Defining a Protective Ebola Vaccine in Non-Human Primates

 描述（由申请方提供）：丝状病毒引起暴发性出血热，在人类暴发中病死率高达90%。虽然丝状病毒（埃博拉病毒（EBOV）和马尔堡病毒（MARV））仅在中非和菲律宾的某些地区流行，但它们的极端毒性和武器化潜力已导致确定两者都是对美国国家安全的高度优先生物威胁。因此，丝状病毒医疗对策已被优先纳入国家战略储备。虽然被动免疫治疗策略在过去两年中取得了重大进展，但疫苗接种仍然是保护更多人群免受这些病毒性疾病威胁的最经济和技术可行的方法。2014年埃博拉病毒在几个西非国家爆发期间，医护人员获得性感染的发病率很高，这表明疫苗在控制疾病传播方面可以发挥重要作用。虽然正在开发多种候选疫苗，但进展缓慢，并且仍然需要满足储存要求的替代丝状病毒疫苗。 该项目的总体目标是开发一种非复制型重组亚单位EBOV疫苗，可以安全可靠地保护高危人群免受EBOV感染。该疫苗基于由稳定转化的果蝇Schneider 2（S2）细胞表达的高度纯化的重组EBOV亚单位蛋白。该生产系统的一个关键优势是能够持续生产大量纯的、稳定的和正确折叠的病毒蛋白。通过免疫亲和层析的纯化对于高效生产是必不可少的，并且通过使用植物表达的单克隆抗体而得到促进。抗原剂量、免疫时间表和佐剂选择的微调允许将新的或修饰的靶标快速包含到核心疫苗制剂中，以允许将来配制广泛保护性疫苗。该核心制剂将具有安全性 这是一个只有使用高度纯化的亚基蛋白才能实现的特征。 这项研究分为 三个具体目标：在目标1中，将选择EBOV GP（前导抗原）的理想佐剂，特别关注在非人灵长类动物（NHP）中实现一致的体液免疫。目的2将评估EBOV VP24和VP40抗原增强先导候选制剂在灵长类动物中的功效的能力，如先前在啮齿动物研究中观察到的。随后评价所选最终制剂的耐久性。目标3将与目标1和2同时处理。它将侧重于使用常规方法以及基于肽阵列的“免疫特征”技术对体液和细胞免疫应答的详细分析。由于我们将从我们的三个NHP有效性研究中获得样本，因此样本量应足以使我们将挑战结果与免疫学读数相关联，从而鉴定可用于未来临床开发的保护性EBOV疫苗的通用免疫特征。

 DESCRIPTION (provided by applicant): Filoviruses cause fulminant hemorrhagic fevers with a case-fatality rate of up to 90% in human outbreaks. Although filoviruses (Ebolavirus (EBOV) and Marburgvirus (MARV)) are endemic only to certain parts of central Africa and the Philippines, their extreme virulence and potential for weaponization have lead to the determination that both are high priority biothreats to US national security. Consequently, filovirus medical countermeasures have been prioritized for acquisition into the Strategic National Stockpile. While strategies for passive immunotherapy have made significant progress in the past two years, vaccination remains the most economical and technically feasible approach to protect larger groups of people from the threat of acquiring these viral diseases. The high incidence of acquired infection among healthcare workers during the 2014 Ebola virus outbreak in several West African countries demonstrates the important role a vaccine could play in controlling the spread of the disease. While multiple vaccine candidates are under development, progress has been slow and a continuing need exists for alternate filovirus vaccines that meet stockpiling requirements. The overall goal of this project is to develop a non-replicating recombinant subunit EBOV vaccine that can safely and reliably protect at-risk populations against EBOV infections. This vaccine is based on highly purified recombinant EBOV subunit proteins expressed by stably transformed Drosophila Schneider 2 (S2) cells. A key advantage of this production system is the ability to consistently produce large quantities of pure, stable, and properly folded viral proteins. Purification by immunoaffinity chromatography is essential for the highly efficient production and is being facilitated by the use of plant-expressed monoclonal antibodies. Fine tuning of antigen dosing, immunization schedule, and adjuvant selection allow the rapid inclusion of new or modified targets into a core vaccine formulation to allow the formulation of a broadly protective vaccine in the future. This core formulation will have a safety profile only achievable with the use of highly purified subunit proteins. This research is divided into three Specific Aims: In Aim 1, the ideal adjuvant for the EBOV GP (lead antigen) will be selected with a specific focus on achieving consistent humoral immunity in non-human primates (NHPs). Aim 2 will evaluate the ability of EBOV VP24 and VP40 antigens to enhance efficacy of the lead candidate formulation in primates as previously observed in rodent studies. This is followed by evaluation of durability of the selected final formulation. Aim 3 will be addressed concurrently with Aims 1 and 2. It will focus on detailed analysis of the humoral and cellular immune responses using conventional methods as well as the peptide-array based "immunosignaturing" technology. As we will have the samples from our three NHP efficacy studies, the sample size should be adequate for us to correlate challenge outcome with the immunologic readouts leading toward identification of a universal immunosignature for a protective EBOV vaccine that can be used for future clinical development.