-cell receptor (TCR) stimulation and suppression of CD25- T cells. Thus far, the detailed characterization and potential clinical application of human CD4(+)CD25+ Treg cells have been hampered by their paucity in peripheral blood and the lack of appropriate expansion protocols. Here we describe the up to 40 000-fold expansion of highly purified human CD4(+)CD25high T cells in vitro through the use of artificial antigen-presenting cells for repeated stimulation via CD3 and CD28 in the presence of high-dose interleukin 2 (IL-2). Expanded CD4(+)CD25high T cells were polyclonal, maintained their phenotype, exceeded the suppressive activity of freshly isolated CD4(+)CD25high T cells, and maintained expression of the lymph node homing receptors L-selectin (CD62L) and CCR7. The ability to rapidly expand human CD4(+)CD25high Treg cells on a large scale will not only facilitate their further exploration but also accelerate their potential clinical application in T cell-mediated diseases and transplantation medicine.     

Phosphoantigen-activated V gamma 2V delta 2 T cells antagonize IL-2-induced CD4+CD25+Foxp3+ T regulatory cells in mycobacterial infection

Although Foxp3(+) T regulatory cells (Tregs) are well documented for their ability to suppress various immune cells, T-cell subsets capable of counteracting Tregs have not been demonstrated. Here, we assessed phosphoantigen-activated Vgamma2Vdelta2 T cells for the ability to interplay with Tregs in the context of mycobacterial infection. A short-term IL-2 treatment regimen induced marked expansion of CD4(+)CD25(+)Foxp3(+) T cells and subsequent suppression of mycobacterium-driven increases in numbers of Vgamma2Vdelta2 T cells. Surprisingly, activation of Vgamma2Vdelta2 T cells by adding phosphoantigen Picostim to the IL-2 treatment regimen down-regulated IL-2-induced expansion of CD4(+)CD25(+)Foxp3(+) T cells. Consistently, in vitro activation of Vgamma2Vdelta2 T cells by phosphoantigen plus IL-2 down-regulated IL-2-induced expansion of CD4(+)CD25(+)Foxp3(+) T cells. Interestingly, anti-IFN-gamma-neutralizing antibody, not anti-TGF-beta or anti-IL-4, reduced the ability of activated Vgamma2Vdelta2 T cells to down-regulate Tregs, suggesting that autocrine IFN-gamma and its network contributed to Vgamma2Vdelta2 T cells' antagonizing effects. Furthermore, activation of Vgamma2Vdelta2 T cells by Picostim plus IL-2 treatment appeared to reverse Treg-driven suppression of immune responses of phosphoantigen-specific IFNgamma(+) or perforin(+) Vgamma2Vdelta2 T cells and PPD-specific IFNgamma(+)alphabeta T cells. Thus, phos-phoantigen activation of Vgamma2Vdelta2 T cells antagonizes IL-2-induced expansion of Tregs and subsequent suppression of Ag-specific antimicrobial T-cell responses in mycobacterial infection.