高致病性禽流感缘何这样可怕

自去年12月以来，高致病性禽流感在亚洲国家迅速蔓延，越南、泰国还出现了人因感染H5N1型病毒(禽流感病毒)而死亡的病例，世界卫生组织对此也是高度重视。最近，在我国广西、湖北、湖南等地也发生高致病性禽流感疫情，党中央、国务院对防治工作高度重视，胡锦涛总书记、温家宝总理多次向有关部门和地方作出重要指示，强调要依靠科学、依靠法制、依靠群众做好防治工作。     

科学看待禽流感

人们对禽流感的研究历史悠久，第一次禽流感发现于1878年。全世界已经历了十二次大流行，近几年在亚洲地区发生的频率较高。经过多年的科学研究，已经有了控制禽流感的有效方法。流行病学调查证明禽流感为水平传播，切断它的传播途径，就可控制     

禽流感病毒H5亚型特异性抗原捕捉ELISA检测方法的研究

 在获得禽流感病毒多克隆抗体及H5亚型特异性单克隆抗体的基础上,研究建立H5亚型特异性抗原捕捉ELISA检测方法,用于检测H5亚型禽流感病毒.优化反应条件,确定包被抗体、检测抗体及酶结合物的最佳工作浓度,进行敏感性、特异性、重复性及稳定性分析,并与RT-PCR方法比较.同时使用该方法对野外样品进行检测.结果表明:该方法敏感、特异,具有良好的重复性和稳定性,可用于检测临床样品、鸡胚培养物及细胞培养物中的H5亚型禽流感病毒.     

H5N1亚型禽流感的诊断及临床病理学研究

对一起鸡传染病进行了病原鉴定并对其自然死亡的46例蛋鸡进行了临床病理学研究，结果表明，本起鸡病为A型禽流感，H5N1亚型，属高致死性(HPAI)；急性热性出血性败血症；急性坏死性胰腺炎；非化脓性脑炎；卡他性上呼吸道炎；卡他性、间质性肺炎。     

H5N1亚型禽流感病毒血凝素基因的克隆与表达

 根据已知H5N1亚型禽流感病毒血凝素(HA)基因序列设计、合成克隆引物.自灭活的云南地方H5N1亚型病毒阳性临床组织样品中提取总RNA,反转录后采用高可信度DNA聚合酶(Pyobest^TMDNA Polymerase)扩增HA基因,采用Invitrogen定向表达系统(Champion^TMpET directional TOPO expression system)进行克隆表达,纯化获得N末端携带多聚组氨酸标签的重组HA,分子质量约78ku.采用阳性血清经免疫印迹及ELISA分析重组HA的免疫反应性,结果表明重组HA能与H5N1亚型病毒抗血清发生特异性结合,具有良好的免疫反应性.     

禽流感疫苗快速检测方法问世

H5N1型病毒已引发人禽流感病例,目前尚未变异至“人传人”的程度。医学界担心,H5N1型病毒可能继续变异,致使禽流感在人类中出现大规模流行。     

禽流感病毒H9亚型特异性抗原捕捉ELISA检测方法的研究

 采用禽流感病毒多克隆抗体及H9亚型特异性单克隆抗体,研究建立H9亚型特异性抗原捕捉ELISA检测方法,用于检测H9亚型禽流感病毒.优化了反应条件,确定了包被抗体、检测抗体及酶结合物的最佳工作浓度,对该方法的敏感性、特异性、重复性及稳定性分析,并与RT-PCR方法比较.通过使用该方法对野外样品进行检测.结果表明该方法敏感、特异,具有良好的重复性和稳定性,可用于检测临床样品、鸡胚培养物及细胞培养物中的H9亚型禽流感病毒.     

一起高致病性禽流感的诊断与防治

禽流感病毒具有高致病性和高致死率,它不仅给养殖业造成很大的危害,而且对人类的健康和生命安全也构成了威胁.近几年来,世界各地相继出现了感染禽流感病毒发病病例,蔓延迅速,病情较重,死亡率较高.根据流行病学调查、临床症状、病理解剖和实验室诊断,确诊了一起高致病性禽流感疫情,以提高人们对本病的认识.     

