LV expression after systemic administration into immunocompetent mice. (A) Confocal microscopy of liver sections from the indicated mice injected into the tail vein with LVs expressing GFP from the human cytomegalovirus promoter (CMV) and analyzed at the indicated time after injection. Immunostaining for GFP (green) and DNA staining by TOPRO3 (blue). Representative sections are from 3 injected mice per time point per mouse strain. Original magnification, × 400. (B) FACS analysis of GFP expression in bone marrow and spleen of vector-injected mice at different times after injection. Single cell suspensions were obtained by mechanical disruption of the tissue. Mean frequency of GFP⁺ cells in 3 mice analyzed per time point per strain. (C) Quantitative real-time PCR of vector DNA in liver and spleen DNA of injected mice at different times after injection. Means ± SD, n = 3, are shown.