Figure 3.

Cysteamine and cystamine inhibited SARS-CoV-2-induced CPE in Vero E6 cells independent of the time of treatment. (A,B) Vero E6 cells were treated with different doses of cysteamine (panel A) or cystamine (panel B), as indicated, in respect to SARS-CoV-2 infection (MOI = 0.001): (i) 1 h before infection (pre-treatment; white columns), (ii) during infection (co-treatment; grey columns) and (iii) 1 h after infection (post-treatment; black columns), as described in the text. Cells were then treated every 24 h and incubated at 37 °C with 5% CO₂ for 72 h when the survival of infected cells was measured by crystal violet staining assay. The results were evaluated by setting the 1 h pre-treated cells as the 100% of CPE-inhibition activity of either cysteamine or cystamine.