期刊文献+
共找到1,568篇文章
< 1 2 79 >
每页显示 20 50 100
Revolutionizing tumor immunotherapy:unleashing the power of progenitor exhausted T cells
1
作者 Zhang Fang Xinyi Ding +3 位作者 Hao Huang Hongwei Jiang Jingting Jiang Xiao Zheng 《Cancer Biology & Medicine》 SCIE CAS CSCD 2024年第6期499-512,共14页
In exploring persistent infections and malignancies, a distinctive subgroup of CD8^(+) T cells, progenitor exhausted CD8^(+) T(Tpex) cells, has been identified. These Tpex cells are notable for their remarkable self-r... In exploring persistent infections and malignancies, a distinctive subgroup of CD8^(+) T cells, progenitor exhausted CD8^(+) T(Tpex) cells, has been identified. These Tpex cells are notable for their remarkable self-renewal and rapid proliferation abilities. Recent strides in immunotherapy have demonstrated that Tpex cells expand and differentiate into responsive exhausted CD8^(+) T cells, thus underscoring their critical role in the immunotherapeutic retort. Clinical examinations have further clarified a robust positive correlation between the proportional abundance of Tpex cells and enhanced clinical prognosis. Tpex cells have found noteworthy applications in the formulation of inventive immunotherapeutic approaches against tumors. This review describes the functions of Tpex cells in the tumor milieu, particularly their potential utility in tumor immunotherapy. Precisely directing Tpex cells may be essential to achieving successful outcomes in immunotherapy against tumors. 展开更多
关键词 Progenitor exhausted CD8^(+)t cells tCF-1 IMMUNOtHERAPY tumor microenvironment cellular crosstalk
下载PDF
金匮肾气丸联用cART对HIV-1感染者的疗效及不良反应分析
2
作者 董雁 刘锦 +5 位作者 闵奇萍 黄金龙 何妙翠 王黎芳 钱峰 刘义安 《中国药理学通报》 CAS CSCD 北大核心 2024年第1期197-198,共2页
获得性免疫缺陷综合征(acquired immunodeficiency syndrome,AIDS)的主要治疗方法为联合抗逆转录病毒治疗(combined antiretroviral therapy,cART),但部分患者由于免疫功能重建不全和不良反应,可能出现药物性肝损伤、消化功能下降、神... 获得性免疫缺陷综合征(acquired immunodeficiency syndrome,AIDS)的主要治疗方法为联合抗逆转录病毒治疗(combined antiretroviral therapy,cART),但部分患者由于免疫功能重建不全和不良反应,可能出现药物性肝损伤、消化功能下降、神经系统毒性和代谢紊乱等,严重影响了抗病毒疗效和患者生存质量,已成为AIDS治疗领域的瓶颈[1]。部分国家资助的中医药防治AIDS科研课题提出正虚(主要为肾虚)是AIDS发生发展的内在病理基础,以肾气与肾阴肾阳的功能下降为主要特征[2-3]。补肾制剂可能是缓解人类免疫缺陷病毒(human immunodeficiency virus,HIV)感染患者病情和不良反应的可靠方式。金匮肾气丸是由地黄、山药、茯苓、牡丹皮、山茱萸、牛膝、泽泻等多味中药制成的综合制剂[4],具有温补肾阳、化气行水的作用。本研究首次采用金匮肾气丸与cART联用治疗HIV-1感染者,比较了金匮肾气丸与cART联用、单用cART对HIV-1感染者抗病毒疗效和不良反应的差异,试图为探索HIV-1感染者治疗的新途径提供参考。 展开更多
关键词 金匮肾气丸 联合抗逆转录病毒治疗 人类免疫缺陷病毒1 获得性免疫缺陷综合征 不良反应 t细胞亚群 HIv感染者医疗结局健康调查量表
下载PDF
Secondary metabolites of mulberry leaves exert anti-lung cancer activity through regulating the PD-L1/PD-1 signaling pathway
3
作者 Guiqin Ye Xin Sun +3 位作者 Jiuzhou Li Yuanyuan Mai Ruilan Gao Jianbin Zhang 《Journal of Pharmaceutical Analysis》 SCIE CAS CSCD 2024年第6期914-925,共12页
Lung cancer ranks the top of malignancies that cause cancer-related deaths worldwide.The leaves of Morus alba L are traditional Chinese medicine widely applied in respiratory diseases.Our previous work has demonstrate... Lung cancer ranks the top of malignancies that cause cancer-related deaths worldwide.The leaves of Morus alba L are traditional Chinese medicine widely applied in respiratory diseases.Our previous work has demonstrated the anti-lung cancer effect of secondary metabolites of mulberry leaf,but their mechanism of action has still not fully elucidated.We synthesized Moracin N(MAN)-Probe conjugated with alkyne to label lung cancer cells and identified protein targets by chemical proteomic analysis.MAN and its probe exerted similar growth-inhibitory effect on human lung cancer cells.Chemical proteomic results showed that MAN targeted the programmed death ligand 1(PD-L1)checkpoint pathway and T cell receptor(TCR)signaling pathway,indicating its immune-regulatory function.Cell-free surface plasmon resonance(SPR)results showed the direct interaction of MAN with PD-L1 protein.Molecular docking analysis demonstrated that MAN bound to E158 residue of PD-L1 protein.MAN downregulated the expression levels of PD-L1 in a time-and dose-dependent manner and disrupted the PD-L1/programmed death 1(PD-1)binding,including other secondary metabolites of mulberry leaves Guangsangon E(GSE)and Chalcomoracin(CMR).Human peripheral blood mononuclear cells(PBMCs)co-cultured with MAN-treated A549 cells,resulting in the increase of CD8^(+)GZMB^(+)T cells and the decrease of CD8^(+)PD-1^(+)T cells.It suggested that MAN exerts anti-cancer effect through blocking the PD-L1/PD-1 signaling.In vivo,MAN combined with anti-PD-1 antibody significantly inhibited lung cancer development and metastasis,indicating their synergistic effect.Taken together,secondary metabolites of mulberry leaves target the PD-L1/PD-1 signaling,enhance T cell-mediated immunity and inhibit the tumorigenesis of lung cancer.Their modulatory effect on tumor microenvironment makes them able to enhance the therapeutic efficacy of immune checkpoint inhibitors in lung cancer. 展开更多
