调节性T细胞诱导肿瘤免疫耐受的机制

调节性T细胞(Treg)是一类免疫抑制性T辅助(Th)细胞.研究表明,Treg可在肿瘤细胞分泌的趋化因子CCL22作用下大量募集于肿瘤周围,分泌或表达免疫抑制性的细胞因子和受体,形成以Th2型免疫为主的微环境,引导宿主免疫耐受.通过抗体等药物降低Treg数量和活性后可打破肿瘤免疫耐受,抑制肿瘤的发生和转移.     

吲哚胺-2,3-双加氧酶在非小细胞肺癌中的表达及意义

背景与目的免疫耐受(Tumor tolerance)在肿瘤的发生、发展和转移中发挥了重要作用,但其发生机制尚不完全清楚。本课题拟通过研究吲哚胺2,3-双加氧酶(indoleamine-2,3-dioxygenase,IDO)在非小细胞肺癌(Non-small cell lung cancer,NSCLC)细胞中的表达和调节性T细胞(Regulatory T cell,Treg)在肺癌组织和转移淋巴结内的分布来探讨IDO在诱导肺癌免疫耐受中的机制。方法收集在第三军医大学附属新桥医院和西南医院手术治疗的62例患者肺癌组织和周围正常肺组织、以及15例肺良性病变组织的新鲜标本和石蜡切片。采用免疫组织化学SP法和荧光半定量RT-PCR方法检测IDO蛋白和cDNA在肺癌组织、周边正常肺组织和肺良性病变组织中的表达,并利用免疫组化SP法检测Treg细胞在上述各种组织内的分布情况。结果肺癌组织、周边正常肺组织和肺良性病变组织中IDO表达阳性率分别为67.7%(42/62)、0和13.3%(2/15),前者与后二者比较有统计学差异(P<0.01),转移淋巴结内肺癌细胞IDO表达阳性率为75.0%(15/20),荧光半定量RT- PCR结果与免疫组化基本一致;肺癌组织、转移淋巴结、周边正常肺组织和肺良性病变组织中Treg细胞阳性率分别为83.9%(52/62)、90.0%(18/20)、0和13.3%(2/15),前二者与后二者相互比较有差异(P<0.01),前二者之间或后二者之间相比较差异无统计学意义(P>0.05),IDO阳性表达率与Treg细胞阳性率之间具有相关性(P<0.01)。结论IDO在NSCLC细胞和转移淋巴结内主要为高表达,在周边正常肺组织和肺良性病变中主要为低表达,Treg细胞在NSCLC组织和转移淋巴结内主要为阳性,而在正常肺组织和肺良性病变中主要为阴性,提示肺癌组织和转移性淋巴结内的免疫耐受可能与NSCLC细胞通过增强IDO表达来促进Treg细胞增殖有关。     

健择联合顺铂化疗对非小细胞肺癌患者外周血CD4~+CD25~+Foxp3~+调节T细胞的影响

目的探讨健择联合顺铂对非小细胞肺癌患者免疫耐受的调控作用。方法38例经病理学或细胞学确诊的NSCLC患者,采用健择、顺铂联合化疗方案,应用流式细胞仪检测化疗前后外周血CD4+CD25+Foxp3+调节T细胞(Treg)占CD4+T细胞的百分率。结果化疗前NSCLC患者外周血CD4+CD25+Foxp3+调节T细胞(Treg)占CD4+T细胞的比率明显高于健康对照组(P<0.05);化疗后NSCLC患者外周血CD4+CD25+Foxp3+调节T细胞(Treg)占CD4+T细胞的百分率较化疗前显著降低(P<0.05);但鳞癌、腺癌及腺鳞癌3组间化疗前、化疗后各项指标之间差异无统计学意义(P>0.05)。结论健择联合顺铂化疗可调控晚期非小细胞肺癌机体的肿瘤免疫耐受,改善患者的免疫功能。     

肿瘤免疫中Treg细胞与趋化因子及受体的研究进展

近年来的研究发现,趋化因子系统和调节性T细胞在肿瘤发生、发展及转移中发挥重要作用。作为一种免疫抑制性调节细胞,CD4+CD25+调节性T细胞(regulatory T cells,以下简称Treg细胞)在体内通过多种途径发挥抑制效应性T细胞增殖,在诱导机体对肿瘤的免疫耐受和免疫逃逸中发挥关键作用。肿瘤可以通过多种途径来引导调节性T细胞在肿瘤局部的聚集和维持,其中最重要的一种方式为肿瘤细胞表面高表达趋化因子。现将近年来国内外对趋化因子及受体(特别是趋化因子受体5)与Treg细胞关系的研究进行综述。     

