系统性红斑狼疮患者CD4^+CD25^+CD45RA^-T细胞中转录因子Bach2的表达及其影响

目的·研究系统性红斑狼疮(systemic lupus erythematosus,SLE)患者CD4^+CD25^+CD45RA^-T细胞中转录因子BTB与CNC同源基因2(BTB and CNC homology 2,Bach2)的表达及其对细胞功能的影响。方法·采用流式细胞仪分选获得活动期SLE患者(SLE组)和健康对照者(对照组)外周血CD4^+CD25^+CD45RA^-T细胞,荧光定量PCR和Western blotting检测该类细胞中Bach2的表达;分析SLE患者该类细胞中Bach2的平均荧光强度(median fluorescence intensity,MFI)与SLE疾病活动指数(systemic lupus erythematosus disease activity index,SLEDAI)的相关性。采用流式细胞术比较SLE患者IL-17+CD4^+CD25^+CD45RA^-T细胞和IL-17-CD4^+CD25^+CD45RA^-T细胞中Bach2的MFI。在Bach2过表达体系中,采用流式细胞术检测CD4^+CD25^+CD45RA^-T细胞表达IL-17的细胞比例,采用ELISA方法检测细胞培养上清液中IL-17的含量。结果·与对照组相比,SLE组CD4^+CD25^+CD45RA^-T细胞Bach2的m RNA和蛋白表达水平均显著降低(均P<0.01);SLE组Bach2的MFI与SLEDAI呈显著负相关(R2=0.433,P=0.001)。SLE患者IL-17+CD4^+CD25^+CD45RA^-T细胞Bach2的MFI显著低于IL-17-CD4^+CD25^+CD45RA^-T细胞(P=0.013)。当Bach2过表达时,SLE患者CD4^+CD25^+CD45RA^-T细胞表达炎症因子IL-17的细胞比例明显下降(P=0.032),细胞培养上清液中IL-17含量显著降低(P=0.008)。结论·SLE患者CD4^+CD25^+CD45RA^-T细胞Bach2表达下降,在该类细胞中过表达Bach2可使IL-17表达下降。

Effects of estrogen on CD4^+ CD25^+ regulatory T cell in peripheral blood during pregnancy

Objective To investigate the effects of estrogen(E_2)level on regulatory T cells(Treg)in peripheral blood during pregnancy.Methods:A total of 30 healthy non-pregnant women were selected as control group,90 pregnant women of early,middle and late pregnancy and 30 postpartum women at 1 month after parturition were selected as experimental groups including early pregnancy group,middle pregnancy group and late pregnancy group;the proportions of CD4^+CD25^+Treg and CD4^+CD25^+CD127^-Treg among CD4 T cells were detected by flow cytometry;the serum estrogen content in peripheral blood was detected by electrochemical immune luminescence method.Results:E_2 level was coincident with the change of Tregs number during pregnancy.The estrogen content in peripheral blood increased gradually from early pregnancy to late pregnancy,then decreased significantly after parturition,and the level at 1 month after parturition down to the level in non-pregnancy group(P>0.05);the level of E_2 in pregnancy groups were significantly higher than those in non-pregnancy group(P<0.01);and there were significant differences among early pregnancy group,middle pregnancy group and late pregnancy group(P<0.05).The proportions of CD4^+CD25^+Treg and CD4^+CD25^+CD127^-Treg in pregnancy groups were significantly higher than those in non-pregnancy group(P<0.05),but decreased significantly after parturition,and there was no significant difference between non-pregnancy group and postpartum women group(P>0.05):the proportions in middle and late pregnancy groups were significantly higher than those in early pregnancy group(P<0.05).but decreased slightly in late pregnancy group,there was no significant difference between late pregnancy group and middle pregnancy group(P>0.05).There was correlation between Tregs number with estrogen level during pregnancy.The proportion of CD4^+CD25^+Treg and CD4^+CD25^+CD 127^-Treg were positively correlated with estrogen level.Conclusions:High proportion of CD4^+CD25^+Trcg and CD4^+CD25^+CD127^-Treg is closely related to the high level of E,during pregnancy.It suggested that high level of estrogen may induce an increase of CD4^+CD25^+Treg in peripheral blood.and then influence the immune function of pregnant women.The results of this experiment might play an important role of estrogen in immune-modulation during pregnancy.