关键词 Moracin N Click chemistry PD-L1 t cell Lung cancer
下载PDF
Predicting the Prognosis and Immunotherapeutic Response of Triple-Negative Breast Cancer by Constructing a Prognostic Model Based on CD8+T Cell-Related Immune Genes
4
作者 Nani Li Xiaoting Qiu +3 位作者 Jingsong Xue Limu Yi Mulan Chen Zhijian Huang 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2024年第6期581-593,共13页
Objective Triple-negative breast cancer(TNBC)poses a significant challenge for treatment efficacy.CD8+T cells,which are pivotal immune cells,can be effectively analyzed for differential gene expression across diverse ... Objective Triple-negative breast cancer(TNBC)poses a significant challenge for treatment efficacy.CD8+T cells,which are pivotal immune cells,can be effectively analyzed for differential gene expression across diverse cell populations owing to rapid advancements in sequencing technology.By leveraging these genes,our objective was to develop a prognostic model that accurately predicts the prognosis of patients with TNBC and their responsiveness to immunotherapy.Methods Sample information and clinical data of TNBC were sourced from The Cancer Genome Atlas and METABRIC databases.In the initial stage,we identified 67 differentially expressed genes associated with immune response in CD8+T cells.Subsequently,we narrowed our focus to three key genes,namely CXCL13,GBP2,and GZMB,which were used to construct a prognostic model.The accuracy of the model was assessed using the validation set data and receiver operating characteristic(ROC)curves.Furthermore,we employed various methods,including Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway,immune infiltration,and correlation analyses with CD274(PD-L1)to explore the model's predictive efficacy in immunotherapeutic responses.Additionally,we investigated the potential underlying biological pathways that contribute to divergent treatment responses.Results We successfully developed a model capable of predicting the prognosis of patients with TNBC.The areas under the curve(AUC)values for the 1-,3-,and 5-year survival predictions were 0.618,0.652,and 0.826,respectively.Employing this risk model,we stratified the samples into high-and low-risk groups.Through KEGG enrichment analysis,we observed that the high-risk group predominantly exhibited enrichment in metabolism-related pathways such as drug and chlorophyll metabolism,whereas the low-risk group demonstrated significant enrichment in cytokine pathways.Furthermore,immune landscape analysis revealed noteworthy variations between(PD-L1)expression and risk scores,indicating that our model effectively predicted the response of patients to immune-based treatments.Conclusion Our study demonstrates the potential of CXCL13,GBP2,and GZMB as prognostic indicators of clinical outcomes and immunotherapy responses in patients with TNBC.These findings provide valuable insights and novel avenues for developing immunotherapeutic approaches targeting TNBC. 展开更多
关键词 Breast Cancer IMMUNOtHERAPY PROGNOSIS CD8+t cells PD-L1
下载PDF
外周血CD4^(+)PD-1^(+)Tcells及CD4^(+)T淋巴细胞ATP含量与复发性卵巢癌疗效的相关性分析
5
作者 李慧芬 《实用妇科内分泌电子杂志》 2023年第27期24-26,共3页
目的 探讨外周血CD4^(+)程序性细胞死亡受体-1(PD-1)^(+)T cells及CD4^(+)T淋巴细胞三磷酸腺苷(ATP)含量与复发性卵巢癌疗效的相关性。方法 选取30例复发性卵巢癌患者为复发组,30例未复发卵巢癌患者为非复发组;另选取30名同期体检健康... 目的 探讨外周血CD4^(+)程序性细胞死亡受体-1(PD-1)^(+)T cells及CD4^(+)T淋巴细胞三磷酸腺苷(ATP)含量与复发性卵巢癌疗效的相关性。方法 选取30例复发性卵巢癌患者为复发组,30例未复发卵巢癌患者为非复发组;另选取30名同期体检健康者作为对照组。评估外周血CD4^(+)PD-1^(+)T cells及CD4^(+)T淋巴细胞ATP含量与复发性卵巢癌疗效的相关性。结果 复发组和非复发组的CD4^(+)PD-1^(+)T cells较对照组明显升高(P<0.05)。复发组和非复发组的CD4^(+)T淋巴细胞ATP含量较对照组明显降低(P<0.05)。复发组治疗后CD4^(+)PD-1^(+)Tcells显著低于治疗前(P<0.05),治疗后CD4^(+)T淋巴细胞ATP含量显著高于治疗前(P<0.05)。CD4^(+)PD-1^(+)T cells与复发性卵巢癌疗效成负相关(r=-0.393,P=0.039),CD4^(+)T淋巴细胞ATP含量与复发性卵巢癌疗效成正相关(r=0.449,P=0.031)。结论 复发性卵巢癌患者外周血CD4^(+)PD-1^(+)T cells及CD4^(+)T淋巴细胞ATP含量与疗效密切相关。 展开更多
关键词 复发性卵巢癌 CD4^(+)PD-1^(+)t cells CD4^(+)t淋巴细胞AtP含量
下载PDF
The anti-neoplastic effects of metformin modulate the acquired phenotype of fbroblast cells in the breast cancer-normal fbroblast co-culture system
6
作者 SAMANEH MOSTAFAVI ZUHAIR MOHAMMAD HASSAN 《Oncology Research》 SCIE 2024年第3期477-487,共11页
