Subcellular localization of FITC-labeled ODN. After transfection of 0.3 μmol/L FITC-labeled ODN using DOTAP, cells were transferred on slides by centrifugation, stained by DAPI, and analyzed by fluorescence microscopy. The upper row shows the DAPI stained nuclei, the lower row the intracellular distribution of FITC-labeled ODN. (A and B) Representative cells after incubation with ODN/DOTAP complexes for 2 hours. (C through E) Representative cells after an incubation time of 24 hours.