H5N1亚型禽流感的研究

对发生在通辽地区的一起鸡的传染病进行了病原及其型的鉴定、流行病学调查、临床病理学研究，同时采取了综合性防制措施，结果为：该起鸡病为A型禽流感(Avian Influenza AI)H5N1亚型、为高致死性(HPAI)、极具传染性．临床病理学表现为急性热性出血性败血症、急性坏死性胰腺炎、非化脓性脑炎、卡他性上呼吸道炎、卡他性间质性肺炎及多个器官变质性坏死性炎．由于及时采取了隔离封锁，扑杀、消毒、无害化处理，疫情跟踪监测和免疫接种等有效的综合性防制措施，而使该传染病就地扑灭，疫情未造成扩散蔓延．     

Prediction of a common neutralizing epitope of H5N1 avian influenza virus by in silico molecular docking

The H5N1 avian influenza virus (AIV) has widely spread in Asia, Europe and Africa, making a large amount of economic loss. Recently, our research group has screened a common neutralizing mono- clonal antibody named 8H5, which can neutralize almost all H5 subtype AIV ever isolated so far. Obvi- ously, this monoclonal antibody would benefit for research and development of the universal AIV vac- cine and design of the drug against H5N1 AIV in high mutation rate. In this study, the homology mod- eling was applied to generate the 3D structure of 8H5 Fab fragment, and canonical structure method was used to define the specified loop conformation of CDR regions. The model was subjected to en- ergy minimization in cvff force field with Discovery module in Insight II program. The resulting model has correct stereochemistry as gauged from the Ramachandran plot calculation and good 3D-structure compatibility as assessed by interaction energy analysis, solvent accessible surface (SAS) analysis, and Profiles-3D approach. Furthermore, the 8H5 Fab model was subjected to docking with three H5 subtype hemagglutinin (HA) structures deposited in PDB (ID No: 1jsm, 2ibx and 2fk0) respectively. The result indicates that the three docked complexes share a common binding interface, but differ in bind- ing angle related with HA structure similarity between viral subtypes. In the light of the three HA inter- faces with structural homology analysis, the common neutralizing epitope on HA recognized by 8H5 consists of 9 incontinuous amino acid residues: Asp68, Asn72, Glu112, Lys113, Ile114, Pro118, Ser120, Tyr137, Tyr252 (numbered as for 1jsm sequence). The primary purpose of the present work is to provide some insight into structure and binding details of a common neutralizing epitope of H5N1 AIV, thereby aiding in the structure-based design of universal AIV vaccines and anti-virus therapeutic drugs.     

Prediction of a common neutralizing epitope of H5N1 avian influenza virus by in silico molecular docking

The H5N1 avian influenza virus （AIV） has widely spread in Asia, Europe and Africa, making a large amount of economic loss. Recently, our research group has screened a common neutralizing mono-clonal antibody named 8H5, which can neutralize almost all H5 subtype AIV ever isolated so far. Obviously, this monoclonal antibody would benefit for research and development of the universal AIV vac-cine and design of the drug against H5N1 AIV in high mutation rate. In this study, the homology modeling was applied to generate the 3D structure of 8H5 Fab fragment, and ＂canonical structure＂ method was used to define the specified loop conformation of CDR regions. The model was subjected to energy minimization in cvff force field with Discovery module in Insight II program. The resulting model has correct stereochemistry as gauged from the Ramachandran plot calculation and good 3D-structure compatibility as assessed by interaction energy analysis, solvent accessible surface （SAS） analysis, and Profiles-3D approach. Furthermore, the 8H5 Fab model was subjected to docking with three H5 subtype hemagglutinin （HA） structures deposited in PDB （ID No： ljsm, 2ibx and 2fk0） respectively. The result indicates that the three docked complexes share a common binding interface, but differ in binding angle related with HA structure similarity between viral subtypes. In the light of the three HA inter-faces with structural homology analysis, the common neutralizing epitope on HA recognized by 8H5 consists of 9 incontinuous amino acid residues： Asp^58, Asn^72, Glu^112, Lys^113, lie^114, Pro^118, Ser^120, Tyr^137, Tyr^252 （numbered as for ljsm sequence）. The primary purpose of the present work is to provide some insight into structure and binding details of a common neutralizing epitope of H5N1 AIV, thereby aiding in the structure-based design of universal AIV vaccines and anti-virus therapeutic drugs.     

