鸭源H9N2AIV血凝素基因序列比较

为明确国内外鸭源H9N2亚型禽流感病毒(Avian influenza virus,AIV)血凝素基因(hemagglutinin,HA)的遗传进化关系、血凝素蛋白裂解位点的氨基酸结构特征和血凝素蛋白受体结合位点的氨基酸变异特征,本研究选取GenBank中登录鸭源H9N2亚型AIV HA基因,通过MEGA4.1进行比对和分析,并绘制其遗传进化树。结果表明,鸭源H9N2亚型AIV在遗传进化上分为2大谱系:即Ck-Bj-1-94-like和North-Ame-like,中国大陆鸭源H9N2亚型AIV和亚欧美其它国家鸭源H9N2亚型AIV在遗传进化上分居完全不同的谱系,相互之间遗传进化关系较远。从血凝素受体结合位点看,亚欧美国家鸭源H9N2亚型AIV在第183、190和226位点的氨基酸均为鸭源AIV经典H、E和Q,且高度保守。但中国大陆地区H9N2亚型AIV第183位为N;第190位为A or V or T,与中国大陆鸡源H9N2亚型AIV一致;第226位中国鸭源H9N2亚型AIV有相当一部分为L,且近年福建省H9N2亚型AIV分离株在此处均为L。提示我们,中国大陆地区H9N2亚型AIV鸭鸡和鸡鸭相互交叉感染较为普遍。     

禽流感病毒血凝素疫苗在转基因马铃薯中的表达

利用转基因马铃薯表达禽流感病毒血凝素疫苗,将含有禽流感病毒血凝素序列的表达载体导入农杆菌,再感染马铃薯的幼茎外植体。转化植株的再生及温室栽培,Western blot分析表明,83％的转化植株在其块茎组织中表达了重组血凝素,表达量占总蛋白量的0．03－0．04％,结果显示用马铃薯生产口服禽流感疫苗是可行的。     

抗体选择压作用下H9N2亚型禽流感病毒HA基因的变异

摘要：【目的】了解H9N2亚型禽流感病毒(AIV)在抗体选择压作用下的遗传变异。【方法】将制备疫苗用的LG1株H9N2亚型AIV分别接种含有母源抗体鸡胚(A组)和不含有母源抗体的SPF鸡胚(B组),并连续传代。其中A组再分为4 个独立的传代系列A1-4,B组再分为2 个独立传代系列B1-2。在每个传代系列,分别对第10,20,30,40,50 代病毒的HA基因进行扩增克隆测序,并与原始病毒的序列比较。【结果】LG1株H9N2在没有抗体的鸡胚的传代过程中,仅发生少数碱基的不稳定随机变异,且多为无义突变。在2 个传代系列的10 个代次病毒,共出现了29 个位点变异,有义突变(NS)与无义突变(S)比值NS/S为1.42 。但在有抗体的鸡胚的传代过程中,发生了多个呈现稳定遗传的有义突变。在4 个传代系列的20 个代次病毒,共出现了45 个位点变异,有义突变(NS)与无义突变(S)比值NS/S为3.46。【结论】在鸡胚传代过程中母源抗体提供的免疫选择压确实能影响H9N2的HA基因的变异。同时表明,带有母源抗体的鸡胚是实验室条件下研究免疫选择压对病毒抗原性变异影响的一种有效的实验模型。     

