Effect of E4⁺ GFP Ad vector or E4^– GFP Ad vector on HSP70 expression in HUVECs. Confluent ECs infected with the E1^–E4^– AdGFP or E1^–E4⁺ AdGFP vector, or uninfected controls, were cultured in growth factor–free medium for 48 hours. Immunoblots were probed with antibody specific for HSP70, GFP, and β-actin.