An Association between Immunosenescence and CD4^+CD25^+ Regulatory T Cells: A Systematic Review

Objective Age-related increment of the prevalence of CD4^＋CD25^＋ regulatory T （Treg） cells were described controversially, and whether such changes explain immune dysfunction in the elderly is still unclear. The aim of this systematic review is to evaluate the role of the Tregs in immunosenescence. Methods Medline and manual searches were performed to identify all published epidemiological and animal studies investigating the efficacy of the association between immunosenescence and Treg cells. Results It was founded that the frequency, phenotypic characteristics, and number/function of Tregs were altered significantly with aging. Medical conditions in individuals with advanced ageas well as apoptosis intensity of Treg cells had an impact on the accumulation of Tregs which in turn could deteriorate cytotoxic activity of CD8＋ T and NK cells and production of IL-2. The range of immune cells that could be suppressed by Treg cells was quite wide and covered CD4^＋CD25^＋ T cells, NK cells, dendritic cells and even monocytes. These changes were observed both in humans and experimental animals. Besides, it was believed that frequency of Tregs increased with age and was accompanied by intensified suppressive activity for Tregs in patients, for example, with Alzheimer disease （AD） and Parkinson disease （PD）. The impaired condition of CD4＋ T cells, so-called immunosenescence, rendered transplant recipients less responsive to an allogeneic kidney graft, an effect that was limited to transplant recipients who were aged over 60 years. Conclusions Treg cells are associated with immunosenescence. All these changes contribute to the aging-related decline of immune responses and lead to the higher risk of immune-mediated diseases, cancer or infections in aged individuals.

Analysis of CD4^+CD25^+ Regulatory T Cells and Foxp3 mRNA in the Peripheral Blood of Patients with Asthma

The changes of CD4^＋CD25^＋ regulatory T cells （CD4^＋CD25^＋ Treg） and Foxp3 mRNA in peripheral blood mononuclear cells （PBMCs） from patients with asthma were investigated in order to elucidate the possible roles of CD4^＋CD25^＋ Treg in the development of asthma. The peripheral blood samples were collected from 29 healthy controls （normal control group） and 78 patients with asthma which included 30 patients in exacerbation group, 25 patients in persistent group, and 23 patients in remission group. By using flow cytometry and RT-PCR, the CD4^＋CD25^＋ Treg ratio and Foxp3 mRNA in PBMCs were detected. The CD4^＋CD25^＋ Treg ratio and Foxp3 mRNA in PBMCs of exacerbation and persistent groups were lower than that of remission and normal control groups （P〈0.05）. Although the CD4^＋CD25^＋ Treg ratio and Foxp3 mRNA of remission group were also lower than that of normal control group, there was no significant difference between them （P〉0.05）. As compared with persistent group, exacerbation group had lower CD4^＋CD25^＋ Treg ratio and Foxp3 mRNA （P〈0.05）. It was indicated that the decrease of CD4^＋CD25^＋ Treg ratio and its function in PBMCs may be responsible for pathogenesis of asthma.

