表达呼吸道合胞病毒F蛋白编码基因的重组腺病毒载体的构建

目的 构建表达呼吸道合胞病毒(respiratory syncytial virus,RSV)F蛋白编码基因片段的重组腺病毒.方法 以RSV RNA为模板,利用RT-PCR扩增出F基因片段,应用AdEasy腺病毒载体系统,构建含有目的 基因的蕈组穿梭质粒pShuttle-CMV/F,再转化含有骨架质粒pAdEasy-1的大肠杆菌BJ5183-AD-1获得重组腺病毒质粒pAdEasy/F.将该质粒转染293细胞包装产生出重组腺病毒rAd/F.重组腺病毒分别经电子显微镜技术、RT-PCR、Western blot和间接免疫荧光方法进行鉴定.并对该重组腺病毒的滴度和遗传稳定性进行了初步研究.结果 获得了含有RSV F基因片段的重组腺病毒rAd/F,电子显微镜下可见典型腺病毒颗粒形态,RT-PCR、Western blot和间接免疫荧光方法分析显示rAd/F中的F基因片段可以在293细胞中有效转录和表达.结论 成功构建出含有RSV F基因片段的苇组腺病毒rAd/F,为进一步研究重组腺病毒载体疫苗奠定了基础.     

呼吸道合胞病毒融合蛋白F在重组杆状病毒表达系统中的表达及抗原性研究

目的 利用杆状病毒表达系统对RSV A型Long株F基因进行表达研究,为RSV重组亚单位疫苗的研制奠定基础.方法 用反转录聚合酶链反应(RT-PCR)扩增F基因,将其克隆到pFastBacHT A载体中,阳性重组质粒转化DH10Bac感受态细胞,PER鉴定获得阳性克隆,碱裂解法提取阳性质粒,转染Sf9昆虫细胞,获得含F基因的重组杆状病毒质粒,重组病毒感染Sf9细胞72 h后,进行SDS-PAGE电泳、间接免疫荧光和Western-blot试验.免疫Balb/c小鼠,用ELISA测定抗体滴度,MTT试验检测T淋巴细胞增殖.结果 目的 蛋白F在昆虫细胞中有特异性表达,能被F蛋白单克隆抗体所识别,该蛋白诱导了高滴度的RSV特异性抗体.结论成功克隆RSV F基因,并在Sf9昆虫细胞中获得表达,该蛋白具有良好的免疫原性,为进一步研究开发RSV重组亚单位疫苗奠定了基础.     

呼吸道合胞病毒分泌型融合蛋白的真核表达和纯化

目的 研究人呼吸道合胞病毒(human respiratory syneytial viruse,RSV)分泌型融合蛋白(secreted fusion protein,sF)基因在杆状病毒中的表达及纯化.方法 根据编码F蛋白的基因序列设计引物,以PCR方法将F蛋白基因的跨膜区和胞质区核酸序列替换为6×His核酸序列.获得COOH'端带有His标签的重组sF-His蛋白编码基因,利用Bac-to-Bac杆状病毒表达系统,构建可表达sF蛋白的重组杆状病毒,用脂质体Cellfectine reagent转染sf9细胞,实现sF在sf9细胞中的表达,Ni柱亲和层析纯化sF蛋白.结果 成功获得了sF-His编码基因,构建的重组杆状病毒可高效表达sF,Ni-柱纯化后sF的浓度为1.084 mg/ml,纯度达90%以上.结论 杆状病毒系统是制备8F的有效方法,纯化的sF蛋白为RSV新型疫苗及单克隆抗体和诊断试剂等研究奠定了基础.     

中国呼吸道合胞病毒地方株G蛋白在重组痘苗病毒中的表达

目的　构建表达中国呼吸道合胞病毒 (RSV)地方株G蛋白基因的重组痘苗病毒 ,以用于RSV感染防治的研究。方法　用基因克隆技术将中国RSV地方株G蛋白基因插入到痘苗病毒载体中 ,与痘苗病毒共感染获得重组病毒。用免疫印迹、ELISA、蚀斑减少试验等方法检测表达产物的免疫原性及生物活性。结果　RSV地方株G蛋白在痘苗病毒中获得较好的表达 ,表达产物的糖基化程度较高 ,且该重组病毒免疫家兔可诱发特异性抗体产生。蚀斑减少试验证明 ,用该表达产物制备的抗血清具有中和病毒的活性。结论　重组病毒表达的中国RSV地方株G蛋白具有较好的抗原性、免疫原性等生物活性     