Intracellular communications between breast cancer and fibroblast cells were reported to be involved in cancer proliferation,growth,and therapy resitance.The hallmarks of cancer fibroblast interactions,consisting of c... Intracellular communications between breast cancer and fibroblast cells were reported to be involved in cancer proliferation,growth,and therapy resitance.The hallmarks of cancer fibroblast interactions,consisting of caveolin 1(Cav1)and mono-carboxylate ransporter 4(MCT4)(metabolic coupling markers),along with IL-6,TGFB,and lactate secretion,are considered robust biomarkers predicting recurrence and metastasis.In order to promote a novel phenotype in normal fibroblasts,we predicted that breast cancer cells could be able to cause loss of Cavl and increase of MCT4,as well as elevate IL 6 and TGF in nearby nomal fibroblasts.We created a co culture model using breast cancer(4T1)and normal fibroblast(NIH3T3)cell lines cultured under specific experimental conditions in order to directly test our theory.Moreover,we show that long-term co-culture of breast cancer cells and normal fibroblasts promotes loss of Cavl and gain of MCT4 in adjacent fibroblasts and increase lactate secretion.These results were validated using the monoculture of each group separately as a control.In this system,we show that me tformin inhibits IL-6 and TGFB secretion and re expresses Cavl in both cells.However,MCT4 and lactate stayed high after treatment with metformin.In conclusion,our work shows that co-culture with breast cancer cells may cause signifcant alterations in the phenotype and secretion of normal fibroblasts.Metformin,however,may change this state and affect fibroblasts'acquired phenotypes.Moreover,mitochondrial inhibition by metformin after 8 days of treatment,signi ficantly hinders tumor growth in mouse model of breast cancer. 展开更多
关键词 Caveolin 1 Lactic acid MEtFORMIN NIH 3t3 cells Neoplasms
下载PDF
Combined TIM-3 and PD-1 blockade restrains hepatocellular carcinoma development by facilitating CD4+ and CD8+T cellmediated antitumor immune responses
7
作者 Xu-Sheng Zhang Hong-Cai Zhou +5 位作者 Peng Wei Long Chen Wei-Hu Ma Lin Ding Shi-Cai Liang Ben-Dong Chen 《World Journal of Gastrointestinal Oncology》 SCIE 2023年第12期2138-2149,共12页
BACKGROUND Immune checkpoint inhibitors(ICIs)targeting programmed cell death protein 1(PD-1)and T cell immunoglobulin and mucin domain-containing protein 3(TIM-3)are beneficial to the resumption of anti-tumor immunity... BACKGROUND Immune checkpoint inhibitors(ICIs)targeting programmed cell death protein 1(PD-1)and T cell immunoglobulin and mucin domain-containing protein 3(TIM-3)are beneficial to the resumption of anti-tumor immunity response and hold extreme potential as efficient therapies for certain malignancies.However,ICIs with a single target exhibit poor overall response rate in hepatocellular carcinoma(HCC)patients due to the complex pathological mechanisms of HCC.AIM To investigate the effects of combined TIM-3 and PD-1 blockade on tumor development in an HCC mouse model,aiming to identify more effective immunotherapies and provide more treatment options for HCC patients.METHODS The levels of PD-1 and TIM-3 on CD4+and CD8+T cells from tumor tissues,ascites,and matched adjacent tissues from HCC patients were determined with flow cytometry.An HCC xenograft mouse model was established and treated with anti-TIM-3 monoclonal antibody(mAb)and/or anti-PD-1 mAb.Tumor growth in each group was measured.Hematoxylin and eosin staining and immunohistochemical staining were used to evaluate T cell infiltration in tumors.The percentage of CD4+and CD8+T cells in tissue samples from mice was tested with flow cytometry.The percentages of PD-1+CD8+,TIM-3+CD8+,and PD-1+TIM-3+CD8+T cells was accessed by flow cytometry.The levels of the cytokines including tumor necrosis factor alpha(TNF-α),interferon-γ(IFN-γ),interleukin(IL)-6,and IL-10 in tumor tissues were gauged with enzyme-linked immunosorbent assay kits.RESULTS We confirmed that PD-1 and TIM-3 expression was substantially upregulated in CD4+and CD8+T cells isolated from tumor tissues and ascites of HCC patients.TIM-3 mAb and PD-1 mAb treatment both reduced tumor volume and weight,while combined blockade had more substantial anti-tumor effects than individual treatment.Then we showed that combined therapy increased T cell infiltration into tumor tissues,and downregulated PD-1 and TIM-3 expression on CD8+T cells in tumor tissues.Moreover,combined treatment facilitated the production of T cell effector cytokines TNF-α and IFN-γ,and reduced the production of immunosuppressive cytokines IL-10 and IL-6 in tumor tissues.Thus,we implicated that combined blockade could ameliorate T cell exhaustion in HCC mouse model.CONCLUSION Combined TIM-3 and PD-1 blockade restrains HCC development by facilitating CD4+ and CD8+T cell-mediated antitumor immune responses. 展开更多
