Bcl2 and Bax protein levels in primary human endothelial cells after infection with an E1⁻E4⁺ Ad vector. Confluent endothelial cells were infected with the E1⁻E4⁺ AdNull vector or no vector (“control”), cultured in growth factor–free medium for 0 to 48 hours and assessed by Western analysis for human Bcl2 and Bax using rabbit polyclonal and mouse monoclonal antibodies, respectively. Equal protein loading was confirmed with a control antibody to detect human β-actin detected by a rabbit polyclonal antibody. Blots were developed by enhanced chemiluminescence.