EBV-LMP2A重组腺病毒体外转染树突状细胞激发特异性CTL的研究

目的：用EBV潜伏膜蛋白2A(EBV-LMP2A)重组腺病毒转染树突状细胞(DC)激发特异性细胞毒性T细胞(CTL)，分析CTL的特性。方法：用AdS-LaMP2A重组腺病毒转染EBV健康携带者及鼻咽癌患者的DC，与自体来源的外周血单个核细胞(PBMC)混合培养，激发LMP2A特异性CIL。用LDH释放法检测CIL杀伤活性；流式细胞术(FACS)检测培养细胞群体中CD3^ 、CD4^ 、CD8^ 、CD56^ 细胞的组成；生物活性法检测细胞培养上清中IFN-γ含量；RT-PCR分析CTL的FasL mRNA表达。结果：EBV健康携带者及鼻咽癌患者的PBMC，经AdS-LMP2A转染的自体DC两次刺激后，都能诱导出显著的EBV-LMP2A特异的CIL。EBV健康携带者CTL的杀伤活性，随DC刺激次数的增加而逐渐增强，诱导的CTL细胞群体以CD^4 和CD8^ 细胞组成为主，且CD4^ 细胞比例高于CD8^ 细胞，另含少量CD56^ 细胞；在不同时段所诱导的CTL上清中，均含一定量的IFN-γ并随刺激次数和诱导时间的延长呈上升趋势；RT-PCR研究表明，所诱导的CTL有FasL mRNA的表达。结论：以腺病毒载体介导EBV-LMP2A基因转染的成熟DC，在体外能激发较强的LMP2A特异的功能性CTL，可用于EBV相关NPC的免疫治疗。     

Epstein—Barr病毒潜伏膜蛋白2A重组痘苗病毒转染DC及特异性CTL的体外诱导

通过ＥＢ病毒ＬＭＰ２Ａ重组痘苗病毒转染的ＤＣＳ体外诱导ＬＭＰ２Ａ特异性ＣＴＬ,并通过ＧＭ－ＣＳＦ、ＩＬ－４和ＴＮＦ－ａ培养体系,我们诱导出了人外周血单核细胞来源的ＤＣ。同时选用在鼻咽癌患者中表达的ＥＢ病毒潜伏蛋白之一ＬＭＰ２Ａ作为靶基因,利用重组痘苗病毒转染诱导的ＤＣＳ。ＤＣＳ与自体ＰＢＭＣＳ混合培养,在ＩＬ－２的刺激作用下获得特异性ＣＴＬ。结果如下：１．人外周血单核细胞经ＧＭ－ＣＳＦ、ＩＬ－４、ＴＮＦ－ａ的混合培养,１０天可获得成熟的功能性ＤＣＳ。ＦＡＣＳ检测显示ＤＣ表面相对特异性标志ＣＤ８３…     

RNA激发的DC体外诱导EBV特异性CTL的研究

本研究采用酶切等方法将质粒pSVTP1中LMP2a (latentmembraneprotein 2a)的编码基因克隆至pGEM 3Zf+,再经体外转录系统转录获得EBV LMP2aRNA ,将以此RNA激发的DC所诱导生成的CTL作为效应细胞分别与含EBV基因之一EBNA1、EBNA2、EBNA3c、LMP2a的重组病毒感染的正常人成纤维细胞混合后 ,采用LDH释放法检测细胞毒活性。结果显示 ,经体外转录的LMP2aRNA激发的DC所诱导的淋巴细胞对表达LMP2a抗原的成纤维细胞产生特异性的细胞毒活性 ,证实了这种RNA激发的DC能有效地诱导EBV特异性CTL的生成 ,为EBV相关肿瘤的免疫治疗提供了新的实验依据。     

人脐带血抗巨细胞病毒和EB病毒的特异性细胞毒？…

目的：探讨用人的脐带血单个核细胞体外同时扩增对抗ＥＢ病毒（ＥＢＶ）和巨细胞病毒（ＣＭＶ的特异性细胞毒性Ｔ淋巴细胞的可行性。方法：利用人的脐带血单个核细胞（ＣＢＭＣ）,通过ＥＢＶ感染转化成Ｂ成淋巴细胞细胞株（ＢＬＣＬ）,再通过逆转录病毒载体,将ＣＭＶ蛋白基因ｐｐ６５导入ＢＬＣＬ,用这种细胞体外刺激同一供者脐带血的ＣＢＭＣ产生细胞毒性Ｔ细胞（ＣＴＬ）,经「＾５１Ｃｒ」释放实验（ＣＲＡ）检测产生的ＣＴＬ     