关键词 Hepatocellular carcinoma t cell immunoglobulin and mucin domain-containing protein 3 Programmed cell death protein 1 CD4+t cells CD8+t cells
下载PDF
Intracellular accumulation of tau inhibits autophagosome formation by activating TIA1-amino acid-mTORC1 signaling
8
作者 Meng-Zhu Li En-Jie Liu +11 位作者 Qiu-Zhi Zhou Shi-Hong Li Shi-Jie Liu Hai-Tao Yu Qi-Hang Pan Fei Sun Ting He Wei-Jin Wang Dan Ke Yu-Qi Feng Jun Li Jian-Zhi Wang 《Military Medical Research》 SCIE CAS CSCD 2023年第2期175-190,共16页
Background:Autophagy dysfunction plays a crucial role in tau accumulation and neurodegeneration in Alzheimer’s disease(AD).This study aimed to investigate whether and how the accumulating tau may in turn affect autop... Background:Autophagy dysfunction plays a crucial role in tau accumulation and neurodegeneration in Alzheimer’s disease(AD).This study aimed to investigate whether and how the accumulating tau may in turn affect autophagy.Methods:The primary hippocampal neurons,N2a and HEK293T cells with tau overexpression were respectively starved and treated with vinblastine to study the effects of tau on the initiating steps of autophagy,which was analysed by Student’s two-tailed t-test.The rapamycin and concanamycin A were employed to inhibit the mammalian target of rapamycin kinase complex 1(mTORC1)activity and the vacuolar H+-ATPase(v-ATPase)activity,respectively,which were analysed by One-way ANOVA with post hoc tests.The Western blotting,co-immunoprecipitation and immunofuorescence staining were conducted to gain insight into the mechanisms underlying the tau effects of mTORC1 signaling alterations,as analysed by Student’s two-tailed t-test or One-way ANOVA with post hoc tests.The autophagosome formation was detected by immunofuorescence staining and transmission electron microscopy.The amino acids(AA)levels were detected by high performance liquid chromatography(HPLC).Results:We observed that overexpressing human full-length wild-type tau to mimic AD-like tau accumulation induced autophagy deficits.Further studies revealed that the increased tau could bind to the prion-related domain of T cell intracellular antigen 1(PRD-TIA1)and this association significantly increased the intercellular level of amino acids(Leucine,P=0.0038;Glutamic acid,P=0.0348;Alanine,P=0.0037;Glycine,P=0.0104),with concordant upregulation of mTORC1 activity[phosphorylated eukaryotic translation initiation factor 4E-binding protein 1(p-4EBP1),P<0.0001;phosphorylated 70 kD ribosomal protein S6 kinase 1(p-p70S6K1),P=0.0001,phosphorylated unc-51-like autophagyactivating kinase 1(p-ULK1),P=0.0015]and inhibition of autophagosome formation[microtubuleassociated protein light chain 3 II(LC3 II),P=0.0073;LC3 puncta,P<0.0001].As expected,this tau-induced deficit of autophagosome formation in turn aggravated tau accumulation.Importantly,we also found that blocking TIA1 and tau interaction by overexpressing PRD-TIA1,downregulating the endogenous TIA1 expression by shRNA,or downregulating tau protein level by a small proteolysis targeting chimera(PROTAC)could remarkably attenuate tau-induced autophagy impairment.Conclusions:Our findings reveal that AD-like tau accumulation inhibits autophagosome formation and induces autophagy deficits by activating the TIA1/amino acid/mTORC1 pathway,and thus this work reveals new insight into tau-associated neurodegeneration and provides evidence supporting the use of new therapeutic targets for AD treat-ment and that of related tauopathies. 展开更多
关键词 tAU Autophagy Amino acid pathway Mammalian target of rapamycin kinase complex 1(mtORC1) t cell intracellular antigen 1(tIA1)
下载PDF
结直肠癌组织高表达IL-35对Th1和Th17可塑性的作用
9
作者 许耘川 皇甫昱婵 马妍慧 《检验医学》 CAS 2024年第4期343-350,共8页
目的 探讨结直肠癌组织中高表达的抑制性细胞因子白细胞介素(IL)-35对辅助性T细胞1(Th1)和辅助性T细胞17(Th17)可塑性的作用。方法 选取2019年3月—2020年2月上海交通大学医学院附属新华医院结直肠癌患者90例(结直肠癌组)和健康体检者28... 目的 探讨结直肠癌组织中高表达的抑制性细胞因子白细胞介素(IL)-35对辅助性T细胞1(Th1)和辅助性T细胞17(Th17)可塑性的作用。方法 选取2019年3月—2020年2月上海交通大学医学院附属新华医院结直肠癌患者90例(结直肠癌组)和健康体检者28名(正常对照组)。采用流式细胞术检测结直肠癌组和正常对照组外周血Th1百分比(Th1%)和Th17百分比(Th17%)。基于Kaplan-Meier Plotter数据库分析γ-干扰素(IFN-γ)和IL-17A高表达对结直肠癌患者总生存期和预后不良的影响。采用免疫组化法检测结直肠癌患者癌组织和癌旁组织(距肿瘤边缘≥2 cm)中IL-35的表达。采用酶联免疫吸附试验检测结直肠癌患者和正常对照者血清IL-35水平。采用体外诱导Th1分化实验观察IL-35对Th1分泌IL-17A和IFN-γ的影响。结果与正常对照组比较,结直肠癌组Th1%显著降低(P=0.019),Th17%显著升高(P<0.001)。结直肠癌组Th1%与Th17%的r2值(0.393 4)与正常对照组(0.041 0)比较差异有统计学意义(P=0.007)。基于KaplanMeierPlotter数据库的分析结果显示,IFN-γmRNA低表达是结直肠癌患者总生存期缩短的危险因素[风险比(HR)=0.74,95%可信区间(CI)为0.58~0.94,P=0.013],IL-17A mRNA高表达是结直肠癌患者总生存期缩短的危险因素(HR=1.26,95%CI为1.02~1.59,P=0.020)。结直肠癌患者癌组织IL-35表达显著高于癌旁组织(P<0.001)。Ⅰ~Ⅱ期(早期)和Ⅲ~Ⅳ期(晚期)结直肠癌患者血清IL-35水平均显著高于正常对照者(P<0.05)。体外诱导Th1分化实验结果显示,IL-35可降低Th1中IFN-γ表达,提高IL-17A表达。结论 结直肠癌患者外周血Th1和Th17呈异常变化,且IL-35表达增加。高表达的IL-35可降低Th1中IFN-γ表达,提高IL-17A表达。 展开更多
