Characterization of multi-drug resistant HBV mutant 50–2 isolated from a chronic HBV patient.

<p>(A) Schematic representation of the mutations in RT and overlapping surface gene of clone 50–2. The amino acid changes in polymerase and corresponding surface gene are indicated by arrows. (B) Comparison of intracellular and extracellular secreted HBV DNA levels between WT virus and clone 50–2. The HBV 1.2mer construct plasmids (2 μg) were transfected into Huh7 hepatoma cells and harvested at 72h post-transfection. The linearized 3.2kb HBV genome was loaded in lane 1 as a marker. (C) & (D) <i>In vitro</i> susceptibility WT HBV (C) and clone 50–2 (D) to lamivudine (LMV), clevudine (CLV), entecavir (ETV), adefovir (ADV), and tenofovir (TDF). Cells were treated for 3 days with each drug, and the replication level was compared with that of the WT (without drug treatment). The relative HBV replication level was quantified using Phosphorimager. The standard deviation of three independent experiments was measured (***, <i>P</i> < 0.001).