RNA干扰抗A型H1N1流感病毒的研究

目的 制备靶向A型H1N1流感病毒RNA聚合酶(PA)基因的小干扰RNA(siRNA),研究其抑制病毒复制的效果.方法 设计并合成3对靶向A型H1N1流感病毒PA基因的siRNA,构建表达质粒pS-PA646、pS-PA841、pS-PA1537,分别转染MDCK细胞及鸡胚,并感染H1N1亚流感病毒,检测siRNA抑制流感病毒复制的效果.结果 设计的3对siRNA中,pS-PA1537可明显抑制A型H1N1流感病毒在MDCK细胞及鸡胚中的复制.结论 该研究为开发抗H1N1治疗制剂研究奠定了基础.     

2009H1N1流感病毒对A549细胞和BEAS-2B细胞作用的初步研究

目的 探求2009H1N1流感病毒对A549细胞和BEAS-2B细胞作用,为研究2009H1N1流感病毒的致病机理提供线索。方法 不同来源(死亡、重症、普通病例分离)的2009H1N1流感病毒和季节性H1N1流感病毒分别感染A549和BEAS-2B细胞12、24、48、72 h后用流式细胞术检测细胞凋亡和细胞周期。结果 感染A549细胞12和24 h,普通病例分离的2009H1N1流感病毒组的细胞凋亡率最高(P<0.05),重症组的细胞凋亡率最低(P<0.05);48 h和72 h,死亡组细胞凋亡率最高(P<0.05)。感染BEAS-2B细胞12 h,重症组细胞凋亡率最高(P<0.05);48 h,死亡组和重症组细胞凋亡率高(P<0.05);72 h,死亡组和普通组细胞凋亡率高(P<0.05)。4株病毒主要将A549细胞阻滞在S期,将BEAS-2B细胞阻滞在G0/G1期。结论 在细胞凋亡和细胞周期的细胞学观察水平上2009H1N1流感病毒和季节性H1N1流感病毒之间存在差异,不同来源的2009H1N1流感病毒之间也存在差异。     

我国鸡源与人源H9N2亚型流感病毒聚合酶PB1基因的关系分析

目的　通过对 1996～ 2 0 0 1年自我国部分养鸡场分离鉴定的 8株H9N2亚型鸡流感病毒聚合酶PB1基因测序 ,了解鸡源与人源H9N2亚型流感病毒聚合酶PB1基因的关系。方法　病毒在鸡胚中传代 ,自收获的尿囊液提取RNA ,通过RT-PCR ,扩增聚合酶PB1基因片段 ,并进行序列测定 ,测序结果采用PHYLIP软件在Internet网上分析处理 ,并用TreeView软件绘制系统进化树。结果　 8株H9N2亚型鸡流感病毒聚合酶PB1基因的核苷酸同源性为 97 4 %～ 99 7% ,与三株人源H9N2病毒A/Guangzhou/ 333/ 99、A/HongKong/ 10 73/ 99、A/HongKong/ 10 74 / 99的同源性分别为 90 6 %～ 91 9%、90 4 %～91 5 %、90 2 %～ 91 3%。该 8株鸡源H9N2病毒PB1基因属于相同的进化分支 ,即A/duck/HongKong/Y2 80 / 97-like分支 ,而与该 3株人源株H9N2病毒属于不同的进化分支 ;尚未发现PB1基因属于A/ quail/HongKong/G1/ 97或A/duck/Hong/Y4 39/ 97分支的鸡源分离株。结论　在我国养鸡业流行的H9N2病毒分离株与目前已分离的人源株H9N2病毒其PB1基因属于不同的进化亚分支 ,人源株H9N2病毒PB1基因不是来源于鸡源H9N2病毒。     

利用CRISPR/Cas9技术构建FSTL1基因敲除的SiHa细胞稳定株

目的利用CRISPR/Cas9技术敲除SiHa细胞中的卵泡抑素样蛋白1(FSTL1)基因,构建FSTL1基因敲除的SiHa细胞稳定株。方法构建sgRNA-FSTL1重组质粒并包装成慢病毒。收集病毒液并感染SiHa细胞,使用嘌呤霉素筛选FSTL1基因敲除的SiHa细胞稳定株;采用RT-qPCR和Western blot检测SiHa细胞稳定株FSTL1 mRNA和蛋白的表达情况。结果 FSTL1-sgRNA慢病毒构建成功并筛选出FSTL1基因敲除的SiHa细胞稳定株;FSTL1的mRNA和蛋白表达水平在SiHa细胞稳定株中的表达量均比对照组低,差异有统计学意义(P0.05)。结论利用CRISPR/Cas9技术成功构建FSTL1基因敲除的SiHa细胞稳定株。     

