CD4＋CD25＋Foxp3＋Treg细胞调控肿瘤免疫抑制微环境的研究进展

目的： CD4＋CD25＋Foxp3＋调节性T细胞（ Treg ）是肿瘤免疫抑制微环境的主要组成部分,其在肿瘤的免疫抑制微环境中分泌IL－10、IL－35、TGF－β1和FGL2等细胞因子发挥免疫抑制作用。Treg细胞抑制CD4＋T、CD8＋T淋巴细胞和NK细胞,进而抑制特异性抗肿瘤免疫反应使肿瘤细胞更容易逃避免疫监视。进一步研究Treg细胞在肿瘤免疫中的作用机制,对深入了解恶性肿瘤的发病机制及免疫治疗具有重要的理论意义。此外,Treg细胞及其分泌的细胞因子在肿瘤治疗和预后评估等方面也具有广阔的临床应用前景。     

CD4+CD25+FOXP3+调节性T细胞在肿瘤免疫逃逸中的作用研究进展

CD4^＋CD25^＋FOXP3^＋调节性T细胞是具有特定表型和抑制功能的T淋巴细胞亚群,可通过多种方式抑制抗肿瘤免疫反应从启动到效应的整个阶段,在肿瘤免疫逃逸中起着重要作用.肿瘤患者体内调节性T细胞增多,不仅是一个普遍现象,而且对预后及疗效评价等多方面具有指导意义,是免疫治疗的新的有效靶点.     

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.     

调节性T细胞在肿瘤免疫和肿瘤免疫治疗中的作用

肿瘤局部存在多种类型的免疫抑制性细胞,其中调节性T细胞 (regulatory T cell,Treg)在肿瘤的发生、发展过程中发挥着极为重要的作用。Treg通过多种机制抑制免疫效应细胞的功能,是肿瘤免疫逃逸的关键因素。这些机制包括分泌抑制性细胞因子抑制效应细胞功能、分泌颗粒酶和穿孔素杀伤效应细胞、干扰效应细胞的代谢功能,以及通过调控树突状细胞影响Treg的分化和增殖,等等。Treg的深入研究为肿瘤免疫治疗提供了新的思路,以Treg及相关免疫抑制性分子作为靶点,通过特异性或非特异性清除Treg、控制Treg的数量和功能等开展肿瘤免疫治疗具有良好的临床应用前景。     

监测肾癌患者外周血CD4~+CD25~+调节性T细胞在术后免疫治疗中的作用

目的:探讨肾癌患者外周血CD4+CD25+T淋巴细胞的监测在术后辅助免疫治疗中的作用。方法:将24例肾癌患者随机分为两组:A组,根治性肾切除术后行IFN-α辅助免疫治疗;B组,单纯行根治性肾切除术;C组,10例健康对照。分别在术前、术后1周以及术后3个月免疫治疗结束时采集外周血样本,流式细胞仪检测CD4+、CD8+、CD4+CD25、CD4+CD25high T淋巴细胞亚群含量,并计算各部分比值。结果:A、B组术前CD4+CD25+、CD4+CD25high T淋巴细胞亚群总体上增加,并且其含量随肿瘤分期的进展而增加(P<0.05),但部分患者并不高于健康对照组。免疫治疗后,肾癌患者CD4+CD25+T淋巴细胞总体略有上升,但术前较高的患者中,约2/3下降。结论:利用流式细胞仪监测肾癌患者外周血CD4+CD25+T淋巴细胞亚群可反映机体抗肿瘤免疫状态,有助于预测免疫治疗的预后,为肾癌尤其是早期肾癌术后辅助免疫治疗的选择提供参考。     

CD19+CD24hiCD38hiBregs involved in downregulate helper T cells and upregulate regulatory T cells in gastric cancer

Regulatory B cells (Bregs) play a critical role in inflammation and autoimmune disease. We characterized the role of Bregs in the progression of gastric cancer. We detected an increase in Bregs producing IL-10 both in peripheral blood mononuclear cells (PBMCs) and in gastric tumors. Multicolor flow cytometry analysis revealed that a subset of CD19⁺CD24^hiCD38^hi B cells produces IL-10. Functional studies indicated that increased Bregs do not inhibit the proliferation of CD3⁺T cells or CD4⁺ helper T cells (Th cells). However, Bregs do suppress the secretion of IFN-γ and TNF-α by CD4⁺Th cells. CD19⁺CD24^hiCD38^hiBregs were also found to correlate positively with CD4⁺FoxP3⁺ regulatory T cells (Tregs). Neutralization experiments showed that Bregs convert CD4⁺CD25⁻ effector T cells to CD4⁺FoxP3⁺Tregs via TGF-β1. Collectively, these findings demonstrate that increased Bregs play a immunosuppressive role in gastric cancer by inhibiting T cells cytokines as well as conversion to Tregs. These results may provide new clues about the underlying mechanisms of immune escape in gastric cancer.     

