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Fig. 5 | Journal for ImmunoTherapy of Cancer

Fig. 5

From: Mechanisms regulating PD-L1 expression on tumor and immune cells

Fig. 5

Roles of STAT1 and STAT3 in cytokine-induced PD-L1 protein expression on monocytes. a and b. Cytokine-induced PD-L1 protein expression on Monos was associated with new PDL1 mRNA transcription. Monos were treated with IL-1a, IL-10, IL-27, IL-32 g or IFN-g. PD-L1 mRNA and surface protein were measured by q-RT-PCR and flow cytometry after 16 h or 48 h, respectively. Fold changes in PD-L1 protein and mRNA were calculated. Representative data from Monos derived from one of two normal donors are shown. a. Fold changes in PD-L1 protein and mRNA levels in normal donor Monos after IL-10 (100 ng/ml), IL-32 g (100 ng/ml) or IFN-g (100 IU/ml) exposure. b. Fold changes of PD-L1 protein and mRNA levels in normal donor Monos after IL-1a (10 ng/ml), IL-27 (50 ng/ml) or IFN-g (100 IU/ml) treatment. c and d. Fresh isolated Monos were transfected with 300 pmol STAT1 or STAT3 siRNA and treated with the indicated cytokines 2 days later. Total or phosphorylated STATs and cell surface PD-L1 expression were assessed with Western blotting and flow cytometry after 15 min or 1 day, respectively. c. siRNA knockdown significantly reduced total and phosphorylated STAT1 and STAT3. d. STAT1 knockdown reduced IFN-g- and IL27-induced PD-L1 protein expression, while STAT3 knockdown reduced IL10-induced PD-L1 expression. Numbers in parentheses indicate number of normal donors having Monos with these findings

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