Fig. 4.

Antiviral activity of PLE and remdesivir used in combination (A). Vero E6 cells were infected with SARS-CoV-2 with serial dilutions of PLE in combination with remdesivir and subsequently harvested at 24 h p.i. to quantify viral RNA loads by qRT-PCR. Expression levels of viral RNA were initially normalized to GAPDH mRNA. The ratio of drug-treated cells was subsequently normalized to the RNA level of virus control (arbitrarily set to 1). (B) The ratio of drug inhibition elicited by the combination of PLE and remdesivir was calculated with the HSA reference synergy model available in the SynergyFinder software (version 2). The graphs illustrate average results from two independent experiments carried out in duplicate.