Depletion of CD4+CD25+ human regulatory T cells in vivo: kinetics of Treg depletion and alterations in immune functions in vivo and in vitro

The aim of this study was to investigate whether depletion of CD4(+)CD25(+) regulatory T cells (Treg) from melanoma patients affects immune responses against tumors. By application of recombinant IL-2-diphteria toxin fusion protein, also known as ONTAK, we were able to significantly reduce the frequency of Treg in peripheral blood, whereas other cell populations remained unaffected. The reduction of Treg started immediately after the first bolus of ONTAK with a dose of 5 microg ONTAK per kg bodyweight and lasted for 13 days with subsequent recovery thereafter. Successive ONTAK treatments further reduced the number of circulating Treg. Using the contact sensitizer DCP we show that all patients developed vast eczema after Treg depletion, whereas no or only mild eczematous reactions were detectable before ONTAK treatment. Corresponding induction of DCP-specific CD4(+) and CD8(+) T cells were detectable. Moreover, after immunization of ONTAK treated patients with tumor antigen peptides, MelanA/MART-1 and gp100, significant induction of peptide specific CD8(+) T cells could be observed in 90% of the patients treated. These cells displayed effector functions, as they were able to lyse peptide-pulsed target cells and secreted IFNgamma upon restimulation. In aggregate, our data indicate that ONTAK depletes Treg in vivo significantly, resulting in enhanced immune functions and substantial development of antigen-specific CD8(+) T cells in vaccinated individuals.     

CD+4CD+25调节性T细胞与肿瘤免疫

 近期研究发现一个有独特免疫调节功能的T细胞亚群：CD+4 CD+25调节性T细胞,不仅能抑制自身免疫性疾病发生,还参与肿瘤免疫的调节。这群细胞具有免疫无能和免疫抑制特性,与肿瘤免疫逃逸有密切的关系。肿瘤环境中CD+4 CD+25调节性T细胞增加,导致肿瘤免疫失调,去除这群细胞可有效诱导肿瘤免疫,为肿瘤治疗提供了一种新的思路。     

Prognostic significance of regulatory T cells in tumor

Since entering the immunological stage several decades ago, regulatory T cell biology has been realized as fundamentally important in the prevention of autoimmune conditions, induction of transplant tolerance and the immune response to cancer. The role of regulatory T cells in tumor immunobiology is still being elucidated. Currently, regulatory T cells are implicated in the dampening of antitumor T‐cell responses both through direct and indirect means. A number of investigators have demonstrated that regulatory T cell density and location may serve as independent prognostic factors in several types of cancer and are alternately detrimental or beneficial to patient survival. In this article, we will review the characteristics and functional phenotype of classical regulatory T cells, describe their distribution and quantification in tumor‐bearing hosts and summarize recent studies investigating the prognostic significance of regulatory T cell number and locality in various cancers.     

UV irradiation of immunized mice induces type 1 regulatory T cells that suppress tumor antigen specific cytotoxic T lymphocyte responses

