Exosurf enhances adenovirus-mediated gene transfer to alveolar type II cells

We assessed the role of surfactant replacement mixtures in the enhancement of adenovirus-mediated gene transfer to pulmonary epithelial cells both in vitro and in vivo. A549 cells, a pulmonary epithelium-derived adenocarcinoma cell line, were incubated with either media alone or media containing 10 mu g phospholipid/ml Exosurf or Infasurf for 50 min followed by addition of a replication-deficient adenovirus (E1-deleted) expressing the luciferase reporter gene [AdCMV-Luc; 10 plaque-forming units (PFU)/ cell] for 4 h. Pretreatment with Exosurf, but not Infasurf, at 37 degrees C, but not at 4 degrees C, enhanced luciferase activity in A549 cells 24 h later by 156% (P < 0.01). Intratracheal instillation of AdCMV-Luc (2 x 10(9) PFU) into rats resulted in luciferase expression mainly in alveolar macrophages and to a smaller extent in alveolar type II (ATII) cells 24 h later. However, when the AdCMV-Luc instillation was preceded by Exosurf(250 mu l; 25 mg/ml), a 10-fold increase in ATII cell luciferase activity was noted. Preincubation of cultured ATII cells with Exosurf also enhanced their transfection by AdCMV-Luc by 515% (P < 0.001). The results of these studies provide a new strategy for targeting ATII cells for gene delivery.