Aerosol and lobar administration of a recombinant adenovirus to individuals with cystic fibrosis. II. Transfection efficiency in airway epithelium

A phase I clinical trial was conducted in which recombinant adenovirus cont aining the cystic fibrosis transmembrane regulator (CFTR) (Ad2/CFTR) was ad ministered by bronchoscopic instillation or aerosolization to the lungs of cystic fibrosis (CF) patients. In this paper, we evaluate the efficiency of Ad2/CFTR-mediated transduction of bronchial airway cells. The ability of a n Ad2/CFTR vector to transduce airway cells was first evaluated in patients to whom the vector was administered by bronchoscopic instillation. Cells a t the administration site were collected 2 days after treatment by bronchos copic brushing. Ad2-specific CFTR DNA was detected in four of five individu als by PCR, and Ad2-specific CFTR RNA was detected in three of five individ uals by RT-PCR. Ad2/CFTR-mediated transduction of airway epithelial cells w as then determined in CF individuals receiving this vector by aerosol inhal ation. Ad2-specific CFTR DNA was detected in 13 of 13 individuals 2 days af ter aerosolization, and in 3 of 5 individuals 7 days after aerosolization. Ad2-specific RNA was detected in 4 of 13 individuals on day 2, but was not detected in the 5 individuals tested on day 7. The percentage of airway epi thelial cells containing nuclear-localized vector DNA was less than or equa l to2.4% as determined by fluorescence in situ hybridization (FISH). Howeve r, in some cases, a high percentage of nonepithelial mononuclear cells or s quamous metaplastic epithelial cells was infected with the adenoviral vecto r. In conclusion, aerosol administration is a feasible means to distribute adenoviral vectors throughout the conducting airways, but improvements in a denovirus-mediated transduction of airway epithelial cells are necessary be fore gene therapy for CF will be effective.