人CD4^+CD25^-CD45RA^+T细胞和CD4^+CD25^-T细胞诱导获得iTreg细胞的方法学研究

目的:分析比较CD4^+CD25 ^-CD45RA^+T细胞和CD4^+CD25^-T细胞在普通/炎性(加入IL-1β和IL-6)条件下,由TGF-β、IL-2和CD3/CD28磁珠共刺激诱导生成iTreg细胞的效率,并对比各组iTreg细胞相关蛋白和细胞因子表达水平变化及其免疫抑制能力的差异。方法:通过Ficoll细胞分离液分离出淋巴细胞,利用MACS分选机,结合CD4阴选磁珠筛出CD4阳性的T细胞,最后再提取其中CD45RA ^+和CD25 ^-T细胞。体外实验中,在普通/炎性条件下诱导iTreg生成,3、6 d通过流式观察各组iTreg细胞的诱导情况及相关分子的表达变化趋势。体内实验分为:CD4 +CD25^-CD45RA ^+T细胞诱导的iTreg组、CD4^+CD25 ^-T细胞诱导的iTreg组和空白对照组,通过观察iTreg对GVHD小鼠模型的免疫调节,分析其免疫抑制能力的差异。结果: CD4^+CD25 -CD45RA +T细胞组和CD4 +CD25 -T细胞组普通条件下iTreg产率分别为(96.00±0.21)%和(60.23±0.50)%,炎性环境下为(81.97±1.29)%和(56.80±0.43)%,前者都显著高于后者( P <0.001)。各组iTreg细胞中CTLA-4、TGF-β和IL-10的表达未见明显差异,而炎性因子IL-2、IL-17前者均低于后者( P <0.001),前者IFN-γ也低于后者( P <0.05)。体内实验表明iTreg均具有免疫调节能力,但CD4^+CD25 ^-CD45RA^+T细胞组诱导的iTreg能力强于后者。结论: CD4^+CD25 ^-CD45RA^+T细胞组和CD4^+CD25^-T细胞组都可以成功诱导iTreg细胞,但是前者在普通和炎性微环境下诱导效率高于后者,免疫调节能力也优于后者。

Influence of Danshen Injection on airway inflammation and CD4^+ CD25^+ regulatory T cells of asthmatic rats

Objective： To investigate the influence of Danshen Injection on airway inflammation and CD4^＋CD25^＋ regulatory T cells（CD4^＋CD25^＋ Tr） of asthmatic rats, and elucidate the possible mechanism of Danshen Injection in treatment of asthma. Methods： 30 Wister rats were randomly divided into control group, asthma group and Danshen Injection treated group. Bronchoalveolar lavage fluids （BALF） were collected, and cytology studies were conducted. Lung tissues were obtained and pathologic analyses were done with hematoxylin and eosin stain （HE）. Flow cytometry was used to detect the CD4^＋CD25^＋ Tr ratio in peripheral blood mononuclear cells （PBMCs）. Results： Total cell, the percentage of lymphocytes, neutrophils and eosinophils （Eos） in BALF of Danshen Injection-treated group were lower than that in asthma group （P〈0.05, P〈0.01）. Compared with asthma group, less infiltration of inflammatory cells in lung tissues was observed in Danshen Injection-treated group. CD4^＋CD25^＋ Tr of asthma group was lower than that of control and Danshen Injection treated group （P〈0.05）. Conclusion： Danshen Injection can suppress airway inflammation of asthmatic rats, probably by increasing the number of CD4^＋CD25^＋ Tr.

成人隐匿性自身免疫性糖尿病患者CD_4^+CD_(25)^+ T细胞亚群的变化

目的探讨成人隐匿性自身免疫性糖尿病(LADA)患者外周血免疫调节性CD4+CD25+T细胞亚群的变化及其意义。方法以流式细胞仪检测32例LADA、16例T1DM、25例T2DM及27例正常对照外周血CD4+CD25+、CD3+CD8+T细胞。结果①LADA组外周血CD4+CD25+T细胞低于而CD3+CD8+T细胞高于T1DM组、T2DM组和正常对照组;②LADA患者CD3+CD8+T细胞比例与起病年龄、FC-P、2hC-P呈负相关。结论LADA患者免疫调节性CD4+CD25+T细胞减少,不能有效维持对胰岛自身抗原的耐受;细胞毒性CD3+CD8+T细胞增多从而破坏胰岛β细胞,导致自身免疫性糖尿病的发生和发展。

