(A) Western blot analysis of PD-L1 expression in Calu-3 sublines in serum-free cultures (SF) or treated with IFNγ at 100 ng/ml for various times as indicated. (B) Bar graph of IFNγ-induced PD-L1 expression in Calu-3 sublines normalized against GAPDH expression at various times shown in (A). (C) RT-qPCR analysis of PD-L1 and PD-L2 expression normalized against the GAPDH expression. Data are presented as mean ± SD (n=3). ANOVA P<0.05, * denotes P<0.05 as compared with the vector control (V). Abbreviation: RT-qPCR, real-time quantitative polymerase chain reaction.