表达绿色荧光蛋白的重组人偏肺病毒的构建及其中和抗体检测方法的应用

人偏肺病毒(hMPV)是最新发现的与呼吸道疾病有关的病原体.为构建表达增强型绿色荧光蛋白(EGFP)的B型重组hMPV,本研究利用反向遗传学技术,以表达EGFP的hMPV NL/1/99株全长cDNA质粒重组pPS-hMPV-EGFP,及其4种辅助重组质粒pCITE-N、pCITE-P、pCITE-L、pCITE-M2.1为基础,共转染BHK-21细胞进行重组病毒的拯救.鉴定结果表明拯救的重组病毒rhMPV-NL-EGFP高效表达外源基因EGFP.rhMPV-NL-EGFP与亲本病毒株具有相似的生物学特性,生长滴度可达106.7 TCID50/mL.rhMPV-NL-EGFP在细胞中连续传代10代仍然维持外源基因的高效和稳定表达,病毒滴度于室温条件下可维持长时间稳定.分别利用亲本病毒株和重组病毒rhMPV-NL-EGFP进行免疫小鼠血清中和抗体检测,结果显示两种方法具有较好的相似性(p＞0.05).本研究为病毒中和抗体的检测提供了更为快捷的新方法,同时为hMPV感染发病机制及疫苗研究奠定了基础.     

重组辛德毕斯病毒E基因痘苗病毒的构建

为了构建表达辛德毕斯病毒E基因的重组痘苗病毒,本研究通过基因重组的方法将辛德毕斯病毒E基因及绿色荧光蛋白（enhanced green fluorescent protein,EGFP）基因分别连接至痘苗病毒转移载体pSTK,酶切鉴定得到阳性重组质粒pSTK-SINE-EGFP。采用脂质体转染的方法,将该重组质粒与痘苗病毒天坛株共转染BHK-21细胞,通过同源重组获得重组痘苗病毒。利用EGFP筛选阳性重组痘苗病毒vTTVV-SINE-EGFP,收集感染重组痘苗病毒的BHK-21细胞,SDS-PAGE电泳检测辛德毕斯病毒E基因在细胞中的表达情况,Western blot分析表达产物的免疫原性。结果证明辛德毕斯病毒E基因能在重组痘苗病毒vTTVV-SINE-EGFP中获得表达,且表达产物具有良好的免疫原性。表达辛德毕斯病毒E基因的重组痘苗病毒的成功构建,为研制辛德毕斯病毒活载体疫苗奠定了基础。     

狂犬病病毒囊膜糖蛋白基因DNA免疫研究

狂犬病病毒(RV)囊膜糖蛋白(G)是该病毒诱导保护性免疫反应的主要抗原.为研究G蛋白基因的DNA免疫效果,本研究构建了表达哺乳动物密码子优化的RVG基因的重组真核表达质粒pCAGG-RVG,间接免疫荧光试验及westem blot结果表明,重组RV G基因在pCAGG-RVG转染的BHK-21细胞中获得正确表达.将pCAGG-RVG按500 μg剂量经肌肉注射途径免疫比格犬,间隔4周以相同剂量、途径加强免疫一次,并于初次免疫前、后不同时间检测血清RV的中和抗体.结果显示,pCAGG-RVG一次免疫即可诱导产生显著的中和抗体反应,二次免疫中和抗体滴度表现出显著地增强效果.二次免疫后,中和抗体滴度缓慢下降,保持持续平稳,至初次免疫后第54周,7只免疫犬病毒中和抗体滴度平均为2.88 IU/mL,并且全部高于0.5 IU/mL,即全部高于对强毒攻击保护的最低中和抗体滴度要求.因此,本研究构建的pCAGG-RVG具有预防狂犬病的潜力,是一种有希望的狂犬病候选疫苗.     

