CD4+ CD25+ Treg: divide and rule?

Research on CD4+ CD25+ regulatory T cells (Treg) has gathered momentum over the last five years but many aspects of their fundamental biology remain elusive. Treg have been considered to be 'naturally anergic' based on their failure to proliferate in response to T-cell receptor ligation in vitro. Several recent studies challenge this view and demonstrate a robust proliferative capacity for CD25+ cells. The significance of this finding for Treg homeostasis and function is considered below.     

CD4+LAP+ and CD4+CD25+Foxp3+ Regulatory T Cells Induced by Nasal Oxidized Low-Density Lipoprotein Suppress Effector T Cells Response and Attenuate Atherosclerosis in ApoE−/− Mice

Increasing studies have demonstrated that atherosclerosis is a chronic immunoinflammatory disease, and that oxidized low-density lipoprotein (oxLDL)-specific T cells contribute to the autoimmune process in atherosclerosis. Oral administration of oxLDL, which was identified as a candidate autoantigen in atherosclerosis, was shown to induce tolerance and suppress atherogenesis. However, the precise mechanisms of mucosal tolerance induction, in particular nasal tolerance, remain unknown. In this study, we explored the effect of nasal oxLDL on atherosclerosis as well as the cellular and molecular mechanisms leading to atheroprotective responses, and then found that nasal oxLDL drastically ameliorate the initiation (47.6 %, p?p?=?0.001) of atherosclerosis. Most importantly, a significant 35.8 % reduction of the progression of atherosclerosis was observed in the enhanced immunization group (p?+ latency-associated peptide (LAP)⁺ regulatory T cells (Tregs) and CD4⁺CD25⁺Foxp3⁺ Tregs in spleens and cervical lymph nodes, together with increased transforming growth factor (TGF)-β production and suppressed T-helper cells type 1, 2, and 17 immune responses. Surprisingly, neutralization of TGF-β in vivo partially counteracted the protective effect of nasal oxLDL treatment, indicating that the presence of TGF-β was indispensable to CD4⁺LAP⁺ Tregs and CD4⁺CD25⁺Foxp3⁺ Tregs to acquire regulatory properties. Our studies suggest that CD4⁺LAP⁺ Tregs and CD4⁺CD25⁺Foxp3⁺ Tregs induced by nasal delivery of oxLDL can inhibit oxLDL-specific T cells response and ameliorate atherosclerosis process.     

PAS-1, an Ascaris suum protein, modulates allergic airway inflammation via CD8+γδTCR+ and CD4+CD25+FoxP3+ T cells

We have previously demonstrated that PAS‐1, a 200 kDa protein from Ascaris suum, has a potent immunomodulatory effect on humoral and cell‐mediated responses induced by APAS‐3 (an allergenic protein from A. suum) or unrelated antigens. In this study, we investigated the mechanisms by which PAS‐1 is able to induce this effect on an allergic airway inflammation induced by OVA in mice. C57BL/6 mice were adoptively transferred on day 0 with seven different PAS‐1‐primed cell populations: PAS‐1‐primed CD19⁺ or B220⁺ or CD3⁺ or CD4⁺ or CD8⁺ or CD4⁺ CD25^? or CD4⁺ CD25⁺ lymphocytes. These mice were immunized twice with OVA and alum by intraperitoneal route (days 0 and 7) and challenged twice by intranasal route (days 14 and 21). Two days after the last challenge, the airway inflammation was evaluated by antibody levels, cellular migration, eosinophil peroxidase levels, cytokine and eotaxin production, and pulmonary mechanical parameters. Among the adoptively transferred primed lymphocytes, only CD4⁺ CD25⁺, CD8⁺ or the combination of both T cells impaired the production of total IgE and OVA‐specific IgE and IgG1 antibodies, eosinophilic airway inflammation, Th2‐type cytokines (IL‐4, IL‐5 and IL‐13), eotaxin release and airway hyperreactivity. Moreover, airway recruited cells from CD4⁺ CD25⁺ and CD8⁺ T‐cell recipient secreted more IL‐10/TGF‐β and IFN‐γ, respectively. Moreover, we found that PAS‐1 expands significantly the number of CD4⁺ CD25⁺ FoxP3⁺ and CD8⁺ γδTCR⁺ cells. In conclusion, these findings demonstrate that the immunomodulatory effect of PAS‐1 is mediated by these T‐cell subsets.     

