Designing mammarenavirus live vaccines with unbreachable attenuation

项目总结/摘要 拉沙乳房病毒（LASV）是西非的地方病，感染了数十万人。 个人每年导致大量拉沙热（LF）病例与高发病率， mortality.没有美国FDA批准的LASV疫苗，目前的抗LASV治疗仅限于标签外使用。 使用利巴韦林的效果有限。LF已被列入世界卫生组织的优先疾病修订名单 研发蓝图，强调迫切需要疫苗来对抗LF。流行病学研究表明， 减毒活疫苗（LAV）是控制LF最可行的方法。哺乳动物肾病毒是 具有双节段负链RNA基因组的包膜病毒。每个基因组片段包含两个开放的 阅读由非编码基因间区（IGR）分隔的框架。大（L）片段编码RNA 依赖的RNA聚合酶、L蛋白和Z基质蛋白，而小（S）片段编码依赖的RNA聚合酶、L蛋白和Z基质蛋白。 表面糖蛋白前体（GPC）和核蛋白（NP）。我们已经证明，重组（r）形式 表达密码子去优化的原型乳房病毒淋巴细胞性脉络丛脑膜炎病毒（LCMV） (CD)GPC或在S和L片段中同时含有S片段的IGR的rLCMV/IGR（S-S）是稳定的 并且在小鼠中完全减毒，但能够在单次给药后提供针对 随后用WT LCMV进行致死性攻击。重要的是，我们用LASV复制了这些发现， 验证使用LCMV生成概念验证结果，以指导LASV研究。的中心目标 本申请是为了检验以下假设： S和L基因组片段，以下称为rLCMV/IGR-CD，将具有优异的安全性和保护效力， 具有LAV和不可破坏的衰减功能。为了验证我们的假设，我们将评估安全性， 免疫原性和保护效力的rLCMV/IGR-CD（目的1），并检查rLCMV/IGR-CD是否 在共同感染的小鼠中，防止产生具有增加的毒力的LCMV抑制剂（Aim 2），以及 在FDA批准用于生产人用重组LCMV/IGR-CD的多轮感染中评价rLCMV/IGR-CD的稳定性 疫苗Vero E6细胞和体内（目的3）。

Project Summary/Abstract The mammarenavirus Lassa (LASV) is endemic to West Africa where it infects several hundred thousand individuals yearly resulting in a high number of Lassa fever (LF) cases associated with high morbidity and mortality. There are no US FDA-approved LASV vaccines and current anti-LASV therapy is limited to an off-label use of ribavirin that has limited efficacy. LF has been included on the revised list of priority diseases for the WHO R&D Blueprint, underscoring an urgent need for vaccines to combat LF. Epidemiological studies indicate that a live-attenuated vaccine (LAV) represents the most feasible approach to control LF. Mammarenaviruses are enveloped viruses with a bi-segmented negative strand RNA genome. Each genome segment contains two open reading frames separated by a non-coding intergenic region (IGR). The large (L) segment encodes the RNA dependent RNA polymerase, L protein, and the Z matrix protein, whereas the small (S) segment encodes the surface glycoprotein precursor (GPC) and nucleoprotein (NP). We have documented that recombinant (r) forms of the prototypic mammarenavirus lymphocytic choriomeningitis virus (LCMV) expressing a codon deoptimized (CD) GPC or containing the IGR of the S segment in both the S and L segments rLCMV/IGR(S-S) are stable and fully attenuated in mice but able to provide complete protection, upon a single administration, against a subsequent lethal challenge with WT LCMV. Importantly, we have replicated these findings with LASV, thus validating the use of LCMV to generate proof of concept results to guide studies with LASV. The central goal of this application is to test the hypothesis that an rLCMV combining the features of a CD GPC and the S-IGR in both S and L genome segments, hereinafter rLCMV/IGR-CD, will have excellent safety and protective efficacy features as LAV, and an unbreachable attenuation. To test our hypothesis, we will assess the safety, immunogenicity, and protective efficacy of rLCMV/IGR-CD (Aim 1) and examine whether rLCMV/IGR-CD prevents, in co-infected mice, the generation of LCMV reassortants with increased virulence (Aim 2), as well as evaluate rLCMV/IGR-CD stability during multiple rounds of infection in FDA approved for production of human vaccines Vero E6 cells and in vivo (Aim 3).