E基因在辛德毕斯病毒与辛德毕斯样病毒细胞感染特性中的作用

目的 寻找辛德毕斯病毒(YN87448病毒)与辛德毕斯样病毒(XJ-160病毒)对细胞感染特性差异的分子基础.方法 生物信息学比较两种病毒糖蛋白基因一级结构及二级结构,分析二者之间的差异,并利用病毒基因重组等现代分子生物学技术构建重组病毒来研究糖蛋白基因在病毒感染细胞特性中的贡献.结果 生物信息学分析显示,YN87448病毒和XJ-160病毒基因组分别具有11 717和11 626核苷酸序列,具有相同的基因组结构特征;两种病毒E基因氨基酸的疏水性主峰基本相同但存在82个散在分布的氨基酸差异位点.病毒基因重组研究结果显示,将XJ-160病毒E基因替换为YN87448病毒E基因的重组病毒(XJ-160/YE1E2)无论在致细胞病变时间,空斑形成直径,还是在病毒功能蛋白的表达等方面均完全体现YN87448病毒特征,而与XJ-160病毒野毒株的表现完全不同.结论 E基因在辛德毕斯病毒与辛德毕斯样病毒细胞感染特性差异方面起着重要作用,这一结果为从分子生物学角度解释两病毒间生物学差异提供了分子生物学理论依据.     

基于辛德毕斯病毒载体的重组丙肝病毒颗粒的制备与鉴定

目的 利用自主研发的辛德毕斯病毒载体构建含有丙型肝炎病毒( HCV)结构蛋白E1E2的重组病毒颗粒.方法 将编码HCV包膜糖蛋白的E1 E2基因克隆至辛德毕斯病毒载体,构建重组质粒pBR-XJE1E2和pVA-XJE1E2,转染BHK-21细胞后获得重组丙肝病毒颗粒.并通过RTPCR、间接免疫荧光和Western Blot方法鉴定表达E1E2蛋白的重组病毒颗粒.结果 酶切、PCR和测序分析表明重组质粒构建成功.RT-PCR、间接免疫荧光和Western-Blot鉴定结果表明重组质粒转染细胞后能包装出表达E1E2的丙肝病毒颗粒.结论 以辛德毕斯病毒载体为基础构建的重组质粒可在真核细胞中包装出重组丙肝病毒颗粒,这为进一步研究其在动物体内免疫反应奠定了基础.     

含有增强型绿色荧光蛋白报告基因的辛德毕斯病毒的制备与鉴定

目的 制备含有增强型绿色荧光蛋白(enhanced green fluorescent protein,EGFP)报告基因的辛德毕斯病毒,并对其进行鉴定.方法 采用融合PCR技术将报告基因EGFP融合到辛德毕斯病毒XJ-160感染性克隆pBR-XJ160的结构基因编码框后,并在报告基因前面添加亚基因启动子SP6,通过反向遗传学技术拯救得到EGFP标记的辛德毕斯病毒.结果 成功拯救并获得了EGFP标记的XJ-160病毒,该重组病毒具有良好的荧光表达特性和遗传稳定性.结论 EGFP标记的辛德毕斯病毒可用于观测病毒的侵染轨迹,为进一步研究辛德毕斯病毒嗜性、生物学功能,以及感染机制奠定了基础.     

我国登革2型病毒prM基因与甲病毒载体重组RNA的构建

目的 将我国登革２型病毒的ｐｒＭ（Ｄ２－ｐｒＭ）基因导入甲病毒载体（ＰＳｆＶ）,研究该基因及其编码蛋白介导的抗病毒作用。方法 首先将扩增的病毒ｐｒＭ基因导入ｐＳｆＶ的Ｓｐ６启动子下游并进行核苷酸序列测定。用ＳｐｅⅠ酸将ｐＳｆＶ－ｐｒＭ重组ＤＮＡ线形化,再将其体外转录成５’末端含帽子结构的重组ＲＮＡ。然后通过电穿孔法将此重组ＲＮＡ转染ＢＨＫ－２１／１３细胞。采用Ｘ－Ｇａｌ原位染色和免疫荧光法对转染细     