口蹄疫病毒VP2基因重组表达载体的构建及其稳定表达细胞系的建立

本试验旨在构建Asia 1型口蹄疫病毒(FMDV)的VP2基因重组表达载体,并建立稳定表达VP2基因的BHK-21细胞系。利用RT-PCR方法扩增Asia 1型FMDV的cDNA,获得VP2基因完整的编码区,构建可表达VP2的带有绿色荧光蛋白标记基因的pIRES2-EGFP-VP2重组表达载体。经鉴定正确后,利用LipofectamineTM2000将重组质粒转染293T细胞,通过Western Blot技术检测VP2蛋白的瞬时表达;然后再转染BHK-21细胞,通过G418筛选,形成单克隆细胞系,经荧光筛选到表达EGFP的抗性单克隆细胞,扩繁培养克隆细胞,再通过West-ern Blot技术检测其VP2的表达,最终筛选到稳定表达FMDVVP2基因的BHK-21细胞系。结果表明,VP2基因重组表达载体pIRES2-EGFP-VP2构建正确,能够在293T细胞内瞬时表达;转染BHK-21细胞,经G418筛选到表达VP2基因的BHK-21细胞克隆,经长达60d的传代,获得了稳定表达VP2基因和EGFP的BHK-21细胞系。上述结果表明,我们建立了稳定表达VP2基因的BHK-21细胞系,为进一步探讨VP2基因在FMD...     

牛干扰素诱导跨膜蛋白3对口蹄疫病毒感染的抑制作用

为了研究牛干扰素诱导跨膜蛋白3(bIFITM3)对O型口蹄疫病毒(FMDV)的抑制作用,本试验将表达bIFITM3的重组质粒pLV-bIFITM3和表达增强型绿色荧光蛋白(EGFP)的对照质粒pLV-EGFP分别转染BHK-21细胞,通过嘌呤霉素抗性筛选获得能够稳定表达外源基因的细胞系。用O型FMDV感染稳定细胞系,通过观察细胞病变、噬斑分析和实时荧光定量PCR方法评价bIFITM3对O型FMDV感染的抑制作用。结果表明,成功筛选获得稳定表达bIFITM3与EGFP的BHK-21细胞系,bIFITM3表达后显著抑制FMDV感染BHK-21细胞,且抑制作用在病毒感染循环的早期阶段就已显现。本试验证明bIFITM3在FMDV感染中具有抗病毒作用,为口蹄疫的防控研究提供新的思路和理论依据。     

狂犬病病毒糖蛋白在Bac-to-bac杆状病毒系统中的表达及应用

为表达狂犬病病毒(RV)糖蛋白(G),本研究通过RT-PCR方法克隆RV Flury LEP病毒株G基因,将其克隆至质粒pFastBacHTα中,重组质粒pFastBac-RV-G转化DH10Bac感受态细胞,经同源重组获得重组杆状病毒穿梭质粒Bacmid-RV-G,将其转染昆虫细胞sf21获得含有G基因的重组杆状病毒.采用SDS-PAGE和western blot对重组蛋白进行鉴定及抗原性分析,以重组G蛋白作为包被抗原的ELISA检测36份犬血清样品.结果表明,在Bac-to-bac杆状病毒系统中表达的RV G蛋白能与his-tag单克隆抗体及RV阳性血清发生特异性反应,其相对分子量为60 ku;与以RV为包被抗原的商品化ELISA试剂盒相比,以重组RV G蛋白为抗原建立的间接ELISA的敏感性、特异性和符合率分别为80%、81.8%和80.6%,表明杆状病毒系统表达的RV G蛋白是检测RV抗体的理想抗原蛋白,作为一种亚单位疫苗具有潜在的应用前景.     

表达绿色荧光蛋白的复制缺陷型西尼罗病毒的构建

为构建表达绿色荧光蛋白(GFP)的复制缺陷型西尼罗病毒(WNV),本研究参考NY99株WNV基因组序列,分段合成除结构蛋白基因外的其它基因组序列,以及插入缺失的结构蛋白基因位置的gfp报告基因序列,并按WNV基因组顺序克隆于pCI-neo载体中,构建含有GFP基因的WNV复制子重组质粒pWNVrep-GFP;同时构建表达WNVC蛋白的重组质粒pCAG-WNV-C。将pWNVrep-GFP和pCAG-WNV-C共转染稳定表达WNVprM-E蛋白的W-92细胞系进行WNV粒子包装及病毒粒子拯救。结果显示转染细胞能够表达GFP,将转染细胞培养液接种BHK-21细胞后,能感染细胞并且表达GFP,westernblot可以检测到分子质量为42ku的NS1蛋白条带。然而,感染BHK-21细胞的培养液不能再感染BHK-21细胞,表明拯救的病毒只具有一次感染能力,为复制缺陷型病毒。WNV阳性血清能中和拯救病毒对BHK-21细胞的感染,该复制缺陷型病毒为WNV中和抗体检测和疫苗评价提供了相关的技术平台。     

