Preclinical characterization of a multivalent killed Filovirus/Rabies vaccine

描述（由申请人提供）：HHS突发公共卫生事件医疗对策企业（PHEMCE）表明丝状病毒医疗对策的开发和获取是一个高度优先事项。然而，目前尚无针对埃博拉病毒（EBOV）或马尔堡病毒（MARV）的候选疫苗即将获得许可，开发一种安全有效的针对丝状病毒的疫苗的需求仍在继续。虽然存在几种针对EBOV或MARV的临床前候选疫苗，但它们的进一步开发是一项重大挑战，主要基于1)安全性问题，2)预先存在的媒介免疫，以及3)诸如制造、剂量和可销售性等问题。在此，我们建议进一步开发一种新的、有前景的疫苗平台，该平台基于化学灭活（杀死）狂犬病毒（RABV）病毒粒子，其包膜中含有EBOV糖蛋白（GP）。我们之前的研究表明，用这种重组RABV病毒粒子免疫小鼠对小鼠适应的MA-EBOV和RABV的致命攻击具有良好的保护作用。此外，新型抗原展示载体在非人灵长类动物（NHP）中具有高度的免疫原性。基于我们的初步结果，本应用程序的目标是开发，表征和扩展这种新颖和有前途的丝状病毒疫苗平台。我们建议开发一种基于灭活狂犬病病毒病毒体技术的三价丝状病毒疫苗并对其进行鉴定，用于人类，以保护人类免受所有医学上相关的丝状病毒和RABV的侵害。具体而言，除了先前开发的扎伊尔埃博拉病毒GP疫苗外，还将构建另外两种含有埃博拉病毒苏丹GP或MARV GP的载体。将在小鼠中研究这些疫苗抵抗EBOV、MARV和RABV攻击的效率，然后在NHP中进一步测试EBOV或MARV攻击实验。最后，我们建议研究疫苗载体对丝状病毒攻击的免疫原性。上述为进一步开发我们的疫苗而提出的工作与将疫苗技术从实验室环境转移到GMP条件同时进行。对于这种方法，我们将使RABV回收系统适应GMP设施中的Vero细胞，建立适合生产疫苗的Vero细胞库以及用于三种病毒载体的病毒种子库。已经制定了疫苗的生产计划，这一转化研究申请的最终目标是确定三价丝状病毒疫苗的特性，并为I期临床试验生产足够数量的疫苗。值得注意的是，该疫苗平台的进一步表征不仅将为丝状病毒疫苗建立必要的参数，而且还将为其他新出现和再出现的传染病使用该平台建立必要的参数。

DESCRIPTION (provided by applicant): HHS Public Health Emergency Medical Countermeasures Enterprise (PHEMCE) indicates the development and acquisition of medical countermeasures for filoviruses as a high priority. However, currently no vaccine candidates against Ebola virus (EBOV) or Marburg virus (MARV) are nearing licensure and the need to develop a safe and efficacious vaccine against filoviruses continues. Whereas several preclinical vaccine candidates against EBOV or MARV exist, their further development is a major challenge based on i) safety concerns, ii) pre-existing vector immunity, and iii) issues such as manufacturing, dosage, and marketability. Here we propose to further develop a new and promising vaccine platform based on chemically inactivated (killed) rabies virus (RABV) virions containing EBOV glycoprotein (GP) in their envelope. Our previous research showed that immunization with such recombinant RABV virions provided excellent protection in mice against lethal challenge with the mouse adapted MA-EBOV and RABV. Moreover, the novel antigen display vehicles are highly immunogenic in non-human primates (NHP). Based on our preliminary results, the goal of this application is to develop, characterize, and extend this nove and promising filovirus vaccine platform. We propose the development and characterization a trivalent filovirus vaccine based on the killed rabies virus virions technology for use in humans t confer protection from all medically relevant filoviruses and RABV. Specifically, two additional vectors containing EBOV Sudan GP or MARV GP will be constructed in addition to the previously developed EBOV Zaire GP containing vaccine. The efficiency of these vaccines against challenge with EBOV, MARV and RABV will be studied in mice, followed by the further testing of EBOV or MARV challenge experiments in NHP. Lastly, we propose to study the required immunogenicity induced by the vaccine vectors for protection from filovirus challenge. The work proposed above toward the further development of our vaccine is performed in parallel with the transfer of the vaccine technology from a laboratory setting to GMP conditions. For this approach, we will adapt the RABV recovery system to Vero cells in a GMP facility, establish a Vero cell bank suitable for production of the vaccine as well as viral seed stocks for the three viral vectors. A production plan for the vaccine has been established, and the final goal of this translational research application is characterization of a trivalent filovirus vaccin and the production of the vaccine in sufficient quantities for a phase I clinical trial. Of note, te further characterization of this vaccine platform will establish the necessary parameters not only for a filovirus vaccine but also the use of this platform for other emerging and reemerging infectious diseases.