Development of Recombinant SARS VLP Vaccines

描述（由申请人提供）：本拨款提案的目的是开发和生产由Novasome佐剂配制的新型重组SARS亚基蛋白疫苗，用于在小动物和灵长类动物攻击模型中评估预防SARS冠状病毒感染和疾病。该计划将开发由重组SARS冠状病毒S、M、E蛋白组成的3种SARS候选疫苗，这些蛋白质是由Novavax公司在杆状病毒感染的昆虫细胞中进行密码子优化、克隆并表达的。候选疫苗包括：(1)在novassomes上显示的重组多蛋白免疫原，(2)在体内自组装的VLPs，以及(3)由SARS病毒蛋白和人流感病毒血凝素蛋白组成的嵌合VLPs。在杆状病毒感染的昆虫细胞和/或CHO细胞中表达的疫苗免疫原将通过超离心和层析方法纯化。疫苗免疫原将与佐剂配制，并将初步评估小鼠的粘膜和全身免疫原性。在小鼠免疫原性模型中引起SARS中和抗体的候选疫苗（通过微中和试验确定）将与最近开发该模型的Kanta Subbarao博士（美国国立卫生研究院）合作，在一种新的SARS小鼠攻击模型中进一步评估。与James Estep博士（Battelle研究所）合作，在其BSL3灵长类动物设施中，将在SARS灵长类动物攻击模型中使用食蟹猴进一步测试临床前候选疫苗，这些疫苗可在小鼠攻击模型中引发中和抗体并降低病毒滴度。最后，将生产临床批量的SARS候选疫苗，该疫苗在灵长类动物攻击模型中具有最高的SARS中和抗体滴度和最大的病毒减少量，并进行批量释放测试。SARS候选疫苗的毒理学研究将在兔子身上进行。将准备I期临床研究的临床方案，并向CBER/FDA提交IND申请。

DESCRIPTION (provided by applicant): The objective of this grant proposal is to develop and manufacture preclinical and clinical lots of novel recombinant SARS subunit protein vaccines formulated with Novasome adjuvants for evaluation in small animal and primate challenge models to prevent SARS coronavirus infection and disease. This plan will develop three types of SARS vaccine candidates comprised of recombinant SARS coronavirus S, M, and E proteins, which have been codon-optimized, cloned, and expressed in baculovirus-infected insect cells at Novavax, Inc. Vaccine candidates include the following: (1) recombinant multiprotein immunogens displayed on Novasomes, (2) VLPs self-assembled in vivo, and (3) chimeric VLPs comprised of SARS viral proteins and human influenza virus hemagglutinin proteins. Vaccine immunogens, expressed in baculovirus-infected insect cells and/or CHO cells, will be purified by ultracentrifugation and chromatographic methods. Vaccine immunogens will be formulated with adjuvants and will be evaluated initially for mucosal and systemic immunogenicity in mice. Vaccine candidates that elicit SARS neutralizing antibodies in the murine immunogenicity model, as determined by microneutralization assays, will be evaluated further in a novel SARS mouse challenge model in collaboration with Dr. Kanta Subbarao (NIH), who recently developed the model. Preclinical lots of vaccine candidates that elicit neutralizing antibodies and reduce virus titers in the murine challenge model will be tested further in a SARS primate challenge model using cynomolgus monkeys in collaboration with Dr. James Estep (Battelle Institute) in their BSL3 primate facility. Finally, clinical lots of a SARS vaccine candidate that demonstrates the highest SARS neutralizing antibody titer and the greatest virus reduction in the primate challenge model will be manufactured and lot release tested. Toxicology studies of the SARS vaccine candidate will be conducted in rabbits. A clinical protocol for a Phase I clinical study will be prepared, and an IND application will be submitted to CBER/FDA.