Endogenous miRNA regulation can be exploited to improve vector targeting. Balb/c mice (n = 5/group) were treated by intravenous administration with 5 × 108 TU of the indicated vector and analyzed at 10 days after injection. (A) Confocal immunofluorescence analysis of the liver. Fixed frozen sections were costained with anti-GFP (green) and anti-CD45 (red) antibodies to monitor the vector expression profile. TO-PRO-3 (blue) was used to stain nuclei. Scale bars = 60μm. (B) FACS analysis of total splenocytes from treated animals were analyzed for GFP expression. (C) Confocal immunofluorescence analysis of the spleen. Fixed frozen sections were costained with anti-GFP (green) and anti-CD45 (red) antibodies to monitor the vector expression profile. TO-PRO-3 (blue) was used to stain nuclei. Scale bars are equal to 60 μm.