广西猪源A(2009/H1N1)流感病毒的进化分析及其致病性研究

目的对一株分离自广西兴安的猪源A(2009/H1N1)流感病毒进行遗传演化分析及致病性研究,为流感疫情防控提供科学依据。方法通过SPF鸡胚进行流感病毒分离,对8个基因进行RT-PCR扩增、测序及进化分析;以6周龄雌性BALB/c小鼠为感染模型进行病毒滴定,分析临床数据评估病毒致病性。结果分离的甲型H1N1病毒株A/swine/Guangxi/18/2013(H1N1)HA、NS和NP基因属于古典型H1N1,NA和M基因源于类禽型H1N1,PA和PB2基因归属禽源,PB1基因来自人源H3N2。HA裂解位点序列为PSIQSR↓GLF,具有低致病性特征。以50μl 10~6 TCID_(50)感染小鼠后其体重发生明显变化,最高体重平均变化率为86.98%,死亡率为12.5%;感染第3 d测定肺、鼻甲病毒滴度(Log_(10) TCID_(50)/ml)分别为5.25±0.28和3.89±0.47。结论 A/swine/Guangxi/18/2013(H1N1)为2009/H1N1流感病毒,能感染小鼠而造成体重下降并产生明显的临床症状。该病毒能在小鼠肺与鼻甲中进行复制,具有低致病性特征。     

通用H5N1亚型禽流感病毒样颗粒疫苗的制备

目的高致病性H5N1亚型流感病毒可感染人,并不断衍生出多个新的基因谱系,存在着大规模流行的可能性。我国现有的商品化疫苗无法对不同谱系的H5N1流感病毒感染提供有效的保护。病毒样颗粒(Virus-like particles,VLPs)疫苗具有良好的免疫原性和安全性,成为近年研究的热点。本研究旨在建立H5亚型禽流感病毒通用型病毒样颗粒疫苗的制备方法。方法将优化的H5N1 A/meerkat/Shanghai/SH-1/2012(clade 2.3.2.1)亚型流感病毒的HLHA(HA stem)/5M2e(5个M2e)/HL5M2e(5M2e替代HA的头部嵌入HLHA)、NP基因和M1基因分别插入pFastBacDual载体,得到相应的重组供体。然后将重组供体转化至含Bacmid的DH10Bac感受态细胞中,获得含有目的基因的重组杆粒。结果酶切和PCR鉴定表明成功构建了含目的基因的重组杆粒Bacmid-(HLHA/5M2e/HL5M2e、NP、M1)。将重组杆粒转染Sf9昆虫细胞,IFA试验和Western blot试验皆证实,优化的HLHA(HA stem)/5M2e/HL5M2e、NP基因和M1基因编码的蛋白均获得表达。透射电子显微镜观察VLPs转染Sf9细胞上清的浓缩液中,有球形结构和100 nm左右典型VLPs存在。结论在Sf9昆虫杆状病毒表达系统中成功表达H5N1 A/meerkat/Shanghai/SH-1/2012(clade 2.3.2.1)亚型禽流感病毒的HLHA(HA stem)/5M2e/HL5M2e、NP和M1蛋白,并组装成3种VLPs,为进一步研究流感病毒的VLPs疫苗奠定了基础。     

利用常间回文重复序列丛集及相关蛋白9系统敲除小鼠肾集合管上皮细胞系的水通道蛋白2基因

目的利用常间回文重复序列丛集(CRISPR)/CRISPR相关蛋白9(Cas9)系统敲除小鼠肾内髓集合管3(m-IMCD3)上皮细胞的水通道蛋白2(Aqp2)基因。方法在小鼠Aqp2基因的第1、4个外显子上各设计两个小向导RNA(sgRNA),分别为sgRNA1-1、sgRNA1-2、sgRNA4-1、sgRNA4-2,并将其成功克隆进常间回文重复序列丛集慢病毒载体2上。将测序正确的质粒转染到m-IMCD3细胞中,提取各单克隆细胞系的基因组DNA,通过聚合酶链反应扩增出sgRNA作用靶点的DNA片段并测序。利用逆转录聚合酶链反应(RT-PCR)及免疫荧光检测Aqp2的表达。结果成功构建出含有相应sgRNA的载体;4个sgRNA对Aqp2基因的靶点都有切割作用;sgRNA1-1与sgRNA4-2组合能成功把两者间5500bp的DNA片段敲除;应用RT-PCR及免疫荧光证实应用CRISPR/Cas9系统敲除Aqp2后,该m-IMCD3细胞系中的Aqp2mRNA及蛋白几乎未见表达。结论通过CRISPR/Cas9系统可获得Aqp2基因敲除的肾集合管上皮细胞系。     