缺失E3L基因减毒天坛株痘苗病毒的构建及筛选

通过在E3L同源重组臂中插入含有增强型痘苗病毒早晚期启动子（pE／L）、增强型绿色荧光蛋白基因和同向Loxp（Locus of X-overP1）序列的表达盒构建穿梭质粒pTE—EGFP。利用pTE—EGFP和野生型天坛株痘苗病毒共转染仓鼠肾细胞（BHK-21）,通过对绿色荧光蚀斑的10次筛选,构建缺失E31．基因并含有EGFP基因的重组痘苗病毒rTTVV-TE-EGFP＋利用rTTVV—TE-EGFP＋和含有Cre（Cyclization recombination）重组酶基因的重组质粒pVAX1-Cre共转染BHK-21细胞,通过对无荧光蚀斑的10次筛选,构建无筛选标记的天坛株痘苗病毒减毒株rTTVV—TE一,并利用聚合酶链式反应（PCR）对其进行鉴定。鉴定结果显示,rTTVV-TE-中无ESI。基因转录和EGFP基因表达。以上结果说明,所构建的痘苗病毒减毒株rTTVV—TE--完全缺失了E3L基因和外源筛选标记EGFP基因,且具有良好的遗传稳定性。     

羊口疮病毒VIR蛋白生物活性鉴定及表位预测

为研究羊口疮病毒(ORFV)VIR蛋白的生物活性,扩增了绿色荧光蛋白基因EGFP和ORFV的VIR基因,构建了真核表达载体pVAX1-EGFP和pVAX1-VIR-EGFP,转染至BHK-21细胞,在荧光显微镜下进行了EGFP和VIR与EGFP融合蛋白的绿色荧光检测,用ORFV的全病毒血清作一抗,进行了Western ...     

狂犬病病毒糖蛋白跨膜区和膜内区的替换对其生物学特性的影响

为研究表达狂犬病病毒(RV)糖蛋白(G)重组新城疫病毒(r L-RVG)中RV G跨膜区(TM)及膜内区(CT)对RV G蛋白表达、病毒蚀斑的形成以及免疫原性的影响,本研究采用新城疫病毒(NDV)融合蛋白(F)的TM和CT替换G蛋白的相应部分,构建出表达RV嵌合G蛋白(RVGTC)的重组NDV(r L-RVGTC)。激光共聚焦和western blot检测结果显示,r L-RVG和r L-RVGTC在BHK-21细胞中RVG表达量无显著差异;而且r L-RVG与r L-RVGTC在鸡胚中的病毒增殖滴度也无显著差异。但间接免疫荧光结果表明,r L-RVGTC在BHK-21细胞中丧失RV或r L-RVG形成病毒蚀斑的能力。并且以5×107半数鸡胚感染量(EID50)的r L-RVG和r L-RVGTC分别免疫小鼠后,r L-RVGTC诱导产生的RV中和抗体的滴度显著低于r L-RVG诱导的滴度。本实验结果显示TM和CT对RV G的病毒蚀斑形成及其免疫原性是必不可少的。     

Response of cattle persistently infected with bovine virus diarrhoea virus to bovine leukosis virus

Six cattle persistently infected with bovine virus diarrhoea virus (BVDV) and seronegative, and two control, virus negative seropositive cattle were inoculated with lymphocytes infected with bovine leukosis virus (BLV). The two controls produced a normal immune response to BLV, developing antibodies at four and five weeks after inoculation. Two of the six cattle persistently infected with BVDV developed a strong antibody response by six weeks after inoculation with BLV. Four developed a depressed response to BLV, characterised in three by a 'hooking' reaction in the immunodiffusion test which persisted in successive bleedings but was interspersed occasionally by a weak positive reaction. In one of these animals, a series of 'hooking' reactions was followed by a number of negative results. The fourth animal remained serologically negative until 16 weeks after inoculation when a 'hooking' reaction was observed followed by a series of negative results. BLV was isolated from all the cattle persistently infected with BVDV at 42 or 58 weeks after inoculation regardless of whether the serum samples gave negative, 'hooking', weak positive or positive reactions in the immunodiffusion test. BLV was consistently isolated from the nasal secretions of a steer which was BVDV negative but seropositive. The possibility of decreased immune responsiveness to BLV in animals persistently infected with BVDV should be considered when formulating regulations governing the testing of animals for freedom from BLV.     

