Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, Texas, USA.
J Virol. 2014 Apr;88(7):3678-94. doi: 10.1128/JVI.03540-13. Epub 2014 Jan 15.
Persistent infection is a key feature of hepatitis C virus (HCV). However, chimpanzee infections with cell culture-derived viruses (JFH1 or related chimeric viruses that replicate efficiently in cell culture) have been limited to acute-transient infections with no pathogenicity. Here, we report persistent infection with chronic hepatitis in a chimpanzee challenged with cell culture-derived genotype 1a virus (H77S.2) containing 6 cell culture-adaptive mutations. Following acute-transient infection with a chimeric H77/JFH1 virus (HJ3-5), intravenous (i.v.) challenge with 10(6) FFU H77S.2 virus resulted in immediate seroconversion and, following an unusual 4- to 6-week delay, persistent viremia accompanied by alanine aminotransferase (ALT) elevation, intrahepatic innate immune responses, and diffuse hepatopathy. This first persistent infection with cell culture-produced HCV provided a unique opportunity to assess evolution of cell culture-adapted virus in vivo. Synonymous and nonsynonymous nucleotide substitution rates were greatest during the first 8 weeks of infection. Of 6 cell culture-adaptive mutations in H77S.2, Q1067R (NS3) had reverted to Q1067 and S2204I (NS5A) was replaced by T2204 within 8 weeks of infection. By 62 weeks, 4 of 6 mutations had reverted to the wild-type sequence, and all reverted to the wild-type sequence by 194 weeks. The data suggest H77S.2 virus has greater potential for persistence and pathogenicity than JFH1 and demonstrate both the capacity of a nonfit virus to persist for weeks in the liver in the absence of detectable viremia as well as strong selective pressure against cell culture-adaptive mutations in vivo.
This study shows that mutations promoting the production of infectious genotype 1a HCV in cell culture have the opposite effect and attenuate replication in the liver of the only fully permissive animal species other than humans. It provides the only example to date of persistent infection in a chimpanzee challenged with cell culture-produced virus and provides novel insight into the forces shaping molecular evolution of that virus during 5 years of persistent infection. It demonstrates that a poorly fit virus can replicate for weeks within the liver in the absence of detectable viremia, an observation that expands current concepts of HCV pathogenesis and that is relevant to relapses observed with direct-acting antiviral therapies.
持续性感染是丙型肝炎病毒（HCV）的一个关键特征。然而，用细胞培养衍生病毒（能够在细胞培养中有效复制的 JFH1 或相关嵌合病毒）感染黑猩猩仅限于无致病性的急性短暂感染。在这里，我们报告了一只黑猩猩受到细胞培养衍生的 1a 型病毒（含 6 个细胞培养适应性突变的 H77S.2）的挑战后发生持续性感染和慢性肝炎。在感染嵌合 H77/JFH1 病毒（HJ3-5）后的急性短暂感染后，静脉内（i.v.）用 10（6）FFU H77S.2 病毒进行攻击，立即发生血清转化，在异常的 4 至 6 周延迟后，出现持续性病毒血症，伴有丙氨酸氨基转移酶（ALT）升高、肝内先天免疫反应和弥漫性肝病变。这是首例用细胞培养产生的 HCV 进行的持续性感染，为评估体内细胞培养适应病毒的进化提供了独特的机会。在感染的前 8 周，同义和非同义核苷酸取代率最高。在 H77S.2 中的 6 个细胞培养适应性突变中，Q1067R（NS3）已恢复为 Q1067，S2204I（NS5A）在感染后 8 周内被 T2204 取代。到第 62 周，6 个突变中有 4 个恢复为野生型序列，到第 194 周时所有序列都恢复为野生型。数据表明，H77S.2 病毒比 JFH1 具有更大的持续性和致病性潜力，并证明了非适应病毒在没有可检测到的病毒血症的情况下在肝脏中持续存在数周的能力，以及体内对细胞培养适应性突变的强烈选择压力。
本研究表明，促进在细胞培养中产生传染性 1a 型 HCV 的突变具有相反的效果，并削弱了在除人类以外的唯一完全允许的动物物种肝脏中的复制。它提供了迄今为止用细胞培养产生的病毒感染的黑猩猩发生持续性感染的唯一例子，并为该病毒在 5 年持续性感染期间的分子进化提供了新的见解。它表明，在没有可检测到的病毒血症的情况下，一种适应性差的病毒可以在肝脏内复制数周，这一观察结果扩大了目前对 HCV 发病机制的认识，并且与直接作用抗病毒治疗中观察到的复发有关。
