Development of a vaccine for Ebola virus in plant system

描述(申请人提供)：尽管埃博拉病毒是全世界最可怕的病原体之一，但目前还没有预防埃博拉病毒感染的疫苗。本文提出的研究将推进候选疫苗的开发，重点是将创造大量用于临床前试验的疫苗的技术，以及使用转基因植物安全生产战略疫苗储备的节省成本的放大能力。这项拟议的研究利用植物细胞的便捷能力来表达和积累目前通过其他表达系统无法获得的复杂蛋白质。这项研究建立在国防部正在进行的一项资金投资的基础上，该投资旨在创造一种用于暴露后预防埃博拉病毒感染的单抗(MAb)的“鸡尾酒”；国防部项目使用转基因植物，因为植物来源的MAb可以迅速扩大到商业生产中，而不需要对传统MAb生产设施进行高资本成本投资。最近的研究表明，在植物细胞中表达的单抗可以作为融合分子，其抗原蛋白结构域是抗体重链恒定区的C端延伸。当单抗的可变区识别融合分子的抗原区时，形成高度免疫原性的重组免疫复合体(RICS)。我们将利用三种不同的单抗来创建包含埃博拉病毒糖蛋白(GP)序列以及GP融合的RICS。原型疫苗的生产数量将足以进行临床前试验。该应用的行业参与者将开发注射疫苗的纯化技术。现有的小鼠模型将用于免疫原性和挑战试验，随后将对主要候选疫苗的非人类灵长类疫苗进行评估。

DESCRIPTION (provided by applicant): There are no vaccines to prevent infections by Ebola virus, although it is among one of the most feared pathogens worldwide. The research proposed herein will advance development of vaccine candidates, with emphasis on technology that will create pilot lots of vaccine for preclinical testing and cost-saving scale-up capability using transgenic plants for safe production of strategic vaccine reserves. The proposed research exploits the facile capacity of plant cells to express and accumulate complex proteins that are not currently available via other expression systems. The research builds upon an ongoing funding investment by DoD directed to the creation of a "cocktail" of monoclonal antibodies (MAbs) to use in post-exposure prophylaxis for Ebola virus infections; the DoD project utilizes transgenic plants because plant-derived MAbs can be rapidly expanded in commercial production without high-capital cost investments for traditional MAb production facilities. Recent research has shown that MAbs expressed in plant cells can be created as fusion molecules with antigenic protein domains as a C-terminal extension of the constant region of the antibody heavy chain. Highly immunogenic recombinant immune complexes (RICs) form when the variable region of the MAb recognizes the antigenic region of the fusion molecule. We will utilize three different MAbs to create RICs containing the sequences of the Ebola virus glycoprotein (GP) as well as GP fusions. Prototype vaccines will be produced in quantities sufficient for preclinical trials. Industrial participants of the application will develop purification technology for injected vaccines. An existing murine model will be utilized for immunogenicity and challenge trials, which will be followed by non-human primate vaccine evaluation of the lead vaccine candidates.