关键词 白细胞介素-35 结直肠癌 辅助性t细胞1 辅助性t细胞17 肿瘤免疫
下载PDF
ITP患者PD-1/PD-L1表达特点及其在Treg与Breg细胞之间的相互作用机制分析
10
作者 许腾 崔彦杰 +2 位作者 李智伟 刘红春 郝立君 《西部医学》 2024年第4期608-613,共6页
目的探讨原发免疫性血小板减少症(ITP)患者细胞程序性死亡受体-1(PD-1)/细胞程序性死亡配体1(PD-L1)表达特点及其在调节性T细胞(Treg)、调节性B细胞(Breg)间的相互作用。方法选取2018年12月—2022年1月在我院治疗的ITP患者106例作为观察... 目的探讨原发免疫性血小板减少症(ITP)患者细胞程序性死亡受体-1(PD-1)/细胞程序性死亡配体1(PD-L1)表达特点及其在调节性T细胞(Treg)、调节性B细胞(Breg)间的相互作用。方法选取2018年12月—2022年1月在我院治疗的ITP患者106例作为观察组,其中轻度患者32例,中度患者44例,重度患者30例。同时选取同期健康志愿者100例作为对照组。检测两组Treg细胞百分比、Breg细胞百分比、Treg细胞表面PD-1阳性率、Breg细胞表面PD-L1阳性率等,同时分析观察组不同病情程度患者各指标差异。结果观察组Breg细胞百分比、Treg细胞百分比、TGF-β、IL-10和IL-4水平均明显低于对照组(P<0.05);观察组Treg细胞表面PD-1阳性率、Breg细胞表面PD-L1阳性率、可溶性程序性细胞死亡蛋白-1(sPD-1)和IL-17水平均明显高于对照组(均P<0.05);两组可溶性程序性细胞死亡蛋白配体-1(sPD-L1)水平比较差异无统计学意义(P>0.05)。观察组重度患者Breg细胞百分比、Treg细胞百分比均明显低于轻度和中度患者(均P<0.05),而Treg细胞表面PD-1阳性率、Breg细胞表面PD-L1阳性率均明显高于轻度和中度患者(均P<0.05)。Treg细胞表面PD-1阳性率与Breg细胞表面PD-L1阳性率呈正相关(r=0.446,P<0.05)。观察组治疗后Breg细胞百分比、Treg细胞百分比、TGF-β、IL-10和IL-4水平有所升高(P<0.05),而Treg细胞表面PD-1阳性率、Breg细胞表面PD-L1阳性率、sPD-1和IL-17水平有所降低(P<0.05),治疗前后sPD-L1水平比较差异无统计学意义(P>0.05)。结论ITP患者Treg细胞表面PD-1和Breg细胞表面PD-L1阳性率明显升高,与患者病情严重程度呈正相关,同时Treg细胞表面PD-1和Breg细胞表面PD-L1表达之间存在相关性。 展开更多
关键词 原发免疫性血小板减少症 细胞程序性死亡受体-1 细胞程序性死亡配体1 调节性t细胞 调节性B细胞
下载PDF
Periostin、Notch1、维生素D与自身免疫性甲状腺炎淋巴细胞浸润程度、Treg/Th17的相关性研究
11
作者 冯明 冯涛 李天艺 《海南医学》 CAS 2024年第15期2135-2140,共6页
目的探讨骨外膜素(Periostin)、Notch跨膜受体-1(Notch1)m RNA、维生素D(VitD)与自身免疫性甲状腺炎(AIT)淋巴细胞浸润程度、调节性T细胞/辅助性T细胞17(Treg/Th17)的相关性。方法选取2021年7月至2023年12月郑州大学第一附属医院收治的9... 目的探讨骨外膜素(Periostin)、Notch跨膜受体-1(Notch1)m RNA、维生素D(VitD)与自身免疫性甲状腺炎(AIT)淋巴细胞浸润程度、调节性T细胞/辅助性T细胞17(Treg/Th17)的相关性。方法选取2021年7月至2023年12月郑州大学第一附属医院收治的92例AIT患者纳入AIT组,另选取同期50例无甲状腺疾病的健康人群纳入对照组。比较两组受检者的淋巴细胞浸润程度及抗体水平,采用Spearman、Pearson相关系数分析淋巴细胞浸润程度、Treg/Th17与甲状腺功能、抗体水平的相关性,比较两组受检者的Periostin、Notch1 m RNA、VitD及Treg/Th17,采用Pearson相关系数分析Periostin、Notch1 mRNA、VitD与淋巴细胞浸润程度及Treg/Th17的相关性。结果AIT组患者的CD3^(+)、CD3^(+)CD4^(+)、CD4^(+)CD25^(+)CD127^(-)、TgAb、TPOAb、TRAb水平及甲亢/亚临床甲亢、甲减/亚临床甲减患者占比明显高于对照组,差异均有统计学意义(P<0.05);Pearson相关系数分析结果显示,CD3^(+)(r=0.579、0.602、0.563)、CD3^(+)CD4^(+)(r=0.612、0.637、0.606)、CD~4+CD25^(+)CD127^(-)(r=0.655、0.643、0.687)与TgAb、TPOAb、TRAb呈正相关(P<0.05);AIT组患者的Periostin、Notch1 m RNA分别为(4.27±1.40)μg/L、1.73±0.56,明显高于对照组的(2.86±0.49)μg/L、1.02±0.14,VitD、Treg/Th17分别为(17.82±5.09)ng/mL、2.82±0.97,明显低于对照组的(22.30±3.76)ng/mL、12.36±2.03,差异均有统计学意义(P<0.05);Pearson相关系数分析结果显示,Periostin(r=0.792、0.811、0.737)、Notch1 mRNA(r=0.812、0.775、0.792)与CD3^(+)、CD3^(+)CD4^(+)、CD4^(+)CD25+CD127-呈正相关(P<0.05),VitD(r=-0.687、-0.753、-0.799)与之呈负相关(P<0.05),且Periostin(r=-0.823)、Notch1 m RNA(r=-0.772)与Treg/Th17呈负相关(P<0.05),VitD(r=0.745)与之呈正相关(P<0.05)。结论Periostin、Notch1 mRNA在AIT患者血清中表达上调,VitD表达下调,各指标与AIT淋巴细胞浸润程度及Treg/Th17均具有一定相关性,可为临床判断病情提供参考,并对后续临床治疗具有一定指导价值。 展开更多
关键词 自身免疫性甲状腺炎 骨外膜素 Notch跨膜受体-1 维生素D 淋巴细胞 调节性t细胞/辅助性t细胞 相关性
下载PDF
炎调方通过PD-1/PD-L1通路抑制脓毒症大鼠T淋巴细胞衰竭的实验研究
12
作者 王文清 王庆 +1 位作者 熊旭东 方荣 《河北医药》 CAS 2024年第10期1463-1467,共5页
目的研究炎调方对脓毒症大鼠T淋巴细胞及T淋巴细胞表面表面程序性死亡蛋白(PD-1)、程序性死亡蛋白配体(PD-L1)表达的影响。方法SD大鼠(雄性)分为正常组、假手术组、模型组和炎调方组。盲肠结扎穿孔(CLP)制备脓毒症大鼠模型,于造模后12... 目的研究炎调方对脓毒症大鼠T淋巴细胞及T淋巴细胞表面表面程序性死亡蛋白(PD-1)、程序性死亡蛋白配体(PD-L1)表达的影响。方法SD大鼠(雄性)分为正常组、假手术组、模型组和炎调方组。盲肠结扎穿孔(CLP)制备脓毒症大鼠模型,于造模后12、24、48、72 h采集外周血处死大鼠(每个时间点各5只大鼠),采用流式细胞分析法测定CD3^(+)、CD4^(+)、CD8^(+)比例;双抗体夹心酶联免疫吸附法(ELISA)测定CD4^(+)及CD8^(+)表面PD-1、PD-L1表达水平。结果白介素-6(IL-6)在脓毒症模型组12 h分泌达到高峰后逐渐下降,降钙素原(PCT)在模型组24 h达到高峰后逐渐下降;炎调方组在12 h降低IL-6的水平(P<0.05),24 h时明显降低IL-6、PCT的水平(P<0.01)。模型组CD3^(+)、CD4^(+)、CD8^(+)比例早期分泌开始减少,48 h分泌达最低点(P<0.01);炎调方组在48 h时可升高CD3^(+)、CD4^(+)、CD8^(+)比例,提高CD4^(+)/CD8^(+)的比值而具体调节T细胞活化和增殖的功能。模型组CD4^(+)、CD8^(+)表面PD-1、PD-L1表达水平早期24 h即表达增多(P<0.01),72 h表达最多;炎调方组24 h时即可抑制PD-1、PD-L1的表达水平而具体改善T细胞衰竭的作用。CD4^(+)的比例与CD4^(+)表面PD-1、PD-L1的表达呈负相关(P<0.01);CD8^(+)比例与CD8^(+)表面PD-1、PD-L1的表达呈负相关(P<0.01)。结论脓毒症早期48 h内即出现了T细胞活化和增殖的功能衰竭引起的T细胞免疫抑制。炎调方能在脓毒症早期改善T细胞活化和增殖的功能,其机制可能与抑制PD-1/P-L1通路有关。 展开更多
关键词 炎调方 脓毒症t淋巴细胞衰竭 PD-1/PD-L1通路
下载PDF
帕金森病患者免疫球蛋白、Th9亚群水平变化及其与IGF-1、S-100B蛋白的相关性
13
作者 曹利红 张哲 傅天 《中国免疫学杂志》 CAS CSCD 北大核心 2024年第6期1248-1252,共5页
目的:研究帕金森病(PD)患者免疫球蛋白(IgG、IgA和IgM)、辅助性T细胞亚群Th9水平变化及其与胰岛素生长因子-1(IGF-1)、S-100B蛋白的相关性。方法:选取2020年12月至2022年12月期间在河北省中医院确诊的108例PD患者,将其作为研究组,并根... 目的:研究帕金森病(PD)患者免疫球蛋白(IgG、IgA和IgM)、辅助性T细胞亚群Th9水平变化及其与胰岛素生长因子-1(IGF-1)、S-100B蛋白的相关性。方法:选取2020年12月至2022年12月期间在河北省中医院确诊的108例PD患者,将其作为研究组,并根据患者病变程度分为轻度组(35例)、中度组(44例)和重度组(29例);另选108例健康成人作为对照组。对比研究组和对照组免疫球蛋白和Th9亚群水平,以及轻度组、中度组及重度组免疫球蛋白、Th9亚群、IGF-1和S-100B蛋白水平,采用Pearson相关性分析免疫球蛋白、Th9亚群和IGF-1、S-100B蛋白的相关性。采用Spearman相关性分析PD患者疾病程度和所有差异指标间的相关性。结果:研究组IgM水平较对照组低,且重度组低于中度组,中度组低于轻度组(P<0.05);研究组IgG、IgA、IL-9和Th9亚群水平较对照组高,且重度组高于中度组,中度组高于轻度组(P<0.05)。重度组IGF-1水平低于中度组,中度组低于轻度组;重度组S-100B蛋白水平高于中度组,中度组高于轻度组(P<0.05)。Pearson相关性分析结果显示,PD患者IgM水平与IGF-1水平呈正相关,与S-100B蛋白水平呈负相关;IgG、IgA、IL-9和Th9亚群水平均与IGF-1水平呈负相关,与S-100B蛋白水平呈正相关(P<0.05)。Spearman相关性分析结果显示,PD患者疾病程度与IgM、IGF-1水平呈负相关,与S-100B蛋白、IgG、IgA、IL-9和Th9亚群水平呈正相关(P<0.05)。结论:PD患者IgM水平降低,IgG、IgA、Th9亚群水平升高,且其水平变化与IGF-1、S-100B明显相关,可以用于评估病情的严重程度。 展开更多