We previously showed that exposure to UV radiation after immunization suppresses Th1 and Th2 immune responses, leading to impaired Ab and allo-immune responses, but the impact of UV radiation after immunization on anti-tumor immune responses mediated by tumor-specific CD8(+) T cell responses remains less clear. Furthermore, the exact phenotypic and functional characteristics of regulatory T cell population responsible for the UV-induced immunosuppression still remain elusive. Using the MBL-2 lymphoma cell line engineered to express OVA as a surrogate tumor Ag, here we demonstrate that UV irradiation after tumor Ag-immunization suppresses the anti-tumor immune response in a manner dependent on the immunizing Ag. This suppression was mediated by interleukin (IL)-10 released from CD4(+) CD25(+) T cells, by which impaired the induction of cytotoxic T lymphocytes (CTL) able to kill Ag-expressing tumor cells. In addition, we generated a panel of T cell clones from UV-irradiated and non-irradiated mice, and all of the clones derived from UV-irradiated mice had a Tr1-type regulatory T cell phenotype with expression of IL-10 and c-Maf, but not Foxp3. These Tr1-type regulatory T cell clones suppressed tumor rejection in vivo as well as Th cell activation in vitro in an IL-10 dependent manner. Given that suppression of Ag-specific CTL responses can be induced in Ag-sensitized mice by UV irradiation, our results may imply that exposure to UV radiation during premalignant stage induces tumor-Ag specific Tr1 cells that mediate tumor-Ag specific immune suppression resulting in the promotion of tumor progression.     

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。     

Proportion of CD4+CD25+ regulatory T cell is increased in the patients with ovarian carcinoma

Objective: To study the frequency of the CD4⁺CD25⁺ regulatory T cells (Tregs) in the patients with ovarian carcinoma and its possible mechanism. Methods: The percentages of CD4⁺CD25⁺ Tregs in the peripheral blood lymphocytes (PBLs), tumor infiltrating lymphocytes (TILs) and tumor associated lymphocytes (TALs) from 13 patients with ovarian carcinoma and in the PBLs from 14 healthy women were determined by flow cytometry. The expression of CD69 on CD4⁺PBLs from the patients was detected. PBLs from healthy women were cultured in complete RPMI 1640 containing the supernatant from SKOV3 cell line with or without PHA (phytohemagglutinin) stimulation for 72 hours, then the percentage of CD4⁺CD25⁺ T cells was detected. Results: CD4⁺CD25⁺ Tregs in the PBLs from patients with ovarian carcinoma were significantly increased compared with those from the control. The percentage of CD4⁺CD25⁺ Tregs in TILs was higher than that in PBLs and TALs from the patients, but not significantly. The expression of CD69 on CD4⁺PBLs from the patients was negative. The percentages of CD4⁺CD25⁺ T cells in PBLs cultured with SKOV3 supernatant elevated significantly compared with those without supernatant whether PHA was added or not (P = 0.001 and 0.001, respectively). Conclusion: There is an increasing of the proportion of CD4⁺CD25⁺ Tregs in PBLs, TILs and TALs of the patients with ovarian carcinoma, which probably results from up-regulation of soluble factor secreted by ovarian carcinoma cells.     

Methionine Enkephalin (MENK) Inhibits tumor growth through regulating CD4+Foxp3+ Regulatory T cells (Tregs) in mice

Methionine enkephalin (MENK), an endogenous neuropeptide, plays an crucial role in both neuroendocrine and immune systems. CD4+Foxp3+ regulatory T cells (Tregs) are identified as a major subpopulation of T lymphocytes in suppressing immune system to keep balanced immunity. The aim of this research work was to elucidate the mechanisms via which MENK interacts with Tregs in cancer situation. The influence of MENK on transforming growth factor-β (TGF-β) mediated conversion from naïve CD4+CD25- T cells to CD4+CD25+ Tregs was determined and the data from flow cytometry (FCM) analysis indicated that MENK effectively inhibited the expression of Foxp3 during the process of TGF-βinduction. Furthermore, this inhibiting process was accompanied by diminishing phosphorylation and nuclear translocation of Smad2/3, confirmed by western blot (WB) analysis and immunofluorescence (IF) at molecular level. We established sarcoma mice model with S180 to investigate whether MENK could modulate Tregs in tumor circumstance. Our findings showed that MENK delayed the development of tumor in S180 tumor bearing mice and down-regulated level of Tregs. Together, these novel findings reached a conclusion that MENK could inhibit Tregs activity directly and retard tumor development through down-regulating Tregs in mice. This work advances the deepening understanding of the influence of MENK on Tregs in cancer situation, and relation of MENK with immune system, supporting the implication of MENK as a new strategy for cancer immunotherapy.     

