呼吸道合胞病毒融合蛋白第168～289氨基酸片段的表达与纯化

目的:利用杆状病毒-昆虫细胞表达系统表达RSV融合蛋白中主要抗原性区域的片段(第168～289氨基酸)并纯化重组蛋白.方法:在人胚肺二倍体细胞2BS株上培养RSV Long株,从培养物中提取病毒总核酸.采用RT-PCR法从RSV基因组RNA中扩增出F基因546-881 bp片段(F'),F'插入到转移载体质粒pBacPAK9中再与线性杆状病毒BacPAK6 DNA(Bsu36I digested)共转染Sf9昆虫细胞.重组蛋白经镍离子柱螯合亲和层析纯化.经SDS-PAGE和Western-Blot鉴定重组蛋白.结果:外源基因在昆虫细胞中获得了表达,并通过其所带的信号肽分泌到了无血清培养基中.表达产物的分子量约为15×103,与理论值相符.结论:成功地用昆虫细胞表达系统表达了能分泌到培养基中的呼吸道合胞病毒F基因546-881 bp片段编码的融合蛋白第168～289氨基酸片段.     

汉坦病毒G2糖蛋白在昆虫细胞中的表达及其在免疫诊断中的应用

目的构建汉坦病毒(HV）Z10株包膜糖蛋白G2基因的重组表达载体，探索其在昆虫细胞中的表达及在免疫荧光诊断中的应用。方法以质粒pUCm—Z10M为模板设计引物，用聚合酶链反应(PCR)扩增Z10株G2基因片段，将G2片段克隆入pUCm—T质粒载体，碱法提取质粒pUCm-Z10-G2，酶切后将回收片段插入杆状病毒转移载体pFastBacHTa，构建重组体pFastBacHTa-Z10-G2，重组体转化感受态细胞E．coli DH10Bac后，经2轮筛选，提取重组质粒转染昆虫细胞sf9，并用间接免疫荧光技术检测表达的G2蛋白。结果获得含有编码HV Z10株的包膜糖蛋白G2基因的重组质粒，转染昆虫细胞表达出G2蛋白，与肾综合征出血热(HFRS)阳性血清反应，昆虫细胞内呈现特异性环状荧光。检测40份HFRS血清，与全病毒细胞抗原片的符合率为95％。结论成功构建HV Z10株包膜糖蛋白G2基因的表达载体，并在昆虫细胞中表达。可利用重组G2蛋白检测HV感染。     

人可溶性肿瘤坏死因子受体1基因的克隆及原核表达

目的 构建人可溶性肿瘤坏死因子受体1基因的重组质粒，进行原核表达。方法 以Hela细胞的总RNA为模板，用RT-PCR方法扩增sTNFR1全编码区基因片段，构建含有目的片段的T载体克隆及原核表达载体pMAL-c2x重组质粒亚克隆，经异丙基-B-D半乳糖苷酶(IPTG)诱导重组质粒菌表达sTNFR1，以淀粉树脂亲和层析法纯化重组蛋白，用十二烷基硫酸钠聚丙烯酰胺凝胶电泳(SDS-PAGE)对重组蛋白进行分析。结果经核苷酸序列测序和sDS—PAGE法鉴定，成功构建了人sTNFR1重组质粒基因工程菌，并表达和纯化了sTNFR-MBP融合蛋白。结论成功地构建了人sTNFR1重组质粒克隆，表达并纯化了sTNFR1-MBP融合蛋白。     

卵巢癌相关基因HE4在杆状病毒表达系统的表达与鉴定

目的:使卵巢癌相关基因HE4在杆状病毒表达系统中获得表达。方法:将卵巢癌相关基因HE4克隆到pMagic-his-HE4中,通过转化E.coliDH10B筛选克隆,阳性克隆通过接合转移的方式与杆状病毒框架质粒体外重组,构建Bac-phes-HE4杆状病毒表达载体,后者经Lipofectamine2000介导转染Sf9细胞,获取重组病毒,扩增病毒并感染Sf9细胞进行表达,SDS-PAGE、Western blot分析鉴定表达蛋白。结果:经HE4抗体、6×His单抗鉴定,成功通过杆状病毒表达系统获得重组卵巢癌相关基因HE4。结论:卵巢癌相关基因HE4通过接合转移的方法在杆状病毒表达系统中成功表达。     

人细胞色素CYP2E1基因重组杆状病毒粘粒构建

目的 构建人细胞色素P450 2E1(CYP2E1)基因cDNA重组的杆状病毒粘粒.方法 采用PCR方法,从国外获赠的含有CYP2E1基因cDNA的质粒中扩增CYP2E1 cDNA.将该基因的cDNA连接到测序载体pCMV-Myc载体上,通过内切酶分析及测序加以鉴定,然后将该基因的cDNA克隆到转座载体pFASTBac1载体,转化入DH10Bac大肠埃希菌感受态细胞中,提取含有CYP2E1基因的重组杆状病毒粘粒,并经PCR鉴定分析.结果 测序结果显示,该克隆片段含有CYP2E1完整的编码区,所获得的重组杆状病毒粘粒含有完整1.5kb大小的该片段.结论 获得重组CYP2E1杆状病毒粘粒,为下一步转染昆虫细胞,利用Bac-to-Bac杆状病毒表达系统大量表达人细胞色素P450 2E1蛋白打下基础.     