pLTRNL介导HSV—1 TK基因长期稳定转染人肝癌细胞系的建立

以脂质体基因转移技术，将含ＨＳＶ－１ＴＫ基因的重组逆转录病毒载体ｐＬＴＲＮＬ转染人肝癌细胞系ｈＨＣＣ，经抗生素Ｇ４１８选择，筛选出ＨＳＶ－１ＴＫ基因转染的ｈＨＣＣ再进行克隆化和亚克隆化后扩大培养，应用ＰＣＲ，ＲＴ－ＰＣＲ及ｓｌｏｔ－ｂｌｏｔ狭槽印迹等方法。对转染细胞基因组ＤＮＡ和ＲＮＡ进行了鉴定。结果表明，ＨＳＶ－１ＴＫ基因已整合入ｈＨＣＣ细胞基因组中，且有ＴＫ基因的ｍＲＮＡ转录。ＨＳＶ－１ＴＫ基     

肝癌细胞稳定转染B7.1后的免疫学特性

目的 探讨赋予肝癌细胞第二信号分子Ｂ７．１增强癌细胞与淋巴细胞之间的识别与激活作用,从而达到增强淋巴细胞对肝癌细胞的杀伤或抑制作用。方法 利用逆转录方法,转染Ｂ７．１分子至包装细胞系ＰＡ３１７。筛选获得高滴度的克隆后,以病毒上清感染肝癌细胞,使其表达Ｂ７．１分子,最后以ＬＤＨ释放法测定ＬＡＫ细胞的细胞毒活性。结果 肝癌细胞可稳定表达Ｂ７．１分子,阳性率达９４．３％,未转染的细胞无表达,其所诱发的Ｌ     

HBVx基因在肝癌细胞中的表达及其对肝癌细胞凋？…

目的：研究乙型为病毒Ｘ基因在肝癌细胞中的表达及其对肝癌细胞凋亡的影响。方法：用分子生物学的构建ＨＢＶｘ真核表达载体ｐ＾ＣＤＮＡ３．１．ＨＢＸ,用脂质体将真核表达载体Ｐ＾ＣＤＮＡ３．１－ＨＢＸ转染入肝癌细胞ＨＣＣ９２０４,Ｇ４１８ ５００ｍｇ·Ｌ＾－１筛选,获得稳定表达ＨＢｘ蛋白的细胞,阿霉素２０μｍｏｌ·Ｌ＾－１诱导细胞凋亡。电镜、琼脂糖凝胶电泳和流式细胞仪检测凋亡细胞。结果：２０μｍｏｌ·Ｌ＾－     

HBVx基因在肝癌细胞中的表达及其对肝癌细胞凋亡的影响

目的：研究乙型肝炎病毒 Ｘ 基因在肝癌细胞中的表达及其对肝癌细胞凋亡的影响。方法：用分子生物学的方法构建 Ｈ Ｂ Ｖｘ 基因真核表达载体ｐ Ｃ Ｄ Ｎ Ａ３１ Ｈ Ｂ Ｘ，用脂质体将真核表达载体ｐ Ｃ Ｄ Ｎ Ａ３１ Ｈ Ｂ Ｘ转染入肝癌细胞 Ｈ Ｃ Ｃ９２０４ ， Ｇ４１８ ５００ ｍｇ· Ｌ－ １ 筛选，获得稳定表达 Ｈ Ｂｘ 蛋白的细胞，阿霉素２０ μｍｏｌ· Ｌ－ １ 诱导细胞凋亡。电镜、琼脂糖凝胶电泳和流式细胞仪检测凋亡细胞。结果：２０ μｍｏｌ· Ｌ－ １ 阿霉素可诱导肝癌细胞凋亡，稳定表达 Ｈ Ｂｘ 蛋白的肝癌细胞凋亡率比未进行基因转染的肝癌细胞凋亡率低。结论： Ｈ Ｂｘ 蛋白可抑制阿霉素诱导的肝癌细胞调亡。     

