Biological barriers to cationic vector-mediated gene transfer into the lungs

DOTAP/DNA complexes were aggregated in the lumen of bronchi (A) and did not succeed in obtaining transgene expression (B), as shown by the absence of signal in GFP immunohistochemistry. PEI 25K complexes were distributed mostly in the cytosol of bronchial ephitelial cells (C) and their biodistribution correlated with GFP transgene expression (D), as revealed by immunohistochemistry.
Bar: 10 mm.