H10及H9亚型禽流感病毒的受体结合特性研究

发布时间：2018-05-28 10:21

本文选题：流感病毒 + 血凝素蛋白　；参考：《中国农业大学》2016年博士论文

【摘要】：流感病毒属于正粘病毒科,可以引起急性呼吸道传染病。根据核蛋白和基质蛋白抗原性的不同,流感病毒可分为A、B、C、D四种型别。其中A型流感病毒可以感染包括人、禽、猪、马等在内的多种动物。除H1/H2/H3亚型流感病毒可造成季节性流感或流感大流行外,多种亚型(H5,H6,H7,H9,H10)流感病毒均已出现感染人的病例,给人类生命健康造成了巨大的威胁。A型流感病毒侵入细胞首先需要通过其血凝素(Hemagglutinin, HA)蛋白结合靶细胞表面的唾液酸受体,然后进入细胞内,并在细胞核中进行转录和复制。由于人的上呼吸道主要分布有a-2.6唾液酸受体(人源受体),下呼吸道也分布有一些α-2.3唾液酸受体(禽源受体)。因此偏好性结合禽源受体的禽流感病毒不易在人群中传播。禽流感病毒受体结合特性的转变是其突破宿主障碍感染哺乳动物宿主的关键因素。本研究通过对H10和H9亚型禽流感病毒的血凝素蛋白进行研究。从分子水平上阐述了其结合唾液酸受体的分子机制,对防控禽流感病毒具有重要的意义。自2013年12月以来,我国先后发生3例人感染H10N8亚型禽流感病毒的病例,其中2例死亡。这是世界上首次报道H10亚型流感病毒感染人致死的病例。禽流感病毒引起流感大流行首先需要获得人源受体的结合能力,为了评估H10N8亚型禽流感病毒引起流感大流行的潜力,我们从病毒层面和蛋白层面检测了最早的H1ON8亚型禽流感病毒人分离株——A/Jiangxi-Donghu/346/2013 (JD-H10N8)的受体结合特性。结果表明,与能够结合人源受体的AH-H7N9不同,JD-H10N8特异性结合禽源受体,而对人源受体的结合极弱。JD-H10N8 HA蛋白与禽／人源受体的复合物晶体结构也支持这一观点。这表明JD-H10N8亚型禽流感病毒依然是一种典型的禽流感病毒,对人源受体的亲和力极弱,推测该病毒并不具备在人群中传播的能力。突变试验表明,Q226L或Q226LG228S突变可以增强JD-H10N8 HA与人源受体的结合能力。另外,据数据库序列显示2014年德国和丹麦分别分离到含有HA 226L的H1ON7亚型禽流感病毒。表面等离子共振技术结果显示,其中丹麦株(D14 H10)HA具有双受体结合特性,与AH-H7N9病毒类似。这说明该病毒已经具备侵入哺乳动物细胞的能力。流感病毒较易发生基因突变或者重排而产生新的流感病毒,该种H10N7亚型禽流感病毒极有可能像H7N9亚型流感病毒一样与H9N2亚型流感病毒的内部基因发生重排而引起一定范围的流感病毒感染。因此我们应该关注此亚型流感病毒的流行与演化,并为防控该亚型流感病毒的流行做好准备。H9N2亚型禽流感病毒自1966年发现以来,给养禽业造成了巨大的经济损失。自20世纪90年代以来,H9N2业型禽流感病毒感染人事件也频繁发生。本研究针对H9N2亚型流感病毒的受体结合特性进行了系统地分析,按照受体结合特性的不同将其划分为三个时期,时期Ⅰ为H9N2亚型禽流感病毒偏好性结合禽源受体期,时期Ⅱ,H9N2亚型禽流感病毒获得了人源受体结合能力,但是仍以结合禽源受体为主。时期Ⅲ,H9N2亚型禽流感病毒转变为偏好性结合人源受体,但仍保留对禽源受体的结合能力。同时我们验证了影响H9N2亚型禽流感病毒受体结合特性的关键氨基酸,证实N158糖基化缺失与Q226L突变在H9N2亚型流感病毒受体结合特性转变机制中发挥了重要作用。H9N2亚型流感病毒已经获得人源受体的结合能力,可以通过基因突变或重排引起新的流感大流行,应当引起人类的高度警惕。
[Abstract]:Influenza viruses belong to the family of normal visco virus and can cause acute respiratory infections. According to the antigenicity of nucleoprotein and matrix protein, influenza viruses can be divided into four types, A, B, C, and D. Among them, the A virus can infect a variety of animals, including people, birds, pigs, horses, etc., except for the H1/H2/H3 subtype influenza virus to cause seasonal influenza or Influenza viruses have been infected by influenza viruses (H5, H6, H7, H9, H10), causing a huge threat to human life and health. The.A type of influenza virus invasion cells first need to combine the Hemagglutinin (HA) protein with the sialic acid receptor on the cell surface of the target cell, then enter the cell, and in the nucleus. There are a-2.6 sialic acid receptors (human receptor) in the upper respiratory tract and some alpha -2.3 sialic acid receptors (avian receptor) in the lower respiratory tract. Therefore, the avian influenza virus, which combines with avian source receptor, is not easy to spread in the population. The transition of the binding characteristics of the avian influenza virus receptor is its breakthrough. The key factors for the host infection of the main obstacle in mammals. This study has studied the hemagglutinin protein of the H10 and H9 subtypes of avian influenza virus. The molecular mechanism of the binding sialic acid receptor is described at the molecular level, and it is of great significance for the prevention and control of avian influenza virus. Since December 2013, 3 cases of human infection in H10N8 have occurred in China. A case of avian influenza virus, 2 of them died. This is the world's first reported case of human death from the H10 subtype