Positive selection caused change of hepatitis C virus quasispecies distribution in the natural history of he patitis C infection / 中华传染病杂志

ABSTRACT

Objective To investigate the evolution of hepatitis C virus (HCV) quasispecies in persistent and self limited infection patients. Methods Peripheral blood HCV preserved for 10 years from 8 naive individuals once infected by HCV were analyzed. HCV hypervariable region 1 (HVR1) genes were cloned and sequenced. Entropy, genetic distances, nonsynonymous mutations per nonsynonymous site (K A ), synonymous mutations per synonymous site(K S ) were evaluated for evolutionary analysis. Results The entropy values and genetic distances of HCV quasispecies were lower in self limited infection indivi duals than that of persistent infection individuals. In 3 of the 4 persistent infection individuals there exist no difference between within group and between group genetic distances in HCV HVR1. The ratios of K A /K s were higher than 1 in 7 of these 8 individuals. Conclusions The complexity and diversity degree of HCV quasispecies may affect the outcome of HCV infection. Positive Darwinian selection may be the major cause for the change of HCV quasispecies distribution in hepatitis C infection natural history.