2-Gy whole-body irradiation significantly alters the balance of CD4+CD25? T effector cells and CD4+CD25+Foxp3+ T regulatory cells in mice

CD4⁺CD25⁺ T regulatory (Treg) cells are critical in inducing and maintaining immunological self-tolerance as well as transplant tolerance. The effect of low doses of whole-body irradiation (WBI) on CD4⁺CD25⁺Foxp3⁺ Treg cells has not been determined. The proportion, phenotypes and function of CD4⁺CD25⁺ Treg cells were investigated 0.5, 5 and 15 days after euthymic, thymectomized or allogeneic bone marrow transplanted C57BL/6 mice received 2-Gy γ-rays of WBI. The 2-Gy WBI significantly enhanced the ratios of CD4⁺CD25⁺ Treg cells and CD4⁺CD25⁺Foxp3⁺ Treg cells to CD4⁺ T cells in peripheral blood, lymph nodes, spleens and thymi of mice. The CD4⁺CD25⁺ Treg cells of the WBI-treated mice showed immunosuppressive activities on the immune response of CD4⁺CD25⁻ T effector cells to alloantigens or mitogens as efficiently as the control mice. Furthermore, 2-Gy γ-ray WBI significantly increased the percentage of CD4⁺CD25⁺Foxp3⁺ Treg cells in the periphery of either thymectomized mice or allogeneic bone marrow transplanted mice. The in vitro assay showed that ionizing irradiation induced less cell death in CD4⁺CD25⁺Foxp3⁺ Treg cells than in CD4⁺CD25⁻ T cells. Thus, a low dose of WBI could significantly enhance the level of functional CD4⁺CD25⁺Foxp3⁺ Treg cells in the periphery of naive or immunized mice. The enhanced proportion of CD4⁺CD25⁺Foxp3⁺ Treg cells in the periphery by a low dose of WBI may make hosts more susceptible to immune tolerance induction.     

强直性脊柱炎患者外周血T细胞亚群及其CD3+CD69+、CD3+CD54+检测

强直性脊柱炎(ankylosing spondylitis,AS)是一种主要侵犯脊柱,并累及骶髂关节和周围关节,以慢性进行性炎症为主要表现的自身免疫性疾病.     

CD4+CD25+调节性T细胞研究进展

CD4+CD25+调节性T细胞是调节性T细胞的亚群之一,主要来源于胸腺,具有多种独特的特征,包括可识别自身抗原肽、分泌抑制性细胞因子等.其功能是通过抑制自身反应性T细胞的免疫反应、抑制传统T细胞的活化以及促进一些抑制性细胞因子的分泌等,在维持机体内环境的稳定、肿瘤免疫监测、诱导移植耐受以及自身免疫性疾病的发生中发挥重要作用.     

Differential sensitivity of naïve and subsets of memory CD4+ and CD8+ T cells to hydrogen peroxide-induced apoptosis

CD4+ and CD8+ memory T cells are identified into central and effector memory subsets, which are characterized by distinct homing patterns and functions. In this investigation, we show that na?ve and central memory CD4+ and CD8+ T cells are sensitive to hydrogen peroxide (H2O2)-induced apoptosis, whereas effector memory CD4+ and CD8+ T cells are relatively resistant to H2O2-induced apoptosis. Apoptosis in na?ve and central memory CD4+ and CD8+ is associated with the release of cytochrome c and activation of caspase-9 and caspase-3, upregulation of Bax and voltage-dependent anion channel (VDAC) expression, and decreased intracellular glutathione (GSH). In vitro GSH and a superoxide dismutase mimetic Mn(III) tetrakis (1-methyl-4-pyridyl) porphyrin inhibited H2O2-induced apoptosis in both na?ve and central memory CD4+ and CD8+ T cells. Furthermore, VDAC inhibitor 4,4'-diisothiocynostilbene-2,2'-disulfonic acid blocked H2O2-induced apoptosis. These data demonstrate that H2O2 induces apoptosis preferentially in human na?ve and central memory CD4+ and CD8+ T cells via the mitochondrial pathway by regulating intracellular GSH and the expression of Bax and VDAC.     

检测CD3+、CD4+、CD8+、CD4+/CD8细胞对慢性乙肝患者的临床意义

乙型肝炎病毒（HBV）是一种非细胞毒性病毒,当其进入机体后常可引起一系列复杂的免疫反应。而机体产生的免疫应答的强弱又与HBV感染所致的不同临床结果密切相关。而在这一系列免疫应答中,细胞免疫应答又是决定HBV感染机体后转归的最重要因素。而不同的T细胞亚群对病毒抗原的反应状态也不同,即对临床过程的轻重及转归的影响不同。本实验应用流式细胞仪对健康人、慢性乙型肝炎患者和乙肝肝硬化患者外周血中的测定CD4+、CD4+/CD8+、CD4+/CD8细胞的含量进行了检测计算,来探讨慢性乙型肝炎患者外周血中CD4+、CD4+/CD8+、CD4+/CD8细胞特点及其与肝病病情的关系。     

