【作者】 张乾义；

【导师】 陈化兰； 胡永浩；

【作者基本信息】 甘肃农业大学 ， 预防兽医学， 2011， 硕士

【摘要】 A型流感病毒在温血动物中广泛存在,也是目前导致人类和各种动物流感疾病的主型。在自然情况下流感病毒感染的宿主范围有一定的特异性,分离自人的流感病毒一般不能在鸡、鸭等禽类体内复制,同样禽流感病毒在灵长类动物体内的复制能力也极差。但近年来不断发生禽流感病毒(包括H5N1,H9N2,H7N7亚型病毒)直接传染给人的事件。研究证实,流感病毒的致病性及跨种间传播的深层原因是病毒分子结构差异及其与宿主细胞相互作用。病毒多种结构蛋白和非结构蛋白某些功能位点上氨基酸的差异是病毒致病性及其跨种传播的分子生物学基础。2009年4月初,在墨西哥和美国边境发生了流感疫情,此次疫情通过人与人传播,几周后传播到了全球30多个国家,世界卫生组织(WHO)不断提升全球流感疫情警戒等级,将其升至最高级(6级)。通过对病原的分离鉴定,WHO宣布这场21世纪的第一次流感大流行是由一种新型猪源H1N1亚型流感病毒(novel swine-origin influenza virus A H1N1)引起。这种新型的流感病毒的遗传背景十分复杂,是一种多元重组病毒,其血凝素(HA)基因源于1918年猪流感病毒,其它基因源于人、禽和欧洲猪流感病毒。此前虽然也发生过多起猪流感感染人事件,但传播范围及其局限,此次的猪流感病毒为何能够跨越种间屏障,在人与人之间形成了有效传播成为人们关注的焦点。为了了解此次流感的传播机制,本研究选取了甲型H1N1流感病毒A/Sichuan/01/2009(SC/01)株为亲本毒株,构建了SC/01的8质粒反向遗传操作系统,并获得了甲型H1N1流感病毒救获株Rescue-A/Sichuan/01/2009(R-SC/01)。对救获毒株R-SC/01进行全基因序列测定,证明救获毒株与亲本毒株核苷酸序列完全一致。R-SC/01的小鼠半数感染量及受体结合特性与亲本野毒SC/01相一致。SC/01反向遗传操作系统的成功建立为进一步开展甲型H1N1流感病毒的生物学特性研究,特别是跨宿主传播机制研究奠定了基础。更多还原

【Abstract】 Influenza A virus exists in amlost all of homothermal anmials and is the prime type leading to infection in humans and anmials.Under natura lcircum stances,influenza virus has certa in host range.In general, influenza virus of human origin cannot replicate in birds,such as chickens or ducks.Likewise, avian influenza virus has very low replication ability in prmiates.In the past several years ,however, there have been many incidents that avian in fluenza virus (including H5N1, H9N2 and H7N7 subtypes) have transmitted from avian to human. Studies have demonstrated that the differences in viral molecular structure and the interaction between virus and host cell determine influenza virus pathogenicity and interspecies transmission and the molecular biology basis for such changes are mutations of certa in amino acids in functional sites on structural or nonstructural proteins.In early April 2009, a new influenza pandemic emerged in Mexico and the United States. The surveillance results show that the virus spread worldwide to 30 countries by human-to-human transmission during the first few weeks. For which the World Health Organization (WHO) raise its pandemic alert to level 6/6. After isolation and identification of the pathogen, WHO announced that the first influenza pandemic in this 21st century caused by a novel swine-origin influenza virus A H1N1. The origin of the new influenza virus is very complex. It is a multiple reassortment virus. The hemagglutinin (HA) gene was derived from the 1918 swine influenza virus, other genes from human, avian and Europe swine influenza viruses. Although there were many incidents of human infected with swine influenza, but the scope was very limited. Now, people focus on how this swine influenza virus can break the species barrier and transmit efficiently between human.To understand the transmission of this pandemic, we choose the Pandemic H1N1 Influenza virus A/Sichuan/01/2009(SC/01) as parent virus. Eight plasmids containing SC/01 genome were constructed to rescue SC/01.The rescued virus is named as Rescue-A/Sichuan/01/2009(R-SC/01). The whole genome sequence showed that there was no nucleic acid change in R-SC/01, compared with SC/01. Furthermore, these two viruses showed identical 50% mouse infectious dose (MID50) and receptor binding ability. Our results could provide a technique for further study of SC/01, especially the crossing-host-barrier transmission mechanisms.更多还原