2017–2019年我国南方地区高致病性H5N6亚型禽流感病毒血凝素蛋白分子特征分析

【背景】自2014年以来,H5N6禽流感病毒在我国家禽和活禽市场持续进化,成为人类和动物健康的重大威胁。【目的】对2017–2019年中国南方地区93株高致病性H5N6禽流感病毒的HA基因进行分子进化分析。【方法】接种9–11日龄鸡胚分离核酸检测阳性的H5N6标本,运用下一代测序平台对病毒分离物进行全基因组测序,从NCBI和GISAID数据库下载参考序列,利用BLAST、MEGA6.1及Clustal X等软件进行序列分析。【结果】2017–2019年,从189份江苏省H5亚型禽类/环境标本和1名H5N6患者咽拭子标本中共分离到43株病毒,完成了33株H5N6病毒的全基因组测序。下载网上同时期中国其他地区流行的H5N6毒株序列,对总计93株H5N6病毒的HA基因进行分子进化分析。93株H5N6病毒中有78株属于Clade 2.3.4.4h,9株病毒属于Clade 2.3.4.4e,4株H5N6病毒属于Clade 2.3.4.4b,1株属于Clade 2.3.4.4f,1株属于Clade 2.3.4.4g。所有93株病毒HA蛋白的裂解位点含有多个碱性氨基酸,表明它们都属于高致病性禽流感病...     

一株针对H7N9亚型禽流感病毒血凝素蛋白茎部的单克隆抗体的表征

流感病毒血凝素蛋白(hemagglutinin,HA)的茎部区相对保守,是广谱疫苗、抗体与病毒检测制剂的重要靶点.前期研究获得了一株与H7N9亚型禽流感病毒HA蛋白茎部多肽(aa 428-452)反应的单克隆抗体(5D3-1B5).为系统评价其生物学特性,本研究测定了5D3-1B5的抗体效价(IgG、血凝抑制与病毒中和...     

一种更灵敏的特异性检测H9亚型禽流感抗体的间接ELISA方法的建立

H9亚型禽流感在全球范围内广泛流行,控制其传播需监测H9亚型禽流感病毒的感染情况及疫苗的免疫效果。为了建立便于检测且灵敏特异的H9亚型禽流感抗体间接ELISA方法,本实验利用不同亚型之间变异较大的H9亚型禽流感病毒HA蛋白的头部球状区作为包被抗原,确定了最佳复合封闭液和抗体稀释液,提高了其特异性。结果显示建立的ELISA方法灵敏度高于血凝抑制试验(HI),且与H3N2、H5N2、H7N9亚型流感病毒及新城疫病毒(NDV)、鸡传染性支气管炎病毒(IBV)、鸡传染性法氏囊病毒(IBDV)和产蛋下降综合征病毒(EDSV)的阳性血清均无交叉反应。另外,利用该方法及HI试验对200份临床鸡血清样本进行检测,两种检测方法的符合率达97%,且存在较高的相关性(R2=0.981 1)。     

Antigenic diversity of H5 highly pathogenic avian influenza viruses of clade 2.3.4.4 isolated in Asia

H5 highly pathogenic avian influenza viruses (HPAIV) have spread in both poultry and wild birds since late 2003. Continued circulation of HPAIV in poultry in several regions of the world has led to antigenic drift. In the present study, we analyzed the antigenic properties of H5 HPAIV isolated in Asia using four neutralizing mAbs recognizing hemagglutinin, which were established using A/chicken/Kumamoto/1‐7/2014 (H5N8), belonging to clade 2.3.4.4 and also using polyclonal antibodies. Viruses of clades 1.1, 2.3.2.1, 2.3.4, and 2.3.4.4 had different reactivity patterns to the panel of mAbs, thereby indicating that the antigenicity of the viruses of clade 2.3.4.4 were similar but differed from the other clades. In particular, the antigenicity of the viruses of clade 2.3.4.4 differed from those of the viruses of clades 2.3.4 and 2.3.2.1, which suggests that the recent H5 HPAIV have further evolved antigenically divergent. In addition, reactivity of antiserum suggests that the antigenicity of viruses of clade 2.3.4.4 differed slightly among groups A, B, and C. Vaccines are still used in poultry in endemic countries, so the antigenicity of H5 HPAIV should be monitored continually to facilitate control of avian influenza. The panel of mAbs established in the present study will be useful for detecting antigenic drift in the H5 viruses that emerge from the current strains.     

