Effect of drug-induced and natural amino acid variants at position 719 on the growth kinetics of HCV genotype 1/2a in cell culture.

<p>The drug resistant variant, V719G and three natural amino acid polymorphisms, I719, L719, A719, were introduced into genotype 1a and 1b genetic backgrounds using the QuikChange II XL site-directed mutagenesis kit (Stratagene). Full-length HCV RNAs bearing various polymorphisms at position 719 were prepared and electroporated into naïve target cells. Infected cell cultures were maintained for up to 2.5 months. Every 3–4 days, viral supernatants were harvested and subsequently used to infect naïve target cells. After 72 hrs, <i>Renilla</i> luciferase activity was measured and viral titer/infectivity was expressed in R.L.U. (relative light units). Changes in viral titers were plotted on a logarithmic scale as a function of time. (A) A comparison of the growth kinetics of GT 1a/2a HCV (diamonds) with the drug-induced variant, GT 1a/2a-V719G (squares) (B) A comparison of the growth kinetics of GT 1a/2a HCV (diamonds) with a potential polymorphism, GT 1a/2a-V719A (triangles). (C) A comparison of the growth kinetics of GT 1b/2a HCV (diamonds) with the drug-induced polymorphism, GT 1b/2a-V719G (squares). (D) A comparison of the growth kinetics of GT 1b/2a HCV (diamonds) with a natural polymorphism, GT 1b/2a-V719I (circles) and two potential polymorphisms GT 1b/2a-V719L (squares) and GT 1b/2a-V719A (triangles).