PD-L1 expression in melanoma cells.

<p><b>A</b>. KMJR138 cells were treated with indicated doses of IFN-γ for 48 hours and the cell surface expression of PD-L1 was determined by flow cytometry. The corresponding mean fluorescence intensity (MFI) with values is shown in the histogram and plotted in the graph below and corresponds to the relative fold increase over isotype levels. The time course graph represents the MFI at the indicated times upon treatment with 100ng/ml IFN-γ. All values are an average of two independent replicates. <b>B</b>. PD-L1 protein detection induced after IFN-γ treatment for 48 hours is indicated in the representative immunoblot. * corresponds to a non-specific band. <b>C.</b> A panel of melanoma cell lines were treated with 100ng/ml IFN-γ for 48 hours and cell surface expression of PD-L1 was determined by flow cytometry. MFI is represented in the graphs (average of three independent replicates) and MFI values are indicated along with the histograms. Control refers to dimethyl sulfoxide (DMSO) treatment. <b>D.</b> Quantitative real time PCR was performed to evaluate induction of PD-L1 transcripts on RNA isolated from cells treated with DMSO (control) or 100ng/ml IFN-γ for 24 hours. Levels were normalised to the 18sRNA transcript. Values from one of two independent replicates are shown. ***p-value = 0.0001; **p-value = 0.001; *p-value = 0.01 ns = non-significant.