H7N9禽流感病毒小鼠感染动物模型的建立

目的建立H7N9禽流感病毒小鼠感染模型。方法 1×108,1×107或1×106TCID50H7N9禽流感病毒原液(A/Anhui/1/2013)滴鼻感染BALB/c小鼠。主要观测指标:临床症状、死亡率、病理变化、病毒载量和血清抗体检测。结果被感染的小鼠表现为竖毛、弓背、体重下降;病理表现为间质性肺炎,感染后第2天开始在呼吸道脱落细胞中检测到病毒;免疫组化或病毒分离方法在肺、肾、脑、肠、脾等组织检测到病毒;感染后14 d在小鼠血清中血凝抑制试验特异性抗体效价达到160;淋巴细胞减少,中性粒细胞增多。结论 H7N9感染BALB/c小鼠模型与人类禽流感感染疾病的基本特征相似,为研究该病的发病机制及药物疫苗的研发提供了工作基础。     

Human avian influenza A (H5N1) virus infection in China

Highly pathogenic influenza A (H5N1) virus causes a widespread poultry deaths worldwide. The first human H5N1 infected case was reported in Hong Kong Special Administrative Region of China in 1997. Since then, the virus re-emerged in 2003 and continues to infect people worldwide. Currently, over 400 human infections have been reported in more than 15 countries and mortality rate is greater than 60%. H5N1 viruses still pose a potential pandemic threat in the future because of the continuing global spread and evolution. Here, we summarize the epidemiological, clinical and virological characteristics of human H5N1 infection in China monitored and identified by our national surveillance systems. Chinese Nature Science Foundation Key Project (Grant No. 30599433), Chinese Basic Science Research Program (973)Key Project (Grant No. 2005CB523006)     

共表达H5和H9亚型禽流行性感冒病毒血凝素基因的重组禽痘病毒及其免疫效力

为了构建更为安全有效能同时抵抗高致病性H5亚型和低致病忡H9亚型禽流行性感冒(禽流感)病毒的基因工程疫苗,将H5和H9亚型禽流感病毒分离株的血凝素(HA)基因,分别由鸡痘病毒早晚期启动子PS和PE／L调控其转求,定向插入鸡痘病毒转移载体p11s中,获得H5A和H9A基因分别处于PS及PE／L启动子转录调控下的重组转移载体p11SH5H9。以FuGene^TM6转染法将p11SH5H9转染至已感染鸡痘病毒282E4疫苗株(wt-FPV)的鸡胚成纤维细胞(CEF)中。p11SH5H9与wt—FPV基因组DNA之间的同源重组产生了重组鸡痘病毒rFPV11SH5H9。通过在含X-gal的营养琼脂上连续挑选蓝色病毒蚀斑获得并纯化rFPV-11SH5H9。以间接免疫荧光法试验证实,纯化的rFPV-11SH5H9感染的CEF能同时表达H5A和H9A。初步的动物试验表明,用10^5PFU的rFPV-11SH5H9免疫无特定病原体(SPF)鸡,免疫后血凝抑制(HI)抗体监测阳性率均为100％(8／8);该重组病毒能显著抑制H9亚型AIV滴鼻、点眼后7日龄SPF鸡从气管和泄殖腔排毒,同时也能抵抗H5亚型AIV肌肉注射后对7日龄SPF鸡致死性攻击,保护率均为100％,显示出一定的应用前景。     

H5N8亚型高致病性禽流感病毒的全球流行概况

H5N8亚型高致病性禽流感病毒(highly pathogenic avian influenza virus,HPAIV)随候鸟的迁徙活动及商业贸易活动现已蔓延至亚洲、欧洲、非洲、美洲等国家和地区.2014-2015和2016-2019年H5N8亚型HPAIV已引发两波全球疫情,现正经历第三波疫情,导致家禽及野生鸟类...     

