Collaborative cross mice as a new model for diverse human outcomes of St. Louis encephalitis virus disease

项目摘要 圣路易脑炎病毒（SLEV）是一种重新出现的蚊媒黄病毒，可引起一系列 在人群中的表现从发热性疾病到脑炎和死亡。引起的临床疾病 SLEV与相关的西尼罗河病毒（WNV）无法区分。虽然对于理解疾病和 评估对策，目前的SLEV小鼠模型在几个方面受到限制。使用的既往研究 近交系或免疫缺陷小鼠限制先天免疫作用的评估，颅内接种 人工绕过神经侵袭的病毒株，以及在小鼠大脑中连续传代的病毒株， 人工选择神经毒性。与近交系或免疫缺陷小鼠相比，重组小鼠更好 代表了人类遗传多样性，可以转化为类似的疾病。重组 由一组8个重组近交系产生的协作杂交（CC）小鼠代表了本发明的小鼠。 寨卡病毒、波瓦桑病毒和西尼罗河病毒感染者的无数结果。WNV感染CC小鼠 出现一系列结局，包括无症状、中枢神经系统（CNS）症状 疾病，和无症状的中枢神经系统疾病，其中先天免疫反应是主要介导的 预防CNS疾病。为了规避现有SLEV小鼠模型的局限性，本发明的目标是： 项目是建立SLEV的免疫活性重组CC小鼠模型。我们假设 CC小鼠模拟人SLEV，包括产生临床疾病、病毒嗜性和动力学，其平行于人SLEV。 人类SLEV结局谱以及对中枢神经系统疾病的保护与强大的先天性相关 免疫应答表现为干扰素刺激基因的更高表达或水平，包括抗病毒基因， 传感器RIG-I和效应细胞因子，包括干扰素（IFN）-α/β/γ。这些假设将在两个 项目目标。目的1：明确SLEV临床疾病和病毒在CC小鼠中的嗜性和动力学。我们将使用 CC菌株表现出可变的WNV结果，并通过SLEV蚊子的脚垫感染动物- 传输剂量。我们将评估临床疾病、感染动力学和嗜性以及病毒基因组变化 与神经侵袭有关的疾病目的2：将升高的先天免疫应答与SLEV CNS控制联系起来 CC小鼠的疾病。我们将通过基因表达分析和信号水平来测量先天反应。 和分泌的效应蛋白，并将这些变化与临床疾病、血液中的病毒水平和 靶组织和脑中的组织病理学病变。用IFN-γ治疗的CC小鼠中的疾病增强 受体阻断抗体将支持IFN信号传导作为保护介质。该项目将开发 SLEV的新的人类相关小鼠模型，其可进一步用于研究发病机理谱， 定义病毒-宿主相互作用和易感性和严重性的宿主遗传决定因素，测试干预措施，如 治疗和候选疫苗，并迅速适应其他新的或重新出现的模型疾病 脑炎黄病毒

PROJECT ABSTRACT St. Louis encephalitis virus (SLEV) is a re-emerging mosquito-borne flavivirus that causes a spectrum of manifestations in people ranging from febrile illness to encephalitis and death. Clinical disease caused by SLEV is indistinguishable from related West Nile virus (WNV). Although critical for understanding disease and evaluating countermeasures, current SLEV mouse models are limited in several ways. Prior studies used inbred or immunodeficient mice restricting assessment of the role of innate immunity, intracranial inoculation that artificially bypasses neuroinvasion, and virus strains that were serially passaged in mouse brains which artificially selects for neurovirulence. Compared to inbred or immunodeficient mice, recombinant mice better represent of human genetic diversity which can translate to similar disease to humans. Recombinant Collaborative Cross (CC) mice that were generated from a panel of 8 recombinant inbred strains represent the myriad of outcomes in people infected with the flaviviruses Zika, Powassan, and WNV. WNV-infected CC mice develop a spectrum of outcomes including asymptomatic, symptomatic with central nervous system (CNS) disease, and asymptomatic with CNS disease, where the innate immune response is the major mediator of protection from CNS disease. To circumvent limitations of existing SLEV mouse models, the goal of this project is to develop immunocompetent recombinant CC mouse models of SLEV. We hypothesize that CC mice model human SLEV including to produce clinical disease, viral tropism, and kinetics that parallel the spectrum of human SLEV outcomes, and that protection from CNS disease associates with robust innate immune responses manifest as higher expression or levels of interferon stimulated genes including the antiviral sensor RIG-I and effector cytokines including interferons (IFN)-α/β/γ. These hypotheses will be tested in two project Aims. Aim 1: Define SLEV clinical disease and viral tropism and kinetics in CC mice. We will use CC strains that manifest variable WNV outcomes and inoculate animals via the footpad with a SLEV mosquito- transmitted doses. We will assess clinical disease, infection kinetics and tropism, and viral genomic changes that associate with neuroinvasion. Aim 2: Link elevated innate immune responses to control of SLEV CNS disease in CC mice. We will measure innate responses via gene expression analyses and levels of signaling and secreted effector proteins and correlate these changes with clinical disease, virus levels in blood and target tissues, and histopathologic lesions in the brain. Augmented disease in CC mice treated with IFN- receptor blocking antibody will support IFN signaling as the mediator of protection. This project will develop new human-relevant mouse models of SLEV which can be further used to study the spectrum of pathogenesis, define virus-host interactions and host genetic determinants of susceptibility and severity, test interventions like therapeutics and candidate vaccines, and rapidly adapt to model disease for other new or re-emerging encephalitic flaviviruses.