Crucial Role of CD4+CD 25+ FOXP3+ T Regulatory Cell,Interferon-γ and Interleukin-16 in Malignant and Tuberculous Pleural Effusions

The differential diagnosis between malignant and tuberculous exudative pleural effusions is an important clinical problem. The aim of current study is to evaluate the frequencies of T-regulatory cells (Treg) on the basis of distinct phenotypes in the differential diagnosis between malignant and tuberculous pleural effusion. In addition, to evaluate Interferon-gamma (IFN- γ) and interleukin-16 (IL-16) levels and their correlation to Treg cells in malignant and tuberculous pleural effusions. Sixty patients with pleural effusion (26 tuberculous and 34 malignant) and 20 healthy controls were included in the study. Pleural fluid and peripheral blood were assessed for frequencies of T regs, IL-16, and IFN-γ. Pleural effusions from both tuberculous and malignant groups represented significantly higher levels (more in TB) for the following cell populations than peripheral blood: total lymphocytes, CD3+lymphocyte, CD4+CD25+lymphocyte and Treg (CD4+ CD25+FoxP3+). Levels of IL-16 and IFN-γ in tuberculous group were significantly higher than that in malignant group. Regulatory T cells, INF-γ and IL-16 are new important tools for differentiation between tuberculous and malignant pleural effusion.     

CD4+CD25+T细胞与移植免疫耐受

调节性T细胞是机体维持自身耐受的重要组成部分.CD4+CD25+T细胞以持续高表达CD25为特征,可通过细胞间直接接触或分泌TGF-β、IL-10来发挥抑制功能.它广泛参与自身免疫耐受、肿瘤免疫、移植免疫.现就其发育、特性、发挥功能的机制以及在移植免疫耐受中的作用和应用前景作一综述.     

CD4+CD25+T调节细胞的研究进展

CD4 CD25 TH细胞通过抗原特异性方式或细胞接触的方式抑制自身反应性T细胞的活化,能有效地维持自身免疫耐受,是调节自身反应性T细胞和防止自身免疫病发生的重要调节细胞。     

天然CD4+CD25+Treg细胞的研究进展

天然CD4+ CD25+ Treg细胞在针对自身抗原和外来抗原的免疫应答中起关键控制作用,其缺乏或功能性的缺陷将导致多重病理性的失调.本文就近年在其产生、作用机制以及与免疫耐受的诱导关系等方面的研究进展进行了综述.     

CD4+CD25+调节T细胞及其功能

CD4 CD25 T细胞亚群具有免疫调节功能,是机体内调节性T细胞(Teguolatory T cells,Tr)的主要类型,于1995年首次由Sakaguchi等提出.     

CD4+CD25+T细胞在CD8+T细胞抗肿瘤免疫中的调节作用

实验旨在研究CD4^＋CD25^＋T细胞在CD8^＋T细胞抗肿瘤免疫中的调节作用。将小鼠脾脏中分离的单个核细胞分为两组．即去除CD4^＋CD25^＋T细胞组和未去除CD4^＋CD25^＋T细胞组,测定树突状细胞提呈的肿瘤抗原多肽刺激不同T细胞增殖活性、细胞因子IFN一1分泌,以及多肽特异性CD8^＋T细胞对同源性胃癌细胞株MFC的杀伤活性。结果显示预先去除未致敏T细胞中的CD4^＋CD25^＋T细胞,所诱导的特异性CD8^＋CTL对肿瘤细胞免疫应答增强,表现为反应性T细胞对树突状细胞提呈的肿瘤抗原多肽增殖反应增强,IFN-γ分泌量提高及CD8＋T细胞对MFC杀伤活性增强。这些结果表明。预先去除未致敏T细胞中的CD4^＋CD25^＋T细胞,肿瘤抗原多肽修饰的树突状细胞肿瘤疫苗效能可明显增加。CD4^＋CD25^＋T细胞在CD8^＋T细胞抗肿瘤免疫中起下调作用。     

