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 μg 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°C, but not at 4°C, enhanced luciferase activity in A549 cells 24 h later by 156% ( P < 0.01). Intratracheal instillation of AdCMV-Luc (2 × 109 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 μl; 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.