肝癌微环境中CD4+CD25+调节性T细胞与T细胞免疫的关系

目的 了解肝细胞癌组织CD4 CD25 调节性T细胞(以下简写Treg)与肿瘤微环境T细胞免疫的关系.方法 对52例肝癌组织和癌旁组织用CD4、CD25双重酶标免疫组化染色和用CD8En Vision法染色,对癌组织中Treg细胞和CD4 T、CD8 T、CD4 T/CD8 T比值进行相关性分析.结果 肝癌以及癌旁组织中Treg细胞单个高倍视野平均数分别为7.6308±2.8368、5.1654±1.6718;两组比较有显著差异,P=0.000;肝癌组织中Treg细胞的数量与其浸润性CD4 T淋巴细胞的数量以及CD4 T/CD8 T比值呈显著负相关,r=-0.538,P=0.014;r=-0.545,P=0.000,与浸润性CD8 T淋巴细胞的数量分布无明显相关性,r=-0.403,P=0.078.结论 Treg在肝癌微环境中可能通过细胞接触的方式抑制CD4 T淋巴细胞的增殖来抑制肿瘤局部免疫,使肿瘤细胞逃避免疫监视.因此除去或减少肝癌微环境中的Treg细胞有利于提高肿瘤的免疫治疗效果.     

转录因子Foxp3在肿瘤免疫微环境中的作用

肿瘤免疫微环境可导致肿瘤局部发生免疫耐受,其中以免疫抑制性细胞cD：cD去调节性T细胞（Treg）为主要机制。转录因子Foxp3作为公认的CD4^＋CD25 Treg细胞的特异性标志,对Treg细胞的生长及功能发挥起重要作用,其与肿瘤的重要关系也成为目前研究的热点。本文就Foxp3在肿瘤免疫微环境中作用方面的研究进展作一综述。     

Foxp3仍然是人调节性T细胞的标志？

CD4＋CD25＋调节性T细胞是维持机体免疫稳态和免疫耐受的一个重要机制。缺乏这群细胞与许多自身免疫性疾病的发生和发展密切相关。目前积累的证据表明，在啮齿类动物中，一个叉头样转录因子Foxp3基因及其编码产物（scurfin）是CD4^＋CD25^＋调节性T细胞的特异性标志物。Foxp3基因控制着CD4^＋CD25^＋调节性T细胞的发育,并且直接影响它的功能。虽然早期研究认为Foxp3也在人CD4^＋CD25^＋调节性T细胞上特异性表达，但是越来越多的研究发现Foxp3在人类激活的CD4^＋效应T细胞中也有表达。Foxp3是否也是人的调节性T细胞的特异性分子标志？本文对当前国际免疫调节领域相关方面的工作进展进行总结，以供同行参考。     

Graves病患者外周血CD4^＋CD25^＋T细胞及Foxp3mRNA表达的变化

目的通过比较Graves病患者和正常人外周血中CD4^＋和CD8^＋T细胞占淋巴细胞、CD4^＋CD25^＋T细胞占CD4^＋T细胞的比例以及相关基因Foxp3mRNA表达的变化,探讨Graves病患者免疫机制中CD4^＋CD25^＋T细胞亚群所起的作用。方法选择40例初次确诊Graves病的患者和40名健康自愿者,通过流式细胞仪检测外周血CD4^＋CD8^＋T细胞占淋巴细胞、CD4^＋CD25^和CD4^＋CD25^high细胞占CD4^＋T细胞的比例以及CD4^＋CD25^＋T细胞的荧光强度。应用Real—Time PCR检测外周血单个核细胞Foxp3mRNA的表达。结果Graves病患者外周血中CD4^＋T细胞比例以及CD4^＋／CD8^＋的比值明显升高,而CD4^＋CD25^和CD4^＋CD25^highT细胞占CD4^＋T细胞的比例以及CD4^＋CD25^＋T细胞的荧光强度与正常人比较差异无统计学意义,Graves病患者外周血单个核细胞Foxp3mRNA的表达也无明显减少。结论Graves病主要通过效应性CD4^＋T细胞的体液免疫反应对甲状腺组织产生影响,CD4^＋CD25^＋T细胞的免疫抑制作用减弱可能仅是Graves病发病机制中的一个次要环节。     

