RBD recombinant protein-based SARS vaccine for biodefense

描述（申请人提供）：2002-2003年严重急性呼吸综合征（SARS）大流行对全球公共卫生和社会经济稳定构成了巨大威胁。其病原体SARS相关冠状病毒（SARS-CoV）已被NIAID列为C类优先病原体。SARS爆发仍然是一个严重的问题，主要是由于可能的人畜共患SARS冠状病毒重新引入人类，从实验室意外释放或故意传播的病毒的生物恐怖袭击。因此，我们认为， 为了预防未来SARS的爆发和生物防御准备，迫切需要一种有效和安全的疫苗。我们已经鉴定了一种非常有前途的先导候选疫苗抗原，SARS-CoV刺突（S）蛋白的受体结合结构域（RBD），其包含主要的中和表位，并且可以在动物中诱导有效的中和抗体应答和保护以对抗SARS-CoV感染。为了将我们最初的概念验证结果迅速转化为临床试验的坚实平台，我们组建了一个专家联盟， 由贝勒医学院的科学家组成，该学院是萨宾疫苗研究所产品开发合作伙伴关系（BCM-Sabin）的新家，纽约血液中心（NYBC）和德克萨斯大学医学分支（UTMB）的科学家，并与工业合作伙伴和非营利组织合作。本申请的具体目的是：（1）作为疫苗候选物的重组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，并且将基于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这些表达系统中的一个用于后续研究。将优化免疫方案，并评估rRBD蛋白诱导交叉中和抗体应答、交叉保护和长期免疫应答和保护的能力。(2)工艺开发、表征、配方和稳定性分析。将开发rRBD的可扩展和可重现的发酵工艺（10升规模）和使用色谱技术的纯化工艺。将确认复制性。将开发具有明矾和/或葡萄糖吡喃糖基脂质A（GLA）（一种先天佐剂）的特定产品质量测定和疫苗制剂。这些试验和程序将作为正式批放行和生产后稳定性评价的基础。(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、生产工艺和配制技术将转移到沃尔特里德陆军研究所（WRAIR）中试设施，进行60 L规模的GMP生产、配制以及填充和完成。临床批次将由Sabin- Texas放行，在与美国FDA召开IND前会议后，GLP毒理学将在马里兰州承包商Frontier Biosciences启动。

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.