Lassa virus (LASV) is endemic in Western Africa and is estimated to infect hundreds of thousands of individuals annually. A considerable number of these infections result in Lassa fever (LF), which is associated with significant morbidity and a case-fatality rate as high as 69% among hospitalized confirmed patients. U.S. Food and Drug Administration-approved LF vaccines are not available. Current antiviral treatment is limited to off-label use of a nucleoside analogue, ribavirin, that is only partially effective and associated with significant side effects. We generated and characterized a recombinant LASV expressing a codon-deoptimized (CD) glycoprotein precursor gene (GPC), rLASV-GPC/CD. Comparison of growth kinetics and peak titers showed that rLASV-GPC/CD is slightly attenuated in cell culture compared to wild-type (WT) recombinant LASV (rLASV-WT). However, rLASV-GPC/CD is highly attenuated in strain 13 and Hartley guinea pigs, as reflected by the absence of detectable clinical signs in animals inoculated with rLASV-GPC/CD. Importantly, a single subcutaneous dose of rLASV-GPC/CD provides complete protection against an otherwise lethal exposure to LASV. Our results demonstrate the feasibility of implementing a CD approach for developing a safe and effective LASV live-attenuated vaccine candidate. Moreover, rLASV-GPC/CD might provide investigators with a tool to safely study LASV outside maximum (biosafety level 4) containment, which could accelerate the elucidation of basic aspects of the molecular and cell biology of LASV and the development of novel LASV medical countermeasures.IMPORTANCE Lassa virus (LASV) infects several hundred thousand people in Western Africa, resulting in many lethal Lassa fever (LF) cases. Licensed LF vaccines are not available, and anti-LF therapy is limited to off-label use of the nucleoside analog ribavirin with uncertain efficacy. We describe the generation of a novel live-attenuated LASV vaccine candidate. This vaccine candidate is based on mutating wild-type (WT) LASV in a key region of the viral genome, the glycoprotein precursor (GPC) gene. These mutations do not change the encoded GPC but interfere with its production in host cells. This mutated LASV (rLASV-GPC/CD) behaves like WT LASV (rLASV-WT) in cell culture, but in contrast to rLASV-WT, does not cause disease in inoculated guinea pigs. Guinea pigs immunized with rLASV-GPC/CD were protected against an otherwise lethal exposure to WT LASV. Our results support the testing of this candidate vaccine in nonhuman primate models ofLF.

中文翻译：

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基于病毒糖蛋白基因密码子去优化的拉沙热减毒活疫苗。


拉沙病毒 (LASV) 在西非流行，估计每年感染数十万人。其中相当一部分感染会导致拉沙热 (LF)，该病的发病率很高，住院确诊患者的病死率高达 69%。尚无美国食品和药物管理局批准的 LF 疫苗。目前的抗病毒治疗仅限于超说明书使用核苷类似物利巴韦林，该药物仅部分有效且伴有显着的副作用。我们生成并表征了表达密码子去优化 (CD) 糖蛋白前体基因 (GPC) 的重组 LASV，rLASV-GPC/CD。生长动力学和峰值滴度的比较表明，与野生型 (WT) 重组 LASV (rLASV-WT) 相比，rLASV-GPC/CD 在细胞培养物中略有减弱。然而，rLASV-GPC/CD 在 13 株和 Hartley 豚鼠中高度减毒，这反映在接种 rLASV-GPC/CD 的动物中没有可检测到的临床症状。重要的是，单次皮下剂量的 rLASV-GPC/CD 可以提供完全的保护，防止致命的 LASV 暴露。我们的结果证明了实施 CD 方法来开发安全有效的 LASV 减毒活疫苗候选物的可行性。此外，rLASV-GPC/CD 可能为研究人员提供在最大（生物安全级别 4）遏制之外安全研究 LASV 的工具，这可以加速 LASV 分子和细胞生物学基本方面的阐明以及新型 LASV 医疗对策的开发.重要性 拉沙病毒 (LASV) 感染西非数十万人，导致许多致命的拉沙热 (LF) 病例。 目前还没有获得许可的 LF 疫苗，并且抗 LF 治疗仅限于超说明书使用核苷类似物利巴韦林，且疗效不确定。我们描述了一种新型减毒活 LASV 候选疫苗的产生。该候选疫苗基于病毒基因组关键区域糖蛋白前体 (GPC) 基因中野生型 (WT) LASV 的突变。这些突变不会改变编码的 GPC，但会干扰其在宿主细胞中的产生。这种突变的 LASV (rLASV-GPC/CD) 在细胞培养中的行为类似于 WT LASV (rLASV-WT)，但与 rLASV-WT 不同，它不会在接种的豚鼠中引起疾病​​。用 rLASV-GPC/CD 免疫的豚鼠受到保护，免受 WT LASV 的致命暴露。我们的结果支持在非人灵长类 LF 模型中测试该候选疫苗。