Inhibition of transfection and expression by type I interferons in B16 and mesenchymal stem cells. (a) B16 cells (left) and mesenchymal stem cells (MSCs) (right) were transfected with pmaxCDK-ChFPEMCVEGFP and were either not treated (black bar) or treated (grey bar) with 500 units/ml Mu-IFNαA. Top: bar graph depicting the transfection efficiency. Bottom: bar graph depicting the mean EGFP levels. (b) Contour plot of EGFP levels (horizontal axis) versus monomeric cherry fluorescent protein (ChFP) levels (vertical axis) in B16 cells (top) and in MSC cells (bottom). Cells not treated with Mu-IFNαA are black; cells treated with Mu-IFNαA are red.