胃癌组织吲哚胺2,3-双加氧酶表达及其诱导肿瘤免疫逃逸的研究

目的:检测胃癌组织中吲哚胺2,3双加氧酶(indoleamine 2,3-dioxygenase,IDO)、增殖细胞核抗原(PCNA)、T细胞表面标志CD3、CD4和CD25的表达状况,探讨其在肿瘤细胞增殖、转移和免疫逃逸中的作用.方法:采用免疫组化染色及免疫荧光染色检测胃癌组织中IDO、PCNA、T细胞表面标志CD3、CD4和CD25的表达,分析IDO表达在肿瘤细胞增殖、转移和免疫遮逸中的作用.结果:1)肿瘤细胞和单个核细胞表面表达IDO;胃癌肿瘤组织IDO的阳性表达率为73.33%,高于癌旁组织.肿瘤组织内IDO高表达与PCNA高表达显著相关,X2=4.35, P<0.05.2)胃癌肿瘤组织内CD3阳性表达率为37.67%,低于癌旁对照组,X2=4.45, P<0.05.3)胃癌组织中可见CD4 CD25 调节性T细胞(Treg).4)胃癌患者中转移组IDO阳性表达率为86.36%,无转移组表达率为60.0%,转移组IDO阳性表达率高于无转移组,P=0.01.结论:胃癌细胞高表达IDO,能抑制T细胞活化、增殖和向肿瘤组织内的浸润,在肿瘤组织内造成免疫抑制,从而促进肿瘤的增殖和转移.肿瘤组织中CD4 CD25 Treg细胞参与IDO引发胃癌肿瘤免疫耐受的过程,发挥免疫抑制作用.     

肿瘤患者CD4+CD25+调节性T细胞流式细胞术分析

目的:分析比较肿瘤患者和健康人外周血CD4+CD25+调节性T细胞的特点,为肿瘤免疫学研究及治疗探索新方法.方法:收集并分离30例肿瘤患者和32例健康人的外周血单个核细胞(PBMCs),用荧光标记的抗人CD4及抗人CD25单抗标记肿瘤患者和健康人PBMCs细胞,FCM检测CD4+CD25+Treg细胞,分析CD4+CD25+Treg细胞在肿瘤患者和健康人中的差别.结果:肿瘤患者的CD4+CD25+Treg细胞百分数明显高于健康人(年龄<55者62.4 vs 40.4;年龄≥55者53.1 vs 31.0,P<0.05).结论:肿瘤患者的CD4+CD25+Treg细胞高于健康对照,为肿瘤免疫治疗提供新策略,通过删除CD4+CD25+Treg细胞,有可能增强抗瘤免疫反应.     

Treg细胞与肿瘤免疫关系的研究进展

许多研究表明肿瘤内存在调节性T(Treg)细胞,Treg细胞在肿瘤局部可诱导免疫耐受.对肿瘤患者Treg细胞功能的深入研究将为肿瘤免疫治疗提供新的途径.     

晚期非小细胞肺癌患者外周血CD4~+ CD25~+ FOXP3~+调节性T细胞的表达及临床意义

目的探讨晚期非小细胞肺癌患者外周血CD4~+ CD25~+ FOXP3~+ 调节性T(Treg)细胞的表达及其临床意义。方法采用免疫荧光术及流式细胞仪检测50例晚期非小细胞肺癌患者及50例健康对照组外周血中CD4~+ CD25~+ FOXP3~+ Treg细胞、CD4~+ CD25~+ Treg细胞、CD4~+ T细胞和CD4~+ CTLA-4~+ T细胞的表达。结果晚期非小细胞肺癌患者外周血中CD4~+ CD25~+ FOXP3~+ Treg细胞、CD4~+ CD25~+ Treg细胞和CD4~+ CTLA-4~+ T细胞的比例均高于健康对照组(均P<0.05),CD4~+ T细胞的比例均低于健康对照组(均P<0.05)。结论晚期非小细胞肺癌患者外周血CD4~+ CD25~+ FOXP3~+ Treg细胞比例高于健康对照者,可能与肺癌患者的免疫抑制和肿瘤进展相关。     

