E1A expression in AB clones. IHC for clone AB96 and for other AB clones demonstrated a strict nuclear localization of expressed E1A (A, left panel) in E1A-positive clones. The right panel is stained with a control IgG (200 fold magnification). Expression of E1A by AB clones was confirmed by Western blot (B), with HEK293 cells as positive control. Please note the equal expression of both the 289R- and the 243R-E1A proteins.