沙眼衣原体60kDa外膜蛋白基因的克隆与表达

目的 克隆和表达沙眼衣原体60kDa外膜蛋白(Omp2)基因。方法 D型沙眼衣原体感染McCoy细胞后，抽提基因组DNA，经PCR扩增出omp2基因片段，与pUCm—T克隆载体连接，酶切纯化后克隆到原核表达载体pQE30，构建重组表达载体pQE30／omp2，PCR、酶切及测序鉴定。IPFG诱导表达，SDS—PAGE检测有无蛋白的表达。结果 (1)获得长约1650bp的PCR产物，酶切结果显示所构建的重组质粒已成功地克隆了omp2基因，序列分析结果与已知omp2序列相同；(2)SDS—PACE检测表达产物，在相对分子量60kDa处有表达条带；(3)诱导表达之菌体超声破碎后，目的蛋白主要以包涵体形式存在。结论 获得了Ct omp2基因片段，并在E．coli M15中成功表达。     

单纯疱疹病毒Ⅱ型G蛋白免疫优势肽段在杆状病毒表达系统的表达及其反应原性

目的利用Bac-to-Bac杆状病毒表达系统对单纯疱疹病毒II型(HSV-2)糖蛋白G(gG-2)免疫优势片段gG321-580进行表达,纯化并评价其反应原性,以探索HSV-2免疫诊断试剂的研制。方法提取HSV-2DNA作为模板,PCR扩增gG321-580基因,克隆至pFastBac HTC载体中,通过Bac-to-Bac杆状病毒表达系统表达His-gG321-580融合蛋白,SDS-PAGE和Western-blotting鉴定表达产物,NTA-Ni 2+纯化后间接ELISA评价其反应原性。结果 HSV-2gG321-580在昆虫细胞Sf9中得到特异性表达,纯化后的重组gG321-580蛋白对HSV-2阳性血清抗体有较好的抗原性和特异性。结论 gG321-580蛋白在Bac-to-Bac杆状病毒表达系统中成功表达,表达产物表现出良好的反应原性,为发展HSV-2免疫诊断试剂奠定了基础。     

汉坦病毒核蛋白在免疫荧光诊断技术中的应用

目的从国内生产肾综合征出血热（HFRS）疫苗Z10株中克隆汉坦病毒核蛋白基因,应用杆状病毒-昆虫细胞表达系统使其在昆虫细胞中表达,制成抗原片,用于检测血清中汉坦病毒抗体.方法从汉坦病毒Z10株感染细胞上清液中提取病毒RNA,应用RT-PCR方法扩增S基因,与穿梭质粒连接并转化大肠杆菌,得到重组穿梭质粒.将其转化含杆状病毒基因组的大肠杆菌,筛选出含S基因的重组杆状病毒DNA的大肠杆菌,提取重组杆状病毒DNA转染昆虫细胞,应用ELISA法及间接免疫荧光法检测重组蛋白的抗原性.结果用RT-PCR方法扩增得到S基因,筛选出的重组杆状病毒感染细胞sf9,制成抗原片.此抗原片仅与HFRS阳性患者血清起反应,而与正常人及其它发热患者血清不起反应.检测浙江省各医院送检的97份疑似肾综合征出血热患者血清及36份正常人血清,与传统的抗原片比较,阳性符合率为100%.结论可以应用杆状病毒-昆虫细胞表达系统表达汉坦病毒重组蛋白.以此制备的抗原片,可用于患者血清中汉坦病毒抗体检测,具有特异性强、敏感性高,试剂制备简单、安全,为诊断肾综合征出血热提供新的途径和手段.     

