Department of Pathology, University of Texas Medical Branch (UTMB), Galveston, TX 77555, USA.
Department of Biochemistry and Molecular Biology, University of Texas Medical Branch (UTMB), Galveston, TX 77555, USA.
Viruses. 2022 Mar 4;14(3):527. doi: 10.3390/v14030527.
The disease yellow fever was prevented by two live attenuated vaccines, strains 17D and French neurotropic vaccine (FNV), derived by serial passage of wild-type (WT) strains Asibi and French Viscerotropic virus (FVV), respectively. Both 17D and FNV displayed decreased genetic diversity and resistance to the antiviral Ribavirin compared to their WT parental strains, which are thought to contribute to their attenuated phenotypes. Subsequent studies found that only a few passages of WT strain FVV in HeLa cells resulted in an attenuated virus. In the current study, the genome sequence of FVV following five passages in HeLa cells (FVV HeLa p5) was determined through Next Generation Sequencing (NGS) with the aim to investigate the molecular basis of viral attenuation. It was found that WT FVV and FVV HeLa p5 virus differed by five amino acid substitutions: E-D155A, E-K331R, E-I412V, NS2A-T105A, and NS4B-V98I. Surprisingly, the genetic diversity and Ribavirin resistance of the FVV HeLa p5 virus were not statistically different to WT parent FVV. These findings suggest that while FVV HeLa p5 is attenuated, this is not dependent on a high-fidelity replication complex, characterized by reduced genetic diversity or increased Ribavirin stability, as seen with FNV and 17D vaccines.
黄热病通过两种减毒活疫苗得到预防，即 17D 株和法国神经毒力疫苗（FNV），分别由野生型（WT）菌株 Asibi 和法国内脏毒力病毒（FVV）的连续传代获得。与 WT 亲本株相比，17D 和 FNV 的遗传多样性降低，对抗病毒药物利巴韦林的耐药性增强，这被认为是它们减毒表型的原因。随后的研究发现，仅在 HeLa 细胞中传代 WT 株 FVV 几次，就会导致病毒减毒。在本研究中，通过下一代测序（NGS）确定了在 HeLa 细胞中传代 5 次的 FVV（FVV HeLa p5）的基因组序列，目的是研究病毒减毒的分子基础。结果发现，WT FVV 和 FVV HeLa p5 病毒在五个氨基酸残基上存在差异：E-D155A、E-K331R、E-I412V、NS2A-T105A 和 NS4B-V98I。令人惊讶的是，FVV HeLa p5 的遗传多样性和利巴韦林耐药性与 WT 亲本 FVV 没有统计学差异。这些发现表明，尽管 FVV HeLa p5 是减毒的，但这并不依赖于高保真复制复合物，其特征是遗传多样性降低或利巴韦林稳定性增加，这与 FNV 和 17D 疫苗相似。
