Figure 4

PPRV-del-L behaves as heat-inactivated PPRV. VDS cells were infected with PPRV-del-L (PPRVdelL) or PPRV that had been heat-inactivated (2 h at 58 °C) (inactPPRV) at a nominal moi of 0.5. After removing unattached virus, duplicate wells were harvested immediately for RNA or cultured for 6 days (p1). After 6 days, the infected cells were subjected to 1 freeze-thaw cycle, the cell pellet harvested for RNA, and one third of the supernatant passaged to fresh cells (p2). This procedure was then repeated (p3). RT-qPCR was used to determine the relative amount of viral mRNA in each sample (A); Vero cell L13A mRNA was used as control for the recovery of RNA from each sample (B). Results are expressed as 40-(mean Ct value observed from duplicate PCRs from each of duplicate wells).