北海道型汉坦病毒核蛋白基因的克隆表达及其免疫原性

目的 构建北海道型汉坦病毒(HOKV)核蛋白(NP)基因的重组杆状病毒表达载体,在昆虫细胞中表达出具有免疫原性的抗原,用于HOKV的检测及诊断.方法 应用RT-PCR方法扩增HOKVFusong-Cr-247株的NP基因,并将该基因片段克隆到PCR[R]2.1TA载体,转化到One ShortTM TOP10感受态细胞构建TA克隆载体,并与pFastBacTM1转座质粒载体分别用Kpn I和Not I双酶切,用T4连接酶连接,构建pFast PUUV-S重组转座质粒,经双酶切、PCR扩增及插入序列方向鉴定后.转化到DH10BacTM E.coli 感受态细胞,经三抗培养基筛选和PCR扩增鉴定后获得重组Bacmid质粒,将重组Baemid质粒转染Sf9昆虫细胞制备重组杆状病毒毒液,并继续扩增重组杆状病毒,以第三代毒液感染Sf9昆虫细胞,96h后收获细胞.用间接免疫荧光(IFA)、SDS-PAGE和Western blot对表达产物进行鉴定和分析.结果 实验应用Bac-to-BacTM杆状病毒表达系统,成功构建了含普马拉类汉坦病毒核蛋白基因的重组杆状病毒表达载体.并在昆虫细胞中获得表达.IFA结果显示,感染细胞的胞浆中有亮绿色荧光颗粒,SDS-PAGE和Western blot检测细胞表达产物的50×103(M)的蛋白条带,证实重组病毒感染昆虫细胞后表达了相应的重组核蛋白,与预计的结果相符.并能与抗汉坦病毒抗体结合.结论 成功表达具有HOKV免疫原性及反应性的重组核蛋白,为研制HOKV的诊断试剂奠定了基础.     

胸腺素α1重组原核表达质粒的克隆及诱导表达

目的：构建胸腺素α1（Tα1）基因的原核表达质粒，并诱导表达。方法：根据Tα1的DNA序列设计引物，采用PCR法扩增Tα1的cDNA，将其克隆入T-vector，形成中介重组体pT—Tα1，再将其亚克隆至原核表达载体pGEX-3X，构建重组质粒pGEX-3X-Tα1，用内切酶酶切鉴定及DNA测序分析；将pGEX-3X-Tα1转入大肠杆菌，用RT-PCR方法检测宿主菌中Tα1mRNA，经IPTG诱导，用SDS—PAGE检测有无相应大小的Tα1融合蛋白表达。结果：经DNA测序和SDS—PAGE法鉴定，成功构建了Tα1重组质粒基因工程菌，表达和纯化了具有Tα1融合蛋白。结论：构建的Tα1重组质粒基因工程菌，表达和纯化了具有Tα1融合蛋白，为今后的研究打下了基础。     

Immunological properties of FMDV-gP64 fusion proteins expressed on SF9 cell and baculovirus surfaces

In the present report, we characterized the immune response and the protection conferred by recombinant baculoviruses or infected insect cells expressing the fusions gp64-P1 and gp64-site A FMDV antigens. Mice, vaccinated intraperitoneally with gp64-P1 immunogens, showed a low-antibody response and a variable degree of protection. However, when mice received recombinant baculoviruses or infected insect cells expressing the fusion protein gp64-site A, high-ELISA and seroneutralizing titers (SNT) against FMDV were elicited. All mice immunized with Sf9 cells expressing FMDV site A developed a protective immune response against challenge with virulent FMDV, indicating that the baculovirus display of foreign epitopes is a promising approach to biosynthetic vaccines.     

SEO型汉坦病毒全NP蛋白及NP蛋白型特异区编码基因的克隆、表达

目的：开发简单、可靠的HTN、SEO型汉坦病毒血清学分型检测方法。方法：应用RT－PCR法对全NP蛋白基因及其型特异区基因进行扩增，经TA克隆及Cui-SS、Cui-155杆状病毒载体的构件、转获重组杆状病毒，再感染Sf9细胞进行表达。结果：克隆与表达了SEO病毒NP蛋白的全蛋白编码区及型特异编码区（155到429氨基酸处的编码基因），全NP蛋白表达产物与病毒株感染Vero E6细胞的反应谱完全一致，型特异区表达产物与相应的型特异cAb结合。结论：建立了SEO型病毒全NP蛋白及NP蛋白型特异区编码基因的克隆和表达方法，为开发简便、可靠的SEO型血清学分型检验方法奠定了基础。     

Characterization of recombinant foot-and-mouth disease virus pentamer-like structures expressed by baculovirus and their use as diagnostic antigens in a blocking ELISA

