Vaccines for Prevention of RG3 and RG4 Emerging Tickborne Viral Diseases

项目总结 壁虱传播的疾病在美国和世界范围内仍然是一个重大的公共卫生问题，因为 环境和气候的变化使得扁虱、扁虱栖息地和它们的 哺乳动物的宿主。仅在新英格兰地区，孤星扁虱就于2017年首次报告，随后 通过在2018年建立充满异国情调的亚洲长角蜱。疾控中心最近的一份报告表明， 从2004年到2016年，美国的壁虱传播疾病增加了一倍多，占所有疾病的77% 报告的病媒传播疾病。该报告还表明，美国尚未做好充分准备，以防止和 控制这些威胁。在中国引起脑炎和出血热的一些扁虱传播病毒 在美国，人类尤其令人担忧，例如重新出现的鲍瓦桑病毒(POWV)以及 最近发现的哈特兰病毒(HRTV)。亚洲另一种新出现的壁虱传播病毒是高烧 与HRTV关系密切的血小板减少综合征病毒(SFTSV)由 亚洲长角扁虱正在迅速传播，目前分布在美国12个州。一些附加的 美国关注的外来森林脑炎病毒，包括森林脑炎病毒(TBEV) 鄂木斯克出血热病毒(OHFV)和克里米亚-刚果出血热病毒(CCHFV)。为了更好地 为应对这些新出现的威胁，我们组建了一个(1)疫苗开发专家团队， 康涅狄格大学，(2)康涅狄格州农业实验站的扁虱传播病毒，以及(3) 国家新发传染病实验室最大限度生物遏制的动物模型 并建议开发和测试针对四个风险组3(RG3)和RG4滴虫的疫苗 被列为NIAID A或C类优先病原体的脑炎和出血热病毒；以及 世卫组织在其最新的2018年需要加速发展的优先疾病蓝图清单中将其列为优先事项 研究和开发。我们开发了一种快速产生痘苗病毒(VACV)载体的方法 将使我们能够快速测试一些壁虱传播的病毒基因，以确保保护性基因的稳健表达 抗原和病毒样颗粒(VLP)的分泌。这个平台是基于黄金标准的病毒载体 (VACV)可诱导高水平的体液和细胞免疫反应。这些VACV载体 作为疫苗接种时是复制缺陷的，但很容易在标准细胞培养中繁殖 高滴度，不像其他复制缺陷的痘病毒载体，如MVA。我们还将产生DNA- 基于VLP的疫苗和纯化的VLP(作为亚单位疫苗)，使三种不同类别的疫苗 候选人可以单独或在主要的增强方案中进行免疫原性测试。最后，我们将测试 利用蜱类传播动物模型研究疫苗的免疫效果 这种传播和传播已经通过扁虱饲养记录下来了。

PROJECT SUMMARY Tickborne illnesses continue to be a significant public health concern in the US and worldwide, as environmental and climate changes have allowed the dramatic expansion of ticks, tick habitats, and their mammalian hosts. In the New England region alone, Lone Star ticks were first reported in 2017, followed by the establishment of exotic Asian longhorned ticks in 2018. A recent CDC report indicates that tickborne diseases in the US have more than doubled from 2004 to 2016, accounting for 77% of all reported vector-borne diseases. The report also indicates that the US is not fully prepared to prevent and control these threats. A number of tickborne viruses that cause encephalitis and hemorrhagic fever in humans are of particular concern in the US, such as the re-emerging Powassan virus (POWV), as well as the recently discovered Heartland virus (HRTV). Another emerging tickborne virus in Asia is severe fever with thrombocytopenia syndrome virus (SFTSV), closely related to HRTV, which is transmitted by the Asian longhorned tick that is spreading rapidly and is now present in 12 US states. A number of additional exotic tickborne viral agents are of concern to the US, including tickborne encephalitis virus (TBEV), Omsk hemorrhagic fever virus (OHFV), and Crimean-Congo hemorrhagic fever virus (CCHFV). To better prepare for these emerging threats, we assembled a team of experts in (1) vaccine development at the University of Connecticut, (2) tickborne viruses at the Connecticut Agricultural Experiment Station, and (3) animal models in maximum biocontainment at the National Emerging Infectious Diseases Laboratories and propose the development and testing of vaccines for four Risk Group 3 (RG3) and RG4 tickborne encephalitis and hemorrhagic fever viruses classified as NIAID Category A or C Priority Pathogens, and prioritized by the WHO under its most recent 2018 Blueprint list of priority diseases in need of accelerated research and development. We developed a rapid method to generate vaccinia virus (VACV) vectors that will allow us to quickly test a number of tickborne viral genes to ensure robust expression of protective antigens and secretion of virus-like particles (VLPs). This platform is based on a gold-standard viral vector (VACV) that induces high levels of humoral and cell-mediated immune responses. These VACV vectors are replication-defective when administered as a vaccine, yet easy to propagate in standard cell culture at high titers, unlike other replication-defective poxvirus vectors such as MVA. We will also generate DNA- based vaccines and purified VLPs (as a subunit vaccine), so that three different classes of vaccine candidates can be tested for immunogenicity, either alone or in prime-boost regimens. Finally, we will test the efficacy of the vaccines using tick-transmission animal models to recapitulate the enhancement of transmission and dissemination that has been documented by tick feeding.