呼吸道合胞病毒（RSV）F和G糖蛋白抗体反应与RSV肺…

采用重组痘苗病毒表达的呼吸合胞病毒和Ｇ糖蛋白抗原，应用间接ＥＬＩＳＡ法对１２０名１４岁以下的正常儿童及４４例ＲＳＶ肺炎患儿血清中ＲＳＶ－Ｆ和Ｇ糖蛋白特异性ＩｇＧ抗体水平进行了检测。研究结果表明，正常儿童血清中两种抗体水平随年龄增长而逐渐增高，３岁以内组与３岁以上组的抗体水平有蚶性差异，２岁以上ＲＳＶ肺炎患儿急性期血清ＲＳＶ－Ｆ和Ｇ抗体平均水平明显低于２岁以上正常儿童的水平、以上说明婴幼儿易发生ＲＳ     

北京地区正常人群血清中呼吸道合胞病毒F和G蛋白…

以表达呼吸道合胞病毒（ＲＳＶ）Ｆ和Ｇ蛋白的重组痘苗病毒作为抗原，用间接免疫荧光法检测北京地区不同年龄组正常儿童及成人血清中ＲＳＶ Ｆ和Ｇ蛋白特异性ＩｇＧ抗体。其结果表明：成人及产妇静脉血中有中等滴度的ＲＳＶ抗体及较低水平的Ｆ和Ｇ蛋白特异性ＩｇＧ抗体。初生婴儿脐带血中的ＲＳＶ Ｆ和Ｇ蛋白ＩｇＧ抗体水平同母亲静脉血中的一致，表明属母传抗体。婴幼儿ＲＳＶ抗体水平在生后６个月内迅速降低，６个月以后抗体的滴     

呼吸道合胞病毒病原学和疫苗研究现状

呼吸道合胞病毒（ＲＳＶ）可分为Ａ、Ｂ两亚型，其结构蛋白中，Ｆ蛋白与Ｇ蛋白与诱发保护性免疫应答有关，灭活ＲＳＶ疫苗接种无保护作用，减毒活性疫苗和亚单位疫苗可作为候选疫苗。     

诺如病毒衣壳蛋白重组人3型腺病毒的构建

目的 制备表达诺如病毒衣壳蛋白的重组人3型腺病毒.方法 将诺如病毒衣壳蛋白基因(Noro-orf2)克隆到腺病毒穿梭载体pBSE3CMV-egfp上,与线性化人3型腺病毒骨架质粒pBRAdv3共电转化感受态大肠杆菌BJ5183,使其在细菌内发生同源重组,带Noro-orf2基因的表达框置换腺病毒E3区,PCR及酶切筛选得到重组腺病毒质粒,将重组腺病毒质粒转染Hep-2细胞进行包装,获得感染性的重组腺病毒粒子,免疫组化分析重组腺病毒中诺如病毒衣壳蛋白的表达.结果 同源重组后经酶切和PCR鉴定证明插入Noro-orf2基因的重组腺病毒质粒pBRAdv3E3dNor成功构建,并经转染包装得到高滴度的重组腺病毒Adv3E3dNor,免疫组化证明诺如病毒衣壳蛋白得到表达.结论 成功构建表达诺如病毒衣壳蛋白的重组3型腺病毒Adv3E3dNor,为研制人3型腺病毒-诺如病毒双价疫苗奠定了基础.     

呼吸道合胞病毒的分型研究

目的 了解北京地区１９９０￣１９９１年和１９９７￣１９９８年两个非连续的流行年中呼吸道合胞病毒（ＲＳＶ）Ａ、Ｂ亚型和基因型的流行情况。方法 用间接免疫荧光法（ＩＩＦ）检测ＲＳＶ阳性鼻咽分泌物（ＮＰＳ）标本或ＲＳＶ分离株,划分Ａ、Ｂ亚型。根据Ｎ基因片段的限制性酶切图型将ＲＳＶ分离株分成至少６个基因型ＮＰＩ－６ＮＰＩ,３和６属于Ｂ亚型,ＮＰ２４和５属于Ａ亚型。根据ＳＨ基因片段的核苷酸序列将Ａ亚型分离株     