泰安市甲型H3N2流感病毒HA1氨基酸变异特点分析

目的了解2006~2008年泰安市甲型H3N2流感病毒HA1基因变异特征。方法采集本地区流感样病例咽拭子,分离病毒,选择甲型H3N2流感病毒,提取核酸,采用逆转录-聚合酶链反应(RT-PCR)扩增并测序,推导其编码氨基酸序列,进行基因进化特征分析。结果 2006~2008年共检测咽拭子524份,分离出流感病毒119株,分离阳性率为22.71%。119株流感病毒中H3N2亚型65株,H1N1亚型2株,B型Victoria系13株,B型Yamagata系39株。对8株H3N2病毒进行基因进化树分析,在其推导HA1蛋白分子抗原决定簇A上有3个氨基酸位点(R142G、N144D和I140K)发生突变。结论在近2个年度的流行季节中,本地区以H3N2亚型和B型Yamagata系为优势毒株,也有B型Victoria系和甲型H1N1亚型的存在。泰山分离株HA1区发生氨基酸替换的位点较少。WHO推荐A/Wisconsin/67/2005为北半球2006~2008年度的流感疫苗株,泰山分离株与此疫苗株的相似性较高,因此认为该流感疫苗对当年度优势株H3N2流感病毒的预防有一定效果。     

A/深圳/1/99(H3N2)病毒抗原性及基因特性研究

目的　了解A/深圳 /1/99(H3N2 )病毒抗原性和基因特性 ,为促进深圳地区流感监测水平和流感病毒基因库建立提供科学资料。方法　鸡胚传代病毒 ,收获尿囊液作为抗原性分析抗原并提取病毒的RNA ,进行逆转录 -聚合酶链式反应(PT -PCR) ,扩增产物用纯化试剂盒纯化后测序 ,用MegAlign软件进行基因种系发生树分析。结果　A/深圳 /1/99(H3N2 )病毒抗原与其他毒株均存在着差异 ;他的HA1蛋白分子上共有 8个潜在的糖基化位点 ,除比A/武汉 /35 9/95 (H3N2 )病毒多了一个外 ,与其他毒株均相同 ;基因发生树分析表明 ,它与A/福建 /15 1/2 0 0 0毒株最相近 ,其次最接近的为A/莫斯科 /10 /99毒株。结论　A/深圳 /1/99(H3N2 )毒株为A/福建 /15 1/2 0 0 0类似株 (国内代表性毒株 )分离出时比后者早     

65例甲型H1N1观察病人的护理

甲型H1N1流感病毒是A型流感病毒,携带有H1N1亚型猪流感病毒毒株,包含有禽流感、猪流感和人流感三种流感病毒的核糖核酸基因片断,同时拥有亚洲猪流感和非洲猪流感病毒特征。《中华人民共和国传染病防治法》于2009年7月将甲型H1N1流感规定为乙类传染病,并采取乙类传染病的预防、     

Compatibility of H9N2 avian influenza surface genes and 2009 pandemic H1N1 internal genes for transmission in the ferret model

In 2009, a novel H1N1 influenza (pH1N1) virus caused the first influenza pandemic in 40 y. The virus was identified as a triple reassortant between avian, swine, and human influenza viruses, highlighting the importance of reassortment in the generation of viruses with pandemic potential. Previously, we showed that a reassortant virus composed of wild-type avian H9N2 surface genes in a seasonal human H3N2 backbone could gain efficient respiratory droplet transmission in the ferret model. Here we determine the ability of the H9N2 surface genes in the context of the internal genes of a pH1N1 virus to efficiently transmit via respiratory droplets in ferrets. We generated reassorted viruses carrying the HA gene alone or in combination with the NA gene of a prototypical H9N2 virus in the background of a pH1N1 virus. Four reassortant viruses were generated, with three of them showing efficient respiratory droplet transmission. Differences in replication efficiency were observed for these viruses; however, the results clearly indicate that H9N2 avian influenza viruses and pH1N1 viruses, both of which have occasionally infected pigs, have the potential to reassort and generate novel viruses with respiratory transmission potential in mammals.     

