Preclinical characterization of a multivalent killed Filovirus/Rabies vaccine

描述（由申请人提供）：HHS公共卫生紧急医疗对策企业（PHEMCE）表示开发和获取丝状病毒的医疗对策是高度优先事项。然而，目前没有针对埃博拉病毒（EBOV）或马尔堡病毒（MARV）的候选疫苗接近许可，并且仍然需要开发针对丝状病毒的安全有效的疫苗。尽管存在几种针对EBOV或MARV的临床前候选疫苗，但它们的进一步开发是基于i）安全性问题，ii）预先存在的载体免疫性，和iii）诸如制造、剂量和可销售性的问题的主要挑战。在这里，我们建议进一步开发一种新的和有前途的疫苗平台的基础上化学灭活（杀死）狂犬病病毒（RABV）病毒粒子含有EBOV糖蛋白（GP）在其包膜。我们以前的研究表明，用这种重组RABV病毒粒子免疫小鼠，对小鼠适应的MA-EBOV和RABV的致死性攻击提供了极好的保护。此外，新型抗原展示载体在非人灵长类动物（NHP）中具有高度免疫原性。基于我们的初步结果，本申请的目标是开发、表征和扩展这种新颖且有前途的丝状病毒疫苗平台。我们建议开发和表征一种基于灭活狂犬病病毒病毒粒子技术的三价丝状病毒疫苗，用于人类，以保护免受所有医学相关丝状病毒和RABV的侵害。具体地，除了先前开发的含有EBOV Zaire GP的疫苗之外，还将构建含有EBOV Sudan GP或MARV GP的另外两种载体。将在小鼠中研究这些疫苗对抗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，我们建议研究所需的免疫原性诱导的疫苗载体保护丝状病毒的挑战。上述为进一步开发我们的疫苗而提出的工作与疫苗技术从实验室环境向GMP条件的转移同时进行。对于这种方法，我们将在GMP设施中使RABV回收系统适应Vero细胞，建立适合生产疫苗的Vero细胞库以及三种病毒载体的病毒种子库。已经制定了疫苗的生产计划，这项转化研究申请的最终目标是表征三价丝状病毒疫苗，并生产足够数量的疫苗用于I期临床试验。值得注意的是，该疫苗平台的进一步表征将不仅为丝状病毒疫苗建立必要的参数，而且还将为该平台用于其他新发和再发传染病建立必要的参数。

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.