Replicative Competence of the T131I, K141E, and G145R Surface Variants of Hepatitis B Virus

Variants of hepatitis B surface antigen have been described in different clinical settings, but their replicative capacity in vitro has remained unexplored. Point mutations leading to sT131I, sK141E, and sG145R amino-acid substitutions were engineered by site-directed mutagenesis into an infectious plasmid clone of the virus. The mutated constructs were transfected into Huh7 cells, and their replication capacity was documented by LightCycler (Roche Diagnostics) measurements of virion-associated hepatitis B virus (HBV) DNA, intracellular relaxed circular double-stranded DNA, and pregenomic RNA. The sT131I and sG145R variants replicated with efficiency equal to that of the wild type, whereas the sK141E variant was replication impaired.