关键词 帕金森病 免疫球蛋白 辅助性t细胞亚群 胰岛素生长因子-1 S-100B蛋白
下载PDF
Natural course of chronic hepatitis B is characterized by changing patterns of programmed death type-1 of CD8-positive T cells 被引量:16
14
作者 Liang, Xue-Song Zhou, Ying +1 位作者 Li, Chen-Zhong Wan, Mo-Bin 《World Journal of Gastroenterology》 SCIE CAS CSCD 2010年第5期618-624,共7页
AIM:To investigate if and how programmed death type-1(PD-1)expression affects the natural course of hepatitis B virus(HBV)infection. METHODS:Sixty-four patients in different natural stages of chronic HBV infection wer... AIM:To investigate if and how programmed death type-1(PD-1)expression affects the natural course of hepatitis B virus(HBV)infection. METHODS:Sixty-four patients in different natural stages of chronic HBV infection were enrolled in this study.PD-1 expression in total T cells was detected by flow cytometry.Levels of total CD8+T cell responses and proliferation in relation to PD-1 expression levels were analyzed with intracellular staining and PD-1/ PD-L1 blockage. RESULTS:The PD-1 expression in T cells was dynamically changed during the natural course of chronic HBV infection,did not significantly increase in the immune tolerance phase,and returned to normal in the inactive virus carrier stage.Blockage of the PD-1/PD-L1 pathway could not affect the T-cell response in the immune tolerance and inactive virus carrier stages of chronic HBV infection.However,it could significantly restore the T-cell response in the immune clearance stage of chronic HBV infection.Furthermore,the PD-1 expression level in T cells was associated with the alanine aminotransferase level during the immune clearance stage of chronic HBV infection. CONCLUSION:The PD-l/PD-L1 pathway plays a different role in T-cell response during the natural course of chronic HBV infection. 展开更多
关键词 Programmed death type-1 Hepatitis B virus Chronic hepatitis B Natural stage CD8+t cell Serum viral load Programmed death ligand t cell response
下载PDF
梅毒血清固定患者中NOD样受体蛋白3和Toll样受体4表达与Th1/Th2相关细胞因子的相关性研究
15
作者 张燕 刘健 +1 位作者 黄富琴 王烜 《中国性科学》 2024年第8期136-140,共5页
目的探究梅毒血清固定患者中NOD样受体蛋白3(NLRP3)、Toll样受体4(TLR4)表达与辅助性T细胞1/辅助性T细胞2(Th1/Th2)相关细胞因子的相关性。方法选取2021年2月至2022年4月川北医学院附属三台医院收治的197例梅毒患者作为研究对象。将进... 目的探究梅毒血清固定患者中NOD样受体蛋白3(NLRP3)、Toll样受体4(TLR4)表达与辅助性T细胞1/辅助性T细胞2(Th1/Th2)相关细胞因子的相关性。方法选取2021年2月至2022年4月川北医学院附属三台医院收治的197例梅毒患者作为研究对象。将进行驱梅治疗后血清转阴者纳入转阴组(n=88),未进行驱梅治疗者纳入梅毒组(n=45),接受驱梅治疗后血清固定者纳入固定组(n=64)。另选取同期进行体检的健康人作为对照组(n=53)。采用实时荧光定量聚合酶链反应检测外周血单个核细胞(PBMCs)中NLRP3、TLR4 mRNA相对表达水平;采用酶联免疫吸附试验法检测Th1/Th2相关细胞因子的表达水平;采用Pearson法分析TLR4、NLRP3 mRNA与Th1/Th2相关细胞因子的相关性。结果各组PBMCs中TLR4、NLRP3 mRNA表达水平比较,梅毒组>转阴组>对照组>固定组,差异具有统计学意义(P<0.05);各组白介素(IL)-2、γ干扰素(IFN-γ)水平比较,对照组>转阴组>梅毒组>固定组,差异具有统计学意义(P<0.05);各组IL-1β、IL-4、IL-10及IL-18水平比较,对照组<转阴组<梅毒组<固定组,差异具有统计学意义(P<0.05);梅毒血清固定患者TLR4、NLRP3 mRNA表达与IFN-γ、IL-2呈正相关,与IL-1β、IL-4、IL-10、IL-18呈负相关(P<0.05)。结论梅毒血清固定患者NLRP3、TLR4 mRNA表达水平显著降低,且与Th1/Th2相关细胞因子密切相关。 展开更多
关键词 NOD样受体蛋白3 tOLL样受体4 梅毒血清固定 相关性 辅助性t细胞1/辅助性t细胞2相关细胞因子
下载PDF
T cells expressing a LMP1-specific chimeric antigen receptor mediate antitumor effects against LMP1-positive nasopharyngeal carcinoma cells in vitro and in vivo 被引量:16
16
作者 Xiaojun Tang Yan Zhou +4 位作者 Wenjie Li Qi Tang Renjie Chen Jin Zhu Zhenqing Feng 《The Journal of Biomedical Research》 CAS 2014年第6期468-475,共8页
T cells modified with chimeric antigen receptor are an attractive strategy to treat Epstein-Barr virus(EBV) associated malignancies.The EBV latent membrane protein 1(LMP1) is a 66-KD integral membrane protein enco... T cells modified with chimeric antigen receptor are an attractive strategy to treat Epstein-Barr virus(EBV) associated malignancies.The EBV latent membrane protein 1(LMP1) is a 66-KD integral membrane protein encoded by EBV that consists of transmembrane-spanning loops.Previously,we have identified a functional signal chain variable fragment(scFv) that specifically recognizes LMP1 through phage library screening.Here,we constructed a LMP1 specific chimeric antigen receptor containing anti-LMP1 scFv,the CD28 signalling domain,and the CD3ζchain(HELA/CAR).We tested its functional ability to target LMP1 positive nasopharyngeal carcinoma cells.HELA/CAR cells were efficiently generated using lentivirus vector encoding the LMP1-specific chimeric antigen receptor to infect activated human CD3+ T cells.The HELA/CAR T cells displayed LMP1 specific cytolytic action and produced IFN-γ and IL-2 in response to nasopharyngeal carcinoma cells overexpressing LMP1.To demonstrate in vivo anti-tumor activity,we tested the HELA/CAR T cells in a xenograft model using an LMP1 overexpressing tumor.Intratumoral injection of anti-LMP1 HELA/CAR-T cells significantly reduced tumor growth in vivo.These results show that targeting LMP1 using HELA/CAR cells could represent an alternative therapeutic approach for patients with EBV-positive cancers. 展开更多
