INCORPORATION OF ADENOVIRUS IN CALCIUM-PHOSPHATE PRECIPITATES ENHANCES GENE-TRANSFER TO AIRWAY EPITHELIA IN-VITRO AND IN-VIVO

Adenovirus (Ad)-mediated gene transfer to airway epithelia is ineffici ent because the apical membrane lacks the receptor activity to bind ad enovirus fiber protein. Calcium phosphate (CaPi) precipitates have bee n used to deliver plasmid DNA to cultured cell lines. However, such pr ecipitates are not effective in many primary cultures or in vivo. Here we show that incorporating recombinant adenovirus into a CaPi copreci pitate markedly enhances transgene expression in cells that are resist ant to adenovirus infection, Enhancement requires that the virus be co ntained in the precipitate and viral proteins are required to increase expression, Ad: CaPi coprecipitates increase gene transfer by increas ing fiber-independent binding of virus to cells. With differentiated c ystic fibrosis (CF) airway epithelia in vitro, a 20-min application of Bd:CaPi coprecipitates that encode CF transmembrane conductance regul ator produced as much CF transmembrane conductance regulator Cl- curre nt as a 24-h application of adenovirus alone. We found that Ad:CaPi co precipitates also increased transgene expression in mouse lung in vivo ; importantly, expression was particularly prominent in airway epithel ia. These results suggest a new mechanism for gene transfer that may b e applicable to a number of different gene transfer applications and c ould be of value in gene transfer to CF airway epithelia in vivo.