人癌胚抗原重组痘苗病毒转染树突状细胞体外诱导的抗肿瘤免疫

目的：研究人癌胚抗原重组痘苗病毒（rV-CEA)转染外周血树突状细胞（DC）后在外体诱导的抗CEA分泌性肿瘤免疫。方法：分离晚期结肠癌患者的外周血单核细胞，在体外用人重组粒－巨噬细胞集落刺激因子（GM－CSF）及白细胞介素4（IL－4）培养成DC，再用rV-CEA转染DC后激发自体T细胞，观察其体外激发自体T细胞的增殖能力及其诱导的细胞毒性T淋巴细胞（CTL）对自体CEA分泌性肿瘤细胞的杀伤活性，并与野生型痘苗病毒（W－VV）及无病毒转染的DC所激发的T细胞进行比较。结果：经rV-CEA转染的DC能显著刺激自体T细胞的增殖，其激活的T细胞对CEA分泌性自体肿瘤细胞具有特异性杀伤作用。结论：rV-CEA转染的DC可以诱导体CEA分泌性肿瘤免疫。     

SP2/0细胞膜抗原负载DC诱导体外特异性CTL效应

目的 研究SP2／0细胞膜抗原负载树突状细胞（DC）诱导的特异性细胞毒性T淋巴细胞（CTL）对肿瘤细胞的杀伤活性。方法 密度梯度离心法分离SP2／0细胞膜，负载经rmGM-CSF和rmIL-4诱导扩增的小鼠骨髓来源的DC，活化T淋巴细胞获得肿瘤特异性CTL，MTT法检测对SP2／0细胞的杀伤效果。结果 骨髓单个核细胞在rmGM-CSF和rmIL-4作用下获得了高表达CDS0、CD86和MHC-Ⅱ分子的DC，致敏的CTL对SP2／0骨髓瘤细胞具有高杀伤率，显著高于对I5178Y淋巴瘤细胞的杀伤活性（P〈0．01）。结论 SP2／0细胞膜抗原负载DC能诱导明显的特异性抗肿瘤免疫应答。     

EB病毒潜伏膜蛋白LMP1的信号转导途径

ＥＢ病毒是一类与人伯基特淋巴瘤、鼻咽癌、何杰金氏病相关的γ单纯疱疹病毒，其潜伏膜蛋白（ＬＭＰ１）是具有转化活性的瘤蛋白。ＬＭＰ１通过信号转导途径活化核转录因子ＮＦκＢ和ＡＰ１，调控相关基因的表达。肿瘤坏死因子受体相关蛋白和肿瘤坏死因子受体死亡结构域以及ｃｊｕｎ氨基末端激酶和Ｒａｓ／ｒａｆ１分别参与了ＬＭＰ１活化ＮＦκＢ和ＡＰ１的信号转导途径     

HPV多肽致敏的树突状细胞体外激发特异性CTL能力的研究

目的 观察以高危型人乳头瘤病毒16型(HPV16) E6和E7基因编码的多肽E613-21(KLPDLCTEL)和E786-94(TLGIVCPI)为抗原负载的树突状细胞(DC)体外诱导特异性CTL的能力.方法 采集HPV+HLA-A2+宫颈癌患者外周血,分离单核细胞(Mo)与外周淋巴细胞(PBL);将Mo诱导成DC后负载E6和E7多肽,用其反复致敏PBL(3次);ELISA法检测致敏细胞上清细胞因子分泌水平;流式细胞标记法检测致敏细胞中特异性CTL的比例;MTT法检测致敏细胞杀伤靶细胞的能力.结果 11例HPV 16+ HLA-A2+宫颈癌患者DC平均得率为(10.79±0.88) ×l06(每100 ml外周血),CD11c+ HLA-DR+为(97.15±2.41)％,其中CD80+为(84.28±5.39)％,CD83+为(85.17+5.06)％,CD86+为(97.74±0.87)％.PBLs致敏3次后,平均增殖(15.4±1.5)倍;致敏第21天上清细胞因子水平分别为:IL-2(2551.9±195.3) pg/ml、IL-12(554.9士64.0)pg/ml、IFN-γ(2416.9±281.7)pg/ml,TNF-α(632.4±71.1) pg/ml,明显高于未致敏组(P＜0.05),IL-10(235.1+34.7) pg/ml与对照组比较无显著差异;特异性CTL的平均比例为(6.32±1.54)％,明显高于对照组(P＜0.05),对负载E6、E7多肽的T2细胞株杀伤率明显高于对照组(P＜0.05).结论 HPV E6和E7混合多肽负载的DC体外能有效地诱导特异性CTL,刺激Thl型细胞因子的分泌,为治疗型宫颈癌疫苗的研制提供科学依据.     