Incidence and prognostic impact of FoxP3+ regulatory T cells in human gliomas

PURPOSE: The incidence of regulatory T cells (Treg) in intrinsic central nervous system malignancies is unknown. Immunotherapeutic approaches that inhibit the Treg population may be limited to a subset of patients with gliomas. Our hypothesis is that only the most malignant gliomas have a prominent glioma-infiltrating Treg population that contributes to the immunosuppressive biology and that the presence of Tregs is a negative prognostic variable. EXPERIMENTAL DESIGN: We measured the incidence of Tregs in 135 glial tumors (including all pathologic types) in a glioma microarray using immunohistochemical analysis. Results were categorized according to the total number of Tregs within the tumors. Correlation of the presence of Tregs with prognosis was evaluated using univariate and multivariate analyses. RESULTS: Tregs were not present in normal brain tissue and were very rarely found in low-grade gliomas and oligodendrogliomas. We observed significant differences in the prevalence of Tregs between astrocytic and oligodendroglial tumors, between tumors of different grades, and between different pathologic types of tumors. We identified Tregs most frequently in glioblastoma multiforme (GBM) but very rarely in low-grade astrocytomas. The presence of Tregs within GBMs did not alter the median survival in patients from whom the tumors were obtained. CONCLUSIONS: Treg infiltration differed significantly in the tumors according to lineage, pathology, and grade. Tregs seemed to have the highest predilection for tumors of the astrocytic lineage and specifically in the high-grade gliomas, such as GBM. In both univariate and multivariate analysis, the presence of Tregs in GBMs seemed to be prognostically neutral.     

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.     

Follicular lymphoma B cells induce the conversion of conventional CD4+ T cells to T-regulatory cells

There has been accumulating evidence that CD4(+)CD25(+) FoxP3 expressing regulatory T cells (Treg) are highly concentrated in tumors, thereby fostering an immune-privileged microenvironment. Some studies have shown that T-cell receptor (TCR) stimulation can convert conventional T cells into Treg. Follicular lymphoma (FL) B cells can enhance this Treg conversion. We investigated whether FL tumor B cells, as opposed to normal B cells, are unique in their ability to convert effector T cells into Treg. We found that tumor B cells alone, without artificial TCR stimulation, could induce conventional T cells to express FoxP3 and to acquire regulatory function. In contrast to their malignant counterpart, normal B cells did not induce Treg conversion. Treg conversion was independent of the T cell background, as T cells isolated from FL or normal peripheral blood were equally susceptible to being converted by tumor B cells. Our study provides evidence for a tumor-specific mechanism by which FL tumor cells promote immune escape through the induction of Treg.     

调节性T细胞在甲状腺乳头状癌免疫耐受形成中的作用及意义

目的 研究调节性T细胞(Treg)在甲状腺乳头状癌(PTC)患者外周血和肿瘤微环境中的分布及意义.方法 选择确诊并手术的PTC患者80例作为PTC组,PTC合并桥本氏甲状腺炎(HT)患者80例作为PTC合并HT组,同时选择80例结节性甲状腺肿患者作为对照组.术前用流式细胞仪检测外周血中CD4+CD25+CD127low/-Treg,术后用免疫组化方法检测肿瘤和转移性淋巴结中Foxp3的表达情况.比较各组表达差异及与临床病理特征的关系.结果 外周血中CD4+CD25+CD127low/-Treg比例PTC组患者[(9.01±1.82)％]最高,PTC合并HT组患者[(6.94±1.69)％]次之,对照组患者[(6.01±2.33)％]最低,差异有统计学意义(P﹤0.05);有淋巴结转移、有腺外侵犯的PTC患者外周血CD4+CD25+CD127low/-Treg比例和肿瘤组织中Foxp3高表达者比例均高于无淋巴结转移及无腺外侵犯患者(P﹤0.05).结论 PTC患者外周血及组织微环境中Treg均增加,对癌细胞免疫耐受、组织浸润和转移有促进作用.     