DEFINITION AND MECHANISM RESEARCH OF NK CELLS AC-TIVATION THROUGH THE CD45 PATHWAY

为鉴定介导ＮＫ细胞激活的表面分子及其作用机制，本研究用一系列粘附分子单抗及配体体外刺激ＮＫ细胞，定量检测ＮＫ细胞ＩＦＮ－γ的分泌；检测了ＮＫ细胞经ＩＬ－２诱导后其异构体的变化及其不同异构体单抗对ＮＫ细胞的刺激作用；以ＣＤ２２α、ＣＤ２２β基因导入Ｂ７８Ｈ１细胞后观察转染细胞对ＮＫ细胞的粘附和刺激效应。结果表明：ＩｇＧ２ａ和ＩｇＧ１亚类ＣＤ４５单抗及其Ｆ（ａｂ）２均可独立刺激ＮＫ细胞释放ＩＦＮ－γ；ＮＫ细胞经ＩＬ－２培养诱导后其表面ＣＤ４５分子异构体的表达呈ＲＯ逐渐增加，而ＲＡ逐渐减少的特征；ＣＤ４５ＲＯ单抗可刺激ＮＫ细胞释放ＩＦＮ－γ；ＣＤ２２α、ＣＤ２２β转染细胞可粘附，但不能刺激ＮＫ细胞激活。结果提示：ＮＫ细胞可经ＣＤ４５ＲＯ途径激活并释放ＩＦＮ－γ，该途径与ＣＤ１６分子无关，ＣＤ４５分子的特异性配体并非既往所报道的ＣＤ２２，尚待进一步鉴定     

乙型肝炎病毒在丁型肝炎病毒包装中的作用机理研究

用含ＨＢＶ全基因和ＨＢＶ大、中、小分子表面蛋白基因的真核细胞表达质粒（ＣＭＶ－ＨＢＶ、ＣＭＶ－ＬＳ、ＣＭＶ－ＭＳ、ＣＭＶ－Ｓ）分别与含ＨＤＶ ｃＤＮＡ三聚体的重组质粒共转染ＣＨＯ细胞。转染后３天在上述４种转染细胞内及培养上清中均检出了ＨＤＶ ＲＮＡ和ＨＤＡｇ表明上述４种转染细胞的培养上清中均有ＨＤＶ病毒颗粒的包装和分泌。提示：ＨＤＶ病毒的包装可能仅需ＨＢＶ Ｓ 基因及其小分子表面蛋白的辅助。     

RNAi抑制XJ-160病毒复制的研究

目的通过建立RNA干扰(RNA interference，RNAi)抑制XJ-160病毒复制的模型，在序列特异性、位置效应和量效关系等方面，探讨RNAi对XJ-160病毒复制的影响，为进一步研究RNAi的抗病毒作用和机制奠定基础。方法按照siRNA(short interferencing RNA)的设计要求合成XJ-160病毒特异siRNA，脂质体法转染BHK-21细胞后感染XJ-160病毒，通过测定病毒滴度、蛋白表达量及XJ-160病毒：RNA合成研究siRNA对XJ-160病毒复制的抑制。结果成功建立了RNAi抑制XJ-160病毒复制的模型，探讨了RNAi抑制该病毒复制作用的特点。结论外源导入的siRNA能够抑制XJ-160病毒的复制，并且这种抑制作用具有明显的序列特异性、位置效应和存在量效关系等特点；siRNA是通过降解病毒RNA实现抑制病毒复制作用的。     

Induction of humoral and cellular immune responses against hepatitis C virus by vaccination with replicon particles derived from Sindbis-like virus XJ-160

A replication-defective, recombinant Sindbis virus vector was utilized in a novel immunization strategy to induce humoral and cellular responses against hepatitis C virus (HCV). The recombinant vector, pVaXJ-E1E2, expressing the gene for HCV glycoproteins E2 and E1, was constructed by inserting the E1E2 gene into the replicon pVaXJ, a DNA vector derived from Sindbis-like virus XJ-160. The defective replicon particles, XJ-E1E2, were produced by transfecting BHK-21^E+Capsid cells, the packaging cell lines for the vector from XJ-160 virus, with pVaXJ-E1E2. Both glycoproteins, E2 and E1, were stably expressed, as indicated by immunofluorescence assay (IFA) and Western blotting. Mice were vaccinated using a prime-boost strategy with XJ-E1E2 particles combined with Freund’s incomplete adjuvant via intramuscular injection at 0 and 2 weeks. HCV-specific IgG antibody levels and cellular immune responses were evaluated by IFA and IFN-γ ELISPOT, respectively. The results showed that the defective XJ-E1E2 particles in combination with Freund’s incomplete adjuvant induced effective humoral and cellular immune responses against HCV glycoprotein E1 or E2, suggesting that a defective Sindbis particle vaccine is capable of eliciting an effective immune response. These findings have important implications for the development of HCV vaccine candidates.     