Detection of bovine virus diarrhea virus in a live bovine herpes virus 1 marker vaccine

In February 1999, 12 Dutch herds were vaccinated with a live bovine herpesvirus 1 vaccine from which bovine virus diarrhea virus (BVDV) could be isolated. All vaccine batches that were on the Dutch market and that had not yet reached the expiry date were tested for BVDV. In total, seven of 82 batches tested were found positive. Batch numbers TX3607, VB3914, VB3915, VB4046, TW3391, and TV3294 were positive for BVDV type 1, and batch number WG4622 was positive for BVDV type 2. This latter batch induced clinical signs of BVDV in an animal experiment with susceptible animals.     

登革病毒及其所致疾病的研究概况

登革病毒所致疾病包括登革热、登革出血热及登革休克综合征，是全球分布最广、发病最多的一种虫媒传染病．近年发病呈上升趋势，严重威胁人类健康。文章概述了登革热病原学、流行病学、发病机制、临床表现、诊断进展、治疗、预防和控制等。     

Evaluating the protective efficacy of a trivalent vaccine containing Akabane virus,Aino virus and Chuzan virus against Schmallenberg virus infection

Schmallenberg virus (SBV), an arthropod borne pathogen, spread rapidly throughout the majority of Europe since 2011. It can cause a febrile disease, milk drop, diarrhea, and fetal malformation in ruminants. SBV, a member of the Simbu serogroup within the genus Orthobunyavirus, is closely related to Akabane virus (AKAV) and Aino virus (AINOV) among others. In the present study, 4 Holstein-Friesian calves were immunized twice four weeks apart with a multivalent, inactivated vaccine against AKAV and AINOV. Another 4 calves were kept as unvaccinated controls. All animals were clinically, serologically and virologically examined before and after challenge infection with SBV. AKAV- and AINOV-specific neutralizing antibodies were detected one week before challenge infection, while SBV-specific antibodies were detectable only thereafter. SBV genome was detected in all vaccinated animals and 3 out of 4 controls in serum samples taken after challenge infection. In conclusion, the investigated vaccine was not able to prevent an SBV-infection. Thus, vaccines for other related Simbu serogroup viruses can not substitute SBV-specific vaccines as an instrument for disease control.     

The control of bovine virus diarrhoea virus in Shetland

A scheme to control and eradicate bovine virus diarrhoea (BVD) was initiated in 1994 in the Shetland Islands by local veterinary surgeons and funded by the Shetland Islands Council and Shetland Enterprise Company. Over a 3-year period every bovine animal on the islands was blood-sampled (heparinised) and laboratory tested using MAb-based ELISAs for BVD virus antibody and antigen detection for evidence of disease. A number of BVD virus positive animals (40) were found and culled. A total of 6150 animals were tested from 213 herds and 43% herds were found to be BVD naive. The remaining herds had experienced infection and contained many BVD antibody positive animals. Some repeat sampling of stock in infected herds determined further virus positive animals which were slaughtered and in 1997 the scheme ceased since it appeared that there were no persistent excretors present. The major risk to the Shetland Islands is from bought-in stock, especially animals which are imported in calf. It is vital that all bought-in animals are tested and proven to be free of BVD virus if these animals are in calf, the calves must be tested a birth to determine status. It is strongly advised that only bulls and bulling heifers or cows are bought into Shetland in future, thus, protecting the present stock. Continued surveillance will be required to claim eradication of BVD from Shetland.     

绵羊痘病毒和山羊痘病毒双重PCR检测方法的建立及应用

为建立鉴别绵羊痘病毒(SPPV)和山羊痘病毒(GTPV)的检测方法,本研究针对这2种病毒的基因组序列,分别设计2对特异性引物,通过对引物浓度、退火温度等的优化,建立了快速鉴别检测SPPV和GTPV的双重PCR方法。该方法分别扩增出SPPV长度为177 bp和GTPV长度为222 bp的目的片段。特异性试验结果显示,该方法对牛疙瘩皮肤病病毒、犬细小病毒、大肠杆菌O157、沙门氏菌、健康羊组织和牛组织均无扩增。敏感性试验显示,该方法最低可检测1.725×107copies/μL的SPPV和1.71×106copies/μL的GTPV。应用该方法对50份临床病料样品进行检测的结果与病毒分离鉴定结果一致,均检出5份感染GTPV的病料和2份感染SPPV的病料,表明该方法可以用于临床病料样品的检测。