CD4+CD25+调节性T 细胞对乳腺癌细胞上皮间质转化和ALDH1+干样细胞的影响*

目的:研究CD4+CD25+调节性T 细胞（regulatory T cells ,Tregs）对乳腺癌细胞上皮间质转化（epithelial-mesenchymal transition ,EMT ）、细胞迁移侵袭能力,及ALDH1+干样细胞比例的影响。方法:采用免疫磁珠法分离乳腺癌患者外周血中CD4+CD25+Tregs,CD4+CD25+Tregs与乳腺癌BT474、MCF-7 细胞系共培养（共培养组）,BT474、MCF-7 单独培养（对照组）。 检测共培养组和对照组乳腺癌细胞EMT 相关标志物表达的变化,及细胞迁移和侵袭能力的变化。此外,检测BT474 细胞中ALDH1+干样细胞、微球形成能力和自我更新能力的变化。结果:CD4+CD25+Tregs诱导BT474 和MCF-7 细胞间质性标志物表达增高,诱导MCF-7 细胞上皮性标志物E-cadherin 表达降低。CD4+CD25+Tregs诱导BT474 和MCF-7 细胞迁移和侵袭能力上调。共培养组BT474 细胞中ALDH1+干样细胞比例、微球体形成能力、自我更新能力较对照组增强。结论:CD4+CD25+Tregs可诱导乳腺癌细胞发生EMT ,增强细胞体外迁移和侵袭能力,同时促进ALDH1+干样细胞增加。      

CD103 is a hallmark of tumor-infiltrating regulatory T cells

Regulatory T cells (Treg) mediate tolerance towards self-antigens by suppression of innate and adaptive immunity. In cancer patients, tumor-infiltrating FoxP3+ Treg suppress local anti-tumor immune responses and are often associated with poor prognosis. Markers that are selectively expressed on tumor-infiltrating Treg may serve as targets for immunotherapy of cancer. Here we show that CD103, an integrin mediating lymphocyte retention in epithelial tissues, is expressed at high levels on tumor-infiltrating FoxP3+ Treg in several types of murine cancer. In the CT26 model of colon cancer up to 90% of the intratumoral FoxP3+ cells expressed CD103 compared to less than 20% in lymphoid organs. CD103+ Treg suppressed T effector cell activation more strongly than CD103(neg) Treg. Expression of CD103 on Treg closely correlated with intratumoral levels of transforming growth factor β (TGF-β) and could be induced in a TGF-β-dependent manner by tumor cell lines. In vivo, gene silencing of TGF-β reduced the frequency of CD103+ Treg, demonstrating that CD103 expression on tumor-infiltrating Treg is driven by intratumoral TGF-β. Functional blockade of CD103 using a monoclonal antibody did however not reduce the number of intratumoral Treg, indicating that CD103 is not involved in homing or retention of FoxP3+ cells in the tumor tissue. In conclusion, expression of CD103 is a hallmark of Treg that infiltrate TGF-β-secreting tumors. CD103 thus represents an interesting target for selective depletion of tumor-infiltrating Treg, a strategy that may help to improve anti-cancer therapy.     

胃癌患者调节性T细胞胞内外细胞因子的检测及其意义

背景与目的:目前认为CD4 CD25 调节性T细胞与胃癌患者的免疫功能抑制密切相关,但CD4 CD25 调节性T细胞发挥免疫抑制功能的作用机制并不十分清楚.本研究通过检测胃癌患者CD4 CD25 调节性T细胞产生具有不同生物活性的细胞因子干扰素-γ(interferon-γ,IFN-γ)、白介素4(interleukin-4,IL-4)、IL-10及肿瘤生长因子-β(tumor growth factor-β,TGF-β)的分泌情况,进一步探讨这些细胞因子在胃癌患者CD4 CD25 调节性T细胞发挥免疫抑制功能的作用.方法:按常规方法制备患者外周血单个核淋巴细胞,采用免疫磁珠分选方法分离CD4 CD25 T细胞及CD4 CD25-T细胞后,用细胞内细胞因子染色法及ELISA法分别研究CD4 CD25 T细胞在胞内及胞外产生具有不同生物活性的细胞因子IFN-γ、IL-4、IL-1O及TGF-β的水平.结果:(1)与健康对照组比较,胃癌患者分泌内细胞因子IFN-γ、IL-4及IL-10的CD4 CD25 T细胞占CD4 细胞的百分比均显著增高(P＜0.05).(2)培养96 h后,上清液的各种细胞因子水平,无论是胃癌患者还是健康对照组,CD4 CD25 T细胞分泌的IL-10及TGF-β均显著高于CD4 CD25-T细胞(P＜0.05).CD4 CD25 T细胞分泌的IFN-γ显著低于CD4 CD25-T细胞(P＜0.05).结论:CD4 CD25 调节性T细胞体外免疫抑制作用的发挥可能与一些抑制性细胞因子有关,特别是细胞因子TGF-β在胃癌CD4 CD25 调节性T细胞的免疫抑制功能中起着相当重要的作用.