H5N1-NP蛋白的原核表达及与宿主蛋白相互作用的初步研究

目的 原核表达并纯化禽流感病毒A/Anhui/1/2005（H5N1）的NP蛋白,并筛选人支气管上皮BEAS-2B细胞总蛋白中能够与纯化的NP蛋白相互作用的蛋白.方法 一方面,构建了含有NP基因的原核表达质粒pET30a-NP,并在大肠埃希菌中获得了可溶性表达.亲和层析和离子交换层析两步对NP蛋白进行纯化.另一方面,制备了BEAS-2B细胞总蛋白.在此基础上,联合应用Pull-down与LC-MS/MS技术来筛选并确认细胞中与纯化的NP蛋白相互作用的成分.结果 构建的pET30a-NP质粒在IPTG诱导下在原核细胞中实现了可溶表达,经过两步纯化后,得到可溶的NP蛋白纯品.Pull-down与LC-MS/MS技术初步筛选到BEAS-2B细胞中20个可能与NP蛋白相互作用的细胞蛋白.还需要进一步的实验来验证他们和NP蛋白之间的相互作用.结论 获得了高纯度的可溶NP蛋白及筛选到20个可能与其相互作用的BEAS-2B细胞候选蛋白.     

人高致病性H5N1亚型禽流感病毒NS1蛋白多克隆抗体的制备及鉴定

目的 制备高灵敏度和高特异性的人高致病性H5N1亚型禽流感病毒NS1蛋白抗体并对其效价进行初步评估.方法 构建含有H5N1亚型禽流感病毒NS1序列的pET-28a(+)重组载体的大肠埃希菌BL21(DE3),诱导表达NS1蛋白,并经Ni-NTA色谱柱亲和层析纯化获得NS1重组蛋白,并进行SDS-PAGE和Western Blot鉴定.以纯化的蛋白为抗原免疫新西兰大白兔,获得兔抗NS1血清,亲和纯化获得多克隆抗体.应用ELISA和Western Blot检测纯化抗体的效价和特异性.结果 NS1融合蛋白得到高表达,且纯度＞90％,用该融合蛋白免疫新西兰大白兔后得到的抗NS1多克隆抗体,效价达1∶80 000,并特异性识别H5N1亚型禽流感病毒NS1蛋白.结论 获得了NS1多克隆抗体,具有较好的效价和特异性.     

禽流感病毒非结构蛋白1单克隆抗体的制备及其特异性分析

为研制禽流感病毒(H5N1)非结构蛋白1(NS1)的特异性单克隆抗体(mAb),并鉴定其特异性,本研究在分别表达了具有良好抗原性的A/Vietnam/1194/04(H5N1)-NS1和A/HongKong/486/97(H5N1)-NS1重组蛋白基础上,用A/Viet-nam/1194/04(H5N1)-NS1蛋白免疫BALB/c小鼠,取其脾细胞与小鼠骨髓瘤细胞进行融合,间接ELISA筛选阳性的杂交瘤细胞,并结合免疫荧光和免疫印迹对抗体的特异性进行鉴定,通过竞争抑制实验对单抗识别的抗原位点进行分析。结果共获得19株能识别4个H5N1-NS1蛋白不同抗原位点的mAb,亚类测定显示,5株为IgG2a、1株为IgG2b,另外13株为IgG1。这些mAb均与A/Vietnam/1194/04(H5N1)-NS1和A/HongKong/486/97(H5N1)-NS1重组蛋白特异性结合,免疫荧光检测均与A型流感病毒(H1N1和H3N2)有交叉反应,而与B型流感病毒无交叉现象。表明成功获得特异性针对H5N1-NS1蛋白的mAb,为进一步研究禽流感病毒NS1蛋白的结构与功能奠定基础。     

H5N1流感病毒M1蛋白免疫制备的单克隆抗体的研究

目的 制备抗人流感病毒H5N1株M1蛋白的单克隆抗体,为流感的快速诊断和研究提供新的工具.方法 应用在大肠埃希菌中表达的人H5N1亚型禽流感病毒(A/Anhui/1/2005)株M1蛋白,以纯化的表达产物免疫BALB/c小鼠,取脾细胞与sp2/0细胞系作细胞融合后,间接ELISA法筛选阳性的杂交瘤细胞,并应用间接免疫荧光法对抗体的特异性进行鉴定.结果 获得3株能稳定分泌抗禽流感病毒M1抗原的McAb杂交瘤细胞株,交叉反应试验及间接免疫荧光检测表明,三株McAb具有型特异性.结论 用H5N1禽流感病毒M1蛋白免疫制备的单克隆抗体,具有一定的交叉反应性,可用于多种亚型甲型流感病毒的检测.     