influenza virus. The avian influenza virus causes influenza pandemic first to obtain the binding capacity of human source receptors. In order to assess the potential of the H10N8 subtype avian influenza virus caused by influenza virus pandemic, we are from the virus level and egg. The white layer detected the receptor binding characteristics of the earliest H1ON8 subtype avian influenza virus human isolate, A/Jiangxi-Donghu/346/2013 (JD-H10N8). The results showed that, unlike the AH-H7N9 that can bind to human receptor, JD-H10N8 specifically combines with avian receptor, and the binding weakly.JD-H10N8 HA protein and avian / human receptor of human receptor. The composite crystal structure also supports this view. This indicates that the JD-H10N8 subtype avian influenza virus is still a typical avian influenza virus, and the affinity for human receptor is very weak. It is presumed that the virus does not have the ability to spread in the population. Mutation test indicates that the mutation of Q226L or Q226LG228S can enhance the junction of JD-H10N8 HA and human receptor. In addition, according to the database sequence, the H1ON7 subtype of avian influenza virus containing HA 226L was isolated from Germany and Denmark in 2014. The surface plasmon resonance technique showed that the Danish strain (D14 H10) HA had a dual receptor binding characteristic, similar to that of the AH-H7N9 virus. This indicated that the virus had the ability to invade mammalian cells. The H10N7 subtype avian influenza virus is highly likely to rearrange the internal genes of the H9N2 subtype influenza virus like the H7N9 subtype influenza virus and cause a certain range of influenza virus infection. Therefore, we should pay attention to the influenza virus. Since the discovery of the.H9N2 subtype avian influenza virus (fowl) in 1966, the avian influenza virus has caused great economic loss since its discovery in 1966. Since 1990s, the avian influenza virus infection of the H9N2 industry has also occurred frequently. This study aimed at the receptor binding of the H9N2 subtype influenza virus. A systematic analysis was made to divide it into three periods according to the different receptor binding characteristics. Period I was H9N2 subtype avian influenza virus with preference to avian source receptor phase, period II, H9N2 subtype avian influenza virus obtained human receptor binding ability, but it was still combined with avian receptor receptor. Period III, H9N2 subtype avian influenza virus. It was converted to a preference for human receptor, but still retained the ability to bind to the avian source receptor. At the same time, we verified the key amino acids that affect the binding characteristics of the H9N2 subtype avian influenza virus receptor, and confirmed that the N158 glycosylation loss and Q226L mutation played an important role in the.H9N2 subtype of the H9N2 subtype influenza virus receptor binding characteristic transformation mechanism. Influenza virus has acquired the binding capacity of human source receptors, and can cause a new influenza pandemic through gene mutation or rearrangement. It should arouse the vigilance of human beings.
【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S852.65

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