上海地区H9N2亚型禽流感病毒的遗传演化分析

为阐明上海地区 H9N2亚型禽流感病毒分离株的遗传变异、分子特征和重组模式,选取2002和2006～2014年分离自活禽市场、家禽养殖场和生猪屠宰场的14株 H9N2亚型禽流感病毒进行分析。这14株病毒分别来源于鸡、鸭、鸽、野鸡咽喉和泄殖腔样品及猪肺脏样品,用 H9亚型荧光反转录‐聚合酶链反应（RT‐PCR）试剂盒检测后,阳性样品经无特定病原体（SPF）级鸡胚尿囊腔接种并分离病毒,用血凝抑制（HI）实验进一步确定其血凝素（HA）亚型。RT‐PCR分别扩增这14株病毒全基因并进行序列测定,分析8个基因片段的遗传发生关系,发现这些分离株主要由 F／98亚系、Y280亚系、G1亚系及未知亚系重组而成。根据8个基因片段的组合情况,这14株病毒可分成5个基因型。2002、2006～2008年分离的5株H9N2亚型禽流感病毒代表了4个不同基因型,2009～2014年分离的9株H9N2亚型禽流感病毒属第5种基因型,推测可能与疫苗免疫选择压力有关。因此,在以后工作中加强H9N2亚型禽流感分子流行病学监测是非常必要的。     

禽流感病毒A/Chicken/Guangdong/SS/94(H9N2)HA基因的克隆及序列分析

禽流感是由A型流感病毒引起的禽的一种疾病综合症.1878年首次在意大利爆发流行,当时称该病为"鸡瘟".之后,许多国家和地区都有该病的报道,包括美国、英国、澳大利亚、爱尔兰、比利时、荷兰、法国、俄罗斯、加拿大、以色列、匈牙利、日本、中国(包括香港)等[1-3].     

Proposed lead molecules against Hemagglutinin of avian influenza virus (H5N1)

Human infection with avian influenza H5N1 is an emerging infectious disease characterized by respiratory symptoms and a high fatality rate. Hemagglutinin and neuraminidase are the two surface proteins responsible for infection by influenza virus. Till date, neuraminidase has been the major target for antiviral drugs. In the present study we chose hemagglutinin protein as it mediates the binding of the virus to target cells through sialic acid residues on the host cell-surface. Hemagglutinin of H5 avian influenza (PDB ID: 1JSN) was used as the receptor protein. Ligands were generated by structure-based de novo approach and virtual screening of ZINC database. A total of 11,104 conformers were generated and docked into the receptor binding site using 'High Throughput Virtual Screening'. We proposed potential lead molecules against the receptor binding site of hemagglutinin based on the results obtained from in silico docking and hydrogen bond interaction between the ligand and the 1JSN protein molecule. We found sialic acid derivative 1 to be the lead molecules amongst the ligands generated by structure based de novo approach. However the molecules obtained from ZINC database were showing better docking scores as well as conserved hydrogen bond interactions. Thus we proposed ZINC00487720 and ZINC00046810 as potential lead molecules that could be used as an inhibitor to the receptor binding site of hemagglutinin. They could now be studied in vivo to validate the in silico results.     

流感病毒H1N1血凝素基因和神经氨酸酶基因在酵母菌中的表达

在成功克隆流感病毒H1N1全长HA(Hemagglulinin,HA)、NA(Neuramidinase,NA) 基因并测序的基础上,将部分基因序列克隆到表达载体pMETA上,构建了重组表达质粒pMETA/HA(52~1 557 bp)、pMETA/NA(121~1 263 bp),电转化真核酵母菌pMAD16,甲醇诱导表达,利用Ni2+亲和层析柱对重组蛋白进行纯化,并用Western blotting和ELISA方法检测其抗原性。SDS-PAGE显示重组蛋白在酵母菌中可以高效表达,蛋白纯度占总蛋白的95％以上,ELISA和Western blotting实验证实,重组蛋白具有良好的抗原性。成功克隆和表达了流感病毒H1N1 HA、NA基因序列,为流感病毒H1N1诊断试剂和疫苗的开发等进一步的研究提供了参考。     

Lethal infection by a novel reassortant H5N1 avian influenza A virus in a zoo-housed tiger