Isolation and identification of CD4^+CD25^+ regulatory T cells in rat

Objective： To establish a stable and high efficient method for collection of CD4^＋CD25^＋ regulatory T cells from rats in vitro. Methods： CD4^＋CD25^＋ regulatory T cells were isolated from the rat splenic cells through two steps by magic cell sorting （MACS） system. The first step was negative selection of CD4^＋T cells by cocktail antibodies and anti-IgG magic microbeads, and the second step was positive selection of CD25^＋T cells by anti-CD25 PE and anti-PE magic microbeads. The purity and viability of separated cells were measured by flow cytometry （FACS） and Trypan blue staining. The suppressive ability of seperated cells on the proliferation of CD4^＋CD25^- T cells was assessed by cell proliferation assay. Results： The purity of negatively enriched CD4^＋ T cells was 79%-87% （83.6%±2.5% ） , and the purity of positively enriched CD4^＋CD25^＋ T cells was 86%- 93% （ 90.2±1.8% ） with the viability of 92%～95% （92.8% ± 3.4% ）. The enriched cells significantly suppressed the proliferation of CD4^＋CD25^- T cells in mixed lymphocyte culture （P 〈 0.05）. Conclusion： An effective method can be established for enrichment of CD4^＋CD25^＋ regulatory T cells in two steps by MACS, with satisfied cell purity, viability and function.

Immunotherapy of rat glioma without accumulation of CD4^+CD25^+FOXP3^+ regulatory T cells

Immunotherapy may be used for the treatment of glioblastoma multiforme; however, the induced immune response is inadequate when either T cells or dendritic cells are used alone. In this study we established a novel vaccine procedure in rats, using dendritic cells pulsed with C6 tumor cell lysates in combination with adoptive transfer of T lymphocytes from syngenic donors. On day 21 after tumor inoculation, all the rats were sacrificed, the brains were harvested for calculation of glioma volume, cytolytic T lymphocyte responses were measured by cytotoxic assay, and the frequency of regulatory T lymphocytes （CD4＋CD25~FOXP3~） in the peripheral blood was investigated by flow cytometric analysis. The survival rate of rats bearing C6 glioma was observed. Results showed that the co-immunization strategy had significant anti-tumor potential against the pre-established C6 glioma, and induced a strong cytolytic T lymphocyte response in rats. The frequency of peripheral blood CD4＊CD25＊FOXP3＊ regulatory T lymphocytes was significantly decreased following the combination therapy, and the rats survived for a longer period. Experimental findings indicate that the combined immunotherapy of glioma cell lysate-pulsed dendritic cell vaccination following adoptive transfer of T cells can effectively inhibit the growth of gliomas in rats, boost anti-tumor immunity and produce a sustained immune response while avoiding the accumulation of CD4＋CD25＋FOXP3＋ regulatory r lymphocytes.

Effect of CD4^+CD25^+ regulatory T cells in the development of anterior chamber-associated immune deviation

AIM: To investigate whether CD4(+)CD25(+) regulatory T (Treg) cells play a role in the development of anterior chamber-associated immune deviation (ACAID). METHODS: The dynamic changes in the frequency of CD4(+)D25(+) T cells, CD4(+)D25(+) FoxP3(+) T cells and CD4(+)CD25(+) PD-1(+) T cells from spleens of mice with ACAID were analyzed by flow cytometry. Foxp3 mRNA expression in purified CD4(+)CD25(+) T cells was analyzed using real-time PCR. The suppressive effect of purified CD4(+)CD25(+) T cells on the proliferation of CD4(+)CD25(-) T cells was evaluated by [H-3] thymidine incorporation. A blocking experiment was performed to further address the role of CD4(+)CD25(+) T cells in ACAID. The expression of IL-10 in purified CD4(+)CD25(+) T cells was evaluated by ELISA. RESULTS: Increased frequencies of CD4(+)CD25(+) T cells, CD4(+)CD25(+) Foxp3(+) T cells and CD4(+)CD25(+) PD-1(+) T cells were observed in ACAID. The CD4(+)CD25(+) T cells from mice with ACAID showed enhanced suppressive effect on the proliferation of CD4(+)CD25(-) T cells. Treatment of BALB/c mice with anti-CD25 antibody after injection of OVA into the anterior chamber significantly inhibited the induction of ACAID. Furthermore, purified CD4(+)CD25(+) T cells from ACAID mice secreted IL-10. CONCLUSION: Our results demonstrate that Treg cells are induced in the mice undergoing ACAID. These Treg cells may play a role in the development of ACAID.

