In vitro transcription of HAV or HCV RNA was carried out using T7 RiboMAX™ Express Large Scale RNA Production System (Promega) as per manufacturer’s protocol. Transfection of viral RNA was performed in a Gene Pulser Xcell Total System (Bio-Rad) as previously described33 or using TransIT®-mRNA Transfection Kit (Mirus) for HAV-Luc RNA as described32 (link).