Endothelial growth media components alter SARS-CoV-2 spike-directed growth kinetics

Direct SARS-CoV-2 infection of endothelial cells is challenging to study in vitro. To examine whether endothelial cell culture conditions impact the ability of SARS-CoV-2 to infect cells, we evaluated the effects of commercial cell culture media composition on SARS-CoV-2 Spike-directed viral infection. In African Green Monkey kidney epithelial cells (VeroE6), we found that commercial cell culture media (EGM2) produced inhibitory effects on recombinant vesicular stomatitis virus (rVSV-SARS-CoV-2) growth that is not seen in Dulbecco's Modified Eagle Medium (DMEM). We identified Lonza's GA-1000 supplement as a potential SARS-CoV-2 inhibitor. We then compared how titrations of GA-1000 influenced rVSV-SARS-CoV-2 and SARS-CoV-2 infection. The determined IC50 of GA-1000 is observed at a 1:450 dilution, about 2-fold higher concentration than the typical cell culture concentration, against rVSV-SARS-CoV-2. In contrast, the inhibition against SARS-CoV-2 infection is modest. This work highlights the importance of cell culture medium selection for in vitro models of infections and demonstrates a method to characterize and ameliorate media formulations for infection studies.