Non-infectious recombinant pentamer-like structures of the foot-and-mouth disease virus (FMDV) were expressed by baculovirus, and the antigenicity and immunogenicity of the proteins were analyzed in a blocking ELISA for the detection of FMDV antibodies. The recombinant pentamer-like structures were produced in insect (Sf9) cells that were inoculated with recombinant baculoviruses that expressed, simultaneously, the genes for the P1 and 3C proteins of FMDV from individual promoters. The FMDV pentamer-like structures were processed by viral 3C protease, as shown in Western blots, and were antigenic, as revealed by their reactivities in an indirect ELISA. Analysis by CsCl gradient centrifugation showed that the pentamer-like structures were similar to authentic pentameric subunits from FMDV in terms of sedimentation velocity. Furthermore, the pentamer-like structures induced high levels of FMDV-specific antibodies in mice following immunization. Observations made under the electron microscope revealed that the pentamer-like structures expressed by insect cells self-assembled to form pentameric subunits of 7-8 nm in diameter, which resemble the authentic FMDV (23+/-2 nm in diameter). The results indicate that these pentamer-like structures are as antigenic and immunogenic as authentic FMDV, although the former are smaller in size. Based on these results, a blocking ELISA was developed using the recombinant pentamer-like structure. The ELISA showed specificity of 99.5% and sensitivity of 98.5% when tested with FMDV antibody-negative and -positive sera, respectively. This blocking ELISA is highly specific and offers many advantages over the current ELISAs that use inactivated FMDV antigen. This is the first report of the production and diagnostic application of recombinant pentameric subunits of FMDV.     

Influenza virus-like particles comprised of the HA, NA, and M1 proteins of H9N2 influenza virus induce protective immune responses in BALB/c mice

Avian influenza viruses represent a growing threat for an influenza pandemic. To develop recombinant vaccine for avian influenza of the H9N2 subtype, we expressed in insect cells virus-like particles (VLPs) consisting of three structural proteins of influenza A/Hong Kong/1073/99 (H9N2) virus. Upon infection of Sf9 cells with recombinant baculoviruses, the hemagglutinin (HA), neuraminidase (NA), and matrix (M1) proteins were co-expressed in the infected cells, self-assembled, and released into the culture medium as VLPs of 80–120 nm in diameter. VLPs exhibited functional characteristics of influenza virus including hemagglutination and neuraminidase activities. In BALB/c mice, VLPs elicited serum antibodies specific for influenza A/Hong Kong/1073/99 (H9N2) virus and inhibited replication of the influenza virus after challenge. Thus, VLPs represent a potential strategy for the development of human vaccines against avian influenza H9N2 viruses.     

Recombinant hemagglutinin protein of rinderpest virus expressed in insect cells induces humoral and cell mediated immune responses in cattle.

Rinderpest virus causes a highly contagious and often fatal disease in domestic and wild ruminants. The surface glycoproteins, hemagglutinin (H) and fusion (F) proteins of this enveloped virus are known to confer protective immunity in cattle. We have reported the generation of a recombinant baculovirus expressing H protein and studied its protective properties in cattle. In this report, we demonstrate that the recombinant baculovirus encoded H protein expressed in insect cells gets incorporated into extracellular baculovirus. Single administration of low doses of purified recombinant extracellular virus with or without adjuvant induces virus neutralizing antibody responses and bovine leukocyte antigen (BoLA) class II restricted helper T cell responses in cattle.     

Baculovirus surface display of sigmaC and sigmaB proteins of avian reovirus and immunogenicity of the displayed proteins in a mouse model

Avian reovirus (ARV), an important pathogen in poultry, causes arthritis, chronic respiratory disease, and malabsorption syndrome that cause considerable economic losses to the poultry industry. In present study, we have succeeded in construction of a universal baculovirus surface display system (UBSDS) that can display different foreign proteins on the envelope of baculovirus. Sequences encoding the signal peptide (SS), transmembrane domain (TM), and cytoplasmic domain (CTD) derived from the gp64 protein of baculovirus and histidine tag, respectively were inserted into the pBacCE vector. Four restriction enzyme sites between the histidine tag and gp64 transmembrane domain were established for expression of different foreign proteins. The transmembrane domain and CTD of gp64 in the platform were designed in order to improve stability and quantity of foreign proteins on the envelope of baculovirus. The sigmaC and sigmaB proteins of ARV are known to elicit neutralizing antibodies against ARV. The UBSDS was therefore used to express sigmaC and sigmaB proteins on the envelope of baculovirus. Two recombinant baculoviruses BacSC-sigmaC and BacSC-sigmaB have been successfully constructed. After infection, both His6-tagged recombinant sigmaC (rsigmaC) and sigmaB (rsigmaB) proteins were displayed on the envelope of recombinant baculoviruses and the recombinant viral proteins were anchored on the plasma membrane of Sf-9 cells, as revealed by immunofluorescence staining (IFS) and confocal microscopy. The antigenicity of rsigmaC and rsigmaB proteins was demonstrated by Western blotting assay. Immunogold electron microscopy demonstrated that both recombinant viruses displayed rsigmaC and rsigmaB proteins on the viral surface. Immunization of BALB/c mice with recombinant viruses, demonstrated that serum from the BacSC-sigmaC and BacSC-sigmaB treated models had significant higher levels of virus neutralization activities than the control groups. This demonstrates that the recombinant baculoviruses BacSC-sigmaC and BacSC-sigmaB can be a potential vaccine against ARV infections.