甲型H1N1流感病毒非结构蛋白NS1真核表达载体的构建与表达

目的:构建甲型H1N1流感病毒非结构蛋白NS1真核表达载体并表达其编码蛋白(转染293T细胞)。方法:从江苏首例甲型H1N1流感病毒毒株(A/Nan jing/1/2009(H1N1))提取病毒RNA,采用RT-PCR技术扩增NS1全长基因,将其克隆至pMD18-T Vector中构建pMD18-T-NS1质粒,双酶切pMD18-T-NS1与PXJ40-HA后,构建真核表达载体PXJ40-HA-NS1,经酶切及测序鉴定后将质粒转染到293T细胞中,通过Western blot鉴定NS1蛋白的表达。结果:经双酶切、测序鉴定证实NS1基因的真核表达载体构建成功。West-ern blot法可见NS1基因编码蛋白的成功表达。结论:成功克隆NS1全长基因,并构建了其真核表达载体,该表达载体的构建为后期建立稳定表达NS1蛋白的细胞模型和NS1蛋白功能研究提供了材料。     

人H5N1流感病毒M1基因的亚克隆及其在原核细胞的表达

目的 构建人H5N1亚型禽流感病毒A/Anhui/1/2005 M1蛋白的原核表达系统,为进一步研究M1蛋白的生物学功能和制备其诊断试剂奠定基础。方法 以该病毒基因节段七cDNA为模板,PCR扩增得到M1基因片段。将该片段亚克隆至载体pQE80-L中,构建重组质粒pQE80-L/M1,转化大肠埃希菌BL21（ DE3）。IPTG诱导重组蛋白表达。金属镍离子螯合层析纯化N末端携带多聚组氨酸标签的重组M1蛋白,免疫小鼠制备多克隆抗体。结果 获得了重组M1蛋白,能与抗H5N1亚型流感病毒血清发生特异性结合,且其免疫后能诱导机体产生特异性抗体。结论 成功获得了人H5N1亚型禽流感病毒M1蛋白在原核细胞中高效表达。     

H5N1流感疫苗株在Vero细胞中的研究[英文]

目的产生在Vero(非洲绿猴肾)细胞中能高适应生长的重配H5N1流感病毒疫苗株,并对其生物学特性进行初步测定。方法修饰A/Puerto Rico/8/34(H1N1)(PR8)的NS基因为Vero细胞适应型,并合成NS基因片段,构建质粒pHW2000-NS;通过RT-PCR方法,扩增疫苗株A/Anhui/01/2005(H5N1)的HA、NA基因片段,构建质粒pHW2000-HA、pHW2000-NA;以PR8的其它5个内部基因作为骨架,按照1+2+5模式8质粒共转染Vero细胞拯救流感病毒,并对拯救病毒的生物学特性进行检测。结果由Vero拯救出具有高适应生长特性的H5N1亚型人禽流感病毒疫苗株,并检测了重配疫苗株的生物学特性。结论成功从Vero细胞拯救了具有Vero细胞高适应性生长特性的H5N1亚型人禽流感病毒疫苗株,为应用Vero细胞大规模生产流感疫苗奠定了基础。     

禽流感病毒(H5N1)血凝素蛋白真核表达载体的构建与表达

目的:构建禽流感病毒(H5N1)血凝素蛋白HA真核表达载体并表达其编码蛋白(转染293T细胞)。方法:从江苏H5N1流感病毒毒株(A/Jiangsu/07-4(H5N1))提取病毒RNA,采用RT-PCR技术扩增HA全长基因,将其克隆至pMD18-T Vector中构建pMD18-T-HA质粒,双酶切pMD18-T-HA与PXJ40-MYC后,构建真核表达载体PXJ40-MYC-HA,经酶切及测序鉴定后将质粒转染到293T细胞中,通过West-ern blot鉴定HA蛋白的表达。结果:经双酶切、测序鉴定证实HA基因的真核表达载体构建成功。Western blot法可见HA基因编码蛋白的成功表达。结论:成功构建了H5N1血凝素真核表达载体,该表达载体的构建为后期建立稳定表达HA蛋白的细胞模型和HA蛋白功能研究奠定了基础。     