原发性肝细胞癌患者CD4+CD25+调节性T淋巴细胞的频率、表型及功能

目的探讨CD4^＋CD25^＋调节性T淋巴细胞（CD4^＋CD25^＋Treg）在HCC患者外周血及肿瘤组织中的频率、抑制功能及临床意义。方法收集18例原发性HCC患者的PBMC、肝癌组织及相应的癌旁组织标本,以及10例CHB患者和15名健康对照的外周血标本,以三色与四色流式分析法分析PBMC以及肿瘤浸润的淋巴细胞中CD4^＋CD25^＋Treg的频率及表型,并同时分析其与HBV持续感染、肿瘤TNM分期和其他临床指标的关系,用BrdU掺入法评价CD4^＋CD25^＋Treg的免疫抑制功能。结果与健康对照组相比HCC患者、慢性HBV感染者外周血中CD4^＋CD25^＋Treg频率明显上升（P＜0．01）,且HCC患者肿瘤浸润的淋巴细胞中CD4^＋CD25^＋Treg的频率也明显上调（P＜0．01）;随着肿瘤的进展HCC患者外周血中CD4^＋CD25^＋Treg呈上升趋势（P＜0．05）; HCC患者CD4^＋CD25^＋Treg可非特异性地抑制自身活化的CD4^＋CD25^- T淋巴细胞,并呈剂量依赖性,且抑制能力与健康对照组相比差异无统计学意义。结论HCC患者外周血中及肿瘤组织中CD4^＋CD25^＋Treg的频率升高,增多的CD4^＋CD25^＋Treg可能参与抑制抗HCC的免疫应答,从而使肝癌细胞逃脱机体的“免疫监视”作用。     

肺癌患者胸腔积液及外周血CD4+CD+25 T细胞、Foxp3基因表达及意义

目的探讨CD+4CD+25T细胞及Foxp3基因在肺癌发生、发展中的作用及机制.方法流式细胞仪检测32例肺癌合并胸腔积液患者外周血、胸腔积液及30例无胸腔积液肺癌患者外周血、胸腔冲洗液中CD+4 CD+25T细胞水平,RT-PCR法检测特异性转录因子Foxp3基因在胸腔积液及外周血中的表达.结果肺癌合并胸腔积液患者胸腔积液中CD+4CD+25T细胞水平显著高于无胸腔积液患者胸腔冲洗液及外周血;Foxp3基因在肺癌患者外周血和胸腔积液中呈高表达.结论肺癌患者外周血和胸腔积液中增高的CD+4CD+25T细胞主要是CD+4CD+25调节性T细胞.CD+4cD+25调节性T细胞可促进肺癌的进一步恶化,其机制可能是抑制肿瘤免疫.     

CD4+CD25+调节性T细胞与克罗恩病发病关系

目的研究克罗恩病（CD）患者外周血白细胞介素（IL）-6水平与外周CD4＋CD25^＋调节性T细胞（Treg细胞）频率及体外抑制功能的变化在CD发病中的作用。方法应用流式细胞术检测CD患者与正常对照者外周CD4^＋CD25^＋Treg细胞的频率及表型以及特征性标志叉状头／翅膀状螺旋转录因子（Foxp3）的表达，同时通过MACS缓冲液分选出外周血CD4^＋CD25^＋T细胞和CD4＋CD25^-T细胞，应用[^3H]-胸腺嘧啶渗入法研究CD4^＋CD25^＋T细胞对自体CD4^＋CD25^-效应T细胞增殖的抑制能力。酶联免疫吸附法（ELISA）检测外周血IL-6水平。结果活动性CD患者外周血IL-6水平显著高于非活动性患者及正常对照者。活动性CD患者外周CD4^＋T细胞中CD4^＋CD25^＋Foxp3^＋T细胞的频率显著低于非活动性CD患者，差异有统计学意义。体外抑制功能试验同样提示活动性CD患者的CD4^＋CD25^＋Treg细胞抑制功能减弱。结论CD4^＋CD25^＋Treg细胞抑制功能减弱与CD发病可能有关，可初步解释CD患者出现的免疫耐受缺失现象。     

骨髓间质干细胞对系统性红斑狼疮患者调节性T细胞的免疫调节作用

目的探讨自体与异体骨髓间质干细胞（MSCs）对系统性红斑狼疮（SLE）患者调节性T细胞的免疫调节作用。方法用Percoll密度梯度离心法从14例SLE患者和15例健康人骨髓中分离MSCs,同时用免疫磁珠（MACS）分离SLE患者外周血CD4^＋CD25^＋T细胞。将SLE患者外周血分离的淋巴细胞或CD4^＋CD25^＋T细胞与自体、异体MSCs共培养,观察MSCs对淋巴细胞及CD4^＋CD未T细胞增殖的影响,同时测CD4^＋CD25^＋T细胞分泌IL-10、转化生长因子（TGFβ）水平及细胞毒T淋巴细胞相关抗原4（CTLA-4）表达。结果自体与异体MSCs均抑制淋巴细胞增殖,其抑制率分别为56．32％、65．46％。MSCs以数量依赖性方式促进纯化CD4^＋CD25^＋T细胞增殖,分泌IL-10、TGFβ水平升高。结论MSCs可纠正SLE活动时CD4＋CD25^＋T细胞免疫缺陷,并抑制淋巴细胞过度活化,可能在自身免疫病的外周血造血干细胞和间质干细胞共移植或MSCs单独移植中发挥重要的免疫调节作用。     

