Development of a vaccination platform for emerging flavivirus infections

项目总结： 黄病毒属(称为黄病毒)由许多新出现和重新出现的病毒组成。 对人类具有重要意义的全球病原体。地方性和新兴的黄病毒，如登革热病毒(DENV)， 鲍瓦桑病毒、寨卡病毒、西尼罗河病毒、乙型脑炎病毒和黄热病 病毒继续传播，并导致重大的人类疾病。我们使用的RNA结构数据来自 保守的3‘非翻译区(UTR)伪结，称为xrRNA1，以开发一种衰减方法 黄病毒3‘非编码区高度保守的结构区域，用于疫苗开发。这种方法使我们能够 1)替换我们克隆的黄病毒结构基因，以快速开发嵌合、减毒的黄病毒疫苗 针对蚊媒黄病毒和2)为扁虱传播的黄病毒提供了一个保守的减弱部位，如 POWV。 根据我们的初步数据，我们假设xrRNA1突变的减毒黄病毒疫苗将 在黄病毒病的小鼠模型中是安全的、免疫原性的，并提供免受挑战的保护。这个 拟议研究的目标是完成黄病毒减毒疫苗的临床前开发。 接近了。我们将在评估免疫学和病毒学的三个目标中完成我们提议的工作 接种ZIKV候选疫苗(AIM 1)、DENV疫苗(AIM)后的病毒攻击结果 2)和POWV疫苗(目标3)。 我们最近发表了我们的数据，显示了突变的xrRNA1 ZIKV的减毒作用和免疫原性 (X1)怀孕和未怀孕的小鼠。在这份提案中，我们将首先评估ZIKV X1疫苗的效力 用ZIKV和DENV攻击怀孕和未怀孕的小鼠。这些研究将使我们能够评估 ZIKV疫苗孕期免疫效果及在DENV病中的作用评价 增强功能。接下来，我们将使用我们实验室开发的减毒ZIKV疫苗平台，使用 XrRNA1结构数据，插入来自DENV1-4和DENV1-4的嵌合前膜和包膜结构基因 单价和四价DENV1-4疫苗的减毒效果、免疫原性和免疫效果评价 候选人。鉴于DENV感染的复杂性，我们将评估疾病的增强和 我们的四价疫苗中的免疫优势以及有效性。第三，我们将扩大我们的衰减 通过利用我们最近定义的X1结构中的二级结构来对抗壁虱传播的黄病毒 POWV 3‘UTR.使用在X1结构中具有靶向突变的POWV突变候选疫苗，我们将 POWV疫苗在鼠脑模型中的减毒、免疫原性和有效性的特征 疾病。拟议的研究将开始翻译我们对黄病毒中xrrNAs的结构理解。 3‘非编码区转化为潜在的候选疫苗。此外，该项目将启动研究，重点开发一种 针对新出现的黄病毒感染的疫苗开发平台。

Project Summary: The Flavivirus genus (referred to as flaviviruses) consists of numerous emerging and re-emerging global pathogens of critical human significance. Endemic and emerging flaviviruses like dengue virus (DENV), Powassan virus (POWV), Zika virus (ZIKV), West Nile virus, Japanese Encephalitis virus and Yellow fever virus continue to spread and cause significant human disease. We have used RNA structural data from a conserved 3’ untranslated region (UTR) pseudoknot called xrRNA1 to develop an attenuation approach in a highly conserved structural region of the flavivirus 3’UTR for vaccine development. This approach allows us to 1) swap out flavivirus structural genes in our clone to rapidly develop chimeric, attenuated flavivirus vaccines for mosquito-borne flaviviruses and 2) provides a conserved site for attenuation for tick-borne flaviviruses like POWV. Based on our preliminary data, we hypothesize that xrRNA1-mutant, attenuated flavivirus vaccines will be safe, immunogenic, and provide protection from challenge in murine models of flavivirus disease. The objective of the proposed studies is to complete pre-clinical development of the attenuated flavivirus vaccine approaches. We will complete our proposed work in three aims that will evaluate immunologic and virologic outcomes following virus challenge after vaccination with candidate ZIKV vaccine (Aim 1), DENV vaccine (Aim 2), and POWV vaccine (Aim 3). We have recently published our data showing attenuation and immunogenicity of mutant xrRNA1 ZIKV (X1) in pregnant and non-pregnant mice. In this proposal, we will first evaluate the efficacy of ZIKV X1 vaccine in pregnant and non-pregnant mice challenged with ZIKV and DENV. These studies will allow us to evaluate ZIKV vaccine efficacy during pregnancy and evaluate the role of ZIKV vaccination in DENV disease enhancement. Next, we will use the attenuated, ZIKV vaccine platform developed in our laboratory using xrRNA1 structural data, insert chimeric pre-membrane and envelope structural genes from DENV1-4 and evaluate the attenuation, immunogenicity and efficacy of monovalent and quadrivalent DENV1-4 vaccine candidates. Given the complexity of DENV infection, we will evaluate disease enhancement and immunodominance in our quadrivalent vaccines along with efficacy. Third, we will expand our attenuation strategy in the X1 structure to tick-borne flaviviruses by utilizing our recently defined secondary structure of the POWV 3’UTR. Using POWV mutant vaccine candidates with targeted mutations in the X1 structure, we will characterize attenuation, immunogenicity, and efficacy of a POWV vaccine approach in a murine model of disease. The proposed studies will begin to translate our structural understanding of xrRNAs in the flavivirus 3’UTR into potential vaccine candidates. Moreover, this project will initiate studies focused on developing a platform for vaccine development for emerging flavivirus infections.