EB病毒潜伏感染在不同位T细胞淋巴瘤中的表达

探讨不同部位Ｔ细胞淋巴瘤与ＥＢ病毒感染的关系。方法对１００例不同部位的ＴＭＬ，采用原位杂交法检测肿瘤细胞ＥＢＶ编码的ＲＮＡ。结果（１）１００例中ＥＢＥＲ１／２检出率４８％，结内ＴＬ检出率３０％，结外ＴＭＬ检出率６０％，结内，结外ＥＢＶ检率差异有非常显著意义。     

HBsAg体外冲击的慢性乙肝患者树突状细胞的生物学特性及其对HBV特异性CTL的诱导作用

目的 :研究HBsAg冲击的慢性乙肝患者单核细胞来源的树突状细胞 (DCs)的功能状况及体外对HBV特异性CTL的诱导作用 ,初步探讨诱导特异性抗HBV细胞免疫的途径。方法 :分离慢性乙肝患者外周血单核细胞 ,以GM CSF +IL 4 +TNF α培养诱导DCs,加入HBsAg冲击以诱导HBV特异性DCs。采用FCM测定细胞表面免疫分子CD1a、CD83、CD86、CD80、CD4 0以及HLA DR的表达水平 ,ELISA法检测培养上清中细胞因子IL 6、IL 12的分泌含量 ,MTT法测定DC刺激同种异体淋巴细胞增殖的能力 ,LDH法检测DC诱导的患者外周血T细胞对HepG2 2 2 15 (转染HBVDNA)、HepG2肝癌细胞株及K5 6 2白血病细胞株的细胞毒作用。结果 :HBsAg冲击的DC其表达CD1a、CD83、CD86、CD80、CD4 0、HLA DR表面分子明显高于对照组 (P <0 0 1,P <0 0 5 ) ,分泌IL 12的水平也高于对照组 (P <0 0 1) ,而分泌IL 6的水平则较对照组显著降低(P <0 0 1) ;HBsAg冲击的DC刺激同种异体淋巴细胞增殖的能力明显增强 (P <0 0 5 ) ,并可有效地诱导自体CTL对转HBV基因的HepG2 2 2 15细胞高效特异性杀伤作用 (P <0 0 1)。结论 :慢性乙型肝炎患者单核细胞来源的DCs经HBsAg抗原冲击后 ,生物学活性增强 ,并且能有效地诱导对HBV特异性反应的CTL。     

Expression of the Epstein-Barr virus (EBV)-encoded latent membrane protein 2A (LMP2A) in EBV-associated nasopharyngeal carcinoma

The Epstein-Barr virus (EBV) is associated with virtually all cases of undifferentiated nasopharyngeal carcinoma (NPC) and has been classified as a group I carcinogen. In addition to its potential role in the pathogenesis of NPC, EBV also provides a possible target for immunotherapy of NPC, since a limited number of viral genes are expressed in the neoplastic cells. The EBV-encoded latent membrane protein 2A (LMP2A) is considered a promising target since it provides epitopes recognized by EBV-specific T-cells. Using immunohistochemistry, the present study shows that LMP2A is expressed at the protein level in the neoplastic cells of 16 of 35 (45.7%) NPC biopsies. This finding provides further evidence suggesting that NPC tumour cells may be susceptible to lysis by cytotoxic T-cells directed against LMP2A and should encourage efforts to develop immunotherapeutic approaches for the treatment of NPC.     

The c-Cbl proto-oncoprotein downregulates EBV LMP2A signaling

Latent membrane protein 2A (LMP2A) of Epstein-Barr virus (EBV) plays a key role in regulating viral latency and EBV pathogenesis by functionally mimicking signals induced by the B-cell receptor (BCR) altering normal B cell development. As c-Cbl ubiquitin ligase (E3) is a critical negative regulator in the BCR signal pathway, the role of c-Cbl in the function and formation of the LMP2A signalosome was examined. c-Cbl promoted LMP2A degradation through ubiquitination, specifically degraded the Syk protein tyrosine kinase in the presence of LMP2A, and inhibited LMP2A induction of the EBV lytic cycle. Our earlier studies indicated that LMP2A-dependent Lyn degradation was mediated by Nedd4-family E3s in LMP2A expressing cells. Combine with these new findings, we propose a model in which c-Cbl and Nedd4-family E3s cooperate to degrade target proteins at discrete steps in the function of the LMP2A signalosome.     