Influenza virus H1N1 induced apoptosis of mouse astrocytes and the effect on protein expression

Objective:To investigate the effects of influenza A virus H1N1 infection on the proliferation and apoptosis of mouse astrocytes cells and its protein expression.Methods:After mouse astrocytes was infected with purified influenza A virus H1N1 in vitro,viral integration and replication status of the cells were detected by RT-PCR assay,cell proliferation and apoptosis was determined by MTT method and flow cytometry,respectively.Associated protein expression was delected by Western blotting.Results:Agarose gel electrophoresis showed H1N1 virus can infect astrocytes and can be copied.MTT staining showed H1N1 virus infection can inhibit the proliferation of mouse astrocytes,which makes cell viability decreased significantly.Flow cytometry showed that the proportion of Annein V staining positive vascular endothelial cells in the influenza A virus group was significantly higher than that in the control group.Western blot analysis showed after24 h and 32 h of infection,there were cells caspase-3 protein and the expression of its active form(lysed caspase-3 protein)increased.The proportion of Bax/Bcl-2 also increased.Conclusions:Influenza A virus can infect human vascular endothelial cells and proliferation and it can induce apoptosis of endothelial cells.     

Live attenuated H5N1 vaccine with H9N2 internal genes protects chickens from infections by both Highly Pathogenic H5N1 and H9N2 Influenza Viruses

Please cite this paper as: Nang et al. (2013) Live attenuated H5N1 vaccine with H9N2 internal genes protects chickens from infections by both Highly Pathogenic H5N1 and H9N2 Influenza Viruses. Influenza and Other Respiratory Viruses 7(2) 120–131. Background The highly pathogenic H5N1 and H9N2 influenza viruses are endemic in many countries around the world and have caused considerable economic loss to the poultry industry. Objectives We aimed to study whether a live attenuated H5N1 vaccine comprising internal genes from a cold‐adapted H9N2 influenza virus could protect chickens from infection by both H5N1 and H9N2 viruses. Methods We developed a cold‐adapted H9N2 vaccine virus expressing hemagglutinin and neuraminidase derived from the highly pathogenic H5N1 influenza virus using reverse genetics. Results and Conclusions Chickens immunized with the vaccine were protected from lethal infections with homologous and heterologous H5N1 or H9N2 influenza viruses. Specific antibody against H5N1 virus was detected up to 11 weeks after vaccination (the endpoint of this study). In vaccinated chickens, IgA and IgG antibody subtypes were induced in lung and intestinal tissue, and CD4+ and CD8+ T lymphocytes expressing interferon‐gamma were induced in the splenocytes. These data suggest that a live attenuated H5N1 vaccine with cold‐adapted H9N2 internal genes can protect chickens from infection with H5N1 and H9N2 influenza viruses by eliciting humoral and cellular immunity.     

利用CRISPR/Cas9慢病毒载体构建敲除大鼠肝星状细胞COX-2基因的细胞模型

目的通过构建CRISPR/Cas9慢病毒载体,转染HSC-T6细胞,获得能稳定表达Cas9蛋白的HSC-T6细胞和COX-2基因缺陷的HSC-T6-COX-2-/-细胞,为后期的功能研究提供良好的工具和手段,为临床上治疗肝纤维化提供新策略。方法设计合成COX-2基因特异性的sgRNA(COX-2-sgRNA-1、COX-2-sgRNA-2、COX-2-sgRNA-3),并将其连接至GV371载体上,提取重组后的质粒,将其与包装质粒共同转染到293T细胞,形成慢病毒颗粒,荧光法检测病毒滴度。按照MOI值计算病毒最适用量,先将Lenti-Cas9-puro转染至HSC-T6细胞,嘌呤霉素筛选得到HSC-T6-Cas9细胞,再用Lenti-COX-2-sgRNA-EGFP转染至HSC-T6-Cas9细胞获得HSC-T6-COX-2-/-细胞,通过Cruiser酶切检测及Western Blot等方法在基因和蛋白水平上进行敲除验证。计量资料多组间比较采用方差分析,进一步两两比较采用LSD-t检验。结果通过测序验证COX-2-sgRNA表达载体构建成功。重组表达质粒和包装质粒共同转染到293T细胞,形成慢病毒颗粒,荧光法检测病毒滴度均在1×108以上。成功构建能稳定传代的Cas9蛋白的HSC-T6细胞和COX-2基因缺陷的HSC-T6-COX-2-/-细胞模型。HSC-T6-Cas9细胞中LV-Cas9-Puro mRNA相对表达量(541.93±105.76)高于CON组细胞(1.00±0.02),差异具有统计学意义(t=12.995,P<0.01)。通过Cruiser酶切检测及Western Blot试验,结果提示CRISPR/Cas9慢病毒表达载体能在靶点起作用,其中COX-2-sgRNA-2敲除作用最明显,并且COX-2蛋白表达水平较CON组和NC组相比显著下降(P值均<0.05),提示COX-2-sgRNA有活性。结论成功构建了针对COX-2靶基因的CRISPR/Cas9慢病毒载体,获得稳定的COX-2基因敲除的HSC-T6-COX-2-/-细胞。     