关键词 chimeric antigen receptor LMP1 nasopharyngeal carcinoma EBv adoptive t cell therapy
下载PDF
Rapamycin ameliorates experimental autoimmune uveoretinitis by inhibiting Th1/Th2/Th17 cells and upregulating CD4+CD25+ Foxp3 regulatory T cells 被引量:7
17
作者 Li-Fei Yuan Guang-Da Li +3 位作者 Xin-Jun Ren Hong Nian Xiao-Rong Li Xiao-Min Zhang 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2015年第4期659-664,共6页
· AIM: To determine the effects of rapamycin on experimental autoimmune uveoretinitis(EAU) and investigate of role of rapamycin on T cell subsets in the disease.·METHODS: EAU was induced in rats using peptid... · AIM: To determine the effects of rapamycin on experimental autoimmune uveoretinitis(EAU) and investigate of role of rapamycin on T cell subsets in the disease.·METHODS: EAU was induced in rats using peptides1169 to 1191 of the interphotoreceptor binding protein(IRBP). Rapamycin(0.2 mg/kg/d) was administrated by intraperitoneal injection for a consecutive 7d after immunization. Th1/Th2/Th17 cytokines, TGF-β1, and IL-6produced by lymphocyteswere measured by ELISA, while Th17 cells and CD4 +CD25 + regulatory T cells(Tregs)from rat spleen were detected by flow cytometry.·RESULTS: Intraperitoneal treatment immediately after immunization dramatically ameliorated the clinical course of EAU. Clinical responses were associated with reduced retinal inflammatory cell infiltration and tissue destruction. Rapamycin induced suppression of Th1/Th2/Th17 cytokines, including IFN-γ, IL-2, IL-17, IL-4, and IL-10 release from T lymphocytes of EAU rats, in vitro.Rapamycin also significantly increased TGF-β1production but had no effect on IL-6 productionof T lymphocytes from EAU rats in vitro. Furthermore,rapamycin decreased the ratio of Th17 cells/CD4 +T cells and upregulated Tregs in EAU, as detected by flow cytometry.·CONCLUSION: Rapamycin effectively interferes with T cell mediated autoimmune uveitis by inhibiting antigen-specific T cell functions and enhancing Tregs in EAU.Rapamycin is a promising new alternative as an adjunct corticosteroid-sparing agent for treating uveitis. 展开更多
关键词 experimental autoimmune uveoretinitis RAPAMYCIN regulatory t cells th1 cells th2 cells th17 cells UvEItIS
下载PDF
Higher PD-1 expression concurrent with exhausted CD8+ T cells in patients with de novo acute myeloid leukemia 被引量:12
18
作者 Jiaxiong Tan Shaohua Chen +9 位作者 Yuhong Lu Danlin Yao Ling Xu Yikai Zhang Lijian Yang Jie Chen Jing Lai Zhi Yu Kanger Zhu Yangqiu Li 《Chinese Journal of Cancer Research》 SCIE CAS CSCD 2017年第5期463-470,共8页
Objective: To investigate the association between the T cell inhibitory receptor programmed death 1(PD-1)and T cell exhaustion status in T cells from patients with de novo acute myeloid leukemia(AML) and AML in c... Objective: To investigate the association between the T cell inhibitory receptor programmed death 1(PD-1)and T cell exhaustion status in T cells from patients with de novo acute myeloid leukemia(AML) and AML in complete remission(CR).Methods:Surface expression of PD-1 and the exhaustion and immunosenescence markers CD244 and CD57 on CD3+,CD4+ and CD8+ T cells from peripheral blood samples from 20 newly diagnosed,untreated AML patients and 10 cases with AML in CR was analyzed by flow cytometry.Twenty-three healthy individuals served as control.Results:A significantly higher percentage of PD-1+ cells were found for CD3+ T cells in the de novo AML group compared with healthy controls.In addition,an increased level of PD-1+ CD8+ T cells,but not PD-1+ CD4+,was found for CD3+ T cells in the de novo AML and AML-CR samples.A higher percentage of CD244+ CD4+,CD244+ CD8+,CD57+ CD4+ and CD57+ CD8+ T cells was found in CD3+ T cells in samples from those with de novo AML compared with those from healthy controls.Strong increased PD-1+ CD244+ and PD-1+ CD57+ coexpression was found for CD4+ and CD8+ T cells in the de novo AML group compared with healthy controls.Conclusions:We characterized the major T cell defects,including co-expression of PD-1 and CD244,CD57-exhausted T cells in patients with de novo AML,and found a particular influence on CD8+ T cells,suggesting a poor anti-leukemia immune response in these patients. 展开更多
