Retroviral vectors efficiently transduce basal and secretory airway epithelial cells in vitro resulting in persistent gene expression in organotypic culture.
Gene therapy of the lung requires the introduction and expression of a therapeutic gene in airway cells. Although retroviral vectors may be useful in this context, the ability of retroviruses to infect specific cell types in the airway is not known. In this study, we examined the ability of amphotropic recombinant retroviral vectors to transduce primary cultures of rabbit airway epithelial cell populations purified for basal or secretory cells. Transduction efficiencies in basal and secretory cell populations were found to be similar; about 27% after a single exposure to vector, and up to 77% after multiple exposures. The fate of genetically modified cells from the different populations was followed through terminal differentiation using organotypic cultures. The epithelium of the organotypic cultures generated from each population exhibited both pseudostratified and stratified morphology, produced mucin, and stained positively with antibodies specific for basal and ciliated cells. The mucociliary epithelium also showed co-localization of these phenotypic markers with the expression of the vector-encoded beta-galactosidase gene. We conclude that retroviruses can efficiently transduce primary cultures of basal and secretory cells, and that both of these cell types can be progenitor cells of the airway epithelium. In vivo delivery of a retroviral vector containing a human placental alkaline phosphatase gene resulted in expression of the heterologous gene in rabbit tracheal epithelial cells. However, transduction efficiency was low and occurred only in the wounded trachea.