CD4^+CD25^(high) Regulatory Cells in Peripheral Blood of NSCLC Patients

The proportion and changes of CD4^＋CD25^high regulatory T cells （Trs） in peripheral blood of non-small cell lung cancer （NSCLC） patients were analyzed and their clinical significance explored. The peripheral blood was collected from 61 patients with NSCLC and 15 healthy controls. By using monoclonal antibodies, the blood samples were evaluated with the flow cytometry for lymphocyte subsets （CD3^＋, CD4^＋ and CD8^＋） and CD4^＋CD25^high Tr cells. The results showed that the proportion of CD4^＋CD25^high Tr cells in NSCLC group was significantly higher than in control group [（4.36 ±2.07） % vs （2.04±1.03） %, P〈0.01]. The proportion of CD4^＋CD25^ high Tr cells in late stage was higher than that in early stage [stages Ⅰ ＋Ⅱ （2.264±0.6） %; stage Ⅲ（3.284± 1.38） %; stage IV （6.06 4±4.08） %] （P〈0.05）. Kaplan-Meier survival analysis revealed that the prognosis of the patients who had higher proportion of CD4^＋CD25^high Tr cells in peripheral blood was worse （P=0.0026）. In conclusion, the relative increase in CD4^＋CD25^high Tr cells in peripheral blood may be related to im- munosuppression and tumor progression in patients with NSCLC. This finding suggests that CD4^＋CD25^high Tr cells in peripheral blood of NSCLC may be positive for prognosis analysis. The use of depletion of the CD4^＋CD25^high Tr cell therapy to treat NSCLC patients may be an effective strategy.

The changes and clinical significance of CD4+CD25+ and CD4+CD28-T cells in peripheral blood of patients with stroke

Objective:To study the changes of CD4+CD25+ and CD4+CD28-T cells in peripheral blood of patients with stroke and their correlation with neuronal damage markers, inflammatory cytokines and plaque stability indicators.Methods: The patients who were diagnosed with acute ischemic stroke in our hospital between June 2014 and December 2017 were selected as the stroke group of the research, and healthy volunteers who received physical examination during the same period were selected as the control group. Peripheral blood was collected to determine the contents of CD4+CD25+ and CD4+CD28-T cells, and serum was collected to determine the contents of neuron damage markers, inflammatory cytokines and plaque stability indicators.Results: Peripheral blood CD4+CD25+ cell content as well as serum BDNF, IGF-1, IL-10, TGF-β1, TIMP2 and Vaspin contents of stroke group was lower than those of control group whereas peripheral blood CD4+CD28-T cell content as well as serum NSE, VILIP-1, ET-1, IL-6, CXCL12, VCAM-1, P-selectin, ox-LDL, CatS, ICTP and VEGF contents was higher than those of control group;peripheral blood CD4+CD25+ cell content of stroke group was positively correlated with serum BDNF, IGF-1, IL-10, TGF-β1, TIMP2 and Vaspin contents, and negatively correlated with NSE, VILIP-1, ET-1, IL-6, CXCL12, VCAM-1, P-selectin, ox-LDL, CatS, ICTP and VEGF contents;peripheral blood CD4+CD28-T cell content was negatively correlated with serum BDNF, IGF-1, IL-10, TGF-β1, TIMP2 and Vaspin contents, and positively correlated with NSE, VILIP-1, ET-1, IL-6, CXCL12, VCAM-1, P-selectin, ox-LDL, CatS, ICTP and VEGF contents.Conclusion: The changes of CD4+CD25+ and CD4+CD28-T cells in peripheral blood of patients with stroke can aggravate the neuron damage and promote the inflammatory response activation and plaque stability decline.