In early 2013, a Bengal tiger (Panthera tigris) in a zoo died of respiratory distress. All specimens from the tiger were positive for HPAI H5N1, which were detected by real-time PCR, including nose swab, throat swab, tracheal swab, heart, liver, spleen, lung, kidney, aquae pericardii and cerebrospinal fluid. One stain of virus, A/Tiger/JS/1/2013, was isolated from the lung sample. Pathogenicity experiments showed that the isolate was able to replicate and cause death in mice. Phylogenetic analysis indicated that HA and NA of A/Tiger/JS/1/2013 clustered with A/duck/Vietnam/OIE-2202/2012 (H5N1), which belongs to clade 2.3.2.1. Interestingly, the gene segment PB2 shared 98% homology with A/wild duck/Korea/CSM-28/20/2010 (H4N6), which suggested that A/Tiger/JS/1/2013 is a novel reassortant H5N1 subtype virus. Immunohistochemical analysis also confirmed that the tiger was infected by this new reassortant HPAI H5N1 virus. Overall, our results showed that this Bengal tiger was infected by a novel reassortant H5N1, suggesting that the H5N1 virus can successfully cross species barriers from avian to mammal through reassortment.     

人感染H7亚型禽流感事件

本研究综述了自1959年以来国内外发生的人感染H7亚型禽流感事件。大多数是在家禽爆发禽流感期间,农场工人在处置感染鸡群过程中被暴露而感染;也有曾接触活禽或曾到过活禽市场而感染;有经禽流感病毒致病的哺乳动物（海豹）感染于人或实验室感染（事故）所致。引起人感染的H7亚型中已知有H7N2、H7N3、H7N7以及2013年在中国发现的新的致病亚型H7N9。H7N2、H7N3、H7N7感染以结膜炎为主,大多为轻症;而H7N9感染以严重的呼吸道感染为特征,表现为重症肺炎,呼吸窘迫综合症,病死率高达33.6%。     

Role of receptor binding specificity in influenza A virus transmission and pathogenesis

The recent emergence of a novel avian A/H7N9 influenza virus in poultry and humans in China, as well as laboratory studies on adaptation and transmission of avian A/H5N1 influenza viruses, has shed new light on influenza virus adaptation to mammals. One of the biological traits required for animal influenza viruses to cross the species barrier that received considerable attention in animal model studies, in vitro assays, and structural analyses is receptor binding specificity. Sialylated glycans present on the apical surface of host cells can function as receptors for the influenza virus hemagglutinin (HA) protein. Avian and human influenza viruses typically have a different sialic acid (SA)‐binding preference and only few amino acid changes in the HA protein can cause a switch from avian to human receptor specificity. Recent experiments using glycan arrays, virus histochemistry, animal models, and structural analyses of HA have added a wealth of knowledge on receptor binding specificity. Here, we review recent data on the interaction between influenza virus HA and SA receptors of the host, and the impact on virus host range, pathogenesis, and transmission. Remaining challenges and future research priorities are also discussed.     

季节性流感疫苗对小鼠感染 H7N9 禽流感病毒的保护效力简

目的 评价季节性流感裂解疫苗对流感病毒H7N9的免疫保护效力.方法 用我国2012～2013年度季节性流感裂解疫苗,以腹腔注射方式免疫BALB/c小鼠,并设PBS免疫模型组,末次免疫14 d后以5 LD50 A/Anhui/1（H7N9）进行攻试验.感染后观察记录小鼠临床表现,体重变化,并分别于第2天和第4天每组处死3只小鼠,取肺组织和鼻甲骨测病毒滴度和载量.结果 感染后疫苗与模型组小鼠体重下降明显,疫苗组存活率为10%,模型组全部死亡.感染后第4天疫苗组鼻甲骨滴度显著低于模型组.血凝抑制试验及中和实验表明免疫小鼠血清无中和H7N9病毒抗体.结论 季节性流感疫苗在小鼠中对于H7N9流感病毒感染无明显保护作用.