Fig. 1

Tobacco smoke and carcinogen BaP induces PD-L1 expression on lung epithelial cells. a In microarray datasets of gene expression profiles of normal bronchial epithelial cells exposed to cigarette smoke, the expression of PD-L1 was analyzed. C, control; S, cigarette smoke. Error bars, sd. b, c The cells were treated with cigarette smoke extract (CES) at indicated concentrations for 48 h, and the expression of PD-L1 was assessed by real-time RT-PCR (b) and flow cytometry (c). The experiments were conducted in triplicate and repeated for three times. Error bars, sd. d–h The cells were treated with BaP at indicated concentrations for indicated time points, and the expression of PD-L1 was assessed by real-time RT-PCR (d, e), immunofluorescence assays (f), flow cytometry (g), and western blot (h) assays. Student’s t test, *P < 0.05; **P < 0.01. Error bars, sd