转录因子Foxp3在干燥综合征患者唇腺及外周血的表达

目的观察转录因子Foxp3在干燥综合征（SS）患者外周血及唇腺组织的表达。方法选31例SS患者（SS组）及6例健康体检者（健康对照组）,另选6份健康人和唇腺囊肿患者的唇腺标本。免疫磁珠分选受试者外周血CD4^＋T细胞,实时荧光定量PCR法检测Foxp3 mRNA表达;唇腺组织行免疫组化。观察CD4、Foxp3表达。结果（1）SS组患者唇腺组织中浸润的淋巴细胞以CD4^＋T细胞占大多数。而健康对照组唇腺组织几乎未见CD4^＋T细胞浸润。（2）两组唇腺均未见CD4^＋T细胞Foxp3^＋表达。（3）6例SS患者外周血CD4^＋T细胞Foxp3 mRNA平均相对表达水平为0．21±0．17,低于健康对照组（1．32±0．38）。差异有统计学意义（t=4．68,P〈0．0184）。SS组和健康对照组的唇腺组织均未检测到Foxp3 mRNA表达。结论转录因子Foxp3参与了SS的发病过程。     

原发性肝癌患者T淋巴细胞亚群变化及其与CTCs、TTV及HBV-DNA的关系

目的探讨原发性肝癌(HCC)患者T细胞免疫功能变化及其与外周血循环肿瘤细胞(CTCs)、肿瘤总体积(TTV)及乙肝病毒(HBV-DNA)定量的关系。方法收集45例HCC患者外周血,45例正常成年人外周血作为对照组。用流式细胞学技术测定CD3~+T细胞、CD4~+T细胞及CD4~+/CD8~+比值;采用益善生物技术公司的"免疫去除结合纳米过滤法"Can Patrol TM行CTCs检测。收集患者肿瘤最大直径及乙肝病毒定量(HBV-DNA)等临床病理参数。将HCC组患者依据CD4~+/CD8~+平均值分成高、低两组,比较两组之间CTCs、TTV、HBV-DNA定量的差别。结果 HCC组CD3~+T细胞、CD4~+T细胞及CD4~+/CD8~+明显低于对照组(P0.05),CD8~+T细胞值明显高于正常组(P0.05)。高CD4~+/CD8~+组CTCs总数及间质型CTCs明显低于低CD4~+/CD8~+组(P0.05),而两组上皮型CTCs及混合型CTCs无明显差异(P0.05)。CD4~+/CD8~+比值与TTV呈正相关(P0.05),与CD8~+T细胞百分比呈负相关(P0.05)。不同HBV-DNA组之间,CD4~+/CD8~+没有统计学差异(P0.05)。结论 HCC患者T细胞免疫功能明显降低。T细胞免疫功能与CTCs、TTV与有着密切关系:T细胞免疫功能越差,外周血中CTCs越多、TTV越大。     