质粒型甲病毒复制子载体系统的构建及其功能鉴定

目的 构建质粒型甲病毒复制子载体系统,并对其功能进行鉴定.方法 在XJ-160病毒感染性cDNA克隆的基础上,将病毒非结构基因序列分为三个片段扩增,分步克隆至真核表达载体pVAX1 CMV启动子下游,并用多克隆位点序列替代病毒的结构基因构建XJ-160病毒质粒型复制子载体.将病毒核蛋白基因及包膜糖蛋白基因分别克隆至pVAX1 CMV启动子下游构建载体的两个辅助质粒.通过绿色荧光蛋白报告基因及海肾荧光素酶报告基因的表达检验该质粒型载体系统的功能特性.结果 成功构建了包括复制子载体和辅助质粒的质粒型甲病毒复制子载体系统,且该复制子载体系统可成功表达绿色荧光蛋白报告基因及海肾荧光素酶报告基因.结论 本研究构建了能够表达外源基因的质粒型甲病毒复制子载体系统,为目标基因表达、重组病毒颗粒制备等奠定了基础.     

乙脑病毒SA14-14-2株复制子载体的构建及鉴定

目的 构建乙脑病毒SA14-14-2株复制子载体,为进一步研究以乙脑病毒为载体的新型疫苗奠定基础.方法 (1)构建了两个乙脑病毒复制子:一个为完全缺失PrM/E基因(命名为Full △prM/E Replicon);一个保留E基因C端213 bp(命名为Partial △prM/E Replicon),并代之以多克隆位点.(2)将复制子RNA转染BHK-21细胞,于24、48、72、96 h采用Real-time PCR验证复制子的自主复制能力.(3)于复制子多克隆位点处插入YFP报告基因,并将含报告基因的复制子RNA转染BHK-21细胞,采用荧光显微镜观察及流式细胞仪检测验证YFP的表达.结果 (1)两个复制子RNA转染BHK-21细胞后,RNA有随时间增加而不断增多的趋势.(2)含报告基因的复制子RNA转染BHK-21细胞后,荧光信号持续增强,表达YFP的阳性细胞率也逐渐增多.结论 构建的乙脑病毒SA14-14-2株复制子载体Full △prM/E Replicon及Partial △prM/E Replicon具有自主复制能力及对外源蛋白的表达能力.     

Construction and characterization of subgenomic replicons of New York strain of West Nile virus

The lineage I strain of West Nile virus (WNV) frequently causes human epidemics, including the recent outbreak in North America (Lanciotti et al., 1999, Science 286:2333-2337). As an initial step in studying the replication and pathogenesis of WNV, we constructed several cDNA clones of a WNV replicon derived from an epidemic strain (lineage I) isolated from the epicenter of New York City in the year 2000. Replicon RNAs were in vitro transcribed from cDNA plasmids and transfected into BHK-21 cells. RNA replication in transfected cells was monitored by immunofluorescence analysis (IFA) and 5' nuclease real-time RT-PCR (TaqMan). The replicon RNAs contained large in-frame deletions (greater than 92%) of the C-prM-E structural region yet still replicated efficiently in BHK-21 cells. 5' nuclease real-time RT-PCR showed that a great excess of plus-sense replicon RNA over the minus-sense RNA was synthesized in transfected cells. Replication efficiency decreased upon insertion of a green fluorescent protein (GFP) reporter gene driven by an internal ribosomal entry site (IRES) in the upstream end of the 3' untranslated region of the replicon. Strong GFP expression was detected in cells transfected with a replicon containing IRES-GFP positioned in the plus-sense orientation. IFA showed that GFP and viral proteins were exclusively coexpressed in transfected cells. In contrast, no GFP fluorescence was observed in cells transfected with a replicon containing IRES-GFP positioned in the minus-sense orientation, despite high levels of synthesis of viral proteins and RNA in the cells. Substitution of the GFP gene in the plus-sense GFP replicon with the neomycin phosphotransferase gene allowed selection of geneticin-resistant cells in which WNV replicons persistently replicated without apparent cytopathic effect. These results suggest that WNV replicons may serve as a noncytopathic RNA virus expression system and should provide a valuable tool to study WNV replication.     