Rapamycin increased development of CD4^+ CD25~h ighFoxp3^+ T cells of peripheral blood in liver transplant recipients

Objective To investigate the possible influence of immunosuppressive therapy,including sirolimus ( SRL) and calcineurin inhibitors ( CNI,tacrolimus) ,on level of Treg in liver allo - graft recipients. Methods Forty - seven liver transplant recipients with stable liver function were assessed for at least 2 years,and divided into

乌司他丁对脓毒症患者CD^(4+)CD^(25+)调节性T细胞变化的影响及其与预后的关系

目的探讨乌司他丁对脓毒症患者CD^(4+)CD^(25+)调节性T细胞(Treg)的影响及其与预后的关系。方法脓毒症患者随机分为乌司他丁治疗组和对照组,对照组给予常规的脓毒症治疗,乌司他丁治疗组在对照组的基础上加用乌司他丁治疗。分别于确诊后第1天、第3天、第5天比较两组间CD^(4+)CD^(25+)细胞/CD^(4+)细胞比例、白介素(IL-10)水平以及28 d死亡率。结果乌司他丁治疗组患者的病死率和ICU住院时间均低于对照组,差异均有统计学意义(χ~2=4.21,t=3.12,P均<0.05)。乌司他丁治疗组患者的CD^(4+)CD^(25+)细胞/CD^(4+)细胞比例和血清IL-10值在第1、3、5天组内比较,差异均有统计学意义(Hc分别=114.58、45.93,P均<0.05);乌司他丁治疗组第3天CD^(4+)CD^(25+)细胞/CD^(4+)细胞比例和IL-10值均高于第1天,第5天比例较第3天明显下降,差异均有统计学意义(t分别=10.57、6.43、3.73、5.08,P均<0.05)。在第3天,乌司他丁治疗组CD^(4+)CD^(25+)细胞/CD^(4+)细胞比例低于对照组,在第5天CD^(4+)CD^(25+)细胞/CD^(4+)细胞比例和IL-10值明显低于对照组,差异均有统计学意义(t分别=2.38、7.97、5.79,P均<0.05)。结论乌司他丁能抑制脓毒症患者CD^(4+)CD^(25+)Treg及IL-10的持续上升,避免出现免疫麻痹,降低病死率。

Prognostic value of CD4^+CD25^+ Tregs as a valuable biomarker for patients with sepsis in ICU

BACKGROUND: Sepsis is a common complication ofinfections, burns, traumas, surgeries, poisonings, and post-cardiopulmonary resuscitation. The present study aimed to investigate prognostic value of CD4+CD25+ regulatory T cells(Treg) in peripheral blood of patients with sepsis.METHODS: Periphery blood from 28 patients diagnosed with sepsis was collected on day 1 and 7 after hospitalization in the ICU of Shanghai Changzheng Hospital between December 2013 to April 2014. The blood was used for analyses of Treg ratio using flow cytometry and for analyses of blood routine test, C-reactive protein(CRP), bilirubin, procalcitonin(PCT), and coagulation. APACHE II and sequential organ failure assessment(SOFA) scores were also investigated. The results were compared between two outcome groups of survival or death to evaluate prognostic value for sepsis.RESULTS: The patients had an average age of 60.36±15.03 years, APACHE II score 16.68±7.00, and SOFA score 7.18±3.78. Among the 28 patients, 12 had severe trauma(42.9%), 10 had septic shock(35.7%), and 9(32.2%) died. The median ratio of Tregs was 2.10%(0.80%, 3.10%) in the survival group vs. 1.80%(1.15%, 3.65%) in the death group(Z=–0.148, P=0.883) on day 1; however it was signifi cantly changed to 0.90%(0.30%, 2.80%) vs. 5.70%(2.60%, 8.30%)(Z=–2.905, P=0.004).CONCLUSION: With better prospects for clinical application, dynamic monitoring of Tregs ratio in peripheral blood has potential value in predicting prognosis of sepsis.