IDO在肿瘤中作用的研究进展

摘 要：肿瘤有特异性的肿瘤抗原,能诱导机体产生抗肿瘤作用的免疫应答。但是自然状态下有时免疫系统不能有效地控制肿瘤的发生发展,主要是因为肿瘤微环境中产生了针对肿瘤抗原的免疫耐受,即免疫活性细胞接触肿瘤抗原性物质时所表现的一种特异性无应答状态。最新的研究证实吲哚胺-2,3-双加氧酶(indoleamine 2,3-dioxygenase,IDO)的过度表达导致的色氨酸代谢异常在肿瘤患者的免疫耐受中发挥了重要作用。肿瘤患者体内的IDO表达上调,通过一系列复杂的机制抑制肿瘤微环境中的抗肿瘤免疫反应,促进肿瘤血管生成。抑制IDO的活性则可以打破免疫耐受,增强抗肿瘤免疫反应。IDO及色氨酸代谢产物犬尿氨酸还可以作为肿瘤患者预后的预测因子。     

CD4+CD25+FOXP3+T细胞在人脑星形胶质瘤中的表达和意义

目的:观察调节性T细胞在星形胶质瘤患者体内的表达情况,观察其与星形胶质瘤发展的关系.方法:收集河北医科大学第四医院神经外科在2008年9月至2010年6月期间收治的星形胶质瘤患者,共92例,其中男性54例,女性38例,平均年龄51.4岁,均为初次发病.收集8例行颞叶切除术的癫痫患者为对照组.应用流式细胞术检测观察CD4+CD25+FOXP3+调节性T细胞(Treg)在胶质瘤组织中及患者外周血中的浸润情况,应用免疫酶联反应方法(ELISA)测定转化生长因子β1(TGFβ1)在外周血中的表达,应用SPSS13.0软件进行统计学分析处理.结果:星形胶质瘤患者外周血(9.34±2.13)%和肿瘤组织(24.17±2.54)%中的Treg细胞明显增多,均显著高于对照组(0.67%±0.12%,24.17%±2.54%,P<0.05),并且Treg细胞的含量随着肿瘤级别的升高而增加,WHO Ⅳ级患者外周血和肿瘤组织中的Treg细胞含量(8.34%±2.13%,35.45%±2.47%)明显高于WHO Ⅲ和WHO Ⅱ级(P<0.05).ELISA结果显示:星形胶质瘤患者外周血中TGFβ1的含量明显增高,并与外周血中的Treg细胞的数量明显呈正相关(r=0.564,P=0.001).结论:Treg细胞在星形胶质瘤患者的外周血和肿瘤组织的浸润明显增多,并与肿瘤的恶性程度有关,其数量的增长与TGFβ1的表达相关.Treg细胞的增多能够抑制机体抗肿瘤免疫,促进了星形胶质瘤的发展,其具有成为胶质瘤免疫治疗靶点的潜在价值.     

CD4+CD25+调节性T细胞与大肠癌的关系

近来CD4 CD25 调节性T细胞对肿瘤免疫调节的抑制作用正受到越来越多的重视,许多恶性肿瘤患者外周血都存在CD4 CD25 调节性T细胞比例上调,机体抗肿瘤免疫力下降.大肠癌的发病率正逐年上升,其发病分子机制已为熟知,免疫机制研究不多,国内尚未见大肠癌与该类细胞关系的报道,现对CD4 CD25 调节性T细胞在大肠癌的发生、发展、治疗中的研究综述如下.     

CD4^＋CD25^＋调节性T细胞与肿瘤的相关性研究

通过了解CD4^＋CD25^＋调节性T细胞（CD4^＋CD25^＋Treg）表面分子的特性和CD4^＋CD25^＋Treg在外周血和组织中的表达,认识CD4^＋CD25^＋Treg在肿瘤免疫调节中的作用,探索其作用的分子机制。     

IDO和CD4^＋CD25^＋调节性T细胞在肿瘤免疫逃逸中相互作用的研究进展

肿瘤可以通过多种方式逃逸机体免疫系统的监控。吲哚胺-2,3双加氧酶（indoleamine．2,3-dioxygenase,IDO）和CD4^＋CD25^＋调节性T细胞（CD4^＋CD25^＋ regulatory Tcells,Tregs）是近些年在肿瘤免疫逃逸领域中备受关注的两个重要因素。两者相互作用在肿瘤免疫逃逸机制中起着尤为关键的作用,已引起众多研究者的关注。本文就IDO及Tregs在肿瘤免疫逃逸中的作用以及两者之间的相互关系等方面的研究进展作一综述。     

