Novel Vaccine Technology for Chikungunya

描述(申请人提供)：基孔肯雅病毒(CHIKV)最近从非洲进入城市人蚊循环，导致数百万例高度虚弱、通常是慢性关节痛的疾病。数十例通过病毒携带者输入的CHIKV突显了CHIKV对西半球的风险。基孔肯雅热(CHIK)可能是致命的，目前还没有有效的治疗方法，因此需要有效的疫苗。要在第三世界流行地区使用，理想的疫苗必须生产成本低廉，并在单剂接种后诱导快速、持久的免疫。为了在非流行地区安全使用，疫苗还必须不能在宿主防御受损的接种者中发生病毒血症时感染蚊媒。为了实现这些目标，我们开发了新的创新方法来稳定甲型病毒减毒，既保留了免疫原性，又消除了蚊子感染的可能性。利用在昆虫细胞中功能不佳的微小核糖体内部核糖体进入位点(IRES)，加上驱动结构蛋白过度表达的甲型病毒亚基因组启动子的失活，我们生产出了一种活的CHIKV疫苗株，它结合了已证实的活减毒疫苗的优点，但应该比传统方法更稳定地减毒。这种CHIKV疫苗在小鼠模型中具有高度减毒和免疫原性，并且不能在蚊子细胞中复制。在这个项目中，我们将进一步开发这种CHIK候选疫苗，为新药的研究应用和第一阶段的人体研究做准备，具体目标如下：1.通过分析RNA复制水平、体外蛋白质表达和翻译效率以及体内复制和传播模式来确定疫苗减毒的机制。2.界定保护性免疫的相关因素，并确定控制疫苗复制所需的先天和获得性免疫反应的组成部分。3.优化Vero细胞生产的候选疫苗。4.研制和鉴定GMP母本病毒种源和工作病毒种源。5.开展质量控制和释放试验，并生产一批临床前GMP疫苗。6.在非临床GLP研究中测试疫苗的安全性。7.IND提交和生产第一阶段临床试验的疫苗批次。学术和工业合作伙伴之间的这种合作的创新产品将在亚洲和非洲产生巨大影响，在那里CHIKE既会对健康造成严重影响，也会造成经济困难，并将极大地降低CHIKV在西半球输入和建立的风险。此外，对甲型H1N1流感病毒衰减机制的更好了解，以及我们基于IRES的疫苗平台技术的进一步发展，将使我们能够快速生产出针对其他甲型病毒的可预见的安全有效的疫苗，这些甲型病毒代表着生物防御威胁和/或未来可能出现的甲型病毒。

DESCRIPTION (provided by applicant): Chikungunya virus (CHIKV) recently emerged from Africa into an urban human-mosquito cycle to cause millions of cases of highly debilitating, often chronic arthralgic disease. Dozens of CHIKV importations via viremic travelers underscore the risk of CHIKV to the Western hemisphere. There is no effective treatment for chikungunya fever (CHIK), which can be fatal, so an effective vaccine is needed. For use in third world, endemic locations, an ideal vaccine must be inexpensive to manufacture and induce rapid, long-lived immunity after a single dose. To be used safely in nonendemic locations, the vaccine must also be incapable of infecting mosquito vectors in the event that viremia occurs in a vaccinee with impaired host defense. To achieve these goals, we developed novel, innovative approaches to stable alphavirus attenuation that retain immunogenicity yet eliminate the possibility of mosquito infection. Using a picornavirus internal ribosome entry site (IRES) that functions poorly in insect cells, combined with inactivation of the alphavirus subgenomic promoter that drives overexpression of the structural proteins, we produced a live CHIKV vaccine strain that combines the proven advantages of live-attenuated vaccines, yet which should be more stably attenuated than traditional approaches. This CHIKV vaccine is highly attenuated yet immunogenic in mouse models, and is incapable of replicating in mosquito cells. In this project, we will further develop this CHIK vaccine candidate in preparation for an investigational new drug application and Phase 1 human studies, using the following specific aims: 1. Determine the mechanism of vaccine attenuation by analyzing levels of RNA replication, protein expression and translational efficiency in vitro and patterns of replication and spread in vivo. 2. Define correlates of protective immunity and determine components of the innate and adaptive immune response required to control vaccine replication. 3. Optimize the vaccine candidate for production in Vero cells. 4. Develop and characterize GMP master virus seed and working virus seed stocks. 5. Develop quality control and release tests and manufacture a preclinical GMP lot of the vaccine. 6. Test the vaccine in nonclinical GLP studies for safety. 7. IND submission and manufacture of vaccine lots for Phase 1 clinical testing. The innovative product of this collaboration between academic and industrial partners will have dramatic impacts in Asia and Africa where CHIK causes both severe health effects and economic hardship, and will greatly reduce the risk of CHIKV importation and establishment in the Western Hemisphere. In addition, the improved mechanistic understanding of its attenuation and further development of our IRES-based vaccine platform technology will allow us to rapidly generate predictably safe and effective vaccines against other alphaviruses that represent biodefense threats and/or that have the potential that emerge in the future.