Pangolin linage b 1

All live virus experiments were performed in the BSL3 laboratory at the University of Nebraska Medical Center (Omaha, NE, USA). Calu-3 cells were plated in a 96 well transparent bottom black color plate (15000 cells/well) and cultured for 48 hours before infection. On the day of infection, the cells were treated with different concentrations of JQ1 (Cayman Chemical, Cat # 11187) or OTX015 (Cayman Chemical, Cat # 15947) (0.1 μM to 0.001 μM) two hours before infection. The cells were infected with SARS-CoV-2 (Delta variant of concern (VOC); pangolin linage: B.1.617.2, obtained from BEI Resources, NIAID, NIH; cat # 55672) with 0.5 MOI of viral titer or left uninfected (negative control). One hour post-infection, virus inoculum was removed from the cells, washed 3 times with 1X PBS, replenished with fresh media and treated with respective compounds. The reaction was terminated 24 hours post-infection. The culture supernatant was collected for measuring the viral replication kinetics, and the cells were washed and fixed with 4% PFA for immunofluorescence analysis.