含EBV-LMP2基因重组腺病毒疫苗的构建及其诱导CTL应答的初步探讨

目的　构建包含EBV LMP2基因的重组腺病毒疫苗并探讨它在体内外的免疫性质。方法　采用pAdeasy 1系统构建包含EBV LMP2基因的重组腺病毒疫苗 ,并用IFA、PCR和TCID50 等方法对其特异性进行鉴定。通过重组腺病毒感染人树突状细胞 (DC) ,在体外活化自体T细胞 ;以及通过重组腺病毒感染小鼠淋巴细胞 ,皮下免疫同种小鼠 ,体内活化CTL评价其免疫效果。结果　通过PCR以及间接免疫荧光试验分别证实了病毒目的基因LMP2的存在以及蛋白在 2 93细胞中的表达。采用TCID50 方法 ,测定第 6代的病毒滴度为 2× 10 8。体内外的免疫实验结果显示通过这两种方式均可以有效地引发针对EBV LMP2的CTL反应。结论　包含EBV LMP2基因的重组腺病毒疫苗可以在体内外有效地引发CTL应答 ,这些资料为下一步临床应用含LMP2的重组腺病毒作为疫苗治疗和预防EBV相关肿瘤奠定了基础。     

EBV LMP2A-specific T Cell Immune Responses Elicited by Dendritic Cells Loaded with LMP2A Protein

Type Ⅱ Epstein-Barr virus （EBV） associated malignancies such as nasopharyngeal carcinoma and non-Hodgkin＇s lymphomas consistently express latent membrane 2A （LMP2A） proteins, which have been suggested to be an ideal target for immunotherapy. In previous studies we have demonstrated that using LMP2A protein loaded dendritic cells, the most powerful antigen processing cells in the body can elicit specific and robust anti-tumor cellular immune response in vitro. In this paper, we further investigated the T cell profile of the anti-tumor immune response. We found that LMP2A specific CD4＋ and CD8＋ T cells could be stimulated by LMP2A protein loaded dendritic cells （DCs）. The Thl type immune response is dominant in the immune response mediated by LMP2A specific CD4^＋ T cells. The CD8^＋ cytotoxic T cells can lyse LMP2A bearing cells effectively and specifically. The CD8^＋ cytotoxic T cells can also secrete high level of intracellular IFN-γ, which indicates these cells are EBV-LMP2A specific cytotoxic T cells. Altogether, our studies proved that LMP2A protein loaded DCs can elicit anti-tumor cellular immune responses efficiently. This study provides a rationale for the DC-based immunotherapy against EBV-LMP2A expressing malignancies.     

Epstein-Barr virus genetic variation in Vietnamese patients with nasopharyngeal carcinoma: full-length analysis of LMP1

Genetic variation in tumor virus genes and its impact on function might contribute to the understanding of geographic differences in risks for virus-associated tumors. This is particularly true for the genes known to contribute to the biology of the tumor. It is has been proposed that Epstein-Barr virus (EBV) gene variation has a role in the high risk of nasopharyngeal carcinoma (NPC) in South-East Asia. NPC is among the five most common cancers in Vietnam. EBV-NPC cells always express EBV nuclear antigen 1 (EBNA1) and also frequently latent membrane protein 1 and 2 (LMP1 & LMP2). To investigate EBV gene variation in Vietnamese NPC patients we analyzed the full length of LMP1 gene including its promoter region, and the N-termini of both EBNA1 and LMP2A genes from five NPC biopsies. We detected two EBV variants V1 and V2 based on the LMP1 nucleotide sequence pattern compared with the prototype B95-8 and some available sequences including Chinese variants. The V1 variant shows strong similarity to a variant dominant in Southern China (China 1), while the V2 variant is similar to a Thai variant SEA 2 and partly identity with GD1 in the C-terminus. The promoter region and transmembrane domain of the SEA 2-like samples contained some specific differences compared with previously published variants. In contrast, analysis of EBNA1 N- and LMP2A N-termini only revealed minor changes. Our findings reinforces that the polymorphisms of whole LMP1 sequence should be considered in future EBV molecular epidemiology studies in different geographic populations.