Vero E6 (ATCC-CRL1586) cell stocks were generated in cell growth medium, which comprised MEM without L-glutamine supplemented with 10% (v/v) heat-inactivated FBS and 1% (w/v) L-glutamine. Vero E6 cell monolayers were seeded in 96-well plates at 2 × 104 cells/well in 100 μL growth medium (MEM supplemented with 1% (w/v) L-glutamine, 2% FBS) and incubated overnight at 37 °C in 5% CO2. SARS-CoV-2 infection was established by using an MOI of 0.05 to infect cell monolayers.
Astodrimer sodium or remdesivir were serially diluted 1:3, 9 times and each compound concentration was assessed for both antiviral efficacy and cytotoxicity in triplicate. Astodrimer sodium was added to Vero E6 cells 1 h prior to infection or 1 h post-infection with SARS-CoV-2. Cell cultures were incubated at 37 °C in 5% CO2 for 4 days prior to assessment of CPE. The virus growth media was MEM supplemented with 1% (w/v) L-glutamine, 2% FBS, and 4 μg/mL TPCK-treated trypsin. On Day 4, viral-induced CPE and cytotoxicity of the compound were determined by measuring the viable cells using the methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay (MP Biomedicals, NSW, Australia). Absorbance was measured at 540–650 nm on a plate reader.
Astodrimer sodium or remdesivir were serially diluted 1:3, 9 times and each compound concentration was assessed for both antiviral efficacy and cytotoxicity in triplicate. Astodrimer sodium was added to Vero E6 cells 1 h prior to infection or 1 h post-infection with SARS-CoV-2. Cell cultures were incubated at 37 °C in 5% CO2 for 4 days prior to assessment of CPE. The virus growth media was MEM supplemented with 1% (w/v) L-glutamine, 2% FBS, and 4 μg/mL TPCK-treated trypsin. On Day 4, viral-induced CPE and cytotoxicity of the compound were determined by measuring the viable cells using the methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay (MP Biomedicals, NSW, Australia). Absorbance was measured at 540–650 nm on a plate reader.