儿童过敏性鼻炎特异性免疫治疗过程中外周血CD4^+调节性T细胞的变化及意义

目的探讨儿童过敏性鼻炎(allergic rhinitis,AR)的发病及特异性免疫治疗(specific immunotherapy,SIT)的治疗机制。方法采用流式细胞术检测56例AR患者SIT治疗前、治疗1年后外周血中CD4+CD25+CD127lo/-Treg表达水平:采用ELISA法检测血清中IL-10、TGF-β1,并与30例健康儿童进行对比。结果 56例AR患儿SIT治疗前外周血中CD4+CD25+CD127lo/-Treg占CD4+T细胞的百分比为(5.36±1.31)%,显著低于对照组(10.23±2.26)%,P<0.05,但SIT治疗1年后其数值为(9.37±2.15)%,与对照组无明显差异。AR患儿治疗前血清中IL-10值为(3.68±1.21)pg/ml,显著低于对照组的(12.37±2.18)pg/ml,P<0.05;TGF-β1表达水平与对照组比较差异无统计学意义。SIT治疗1年后血清中IL-10水平亦与对照组差异不明显(P<0.05);而TGF-β1表达水平分别为(20.16±4.45)pg/ml及(9.27±2.38)pg/ml,其差异有统计学意义(P<0.05)。结论儿童AR患者外周血中CD4+Treg表达水平低,且存在功能缺陷,导致体内诱导免疫耐受机能不足,SIT治疗可以明显调节免疫免疫细胞的功能。

Hepatitis C virus core protein triggers expansion and activation of CD4＋CD25＋ regulatory T cells in chronic hepatitis C patients

CD4＋CD25＋FoxP3 ＋ regulatory T ceils （Tregs） are increased in patients with chronic hepatitis C, which may contribute to the sustained suppression of hepatitis C virus （HCV）-specific T-cell responses and viral persistence in HCV-infected individuals. We postulated that HCV core protein （HCVc） directly contributes to the expansion of Tregs in HCV-infected patients, and we provide evidence to support this hypothesis in the report. Peripheral blood mononuclear cells （PBMCs） and sera were collected from 87 treatment-naive chronic HCV-infected patients, CD4＋CD25＋ Tregs were measured by flow cytometry, and HCV RNA and HCVc levels were detected using qPCR and enzyme-linked immunosorbent assay （ELISA）, respectively. CD4＋, CD8＋, CD4＋CD25＋ and CD4＋CD25- T cells were purified from healthy donors and cultured with recombinant HCVc and Toll-like receptor （TLR） ligands. Flow cytometry was used to analyze cell proliferation, and ELISA was performed to measure cytokine production. In the 87 chronic HCV-infected patients, HCVc showed a significant correlation with HCV RNA and CD4＋CD25＋Tregs. Mechanistic studies showed that HCVc, together with anti-CD3 antibody, augmented CD4＋CD25＋ Treg proliferation, but inhibited CD4＋CD25- T-cell proliferation and IFN-γ production, in a dose-dependent and Treg-dependent manner. Moreover, unlike the TLR3 ligand （poly hC） and the TLR4 ligand （lipopolysaccharide, LPS）, the TLR2 ligand （lipoteichoic acid, LTA） and HCVc both inhibited TCR-induced CD4＋ T-cell proliferation and IFN-γ secretion in a Treg-dependent manner. These data indicate that HCVc, like other TLR2 ligands, triggers CD4＋CD25＋ Treg activation and expansion to inhibit host immune responses, which may play a critical role in viral persistence in HCV-infected patients.