Correlation between CD4+CD25+Treg Cells and CCR4 in Nasopharyngeal Carcinoma

OBJECTIVE CD4+CD25+ T regulatory (Treg) cells are a population of T cells which suppress an overactive immune system. CCR4 is a chemokine receptor involved in the recruitment of lymphocytes. Nasopharyngeal carcinoma (NPC) is resistant to immunosurveillance, owing to the increased number of tumor-infiltrating Treg cells which are recruited to the tumor by CCR4.METHODS The percentage of CD4+CD25+Treg cells and CCR4+ cells in tissue or peripheral blood (PB) lymphocytes of patients with untreated NPC or normal subjects was analysed by flow cytometry. RESULTS In both tissue and PB lymphocytes, the percentage of CD4+CD25+ Treg cells and CCR4+ cells was significantly elevated in patients with NPC in comparison with that in the normal tissue of controls. Furthermore, in the patients with NPC, a higher percentage of CD4+CD25+ Treg cells was found in the tumor-infiltrating (T1) lymphocyte population than in the PB population. In the NPC patient group, a general trend towards an increased percentage of Tl Treg cells was found in the patients with advanced stage NPC. The number of CD4+CD25+ Treg cells was positively related to the number of CCR4+ cells in the tumor and in the PB of the patients with NPC, while the number of CD4+CD25+ Treg cells was negatively related to the number of CD4+CD25- T cells.CONCLUSION Immunosuppression was observed in NPC, especially at the tumor sites. CD4+CD25+ Treg cells may suppress CD4+CD25- T cells. CCR4 may have an important role in the recruitment of CD4+CD25+ Treg cells to tumor sites, thus causing resistance to immunosurveillance.     

Increased Frequency of Foxp3+ Regulatory T Cells in Mice with Hepatocellular Carcinoma

The CD4+CD25+ regulatory T cell (Treg) is a special kind of T cell subset. Studies have showed that Tregcells are involved in a number of physiological processes and pathologic conditions such as autoimmune diseases,transplantation tolerance and cancer. Tregs with unique capacity for immune inhibition can impair anti-tumourimmunity and help tumor cells to escape from immune surveillance. The aim of our study was to investigatewhether Tregs are involved in hepatocellular carcinoma (HCC). A BABL/C mouse with HCC in situ model wasestablished to evaluate the Treg existence in carcinoma tissues and the changes of Tregs in spleen using flowcytometry and immunohistochemistry methods. Granzyme B expression in carcinoma tissues was analyzedby immunohistochemistry to investigate the tumor local immune status.The proportion of CD4+CD25+/CD4+spleen lymphocytes of tumor bearing mice (18.8%±1.26%) was found to be significantly higher than that innormal mice (9.99%±1.90%) (P<0.01 ). Immunohistochemistry of spleen tissue also confirmed that there wasan increase in Treg in tumor-bearing mice, while in carcinomas it showed Treg cells to be present in tumorinfiltrating lymphocyte areas while Granzyme B was rarely observed. Anti-tumour immunity was suppressed,and this might be associated with the increase of Tregs. Our observations suggest that the CD4+CD25+Treg/CD4+ proportion in spleen lymphocytes can be a sensitive index to evaluate the change of Tregs in hepatocellularcarcinoma mice and the Treg may be a promising therapeutic target for cancer.     