丙型肝炎病毒F蛋白对p21基因的调节作用

目的研究丙型肝炎病毒（HCV）F蛋白对细胞p21基因转录、表达的影响。方法PCR扩增HCV1b来源的F基因，克隆至pcDNA3．1真核表达载体。F基因质粒转染HepG2细胞，48h后抽提细胞总RNA和总蛋白，实时定量PCR及Westem blot检测p21基因表达变化。结果HCVF蛋白在HepG2细胞内瞬时表达，相对于空载体对照（目标基因表达量为1），HCVF基因质粒转染细胞的p21转录水平为3．2，蛋白表达水平为1．4。结论HCVF蛋白增加p21转录和表达，其生物学效应值得进一步研究。     

Evaluation of single and dual siRNAs targeting rabies virus glycoprotein and nucleoprotein genes for inhibition of virus multiplication in vitro

Small interfering RNAs (siRNAs) targeting rabies virus (RV) glycoprotein (G) and nucleoprotein (N) genes were evaluated as antiviral agents against rabies virus in vitro in BHK-21 cells. To select effective siRNAs targeting RV-G, a plasmid-based transient co-transfection approach was used. In this, siRNAs were expressed as short hairpin RNAs (shRNAs), and their ability to inhibit RV-G gene expression was evaluated in cells transfected with a plasmid expressing RV-G. The nine different siRNAs designed to target RV-G exhibited varying degrees of knockdown of RV-G gene expression. One siRNA (si-G7) with considerable effect in knockdown of RV-G expression also demonstrated significant inhibition of RV multiplication in BHK-21 cells after in vitro challenge with the RV Pasteur virus-11 (PV-11) strain. A decrease in the number of fluorescent foci in siRNA-treated cells and a reduction (86.8 %) in the release of RV into infected cell culture supernatant indicated the anti-rabies potential of siRNA. Similarly, treatment with one siRNA targeting RV-N resulted in a decrease in the number of fluorescent foci and a reduction (85.9 %) in the release of RV. As a dual gene silencing approach where siRNAs targeting RV-G and RV-N genes were expressed from single construct, the anti-rabies-virus effect was observed as an 87.4 % reduction in the release of RV. These results demonstrate that siRNAs targeting RV-G and N, both in single and dual form, have potential as antiviral agent against rabies.     

Novel vectors expressing anti-apoptotic protein Bcl-2 to study cell death in Semliki Forest virus-infected cells

Semliki Forest virus (SFV, Alphavirus) induce rapid shut down of host cell protein synthesis and apoptotic death of infected vertebrate cells. Data on alphavirus-induced apoptosis are controversial. In this study, the anti-apoptotic bcl-2 gene was placed under the control of duplicated subgenomic promoter or different internal ribosome entry sites (IRES) and expressed using a novel bicistronic SFV vector. The use of IRES containing vectors resulted in high-level Bcl-2 synthesis during the early stages of infection. Nevertheless, in infected BHK-21 cells translational shutdown was almost complete by 6h post-infection, which was similar to infection with appropriate control vectors. These results indicate that very early and high-level bcl-2 expression did not have a protective effect against SFV induced shutdown of host cell translation. No apoptotic cells were detected at those time points for any SFV vectors. Furthermore, Bcl-2 expression did not protect BHK-21 or AT3-neo cells at later time points, and infection of BHK-21 or AT3-neo cells with SFV replicon vectors or with wild-type SFV4 did not lead to release of cytochrome c from mitochondria. Taken together, our data suggest that SFV induced death in BHK-21 or AT3-neo cells is not triggered by the intrinsic pathway of apoptosis.