西罗莫司促进TGF-β分泌对小鼠调节性T细胞体外增殖的影响

目的通过观察西罗莫司或环孢霉素A与CD4+CD25+调节性T细胞((regulatory T cell,Treg)体外共培养对CD4+CD25+Treg增殖情况及对Foxp3和转化生长因子-β(transforming growth factor-β,TGF-β)的表达的影响,探讨西罗莫司促进TGF-β分泌诱导Treg体外分化和增殖的机制。方法无菌条件下取C57BL/6小鼠脾脏,分离单个核细胞,免疫磁珠分选获得CD4+CD25+Treg,设空白对照组、西罗莫司组、环孢霉素A组,共培养96h。上流式细胞仪检测CD4+CD25+Treg。反转录聚合酶链、酶联免疫吸附试验法检测西罗莫司或环孢霉素A处理后的CD4+CD25+Treg的FoxP3+、TGF-βmRNA表达水平和分泌情况;Western blot分析TGF-β信号通路重要的活化分子Smad蛋白的表达情况,观察其对CD4+CD25+FoxP3+Treg增殖的影响;使用TGF-β中和抗体进一步验证TGF-β在西罗莫司促进CD4+CD25+FoxP3+Treg分化增殖过程中的重要作用。结果与对照组相比,西罗莫司处理的CD4+T细胞分泌的TGF-β水平增加近2.5倍,差异有统计学意义(P<0.01);而环孢霉素A处理的CD4+T细胞分泌的TGF-β水平则有所下降,但与对照组比较,差异无统计学意义(P>0.05)。与对照组比较,环孢霉素A组CD4+CD25+Treg占CD4+T细胞比例明显降低,差异有统计学意义(41.25%vs.69.22%,P<0.01);西罗莫司组CD4+CD25+Treg占CD4+T细胞稍有下降,但差异无统计学意义(65.21%%vs.69.22%,P>0.05)。西罗莫司组FoxP3+T细胞的比例明显高于对照组,差异有统计学意义(53.7%vs.40.2%,P<0.05);而环孢霉素A组FoxP3+T细胞比例明显低于对照组,差异有统计学意义(23.6%vs.40.2%,P<0.01)。结论西罗莫司在体外培养促进CD4+CD25+Treg的增殖与生长,而环孢霉素A体外抑制CD4+CD25+Treg的增值与生长。西罗莫司通过诱导TGF-β表达分泌来促进CD4+CD25+FoxP3+Treg的增殖。     

Foxp3 expression on normal and leukemic CD4+CD25+ T cells implicated in human T-cell leukemia virus type-1 is inconsistent with Treg cells

Foxp3 is a master gene of Treg cells, a novel subset of CD4⁺ T cells primarily expressing CD25. We describe here different features in Foxp3 expression profile between normal and leukemic CD4⁺CD25⁺ T cells, using peripheral blood samples from healthy controls (HCs), human T-cell leukemia virus type-1 (HTLV-1)-infected asymptomatic carriers (ACs), patients with adult T-cell leukemia (ATL), and various hematopoietic cell lines. The majority of CD4⁺CD25⁺ T cells in HCs were positive for Foxp3, but not all CD4⁺CD25⁺ T cells in ACs were positive, indicating that Foxp3 expression is not always linked to CD25 expression in normal T cells. Leukemic (ATL) T cells constitutively expressing CD25 were characteristic of heterogeneous Foxp3 expression, such as intra- and inter-case heterogeneity in intensity, inconsistency with CD25 expression, and a discrepancy in the mRNA and its protein expression. Surprisingly, a discernible amount of Foxp3 mRNA was detectable even in most cell lines without CD25 expression, a small fraction of which was positive for the Foxp3 proteins. The subcellular localization of Foxp3 in HTLV-1-infected cell lines was mainly cytoplasmic, different from that of primary ATL cells. These findings indicate that Foxp3 has two facets: essential Treg identity and molecular mimicry secondary to tumorigenesis. Conclusively, Foxp3 in normal T cells, but not mRNA, is basically potent at discriminating a subset of Treg cells from CD25⁺ T-cell populations, whereas the modulation of Foxp3 expression in leukemic T cells could be implicated in oncogenesis and has a potentially useful clinical role.     

Numbers of Foxp3-expressing CD4+CD25high T cells do not correlate with the establishment of long-term tolerance after allogeneic stem cell transplantation

OBJECTIVE: Regulatory CD4 T cells that express high levels of CD25 play a vital role in the maintenance of tolerance to self antigens and are required for the induction of nonresponsiveness to alloantigens. The long-term CD4+CD25high T-cell reconstitution after allogeneic stem cell transplantation is unknown. Here, we evaluated whether recovery of this T-cell subset might be linked to the establishment of full donor/recipient tolerance. METHODS: The frequency of CD4+CD25high T cells was determined by Fluorescence Activated Cell Sorter (FACS) analysis in 31 patients, with a mean follow-up of more than 31 months posttransplant. The expression levels of Foxp3 mRNA were assessed by quantitative real-time polymerase chain reaction (RT-PCR). RESULTS: Patients with or without graft-versus-host disease (GvHD) had significant and persistent CD4 T-cell lymphopenia. The relative frequency of CD25high cells and the expression levels of FoxP3 mRNA within this subset were similar between all patients and healthy controls. No significant difference was found in the number of Foxp3-expressing CD4+CD25high T cells in patients with or without GvHD. Finally, younger age and absence of previous GvHD were significantly linked to CD4+CD25high T-cell recovery. CONCLUSION: The low number of Foxp3-expressing CD4+CD25high T cells in grafted patients is not a specific default of this compartment but a consequence of global CD4 T-cell lymphopenia after allogeneic stem cell transplantation. Moreover, levels of Foxp3 mRNA in the CD25+ T-cell compartment do not allow predicting the development of GvHD in the long term.     

