Rescue of the 1947 Zika Virus Prototype Strain with a Cytomegalovirus Promoter-Driven cDNA Clone

Schwarz, Megan C.; Sourisseau, Marion; Espino, Michael M.; Gray, Essanna S.; Chambers, Matthew T.; Tortorella, Domenico; Evans, Matthew J.

To evaluate production of infectious virus, we challenged Vero cells with supernatant from 293T cells transfected with the wild-type or Pol(Ϫ) plasmid or infected with the parental MR766 virus at an approximate MOI of 0.03 TCID 50 per cell. The Vero cells were immunostained with E and NS3 antibodies 3 days postchallenge (Fig. 4A ). The addition of supernatants from wild-type plasmid-transfected or parental virus-infected 293T cells resulted in readily detectable levels of viral proteins. Conversely, no staining was observed in Vero cells challenged with Pol(Ϫ) plasmid transfected 293T cell supernatant. Thus, cells transfected with the wild-type MR766 plasmid produced infectious particles in a manner that was dependent on the capacity of the viral RNA to replicate.