RBD recombinant protein-based SARS vaccine for biodefense

描述（申请人提供）：2002-2003年爆发的严重急性呼吸系统综合症（SARS）对全球公共卫生和社会经济稳定构成了巨大威胁。其致病病原体是 SARS 相关冠状病毒 (SARS-CoV)，已被 NIAID 列为 C 类优先病原体。 SARS 的爆发仍然是一个严重问题，主要是由于 SARS-CoV 可能通过人畜共患重新引入人类、实验室意外释放或生物恐怖袭击故意传播病毒。因此， 迫切需要一种有效且安全的疫苗来预防未来的 SARS 爆发和生物防御准备。我们已经确定了一种非常有前途的主要候选疫苗抗原，即 SARS-CoV 刺突 (S) 蛋白的受体结合域 (RBD)，它包含主要中和表位，可以诱导有效的中和抗体反应并保护动物免受 SARS-CoV 感染。为了快速将我们最初的概念验证结果转化为可靠的临床试验平台，专家组成了一个联盟 该团队由来自贝勒学院医学院、萨宾疫苗研究所产品开发合作伙伴 (BCM-Sabin) 的新所在地、纽约血液中心 (NYBC) 和德克萨斯大学医学分部 (UTMB) 的科学家组成，并与工业合作伙伴和非营利组织合作。本申请的具体目标是：（1）作为候选疫苗的重组RBD（rRBD）蛋白的表达、纯化和临床前表征。 rRBD 蛋白将在细菌和酵母表达系统中表达，并且将根据 rRBD 蛋白的产量、纯度、稳定性、抗原性、功能性、免疫原性和功效选择其中一种表达系统用于后续研究。将优化免疫方案，并评估rRBD蛋白诱导交叉中和抗体反应、交叉保护以及长期免疫反应和保护的能力。 (2) 工艺开发、表征、配方和稳定性分析。将开发可扩展且可重复的 rRBD 发酵工艺（10 升规模）以及使用色谱技术的纯化工艺。将确认再现性。将开发含有明矾和/或吡喃葡萄糖脂 A (GLA)（一种先天佐剂）的具体产品质量测定和疫苗配方。这些测定和程序将为正式批次放行和制造后稳定性评估奠定基础。 （3）技术转让、cGMP生产、GLP毒理学和IND准备。基于 rRBD 的 SARS 疫苗的细胞库生产、生产工艺和配方技术将转移到沃尔特·里德陆军研究所 (WRAIR) 中试设施，进行 60 升规模的 GMP 生产、配方、灌装和完成。临床批次将由 Sabin-Texas 发布，并在与美国 FDA 举行 IND 前会议后，位于马里兰州的承包商 Frontier Biosciences 将启动 GLP 毒理学研究。

DESCRIPTION (provided by applicant): The 2002-2003 pandemic of severe acute respiratory syndrome (SARS) posed an enormous threat to global public health and the social and economic stability. Its causative pathogen, the SARS-associated coronavirus (SARS-CoV), has been classified by NIAID as a Category C Priority Pathogen. SARS outbreaks remain a serious concern mainly due to possible zoonotic reintroduction of SARS-CoV into humans, accidental release from a laboratory or deliberate spreading of the virus by a bioterrorist attack. Therefore, an effective and safe vaccine is urgently needed for preventing future SARS outbreaks and for biodefense preparedness. We have identified a highly promising lead candidate vaccine antigen, the receptor binding domain (RBD) of the SARS- CoV spike (S) protein that contains the major neutralizing epitopes and can induce potent neutralizing antibody response and protection in animals against SARS-CoV infection. To rapidly translate our initial proof of concept findings into a solid platform of clinical trials, a consortium of experts was put together consisting of scientists from Baylor College Medicine, the new home of Sabin Vaccine Institute's product development partnership (BCM-Sabin), the New York Blood Center (NYBC) and the University of Texas Medical Branch (UTMB), and in partnership with industrial partners and non-profit organizations. The specific aims of this application are: (1) Expression, purification and pre-clinical characterization of the recombinant RBD (rRBD) protein as a vaccine candidate. The rRBD protein will be expressed in bacteria and yeast expression systems and one of these expression systems will be selected for subsequent studies based on yields, purity, stability, antigenicity, functionality, immunogenicity, and efficacy of the rRBD protein. The immunization regimens will be optimized and the ability of rRBD protein to induce cross-neutralizing antibody response, cross-protection and long-term immune responses and protection will be assessed. (2) Process development, characterization, formulation and stability profiling. A scalable and reproducible fermentation process for rRBD (10 liter scale) and a purification process using chromatographic technologies will be developed. Reproducibility will be confirmed. The specific product quality assays and vaccine formulations with alum and/or glucopyrranosyl lipid A (GLA), an innate adjuvant, will be developed. These assays and procedures will serve the basis for formal lot release and stability evaluation post-manufacturing. (3) Technology transfer, cGMP Manufacture, GLP toxicology and IND Preparation. The cell bank production, production processes and the formulation technology for the rRBD-based SARS vaccine will be transferred to Walter Reed Army Institute of Research (WRAIR) pilot facility for 60-L scale GMP manufacture, formulation and fill and finish. The clinical lots will be released by Sabin- Texas and following a pre-IND meeting with the U.S. FDA, GLP toxicology will be initiated at Frontier Biosciences, a Maryland-based contractor.