Dickkopf 4 positively regulated by the thyroid hormone receptor suppresses cell invasion in human hepatoma cells

Thyroid hormone (T(3)) mediates cellular growth, development, and differentiation by binding to the nuclear thyroid hormone receptor (TR). Recent studies suggest that long-term hypothyroidism is associated with human hepatocellular carcinoma (HCC) independent from other major HCC risk factors. Dickkopf (DKK) 4, a secreted protein, antagonizes the Wnt signal pathway. In this study, we demonstrate that T(3) may play a suppressor role by inducing DKK4 expression in HCC cells at both the messenger RNA (mRNA) and protein levels. DKK4 was down-regulated in 67.5% of HCC cancerous tissues. The decrease in DKK4 levels was accompanied by a concomitant decrease in TR protein levels in the matched cancerous tissues in 31% of tissues compared by immunoblotting with the adjacent noncancerous tissues. Further, TR and DKK4 expression levels were positively correlated in both normal and cancerous specimens by tissue array analysis. In function assays, stable DKK4 transfected into J7 or HepG2 cells decreased cell invasion in vitro. Conversely, knocking down DKK4 restores cell invasiveness. DKK4-expressing J7 clones showed increased degradation of β-catenin, but down-regulation of CD44, cyclin D1, and c-Jun. To investigate the effect of DKK4 and TR on tumor growth in vivo, we established a xenograft of J7 cells in nude mice. J7-DKK4 and J7-TRα1 overexpressing mice, which displayed growth arrest, lower lung colony formation index, and smaller tumor size than in control mice, supporting an inhibitory role of DKK4 in tumor progression. CONCLUSION: Taken together, these data suggest that the TR/DKK4/Wnt/β-catenin cascade influences the proliferation and migration of hepatoma cells during the metastasis process and support a tumor suppressor role of the TR.     

Role of CD80 in stimulating T lymphocyte activation

AIM:To observe biological characteristics of hepatocar-cinoma cells before and after CD80 transfection and tocompare the effect of CD80-transfected hepatocarcinomacells on T lymphocyte activation.METHODS:Retro virus vector carrying CD80 genewas transfected into HepG2 cells to establish CD80-transfected hepatocarcinoma cells(HepG2/hCD80).Flowcytometry(FCM)was performed to detect CDS0 expres-sion in the transfected cells.RT-PCR was used to evalu-ate CD80 expression at mRNA level.In the presence ofanti-CD3 mAb,the proliferation of T lymphocyte wasobserved by MTT.Meanwhile,the expression of activatedmolecule marker CD25 was analyzed through FCM.RESULTS:A stable cell line HepG2/hCD80 expressingthe human CD80 was established.Growth curve showedthat the molecule CD80 could obviously decrease thegrowth of tumor cells.HepG2/hCD80 was evidenced tohave a potency to enhance T cell proliferation and up-regulate CD25 expression.CONCLUSION:CD80 transfection can lower ma-lignant phenotype of hepatocarcinoma cells.CD80transfection has a down-regulatory effect to activatedT cells in vitro.     

Delineation of Immunoregulatory Properties of Adult T-cell Leukemia Cells

We characterized leukemic cells from 20 adult T-cell leukemia (ATL) cases and 7 ATL-derived cell lines in terms of Foxp3 messenger RNA (mRNA) expression, cytokine production, cell surface markers associated with regulatory T-cells (Treg), and in vitro immunoregulatory activity and compared the results with those of cells from 3 T-cell-type chronic lymphocytic leukemia (T-CLL) patients and normal CD4+ T-cells. Real-time polymerase chain reaction analysis showed that cells from 10 ATL cases, 1 T-CLL case, and 1 ATL cell line had higher Foxp3 mRNA levels than CD4+ T-cells. In 5 ATL cases, Foxp3 levels were comparable to those of CD4+CD25+ T-cells. Flow cytometric analysis revealed that CTLA-4 expression correlated with Foxp3 mRNA level in ATL cells. The cells of all ATL cases examined produced no interleukin 2 or interferon gamma after iono-mycin and phorbolmyristate acetate stimulation. Cases with low Foxp3 expression (Foxp3-low) tended to express higher levels of transforming growth factor beta mRNA, but this trend was not statistically significant. An in vitro inhibition assay showed that the proliferation of normal CD4+CD25- T-cells stimulated with anti-CD3 monoclonal antibody and autologous dendritic cells was significantly suppressed by coculture with Foxp3-high ATL cells. These results indicate that Foxp3 expression is variable in ATL cases and that Foxp3-high ATL cells, which resemble Treg phenotypically as well as functionally, may be involved in immune suppression in ATL.