Figure 4.

ATRA is effective against the SARS-CoV-2 variants of concern in the human lung cell line (A) Calu-3 cells, pre-incubated with ATRA at 37 °C for 3 h, were infected with SARS-CoV-2; A, alpha, beta and gamma (MOI = 0.5) for 2 h. Following this, the non-adsorbed virus was washed, and the infected cells were incubated in a fresh medium containing ATRA for 72 h. (B–F) Inhibition of different VOC by ATRA. The results of RT-PCR for lineage A (B), alpha strain (C), beta strain (D), gamma strain (E), and delta strain (F). Error bars obtained from duplicate testing. p-value < 0.005 (***).