HOST RANGE DETERMINANTS OF INFLUENZA VIRUS

这项研究的长期目标是了解 新的致病性病毒出现的机制 人类，使用甲型流感病毒作为模型。 在过去的三十年里， 几种新的病毒病原体在人类中出现， 小的人类群体或其他动物宿主中。 大流行性流感 菌株是后一类型的典型例子;血凝素（HA）， 1957年和1968年大流行毒株的神经氨酸酶（NA）和PBI基因 是从禽流感病毒衍生而来的。 先前的研究 证明了大流行性流感HA和NA的遗传变化 改变了这些病毒的宿主范围的菌株，尽管 这种影响的结构基础是未知的。 这项建议旨在 确定甲型流感病毒宿主范围的分子基础 限制. 反向遗传学技术的最新进展 Palese及其同事，结合三人提供的信息- HA和NA的尺寸结构，现在允许直接检查 特定氨基酸改变与宿主范围的相关性 甲型流感病毒。 提出了以下具体目标：1。 阐明决定宿主的HA结构特征 甲型流感病毒的范围特异性。 氨基酸的变化 禽流感病毒HA所需的有效复制的病毒， 松鼠猴将被识别，与其受体相关， 特异性，通过使用反向遗传学产生流感病毒 含有HA中的特定突变。2. 测定 影响流感病毒宿主范围的NA分子特征 一种病毒。 NA底物特异性的结构基础 将通过体外诱变建立。 的影响 底物对病毒宿主范围限制的特异性将 然后通过引入 NA中的特定突变，使用反向遗传学。 知识 禽流感病毒HA和NA中的氨基酸变化需要有效的 在哺乳动物中的复制应该可以让我们评估鸟类的潜力- 就像非人类哺乳动物中的病毒一样， 大流行菌株的，使其有可能预测（和可能 预防）未来的人类流感大流行。 它也可以应用于 人类流感病毒的减毒导致产生 活疫苗株。 精细受体的鉴定和 HA和NA的底物特异性应提供基本信息 设计抗病毒药物， 而不影响细胞过程。

The long-term goal is this research is to understand the molecular mechanism(s) permitting the emergence of new pathogenic viruses in humans, using influenza A viruses as a model. In the last three decades, several new viral pathogens appeared in humans after being maintained in small human populations or in other animal hosts. Pandemic influenza strains are classic examples of the latter type; the hemagglutinin (HA), neuraminidase (NA), and PBI genes of the 1957 and 1968 pandemic strains were derived from avian influenza viruses. Previous studies have demonstrated genetic changes in both the HA and NA of pandemic influenza strains that altered the host range of these viruses, although the structural basis of such effects are unknown. This proposal seeks to determine the molecular basis of influenza A virus host range restriction. Recent development of the reverse genetics techniques by Palese and colleagues, combined with information provided by the three- dimensional structures of the HA and NA, now permits direct examination of the relevance of specific amino acid alterations to the host range of influenza A viruses. The following specific aims are proposed: 1. Elucidation of the structural features of the HA that determine the host range specificity of influenza A viruses. Amino acid changes in the avian virus HA required for efficient replication of the virus in squirrel monkeys will be identified, in relation to its receptor specificity, by using reverse genetics to generate influenza viruses containing specific mutations in the HA. 2. Determination of the molecular features of the NA that influence the host range of influenza A viruses. The structural basis of the substrate specificity of the NA will be established by in vitro mutagenesis. The influence of the substrates specificity on the host range restriction of the virus will then be determined in both avian and mammalian systems by introducing specific mutations in the NA, using reverse genetics. Knowledge of the amino acid changes in the avian virus HA and NA required for efficient replication in mammals should allow us to assess the potential of avian- like viruses in nonhuman mammals to provide the genes for the generation of the pandemic strains, making it possible to predict (and possible prevent) future pandemic of human influenza. It could be also applied to the attenuation of human influenza viruses leading to the generation of live vaccine strains. Identification of the fine receptor and substrate specificities of the HA and NA should provide basic information needed for designing antiviral agents that would inhibit the activities of these viral constituents without affecting cellular processes.