肝癌荷瘤小鼠调节性T细胞数量的改变及其与肿瘤生长的关系

目的研究肝癌荷瘤小鼠调节性T细胞数量的改变及其与肿瘤生长的关系。方法采用小鼠肝癌细胞系H22接种BALB／c小鼠,建立肝癌模型;采用流式细胞术方法检测CD4^＋ CD25^＋T／CD4^＋T细胞的比例;以RT-PCR和流式细胞术检测Foxp3基因的表达。以免疫磁珠分选法纯化CD4^＋CD25^＋T和CD4^＋CD25^-T细胞;在体外,用3H-TdR掺入法检测T细胞的增殖情况;在体内,观察荷瘤小鼠来源的CD4^＋CD25^＋T细胞对肿瘤生长的作用。结果（1）荷瘤小鼠在引流淋巴结中,CD4^＋CD25^＋T细胞占CD4＋T细胞（18．80％±0．06％）比例增高,与对照组（9．50％±0．03％）相比,差异有统计学意义（P〈0．01）;在非引流淋巴结（LN）和脾脏（SP）中,荷瘤小鼠CD4^＋CD25^＋T／CD4^＋T比例分别为16．28％±0．02％和17．28％±0．06％,与对照组9．50％±0．03％和11．08％±0．04％相比,差异有统计学意义（P〈0．01,P〈0．05）;同时,调节性T细胞特异性标志Foxp3 mRNA的表达也升高。在同一只荷瘤小鼠中,引流淋巴结中CD4^＋CD25^＋T细胞数量（18．8％±0．06％）较对侧非引流淋巴结（16．28％±0．02％）略有升高,但差异无统计学意义（P〉0．05）。（2）从荷瘤小鼠中纯化的CD4^＋CD25^＋T细胞,在体外对抗CD3单抗的刺激无反应,但能抑制CD4^＋CD25^-T细胞的增殖。（3）CD4^＋CD25^＋T／CD4＋T比例与肿瘤大小呈正相关,并且可以抑制CD4^＋CD25^-T细胞的抗肿瘤效应。结论肝癌细胞在小鼠体内的生长可以提高调节性T细胞的数量,其数量的高低与肿瘤的大小呈正相关,提示清除调节性T细胞将是肿瘤免疫治疗的策略之一。     

CD4~+ CD25~+调节性T细胞及其在肿瘤免疫治疗中的意义

CD4+CD25+调节性T细胞是具有独特免疫调节功能的T细胞亚群。近年来研究发现各种恶性肿瘤患者外周血及肿瘤环境中该细胞比例增加,去除CD4+CD25+调节性T细胞或封闭其抑制功能可以增强抗肿瘤免疫反应。CD4+CD25+调节性T细胞成为肿瘤免疫治疗的新靶点。     

CD+4 CD+25调节T细胞的生物学功能及其在移植物抗宿主病中作用的研究进展

 CCD+4 CD+25 调节T（Treg）细胞具有免疫无能性和免疫抑制性两大功能特征,是抑制性T细胞的一种亚群。能抑制效应细胞CD+4 T细胞和CD+8 T细胞的活化与增殖,从而有效抑制免疫系统对外来器官产生的排异反应,减轻了造血干细胞移植（HSCT）术后移植物抗宿主病（GVHD）,而且不影响移植物抗白血病（GVL）效应,从而在移植免疫耐受中发挥重要的作用。     

Upregulated expression of indoleamine 2, 3-dioxygenase in CHO cells induces apoptosis of competent T cells and increases proportion of Treg cells

Introduction

The inflammatory enzyme indoleamine 2, 3-dioxygenase (IDO) participates in immune tolerance and promotes immune escape of IDO+ tumors. A recent hypothesis suggested that IDO may contribute to the differentiation of new T regulatory cells (Tregs) from naive CD4+ T cells. In this study we investigated the role of IDO in induction of immunosuppression in breast cancer by increasing the apoptosis of T cells and the proportion of Tregs.

Methods

An IDO expression plasmid was constructed and Chinese hamster ovary (CHO) cells were stably transfected with human IDO. Purified CD3+ T cells were isolated from the peripheral blood monouclear cells of breast cancer patients. After co-culturing IDO expressing or untransfected (control) CHO cells with T cells, T cells apoptosis were determined by flow cytometry analysis and annexin-V and PI staining. The proportion of the regulatory T cell (Tregs [CD4 + CD25 + CD127-]) subset was measured by flow cytometry analysis. T cells total RNA and cellular protein samples were isolated for detecting Foxp3 gene and protein expression.

Results

IDO transgenic CHO cells yielded high levels of IDO enzymatic activity, resulting in complete depletion of tryptophan from the culture medium. We found that apoptosis occurred in 79.07 ± 8.13% of CD3+T cells after co-cultured with IDO+ CHO cells for 3 days and the proportion of CD4 + CD25 + CD127- T cells increased from 3.43 ± 1.07% to 8.98 ± 1.88% (P < 0.05) as well. The specific inhibitor of IDO,1-MT efficiently reversed enhancement of T cells apoptosis and amplification of Tregs in vitro. Increased expression of Foxp3, a key molecular marker of Tregs, was confirmed by RT-PCR, real-time RT-PCR and Western blot analysis at the same time.

Conclusions

These results suggest that IDO helps to create a tolerogenic milieu in breast tumors by directly inducing T cell apoptosis and enhancing Treg-mediated immunosuppression.