呼吸道合胞病毒G蛋白基因重组质粒诱导小鼠免疫保护性及机制研究

目的 构建编码呼吸道合胞病毒(RSV)G蛋白基因的重组质粒,观察其对RSV感染小鼠的保护性及特异性免疫效应,为研制安全有效的RSV新疫苗提供线索和实验依据.方法 利用基因重组方法构建含RSV G蛋白编码基因的重组质粒,测序和酶切鉴定,Western blot检测目的 基因经体外表达后的免疫原性.重组质粒免疫小鼠后以RSV感染,病毒滴定法检测肺组织标本中RSV滴度,HE染色法检查肺组织病理改变,ELISA检测血清抗体水平,双抗体夹心ELISA测定肺泡灌洗液(BALF)内Th1/Th2细胞因子表达量,流式细胞术检测BALF中T淋巴细胞亚群数量及活化状态.结果 成功构建了编码RSV G蛋白基因的重组质粒pcDNA3.1~G.Western blot证实目的 蛋白在体外具有免疫原性.被免疫小鼠感染RSV后肺组织病毒滴度降低,肺组织中未见明显的炎性细胞浸润.小鼠血清中产生较高滴度的抗RSV-G IgG.小鼠BALF细胞中CD4~+CD25~+T淋巴细胞比例显著增加,并且IFN-γ(Th1)、IL-4(Th2)两类细胞因子表达显示平衡.结论 编码RSV G蛋白基因的重组质粒pcDNA3.1~G能诱导产生CD4~+ CD25~+T细胞亚群,对小鼠具有明显的保护作用.     

呼吸道合胞病毒F蛋白研究进展

人呼吸道合胞病毒（RSV）融合蛋白（F蛋白）为病毒表面结构蛋白,可以刺激机体产生保护性抗体和细胞免疫反应。因此对F蛋白的深入研究将有助于了解病毒感染的机理,从而为研究RSV的免疫机理、研制特定部位的亚单位或多肽疫苗提供帮助。     

狂犬病病毒核蛋白基因-重组犬2型腺病毒的构建研究

目的获得具有感染性的狂犬病病毒核蛋白-犬2型腺病毒,并对重组病毒生物学和免疫学特性进行初步探讨。方法对克隆的犬2型腺病毒全基因组E3区进行部分缺失后,插入由CMV启动子、狂犬病病毒SRV9株核蛋白基因和牛生长激素polyA构成的长2392bp的表达盒,然后通过AscⅠ和PvuⅠ双酶切,游离重组全基因组,转染犬肾细胞系。结果盲传5代后,细胞产生典型病变。经鉴定,确定得到了狂犬病病毒核蛋白-重组犬2型腺病毒（CAV-2-RN）。Western blot检测表明,狂犬病病毒核蛋白在重组犬2型腺病毒中得到了表达。结论重组病毒可以诱导受试犬产生针对犬2型腺病毒和狂犬病病毒核蛋白的特异性抗体。     

汉滩病毒G1S0.7嵌合基因重组腺病毒的构建及鉴定

目的在本室前期工作的基础上构建汉滩病毒M基因G1片段与S基因0.7kb片段嵌合基因的重组腺病毒。方法构建含有汉滩病毒G1S0.7嵌合基因的转移载体pShuttle-G1S0.7,然后通过特异性的酶切将嵌合基因与腺病毒DNA相连,电转化E.coli JM109,获得重组腺病毒Adeno-G1S0.7 DNA,转染HFX293细胞得到重组腺病毒。进一步对重组腺病毒的滴度和表达产物进行鉴定。结果构建的含G1S0.7嵌合基因的重组腺病毒,滴度可达10^13～10^15 PFU／L;该重组腺病毒感染Vero-E6细胞后,表达出可被抗汉滩病毒核蛋白及糖蛋白G1的特异性单抗（mAb）所识别的融合蛋白。结论利用腺病毒表达系统,成功地表达同时具有核蛋白及糖蛋白G1生物学活性的融合蛋白,为进一步研究其免疫学特性奠定了基础。     

Molecular diversity of the aminoterminal region of the G protein gene of human respiratory syncytial virus subgroup B