利用反向遗传学技术构建H5N9重组流感病毒株

目的 利用反向遗传学技术构建来源人感染禽流感病毒H5N1和H7N9 HA和NA基因的H5N9亚型禽流感病毒.方法 全基因合成A/Beijing/01/2003(H5N1)禽流感病毒HA基因片段和A/Zhejiang/DTID-ZJU10/2013(H7N9)禽流感病毒NA基因片段,插入到pHW2000载体,与携带有A/Puerto Rico/8/34(H1N1)的6个内部基因的pHW2000重组质粒一起转染293T和MDCK混合细胞,拯救H5N9重组病毒.结果 核酸测序、HA和NA基因转录和表达检测、细胞病变分析确定利用该反向遗传学系统可以成功拯救H5N9病毒.重组H5N9病毒在MDCK细胞上复制增殖能力低于相同方法拯救H1N1病毒.结论 利用反向遗传学技术成功构建一株H5N9重组病毒.     

LMNA突变体HEK293、C2C12模型的构建及其核纤层蛋白A/C亚细胞定位

目的构建A型核纤层蛋白基因(LMNA)野生型、突变体的融合蛋白真核表达载体及LMNA突变体慢病毒载体,研究其在HEK293、C2C12中表达、核纤层蛋白A/C亚细胞定位及细胞核改变。方法将野生型全长LMNA cDNA克隆入pEGFP-N1质粒,构建LMNA野生型质粒pEGFP-N1-LMNA,以野生型质粒为模板构建c.1117A>G定点突变质粒pEGFP-N1-LMNA-I373V。将构建的2种质粒分别转染HEK293、C2C12,用G418筛选转染的C2C12,荧光显微镜下观察细胞核形态及GFP标记的核纤层蛋白A/C亚细胞定位。以pEGFP-N1-LMNA-I373V为模板,构建pHBLV-h-LMNA-I373V-3*flag-GFP-PURO慢病毒,对慢病毒进行包装与滴度测定。pHBLV-GFP-PURO、pHBLV-LMNA-C1117-3*flag-GFP-PURO分别转染C2C12,免疫荧光染色法观察转染后细胞核形态及核纤层蛋白A/C亚细胞定位的改变。结果构建的pEGFP-N1-LMNA、pEGFP-N1-LMNA-I373V及pHBLV-h-LMNA-I373V-3*flag-GFP-PURO测序与目的基因序列完全一致。pEGFP-N1-LMNA转染的HEK293、C2C12核纤层蛋白A/C均匀表达于核膜下,pEGFP-N1-LMNA-I373V转染的HEK293、C2C12内核纤层蛋白A/C核内异常聚集,呈散点样分布;与HEK293相比,C2C12细胞转染效率明显降低。慢病毒转染C2C12的转染率高,突变体慢病毒转染的细胞核形态异常及核纤层蛋白A/C核内分布异常。结论成功构建2种LMNA突变体真核表达载体及突变体转染的HEK293、C2C12模型,为LMNA突变体导致疾病的机制研究奠定科学基础。     

Induction of interferon-inducible protein-10 and monokine induced by interferon-gamma from human endothelial cells infected with Influenza A virus

Primary human umbilical vein endothelial cells (HUVECs) were infected with Influenza virus A/Aichi/2/68 (H3N2) in order to determine the role of endothelial cells in mediating inflammation induced upon virus infection. Structural proteins of the virus and mRNA of the M2 protein were detected in the infected cells, indicating that virus infection had occurred in HUVECs. The Influenza A virus-infected HUVECs showed elevated levels of gene expression of interferon (IFN)-inducible protein (IP)-10 and monokine induced by IFN-gamma (Mig), while heat-, formalin- and diethyl ether-inactivated viruses did not enhance the IP-10 and Mig gene expression. The results thus indicate that infection of live Influenza A virus is responsible for elevation of IP-10 and Mig gene expression. The elevation of IP-10 and Mig gene expression in infected HUVECs was not accompanied by the elevation of IFN-gamma gene expression, indicating that the elevation of IP-10 and Mig gene expression was independent of the IFN-gamma pathway.     

含H5N1-HA基因重组腺病毒疫苗的构建及其诱导免疫应答的初步探讨

目的 构建包含H5N1-HA基因的重组腺病毒疫苗并探讨其免疫效果.方法 用Admax系统构建包含H5N1-HA基因的重组腺病毒疫苗,并用PCR、Western-Blot等方法对重组病毒疫苗进行鉴定;疫苗免疫小鼠后,通过HI实验和ELISPOT实验检测其体液免疫和细胞免疫反应,评价其免疫效果.结果 成功得到了含有H5N1-HA基因的重组腺病毒疫苗;基因表达鉴定表明,HA基因能够在细胞中进行表达;血凝抑制实验结果显示小鼠产生的针对HA抗体滴度在1:320和1:640之间;ELISPOT结果显示实验组和对照组(PBS)相比斑点数量差异有统计学意义(P<0.05),以上免疫结果表明重组腺病毒载体疫苗可以诱导小鼠产生良好的特异性体液和细胞免疫反应.结论 含H5NA-HA的重组腺病毒疫苗可以诱导小鼠产生良好的免疫反应,为研制人禽流感疫苗打下基础.     