Avian-to-human transmission of H9N2 subtype influenza A viruses: relationship between H9N2 and H5N1 human isolates

In 1997, 18 cases of influenza in Hong Kong (bird flu) caused by a novel H5N1 (chicken) virus resulted in the deaths of six individuals and once again raised the specter of a potentially devastating influenza pandemic. Slaughter of the poultry in the live bird markets removed the source of infection and no further human cases of H5N1 infection have occurred. In March 1999, however, a new pandemic threat appeared when influenza A H9N2 viruses infected two children in Hong Kong. These two virus isolates are similar to an H9N2 virus isolated from a quail in Hong Kong in late 1997. Although differing in their surface hemagglutinin and neuraminidase components, a notable feature of these H9N2 viruses is that the six genes encoding the internal components of the virus are similar to those of the 1997 H5N1 human and avian isolates. This common feature emphasizes the apparent propensity of avian viruses with this genetic complement to infect humans and highlights the potential for the emergence of a novel human pathogen.     

A Crucial Role of ACBD3 Required for Coxsackievirus Infection in Animal Model Developed by AAV-Mediated CRISPR Genome Editing Technique

Genetic screens using CRISPR/Cas9 have been exploited to discover host–virus interactions. These screens have identified viral dependencies on host proteins during their life cycle and potential antiviral strategies. The acyl-CoA binding domain containing 3 (ACBD3) was identified as an essential host factor for the Coxsackievirus B3 (CVB3) infection. Other groups have also investigated the role of ACBD3 as a host factor for diverse enteroviruses in cultured cells. However, it has not been tested if ACBD3 is required in the animal model of CVB3 infection. Owing to embryonic lethality, conventional knockout mice were not available for in vivo study. As an alternative approach, we used adeno-associated virus (AAV)-mediated CRISPR genome editing to generate mice that lacked ACBD3 within the pancreas, the major target organ for CVB3. Delivery of sgRNAs using self-complementary (sc) AAV8 efficiently induced a loss-of-function mutation in the pancreas of the Cas9 knock-in mice. Loss of ACBD3 in the pancreas resulted in a 100-fold reduction in the CVB3 titer within the pancreas and a noticeable reduction in viral protein expression. These results indicate a crucial function of ACBD3 in CVB3 infection in vivo. AAV-mediated CRISPR genome editing may be applicable to many in vivo studies on the virus–host interaction and identify a novel target for antiviral therapeutics.     

High genetic compatibility and increased pathogenicity of reassortants derived from avian H9N2 and pandemic H1N1/2009 influenza viruses

H9N2 influenza viruses have been circulating worldwide in multiple avian species and repeatedly infecting mammals, including pigs and humans, posing a significant threat to public health. The coexistence of H9N2 and pandemic influenza H1N1/2009 viruses in pigs and humans provides an opportunity for these viruses to reassort. To evaluate the potential public risk of the reassortant viruses derived from these viruses, we used reverse genetics to generate 127 H9 reassortants derived from an avian H9N2 and a pandemic H1N1 virus, and evaluated their compatibility, replication ability, and virulence in mice. These hybrid viruses showed high genetic compatibility and more than half replicated to a high titer in vitro. In vivo studies of 73 of 127 reassortants revealed that all viruses were able to infect mice without prior adaptation and 8 reassortants exhibited higher pathogenicity than both parental viruses. All reassortants with higher virulence than parental viruses contained the PA gene from the 2009 pandemic virus, revealing the important role of the PA gene from the H1N1/2009 virus in generating a reassortant virus with high public health risk. Analyses of the polymerase activity of the 16 ribonucleoprotein combinations in vitro suggested that the PA of H1N1/2009 origin also enhanced polymerase activity. Our results indicate that some avian H9-pandemic reassortants could emerge with a potentially higher threat for humans and also highlight the importance of monitoring the H9-pandemic reassortant viruses that may arise, especially those that possess the PA gene of H1N1/2009 origin.