FIG. 1.

Adenovirus infection of HEK293 cells is mediated by fiber and penton base proteins. (A) Fiber protein mediates Ad binding to HEK293 cells. HEK293 cells (1.5 × 10⁶ cells/sample, in duplicate) in suspension were preincubated with recombinant Ad2 fiber, penton base (10 μg/ml), the anti-CAR antibody (RmcB), anti-penton base antibody (DAV-1), or anti-integrin antibodies at 20 μg/ml at 4°C for 60 min. Specific Ad binding to cells was determined by using ¹²⁵I-labeled Ad2 as previously described (13). (B) Penton base interaction with αv integrins promotes Ad-mediated gene delivery. HEK293 cells (10⁶ cells/sample) were preincubated with fiber protein, anti-CAR, anti-penton base, or anti-integrin antibodies (20 μg/ml) as described above, followed by incubation with Ad.CMV.LacZ at an MOI of 1 particle/cell at 4°C for another 30 min. The cells were then warmed to 37°C for 15 min. Noninternalized virus was removed by trypsinization. Ad-mediated gene delivery was determined at 20 h postinfection by expression of β-galactosidase. Representative data from two independent experiments were plotted as the mean ± standard deviation.