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

在此期间(2008年4月，2012年3月)，我们阐明了导致高致病性流感病毒(H5N1亚型)与人型受体结合的血凝素(HA)突变的几个新机制，并在流感药物开发方面取得了进展。(1)我们在高致病性禽流感病毒(H5N1亚型)的HA(H5)尖峰中发现了几种类型的氨基酸替代，这些突变不仅来自患者，也来自于增加其人型受体(Neu5Acα2，6Gal)特异性的鸟类，这些亚种的病毒在人类呼吸道中的附着性和传染性都有所增加。我们还鉴定了一种实验性的H5HA/H1N1重新配型病毒。包括H5血凝素(来自H5N1病毒)，只有4个氨基酸突变，其余7个基因片段来自2009年大流行的H1N1病毒。它表现出对人类类型受体的依附性增加，并能够“在雪貂模型中传播飞沫”。我们的发现可能有助于我们深入了解禽流感病毒在哺乳动物中传播的机制和进化途径。(2)我们还测定了H5N1病毒HA受体N-连接唾液酸糖链的精细化学结构，这些细胞是H5N1宿主动物的几个靶细胞，如猪、狗、猫、胚胎鸡蛋。(3)我们开发了15个新的合成和天然化合物，这些化合物可以抑制受感染宿主细胞中人流感病毒受体的结合、复制和发芽。

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.