Fig 3.

OM-5 inhibits ACE2 and TMPRSS2 transcription in primary normal human bronchial epithelial cells. Bronchial epithelial cells freshly isolated from a healthy donor were cultured to confluence and differentiated onto collagen-coated polyester 12-mm Transwell insert membranes for 2 weeks at air-liquid interface. Cells were then stimulated apically with PBS or OM-85 (1.92 mg/mL) for 48 or 72 hours. ACE2 and TMPRSS2 expression was determined by RT-qPCR (n = 3 wells/condition, each run in triplicate). mRNA levels at each time point were normalized by GAPDH and are shown relative to PBS. An unpaired, 2-tailed t test was used for statistical analysis after assessing the normality of sample distribution. RT-qPCR, RT-quantitative PCR.