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学对策是高度优先的。然而，目前没有针对埃博拉病毒(EBOV)或马尔堡病毒(MARV)的候选疫苗接近获得许可，开发安全有效的丝状病毒疫苗的必要性仍在继续。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一个主要的挑战，基于i)安全性问题，ii)先前存在的媒介免疫，以及iii)制造、剂量和可销售性等问题。在这里，我们建议进一步开发一种新的、有前景的疫苗平台，该平台基于包膜中含有EBOV糖蛋白(GP)的化学灭活(灭活)狂犬病病毒(RABV)病毒粒子。我们先前的研究表明，这种重组RABV病毒粒子对小鼠适应的MA-EBOV和RABV的致死性攻击具有良好的保护作用。此外，新型抗原展示载体在非人类灵长类动物(NHP)中具有高度的免疫原性。基于我们的初步结果，这项应用的目标是开发、表征和扩展这一新的和有希望的丝状病毒疫苗平台。我们建议开发和鉴定一种基于狂犬病病毒灭活病毒粒子技术的三价丝状病毒疫苗，用于人类，从而提供对所有医学上相关的丝状病毒和RABV的保护。具体地说，除了先前开发的含有疫苗的EBOV扎伊尔GP疫苗外，还将构建另外两个含有EBOV苏丹GP或MARV GP的载体。这些疫苗对抗EBOV、MARV和RABV攻击的有效性将在小鼠身上进行研究，随后将在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所需的免疫原性。上面提出的进一步开发我们疫苗的工作与疫苗技术从实验室环境转移到GMP条件下的工作是并行进行的。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，以及三种病毒载体的病毒种子储备。疫苗的生产计划已经确定，这项转化研究应用的最终目标是确定三价丝状病毒疫苗的特征，并生产足够数量的疫苗，用于I期临床试验。值得注意的是，这一疫苗平台的进一步特征将不仅为丝状病毒疫苗建立必要的参数，而且还将这一平台用于其他新出现和再次出现的传染病。

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.