Department of Virology II, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
Antiviral Res. 2010 Mar;85(3):520-4. doi: 10.1016/j.antiviral.2009.12.008. Epub 2010 Jan 4.
Ribavirin (RBV), a nucleoside analogue, is used in the treatment of hepatitis C virus (HCV) infection in combination with interferons. However, potential mechanisms of RBV resistance during HCV replication remain poorly understood. Serial passage of cells harboring HCV genotype 2a replicon in the presence of RBV resulted in the reduced susceptibility of the replicon to RBV. Transfection of fresh cells with RNA from RBV-resistant replicon cells demonstrated that the RBV resistance observed is largely replicon-derived. Four major amino acid substitutions: T1134S in NS3, P1969S in NS4B, V2405A in NS5A, and Y2471H in NS5B region, were identified. Site-directed mutagenesis of these mutations into the replicon indicated that Y2471H plays a role in the reduced susceptibility to RBV and leads to decrease in replication fitness. The results, in addition to analysis of sequence database, suggest that HCV variants with reduced susceptibility to RBV identified are preferential to genotype 2a.
利巴韦林（RBV）是一种核苷类似物，与干扰素联合用于治疗丙型肝炎病毒（HCV）感染。然而，在 HCV 复制过程中利巴韦林耐药的潜在机制仍知之甚少。在利巴韦林存在的情况下，携带 HCV 基因型 2a 复制子的细胞的连续传代导致复制子对利巴韦林的敏感性降低。用来自利巴韦林耐药复制子细胞的 RNA 转染新鲜细胞表明，观察到的利巴韦林耐药性主要是复制子衍生的。鉴定出四个主要的氨基酸取代：NS3 中的 T1134S、NS4B 中的 P1969S、NS5A 中的 V2405A 和 NS5B 区域中的 Y2471H。将这些突变定点诱变引入复制子表明，Y2471H 在外来利巴韦林敏感性降低中起作用，并导致复制适应性降低。除了对序列数据库的分析之外，这些结果表明，鉴定出的对利巴韦林敏感性降低的 HCV 变体更倾向于基因型 2a。
