Transfection efficiency of pEF3-based plasmids in 293T, B16 and mesenchymal stem cells. Plasmids pEF3-MuIFNαAEMCVChFP, pEF3-EGFPEMCVChFP, pEF3-ChFPEMCVEGFP, and pmaxGFP were transfected (left) into 293T cells using polyethyleneimine, (middle) into B16 cells using Metafectene Easy and (right) into mesenchymal stem cells (MSCs) using Metafectene Easy. The percentage of cells containing significant levels of GFP and/or monomeric cherry fluorescent protein (ChFP) as well as the average green or red fluorescence of these cells were determined. These values were then divided by the related values determined in cells transfected with pEF3-EGFPEMCVChFP, whose actual transfection efficiency (as well as that from pmaxGFP) is shown above the bars. Relative transfection efficiency and relative average fluorescence intensity are indicated by black and grey bars, respectively. The results shown here are representative; the transfection efficiency as well as the relative expression or transfection difference between pEF3-based plasmids and pmaxGFP varied by as much as twofold depending on transfection reagent, passaging time, and cell density.