Rescue of Chimeric Viruses via RNA Transfection

The protocol for the rescue of the chimeric and parental viruses was performed as previously described [32 (link)]. First, each full-length cDNA clone plasmid was separately linearized using the restriction enzyme NotI (New England Biolabs). The linearized plasmid DNA was transcribed and capped using the mMessage High Yield Capped RNA Transcription kit (Ambion) according to the manufacturer’s instructions. The synthetic RNA was transfected into BHK-21 cells using the DMRIE-C reagent (Invitrogen) according to the manufacturer’s protocol. Finally, the supernatants were harvested 24 h post-transfection and serially passaged on MARC-145 cells.