Hemagglutinin mutations responsible for the binding of highly pathogenic influenza virus to human type receptors and influenza drug discovery.

在该资助期间（2008年4月至2012年3月），我们阐明了高致病性流感病毒（H5 N1亚型）与人型受体结合的血凝素（HA）突变的几种新机制，并在流感药物发现方面取得了进展。(1)我们鉴定了不仅从“病人”而且从“鸟”分离的高致病性禽流感病毒（H5 N1亚型）HA（H5）刺突中的几种类型的氨基酸替换，其增加了它们的人型受体（Neu 5Ac α2，6 Gal）特异性。这些亚系中的病毒在人呼吸道中表现出增加的附着和感染性。我们还鉴定了一种实验性抗H5 HA/H1N1病毒。包含仅具有4个氨基酸突变的H5 HA（来自H5 N1病毒）和来自2009年大流行H1N1病毒的其余7个基因片段。其表现出对人型受体的附着增加，并且能够“在雪貂模型中进行液滴传输”。我们的研究结果可能有助于推进我们对禽流感病毒在哺乳动物中传播的机制和进化途径的理解。(2)我们还测定了几种H5 N1宿主动物（如猪、狗、猫、鸡胚）靶细胞的H5 N1病毒HA受体N-连接唾液酸糖链的精细化学结构。(3)我们开发了超过15种新的合成和天然化合物，它们抑制人流感病毒受体结合、复制和从感染的宿主细胞出芽。

During the period(April, 2008.March 2012) of this grant, we clarified several new mechanisms on the hemagglutinin(HA) mutations responsible for the binding of highly pathogenic influenza virus(H5N1 subtype) to human type receptors and got progress on the drug discovery for influenza.(1) We identified several type of amino acid substitutions in the HA(H5) spike of highly pathogenic avian influenza viruses(H5N1 subtype) isolated from not only "patients" but also from "birds" that increase their human-type receptor(Neu5Acα2, 6Gal) specificity Viruses in those sublineages exhibited increased attachment and infectivity in the human respiratory tract. We also identified an experimental reassortant H5 HA/H1N1 virus. comprising H5 HA(from an H5N1 virus) with only four amino acid mutations and the remaining seven gene segments from a 2009 pandemic H1N1 virus. that exhibited increased attachment to the human type receptor and was capable of "droplet transmission in a ferret model". Our findings may help to advance our understanding of the mechanisms and evolutionary pathways that contribute to avian influenza virus transmission in mammals.(2) We also determined the fine chemical structures of H5N1 viral HA receptor N-linked sialo sugar chains of several target cells of H5N1 host animals, such as pig, dog, cat, embryonated chicken eggs.(3) We developed more than 15 new synthetic and native compounds which inhibit human influenza virus receptor binding, replication and budding from the infected host cells.