TGF-β1诱导CD4+CD25-T细胞分化为CD4+CD25+调节性T细胞

目的 研究TGF-β1诱导CD4 CD25 调节性T细胞分化的能力及其相关机理.方法 ①利用丝裂霉素处理的Balb/C裸鼠脾细胞(同种抗原)刺激C57BL/6小鼠T细胞,同时给予TGF-β1予以干预(按TGF-β1剂量不同设立4组:对照组,低浓度组,中浓度组和高浓度组),共同培养5天后,用流式细胞仪检测CD4 CD25 T细胞比例;同时用RT-PCR检测培养细胞中Foxp3的表达水平.②在第一部分实验基础上,通过MACS分离获取C57BL/6小鼠CD4 CD25-T细胞,用同种抗原刺激后,给予TGF-β1干预,培养5 d后分离CD4 CD25 T细胞,利用混合淋巴细胞培养系统检测其抑制淋巴细胞增殖的能力.结果 T细胞经同种抗原刺激后,在中、高浓度TGF-β1诱导下CD4 CD25 T细胞比例均明显升高,Foxp3的表达水平也相应增加,与对照组相比有显著性差异(P＜0.05).TGF-β1可直接诱导CD4 CD25-T细胞转化为CD4 CD25 T细胞,转化后的CD4 CD25 T细胞可有效抑制淋巴细胞增殖.结论 TGF-β1可诱导CD4 CD25-T细胞转化为CD4 CD25 Treg,促进其表达Foxp3,并能够抑制淋巴细胞增殖.     

The capacity of the natural ligands for CD28 to drive IL-4 expression in naïve and antigen-primed CD4+ and CD8+ T cells

The B7/CD28 costimulatory pathway plays a critical role in T cell activation including Th1/Th2 differentiation. However, little is known about whether CD28 costimulation favors polarization of either Th1 and Th2 or both. Here, we show a critical role of the natural ligands for CD28 molecules (B7.2-Ig or B7.1-Ig fusion proteins), particularly in the induction of type 2 T cell polarization. Upon TCR-triggering with suboptimal doses of anti-CD3, costimulation of na?ve CD4+ T cells with anti-CD28 mAb or B7-Ig fusion proteins led to comparable levels of IFN-gamma production. Na?ve T cells could produce IL-4 when CD28 costimulation was done with B7-Ig, but not with anti-CD28. IL-4-selective upregulation was also observed when T cells from anti-OVA TCR transgenic mice were stimulated with OVA in the presence of B7-Ig. Correlating with IL-4 expression, GATA-3 expression was induced much more potently by costimulation with B7-Ig than with anti-CD28 mAb, while T-bet induction by these two costimulatory reagents was comparable. This B7 effect was also applied for na?ve and antigen-primed CD8+ T cells: IL-4-expressing CD8+ T cells were generated when na?ve and alloantigen-primed T cells were stimulated with anti-CD3 and recall antigens, respectively, in the presence of B7-Ig costimulation. Importantly, such CD8+ T cell differentiation required the coexistence of CD4+ T cells during the initial TCR stimulation. These observations indicate that both type 2 CD4 and CD8 T cell polarizations are efficiently induced via costimulation of CD28 with its natural ligands, although the differentiation of CD8+ T cells is dependent on CD4+ cells.     

非小细胞肺癌患者外周血CD11b~+CD33~+CD15~+CD14~-及CD11b~+CD33~+CD15~-CD14~+髓系细胞的比例变化及临床意义

髓源性抑制细胞(myeloid-derived suppressor cell,MDSC)是一群具有免疫抑制作用的细胞,其在外周血中的表达规律与非小细胞肺癌(non-small cell lung cancer,NSCLC)患者的外周免疫逃逸及临床分期密切相关。本研究纳入116例NSCLC患者及30例健康者,流式细胞术检测外周血PBMC中MDSC、调节性T细胞(regulatory T cell,Treg)的比例,研究其与临床分期、病理及免疫的相关规律。结果显示:与健康组比较,粒系髓源性抑制细胞(G-MDSC)、单核系髓源性抑制细胞(M-MDSC)在NSCLC外周血中比例升高,具有统计学意义(P<0.05);G-MDSC、病理类型与临床分期具有相关性(n=116,r=0.330,P<0.001;n=116,r=0.441,P<0.001),而M-MDSC、Treg与临床分期之间未发现相关性(n=116,r=-0.053,P=0.558;n=116,r=0.173,P=0.052);G-MDSC与Treg具有相关性(n=116,r=0.343,P<0.001)且与病理类型也呈现正相关(r=0.333,P<0.001);而M-MDSC与Treg未发现相关性(r=0.122,P=0.174),与病理类型不具有相关性(r=-0.143,P=0.109)。研究表明NSCLC患者外周血PBMC中MDSC比例升高,其中G-MDSC与NSCLC临床分期及Treg呈正相关,调控MDSC的表达有望成为防治肺癌发生及术后复发与转移的新策略[临床研究国际注册号NCT02603003]。