Effect of an E1⁻E4⁺replication–deficient Ad vector on the growth and viability of primary human endothelial cells. (Panels A, B) Subconfluent endothelial cells cultured in poly-D-lysine–coated glass coverslips. (Panels C, D) Confluent endothelial cell cultured in 6 well plates. (A) Number of endothelial cells over time cultured in growth factor medium after exposure to the E1⁻E4⁺ AdNull vector (50 pfu/cell) or to no vector (“control”). (B) Number of endothelial cells over time cultured in growth factor–free medium after exposure to AdNull compared with uninfected cells (“control”). (C) Viability of confluent endothelial cells over time cultured in growth factor medium after infection with E1⁻E4⁺AdNull vector (50 pfu/cell) compared with no vector (“control”). (D) Viability of confluent endothelial cells over time cultured in growth factor–free medium after infection with the AdNull vector compared with control. For panels C and D, viability was assessed by trypan blue dye exclusion. For all panels, the data represents the mean ± standard error of the mean of triplicate measurements.