LSUHSC COBRE: ROLE OF INNATE IMMUNITY IN YELLOW FEVER VIRUS PATHOGENESIS

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。项目1：先天性免疫在黄热病病毒发病中的作用P.I.：Kate D.Ryman，Ph.D.(报告期：07/01/05-06/30/06)摘要背景与原理：由蚊媒黄热病病毒(YFV)引起的高致死性泛系统出血热一直是非洲、欧洲和美洲最可怕的疾病之一，直到1930年S研制出17D减毒活疫苗。尽管17D被认为是一种典型的减毒活疫苗，但黄病毒领域最大的谜团之一是控制这种减毒活疫苗的减毒和免疫原性的分子机制。我们的长期目标是揭示积累在17D基因组中的哪些突变在体内减弱，并确定它们在病毒致病机制中的作用(S)，并确定减弱的感染如何对早期的病毒-宿主相互作用产生不同的影响，在17D免疫后引发YFV特异性保护性免疫反应。拟议的实验将在几个重要方面与先前的分析有所不同。首先，我们将比较17D与亲本ASIBI的表型，以确定与衰减相关的特定核苷酸和氨基酸突变。其次，我们将通过皮内(I.D.)来评估毒力表型。对小鼠的免疫，从而模仿YFV感染蚊子的叮咬或17D免疫，而以前的研究评估了脑内接种后17D特定突变的减弱潜力。最后，我们将关注病毒进入宿主并开始传播时感染的最早事件。我们的假设是，由于在树突状细胞(DC)、单核细胞(MO)和/或巨噬细胞(M？)中复制的能力不同，与强毒亲本Asibi病毒相比，17D减毒活疫苗株的早期病毒传播将受到显著损害。这种减弱的表型与趋化因子/细胞因子的诱导有关，这些趋化因子/细胞因子可刺激区域淋巴组织的获得性免疫。预计我们的发现将有助于其他减毒活疫苗的合理设计，特别是针对其他致病性黄病毒(例如西尼罗河病毒和登革热病毒)和密切相关的甲型病毒(例如东部马脑炎病毒)，这些病毒中的大多数都是新出现的传染病和生物恐怖主义/生物武器的病原体。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Project 1: Role of Innate Immunity in Yellow Fever Virus Pathogenesis P.I.: Kate D. Ryman, Ph.D. (Reporting Period: 07/01/05 - 06/30/06) Abstract Background & Rationale: The highly-lethal, pan-systemic hemorrhagic fever caused by the mosquito-borne yellow fever virus (YFV) was one of the most feared diseases in Africa, Europe and the Americas until the live-attenuated 17D vaccine was developed in the 1930?s. To derive the 17D vaccine strain, the natural wild-type Asibi isolate of YFV was empirically passaged 176 times on primary cultured cells. Although 17D is considered a prototypic live-attenuated virus vaccine, one of the greatest mysteries in the flavivirus field is the molecular mechanism that controls the attenuation and immunogenicity of this live-attenuated vaccine. Our long-term goals are to reveal which of the mutations accumulated in the 17D genome are attenuating in vivo and determine their effect(s) on viral pathogenesis, and to determine how the attenuated infection differentially affects early virus-host interactions, eliciting a YFV-specific protective immune response after 17D immunization. The proposed experiments will differ from prior analyses in several important respects. First, we will compare the phenotype of 17D to parental Asibi to identify specific nucleotide and amino acid mutations correlated with attenuation. Second, we will assess the virulence phenotype by intradermal (i.d.) inoculation of mice, thereby mimicking the bite of a YFV-infected mosquito or 17D immunization, whereas previous studies have assessed the attenuating potential of 17D-specific mutations following intracerebral inoculation. Finally, we will focus on the earliest events in infection as the virus enters the host and begins to disseminate. It is our hypothesis that the early viremic dissemination of the live-attenuated 17D vaccine strain will be significantly impaired in comparison with the virulent parental Asibi virus as a result of a differential ability to replicate in dendritic cells (DCs), monocytes (MO) and/or macrophages (M?) in the skin and that the attenuated phenotype will correlate with induction of chemokine/cytokines appropriate for the stimulation of adaptive immunity in regional lymphoid tissues. It is anticipated that our findings will facilitate the rational design of other live-attenuated virus vaccines, particularly against other pathogenic flaviviruses (e.g., West Nile and dengue viruses) and the closely-related alphaviruses (e.g., eastern equine encephalitis virus), most of which are agents of both emerging infectious disease and bioterrorism/biowarfare.