Genetic characterization of low pathogenic H5N1 and co-circulating avian influenza viruses in wild mallards (Anas platyrhynchos) in Belgium, 2008

As part of a long-term wild bird monitoring programme, five different low pathogenic (LP) avian influenza viruses (AIVs) were isolated from wild mallards (subtypes H1N1, H4N6, H5N1, H5N3, and H10N7). A LP H5N1 and two co-circulating (same location, same time period) viruses were selected for full genome sequencing. An H1N1 (A/Anas platyrhynchos/Belgium/09-762/2008) and an H5N1 virus (A/Anas platyrhynchos/Belgium/09-762-P1/2008) were isolated on the same day in November 2008, then an H5N3 virus (A/Anas platyrhynchos/09-884/2008) 5 days later in December 2008. All genes of these co-circulating viruses shared common ancestors with recent (2001 to 2007) European wild waterfowl influenza viruses. The H5N1 virus shares genome segments with both the H1N1 (PB1, NA, M) and the H5N3 (PB2, HA) viruses, and all three viruses share the same NS sequence. A double infection with two different PA segments from H5N1 and from H5N3 could be observed for the H1N1 sample. The observed gene constellations resulted from multiple reassortment events between viruses circulating in wild birds in Eurasia. Several internal gene segments from these 2008 viruses and the N3 sequence from the H5N3 show homology with sequences from 2003 H7 outbreaks in Italy (LP) and the Netherlands (highly pathogenic). These data contribute to the growing sequence evidence of the dynamic nature of the avian influenza natural reservoir in Eurasia, and underline the importance of monitoring AIV in wild birds. Genetic information of potential hazard to commercial poultry continues to circulate in this reservoir, including H5 and H7 subtype viruses and genes related to previous AIV outbreaks.     

遗传重配获得H5N1流感病毒Vero细胞适应株

目的以传统遗传重配技术选育HSN1流感病毒Veto细胞适应株,制备Vero细胞H5N1流感疫苗。方法以流感病毒Vero细胞适应株A／Yunnan／1／2005Va（H3N2）为母株与反向遗传学技术改造的禽流感病毒疫苗株A／Anhui／1／2005（H5N1）共同感染SPF鸡胚和Vero细胞,用羊抗A／Yunnan／1／2005Va（H3N2）抗体筛选,血抑试验和基因测序鉴定病毒型别,并进行重配株的其他相关生物学试验。结果获得了1株在Vero细胞高产的H5N1流感病毒,重配前后的单价灭活疫苗免疫小鼠抗体血清效价差异无统计学意义（F=0．857,P〉0．05）。结论通过流感病毒Vero细胞适应株与流行株的重配和抗体筛选,可以获得H5N1流感病毒Vero细胞适应株。     

Enhanced expression of secretable influenza virus neuraminidase in suspension mammalian cells by influenza virus nonstructural protein 1

Influenza neuraminidase (NA) is a major target for anti-influenza drugs. With an increasing number of viruses resistant to the anti-NA drug oseltamivir, functionally active recombinant NA is needed for screening novel anti-NA compounds. In this study, the secretable NA (sNA) head domain of influenza A/Vietnam/DT-036/05 (H5N1) virus was expressed successfully in human embryonic kidney (HEK-293T) cells and shown to be enzymatically active. The inclusion of a plasmid encoding nonstructural protein 1 (NS1) of influenza A/Puerto Rico/8/34 virus with the sNA plasmid in the cotransfection demonstrated an increase in H5N1 sNA expression by 7.4 fold. Subsequently, the sNA/NS1 cotransfection protocol in serum-free 293-F suspension cell culture was optimized to develop a rapid transient gene expression (TGE) system for expression of large amounts of H5N1 sNA. Under optimized conditions, NS1 enhanced H5N1 sNA expression by 4.2 fold. The resulting H5N1 sNA displayed comparable molecular weight, glycosylation, K(m) for MUNANA, and K(i) for oseltamivir carboxylate to those of H5N1 NA on the virus surface. Taken together, the NS1-enhancing sNA expression strategy presented in this study could be used for rapid high-level expression of enzymatically active H5N1 sNA in suspension mammalian cells. This strategy may be applied for expression of sNA of other strains of influenza virus as well as the other recombinant proteins.     

