Developing Vertebrate-Specific Replication-Defective Dengue Virus as Novel Single-CycleDengue Vaccine Candidate

脊椎动物特异性复制缺陷登革病毒的研究进展 一种新型单周期登革热疫苗候选疫苗 摘要 估计每年至少有3.9亿人感染登革热病毒(DENV)， 年，世界卫生组织将DENV疫情列为世界十大公共卫生威胁之一 2019年。目前，还没有特效药。迫切需要一种通用的疫苗。 DENV疫苗开发的独特挑战是，登革热疫苗必须诱导 同时对所有四种血清型的长期保护。从历史上看，四价 减毒活疫苗表明，很难实现平衡免疫 所有四种血清型。此外，灭活病毒疫苗不能赋予对 防止潜在的抗体依赖增强(ADE)。考虑到这些障碍， 我们已经研究了单周期、假感染性DENV作为候选疫苗 诱导对所有四种血清型的长期平衡免疫。一个重大的障碍 这种方法的关键是复制假感染性DENV通常需要复杂的 以及低效率的包装单元，使得规模化生产变得困难和昂贵。 因此，朝着发展安全、有效和负担得起的DENV的总目标 疫苗方面，我们将双嗜性DENV转化为人工昆虫特异性病毒，以 克服对包装细胞的依赖，生产单周期病毒疫苗。 这些脊椎动物特有的复制缺陷DENV(VSRD-DENV)是由 通过优化病毒前膜蛋白(PRM)中的Furin裂解位点。初步 VSRD-DENV1和VSRD-DENV2的动物实验证明 VSRD-DENVS诱导小鼠产生强大的保护性免疫，具有固有的高安全水平 老鼠。基于这些极具前景的初步结果，并考虑到紧迫的 需要一种有效的登革热疫苗，腾根生物医学公司和霍华德大学 已经联手加快对基于VSRD-DENVS的登革热的评估 疫苗。为了实现这一目标，我们建议生成并表征VSRD-DENV3 和VSRD-DENV4疫苗候选病毒。然后我们将进行一次全面的 四价VSRD-DENV免疫原性及保护力分析 灵敏的AG129小鼠模型。成功完成这些拟议的研究将 使登革热候选疫苗进入非人类灵长类动物测试，并建立 开发其他重要黄病毒疫苗的平台。

Developing Vertebrate-Specific Replication-Defective Dengue Virus as a Novel Single-Cycle Dengue Vaccine Candidate Abstract With an estimated minimum of 390 million dengue virus (DENV) infections per year, the DENV epidemic was listed as one of the world's top 10 public health threats by WHO in 2019. At present, there is no specific treatment. A universal vaccine is urgently needed. DENV vaccine development's unique challenge is that a dengue vaccine must induce long-term protection against all four serotypes simultaneously. Historically, tetravalent live attenuated viral vaccines have shown that it is difficult to achieve balanced immunity to all four serotypes. Also, inactivated virus vaccines can't confer long-term immunity to prevent potential antibody-dependent enhancement (ADE). Mindful of these obstacles, we have investigated single-cycle, pseudoinfectious DENVs as vaccine candidates to induce balanced long-term immunity against all four serotypes. A significant impediment to this approach is that replicating pseudoinfecious DENVs usually require complicated and low-efficient packaging cells, making the scale-up production difficult and costly. Thus, towards the overall goal of developing a safe, effective, and affordable DENV vaccine, we converted dual-tropic DENVs into artificial insect-specific viruses to overcome the dependence on packaging cells to produce a single-cycle virus vaccine. These vertebrate-specific replication-defective DENVs (VSRD-DENV) were generated by optimizing the furin cleavage site in viral pre-membrane protein (prM). Preliminary animal experiments with VSRD-DENV1 and VSRD-DENV2 demonstrated that the VSRD-DENVs induced robust protective immunity with inherent high safety levels in mice. Based on these highly promising preliminary results and considering the urgent need for an effective dengue vaccine, Tengen Biomedical Co. and Howard University have teamed up to accelerate the evaluation of the VSRD-DENVs-based dengue vaccine. To achieve this goal, we propose to generate and characterize VSRD-DENV3 and VSRD-DENV4 vaccine candidate viruses. We will then perform a comprehensive analysis of the immunogenicity and protective efficacy of tetravalent VSRD-DENVs in a sensitive AG129 mouse model. Successful completion of these proposed studies will enable the dengue vaccine candidate into non-human primate testing and establish a platform for developing vaccines for other important flaviviruses.