FIGURE 1. Human Prostate Cancer Cell Lines Display Varying Expression of PD-L1 in Response to IFN-γ.
Histograms representing PD-L1 surface expression as detected by flow cytometry in human prostate cancer cell lines with and without exposure to IFN-γ. Open histograms represent cells stained with an isotype IgG1 antibody tagged with a matching PE fluorochrome. Shaded histograms represent PD-L1. Quantitative measurements reflect mean fluorescence index. LNCaP does not express PD-L1 at rest or in response to IFN-γ. DU145 expresses PD-L1 at rest and has little response to IFN-γ indicating an innate immune resistance phenotype. PC3 expresses PD-L1 at rest but robustly up-regulates this expression in response to IFN-γ displaying a more classic adaptive immune resistance phenotype.