Avian influenza A virus H7N9 in China,a role reversal from reassortment receptor to the donator

Reassortment can introduce one or more gene segments of influenza A viruses (IAVs) into another, resulting in novel subtypes. Since 2013, a new outbreak of human highly pathogenic avian influenza has emerged in the Yangtze River Delta (YRD) and South-Central regions of China. In this study, using Anhui province as an example, we discuss the possible impact of H7N9 IAVs on future influenza epidemics through a series of gene reassortment events. Sixty-one human H7N9 isolates were obtained from five outbreaks in Anhui province from 2013 to 2019. Bioinformatics analyses revealed that all of them were characterized by low pathogenicity and high human or mammalian tropism and had introduced novel avian influenza A virus (AIV) subtypes such as H7N2, H7N6, H9N9, H5N6, H6N6, and H10N6 through gene reassortment. In reassortment events, Anhui isolates may donate one or more segments of HA, NA, and the six internal protein-coding genes for the novel subtype AIVs. Our study revealed that H7N9, H9N2, and H5N1 can serve as stable and persistent gene pools for AIVs in the YRD and South-Central regions of China. Novel AIV subtypes might be generated continuously by reassortment. These AIVs may have obtained human-type receptor-binding abilities from their donors and prefer binding to them, which can cause human epidemics through accidental spillover infections. Facing the continual threat of emerging avian influenza, constant monitoring of AIVs should be conducted closely for agricultural and public health.     

Non-structural protein 1 from avian influenza virus H9N2 is an efficient RNA silencing suppressor with characteristics that differ from those of <Emphasis Type="Italic">Tomato bushy stunt virus</Emphasis> p19

Non-structural protein 1 (NS1) of influenza A virus is a multifunctional dimeric protein that contains a conserved N-terminal RNA binding domain. Studies have shown that NS1 suppresses RNA silencing and the NS1 proteins encoded by different influenza A virus strains exhibit differential RNA silencing suppression activities. In this study, we showed that the NS1 protein from avian influenza virus (AIV) H9N2 suppressed systemic RNA silencing induced by sense RNA or dsRNA. It resulted in more severe Potato virus X symptom, but could not reverse established systemic green fluorescent protein silencing in Nicotiana benthamiana. In addition, its systemic silencing suppression activity was much weaker than that of p19. The local silencing suppression activity of AIV H9N2 NS1 was most powerful at 7 dpi and was even stronger than that of p19. And the inhibition ability to RNA silencing of NS1 is stronger than that of p19 in human cells. Collectively, these results indicate that AIV H9N2 NS1 is an effective RNA silencing suppressor that likely targets downstream step(s) of dsRNA formation at an early stage in RNA silencing. Although NS1 and p19 both bind siRNA, their suppression mechanisms seem to differ because of differences in their suppression activities at various times post-infiltration and because p19 can reverse established systemic RNA silencing, but NS1 cannot.     

Genome-sequenee Analysis of the Pathogenic H5N1 Avian Influenza A Virus Isolated in China in 2004

Analysis of the sequences of the genome of the avian influenza A/chicken/Hubei/327/2004 (H5N1) virus, isolated from a poultry farm during the outbreak of avian influenza (AI) in Hubei Province, central China, in the spring of 2004, revealed that the hemagglutinin (HA) gene of the virus was genetically similar to those of the H5 highly pathogenic avian influenza virus (HPAI). Notably, the neuraminidase gene of the virus had a 20-amino acid deletion in the stalk region and a 5-amino acid deletion in the NS gene which belonged to allele B. Furthermore, the internal genes (PB2, PA, NP, M2) of the A/chicken/Hubei/327/2004 virus with the particular amino acid residues were more closely related to H5N1 viruses of 2000–2003 isolated in Hong Kong and the AIV of Thailand and Vietnam in 2004, but less likely to evolve from the viruses of Hong Kong 1997. Finally, our results demonstrated that the influenza A/chicken/Hubei/327/2004 (H5N1) virus was similar to those of the AI viruses isolated from Hong Kong (2000–2003), Vietnam, and Thailand rather than the viruses from the 1997 lineage of Hong Kong and with closest genetic relatives to the influenza A/Chicken/Hong Kong/61.9/02 (H5N1) virus. These data suggest that the influenza A/chicken/Hubei/327/2004 (H5N1) virus which circulated in central China derived its internal gene from a virus similar to the influenza A/Chicken/Hong Kong/61.9/02 (H5N1) virus.