FIG. 3.

Cell surface heparan sulfate is required for FIX- and FX-mediated binding of Ad5 to and infection of epithelial cells. Ad5 virions were preincubated with or without physiological concentrations of FIX or FX and increasing concentrations of heparin and then allowed to bind to A549 cells (A) or HCE cells (B) or to infect A549 cells (C) or HCE cells (D). Alternatively, Ad5 virions were preincubated with or without physiological concentrations of FIX or FX and then allowed to bind to A549 or HCE cells (E and G) or to infect A549 or HCE cells (F and H) pretreated with increasing concentrations of heparinase I. In binding assays, cell-associated radioactivity was measured with a scintillation counter, whereas in infection assays, infectivity was quantified by fluorescence microscopy. Values are means ± SD. *, P of <0.05 versus control; **, P of <0.01 versus control; ***, P of <0.001 versus control.