关键词 Acute myeloid leukemia PD-1 t cell exhaustion
下载PDF
Prognostic potential of an immune score based on the density of CD8+ T cells, CD20+ B cells, and CD33+/p-STAT1+ double-positive cells and HMGB1 expression within cancer nests in stage ⅢA gastric cancer patients 被引量:4
19
作者 Jun Dong Jiao Li +5 位作者 Shiming Liu Xingyu Feng Shi Chen Zhiwei Zhou Yingbo Chen Xiaoshi Zhang 《Chinese Journal of Cancer Research》 SCIE CAS CSCD 2016年第5期543-552,共10页
Objoctive: There is heterogeneity in the prognosis of gastric cancers staged according to the tumornodes-metastasis (TNM) system. This study evaluated the prognostic potential of an immune score system to supplemen... Objoctive: There is heterogeneity in the prognosis of gastric cancers staged according to the tumornodes-metastasis (TNM) system. This study evaluated the prognostic potential of an immune score system to supplement the TNM staging system. Mothodsg An immunohistochemical analysis was conducted to assess the density of T cells, B cells, and myeloid-derived suppressor cells (MDSCs) in cancer tissues from 100 stage IIIA gastric cancer patients; the expression of the high-mobility group protein B1 (HMGB1) was also evaluated in cancer cells. The relationship between the overall survival (OS), disease-free survival (DFS), and immunological parameters was analyzed.Results: An immune score system was compiled based on the prognostic role of the density ofT cells, B cells, MDSCs, and the expression of HMGB1 in cancer tissues. The median 5-year survival of this group of patient was 32%. However, the 5-year survival rates of 80.0%, 51.7%, 0%, 5.8%, and 0% varied among the patients with an immune score of 4 to those with an immune score of 0 based on the immune score system, respectively. Similarly, differences in DFS rates were observed among the immune score subgroups. Concluslons: An immune score system could effectively identify the prognostic heterogeneity within stage IliA gastric cancer patients, implying that this immune score system may potentially supplement the TNM staging system, and help in identifying a more homogeneous group of patients who on the basis of prognosis can undergo adjuvant therapy. 展开更多
关键词 Immune score gastric cancer CD33 StAt1 t cell B cell high-mobility group protein BI(HMGB1
下载PDF
Transplantation Expression of 4-1BB molecule on peripheral blood T cells in liver transplanted patients and its clinical implication 被引量:3
20
作者 Yun-Le Wan Shu-Sen Zheng +5 位作者 Chang-Ku Jia Ting-Bo Liang Dong-Sheng Huang Wei-Lin Wang Min-Wei Li Zhi-Cheng Zhao the Department of Hepatobiliary Pancreatic Surgery, Key Laboratory of Combined Multi-Organ Transplantation, Ministry of Public Health, First Affiliated Hospital, Zhe-jiang University School of Medicine, Hangzhou 310003, China 《Hepatobiliary & Pancreatic Diseases International》 SCIE CAS 2003年第1期38-43,共6页
OBJECTIVE: To investigate the gene expression of 4-1BB in peripheral blood mononuclear cells (PBMCs) and its possible significance in clinical liver transplantation. METHODS: Reverse transcription-polymerase chain rea... OBJECTIVE: To investigate the gene expression of 4-1BB in peripheral blood mononuclear cells (PBMCs) and its possible significance in clinical liver transplantation. METHODS: Reverse transcription-polymerase chain reaction (RT-PCR) was used to determine the gene expression of 4-1BB in PBMCs from 22 patients receiving liver transplantation, 13 patients with primary liver carcinoma (PLC), and 12 healthy controls. To determine whether 4-1BB molecule is also expressed on the surface of CD4^+ and CD8^+ T cell, flow cytometry was used to analyse the phenotype of T cell subsets from the blood of liver transplantation patients. RESULTS: 4-1BB mRNA was detected in PBMCs from stable survivors after liver transplantation, but almost not deteeted in PBMCs from PLC patients and healthy controls. Meanwhile, 4-1BB was almost not expressed on the surface of CD4^+ and CD8^+ T cells in healthy controls and PLC patients. A low level of 4-1BB expression, however, was found on the surface of CD4^+ and CD8^+ T cells from the stable survivors after liver transplantation. CONCLUSIONS: This study demonstrates that although patients are stable after liver transplantation, effector T-cells can also be activated through the signal of 4-1BB molecule and persistent irmmune response to grafts. Blockage of 4-1BB/4-1BBL pathway may benefitially reduce the clinical dosage of immunosuppressive agents and prolong the survival of grafts. 展开更多
关键词 4-1BB liver transplantation activation of t cells
下载PDF
上一页 1 2 79 下一页 到第
使用帮助 返回顶部