Two major antigenic subgroups (designated A and B) have been described for human respiratory syncytial virus (HRSV). Between and within the two main subgroups, there is antigenic variation in the attachment protein G. The variability of the G protein is known to be located in two hypervariable regions of the ectodomain. Most investigators have studied the gene segment coding the C-terminal end of the protein, and little is known about the N-terminal variable region. In the present study, the genetic variability of HRSV subgroup B was evaluated by nucleotide sequencing of the N-terminal region of the G gene of 52 Tunisian isolates. Tunisian subgroup B isolates clustered into two main lineages designated arbitrarily as Tu-GB1 and Tu-GB2. Three distinct subtypes were identified within genotype Tu-GB2. The inter- and intragenotype nucleotide variability ranged from 4 to 8% and from 0 to 4%, respectively. Overall divergence values of the G sequences were inferior or equal to 15% at the aminoacid level. Comparison of sequences among Tunisian HRSV strains and viruses isolated in other geographical areas during different epidemics demonstrated close similarity to strains from Kenya, Belgium, the UK, Qatar, Canada and South Korea.     

Elevated temperature triggers human respiratory syncytial virus F protein six-helix bundle formation

Human respiratory syncytial virus (RSV) is a major cause of severe lower respiratory tract infection in infants, immunocompromised patients, and the elderly. The RSV fusion (F) protein mediates fusion of the viral envelope with the target cell membrane during virus entry and is a primary target for antiviral drug and vaccine development. The F protein contains two heptad repeat regions, HR1 and HR2. Peptides corresponding to these regions form a six-helix bundle structure that is thought to play a critical role in membrane fusion. However, characterization of six-helix bundle formation in native RSV F protein has been hindered by the fact that a trigger for F protein conformational change has yet to be identified. Here we demonstrate that RSV F protein on the surface of infected cells undergoes a conformational change following exposure to elevated temperature, resulting in the formation of the six-helix bundle structure. We first generated and characterized six-helix bundle-specific antibodies raised against recombinant peptides modeling the RSV F protein six-helix bundle structure. We then used these antibodies as probes to monitor RSV F protein six-helix bundle formation in response to a diverse array of potential triggers of conformational changes. We found that exposure of ‘membrane-anchored’ RSV F protein to elevated temperature (45-55 °C) was sufficient to trigger six-helix bundle formation. Antibody binding to the six-helix bundle conformation was detected by both flow cytometry and cell-surface immunoprecipitation of the RSV F protein. None of the other treatments, including interaction with a number of potential receptors, resulted in significant binding by six-helix bundle-specific antibodies. We conclude that native, untriggered RSV F protein exists in a metastable state that can be converted in vitro to the more stable, fusogenic six-helix bundle conformation by an increase in thermal energy. These findings help to better define the mechanism of RSV F-mediated membrane fusion and have important implications for the identification of therapeutic strategies and vaccines targeting RSV F protein conformational changes.     

Nosocomial outbreak of respiratory syncytial virus subgroup B variants with the 60 nucleotides-duplicated G protein gene

In January 2001, 20 children among 40 residents under 2 years old at a nursery home in Sapporo, Japan had respiratory symptoms and were confirmed as having respiratory syncytial virus (RSV) infection by a conventional diagnostic kit. Nasopharyngeal aspirates were collected from four RSV-positive patients and total RNA was extracted directly from the specimens for the analysis of RSV grouping and genotyping. All four RSV strains had the same G protein gene sequence of subgroup B and were assigned to identical strains. Interestingly, the G protein gene had a duplication of 60 nucleotides at the C-terminal third of the G protein gene in which three nucleotides differed each other. The predicted polypeptide is lengthened by 20 amino acids. The clinical picture of these cases was not different from those of patients with other RSV strains. These novel mutations were thought to be introduced in vivo.     

His-tag不影响RSV重组蛋白G1F/M2的免疫原性

目的：观察His-tag是否影响RSV重组蛋白G1F/M2的免疫原性。方法：PCR扩增G1和F/M2基因片段,插入表达载体pET-His和pET-DsbA-His中,转化E.coli BL21（DE3）,IPTG诱导表达,采用Ni^＋螯合亲和层析法纯化得His-G1F/M2和DsbA-His-G1F/M2,将后者用凝血酶消化,再经Ni＋螯合亲和层析法纯化得G1F/M2,将His-G1F/M2和G1F/M2免疫BALB/c小鼠,用ELISA测定抗体滴度,MTT法测定细胞毒性T细胞活性（CTL）。结果：两种蛋白在BALB/c小鼠中诱导的RSV特异性抗体和CTL活性无显著差异。结论：His-tag不影响RSV重组蛋白G1F/M2的免疫原性。