Molecular characterization of avian influenza virus (H7N8) isolated from poultry in Central China in the mid-1980s

The molecular and pathogenic properties of avian influenza virus (A/duck/Hubei/216/1985/H7N8) isolated from Hubei Province of China in 1985 were characterized.The hemagglutinin gene (HA) of Dk/Hb/216/85/H7N8 had the multiple amino acid se-quences (-PEIPKGRG-) at the connecting peptide between HA1 and HA2, which is considered to be a distinguishing molecular characteristic of low pathogenicity.The key sites of host markers among the genes (M, NP, NS, PA and PB2) of Dk/Hb/ 216/85/H7N8 were similar to those of...     

Molecular patterns of avian influenza A viruses

Avian influenza A viruses could get across the species barrier and be fatal to humans. Highly pathogenic avian influenza H5N1 virus was an example. The mechanism of interspecies transmission is not clear as yet. In this research, the protein sequences of 237 influenza A viruses with different subtypes were transformed into pseudo-signals. The energy features were extracted by the method of wavelet packet decomposition and used for virus classification by the method of hierarchical clustering. The clustering results showed that five patterns existed in avian influenza A viruses, which associated with the phenotype of interspecies transmission, and that avian viruses with patterns C and E could across species barrier and those with patterns A, B and D might not have the abilities. The results could be used to construct an early warning system to predict the transmissibility of avian influenza A viruses to humans.     

H5N1亚型禽流感毒株A/Duck/HuBei/3/2005的分子特征及致病性研究

采用分子生物学方法,对1株2005年从湖北省某县分离获得的禽流感病毒株(A/Duck/HuBei/3/2005)进行全基因组序列测定.序列分析显示,该分离株为H5N1亚型.HA蛋白在HA1和HA2连接处,含有连续多碱性氨基酸模体(-RRKKR-).根据进化分析结果,分离株A/Duck/HuBei/3/2005的7个基因来源于2004～2005年湖南地区流行株(CK/HN/999/05,DK/HN303/04),但是PA基因片段发生了重排,来源于野禽.动物实验显示DK/HB/3/05对鸡和鸭均具有高致病性;对小鼠有较低致病性.     

禽流感病毒三种检测方法的比较研究

对分别应用病毒分离鉴定、反转录-聚合酶链式反应(RT-PCR)、间接免疫荧光(IFA)3种方法对病料组织中的禽流感病毒(AIV) 进行检测与比较研究。结果显示:经鸡胚尿囊腔接种分离到的病毒,通过用禽流感病毒H5、H9亚型单克隆抗体所进行的血凝(HA)和血凝抑制试验(HI),鉴定为AIV H5亚型毒株;应用RT-PCR技术直接对病料组织抽提的RNA样品进行检测,从病料组织能扩增出大小为229bp的AIV通用目的片段和大小为380bp的H5亚型特异性片段;取病料组织的过滤液接种狗肾上皮细胞(MDCK)单层,24h后用H5亚型AIV特异性的单克隆抗体进行间接免疫荧光试验,结果在细胞核、细胞质内观察到特异性的荧光。研究的结果表明,3种技术都可对病料样品中的AIV进行检测,而RT-PCR和IFA两种方法还可直接对病料样品中的病毒进行亚型的鉴定。相对而言,后两者具有更快速、更敏感、操作更简便的特点。     

抗禽流感iRNA提取及其部分免疫活性的研究

为了比较不同方法抽提抗禽流感iRNA的含量、纯度,以及了解iRNA对小鼠的免疫活性,本研究就抗禽流感iRNA提取及其部分免疫活性进行了研究。结果表明:酚-氯仿抽提与Trizol reagent试剂盒抽提的效果差异不显著,所得到的iRNA含量和纯度较高,而冷热酚法抽提的效果则明显不及酚-氯仿法与Trizol reagent试剂盒;小白鼠腹腔注射提取的iRNA制剂,小白鼠生长良好,10 d内未见小白鼠有死亡,由此说明iRNA对小白鼠是安全的;禽流感HI试验及ELISA试剂盒检测iRNA免疫小白鼠血清抗体,结果为阴性,由此说明抽提的iRNA不能诱导机体产生体液免疫。