Figure 1.

Effect of PPMO on cell viability and SARS-CoV-2 growth. (a) Evaluation of the effect of PPMO treatment on cellular ATP level, as an indicator of cell viability, was carried out using uninfected cells incubated for 48 h with increasing concentrations of the indicated PPMO. ATP levels were determined via luminescence readings and are shown compared with PBS-treated cells. For each PPMO concentration, triplicate samples were assayed and the mean±SD is shown. (b–m) Growth curves of SARS-CoV-2. Vero-E6 cells were treated with the indicated concentration of PPMO for 5 h before infection with SARS-CoV-2 (moi of 0.01), then incubated without PPMO after infection. Cell supernatants were collected at 12, 24, 48 and 72 h post-infection and analysed by qRT–PCR (b–g) or TCID₅₀/mL endpoint dilution (h–m) using three technical repeats. Cells treated with PBS had titres similar to those shown for NC PPMO. The limit of virus detection for the TCID₅₀ assay was 10¹/mL. This experiment was carried out twice, under similar conditions, yielding similar results, and the results from a single experiment are shown. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.