Figure 8.

Dose response of SARS-CoV-2 and the variants of concern, Delta and Omicron, to BAY598. Caco-2 cells were pre-treated with increasing concentrations of BAY598 for 24 h. Afterwards, cells were infected with recombinant SARS-CoV-2 reporter viruses, either expressing WT spike (D614G) and a secreted gaussia luciferase instead of ORF7 (A), or the spike protein of the Delta variant and EYFP instead of ORF6 (B) (MOI = 0.005). In case of the GLuc reporter virus, cell culture supernatants were heat-inactivated after 30 h and analyzed for luciferase activity. To quantify EYFP-expression, cells were fixed 30 h post-infection and viral replication was assessed by reporter quantification. For both reporters, the percentage of viral replication was determined relative to DMSO-treated cells. The 50% effective concentration (EC₅₀) was calculated by nonlinear four-parameter curve fitting using GraphPad Prism and is shown within the respective graph. Mean values of quadruplicates relative to the solvent control ± SD are depicted. One representative result out of four experiments is shown.