Induction of Rel A (p65) and NF-κB1 (p50) by RSV and TNFα is differentially inhibited by NAC and DEX. 2 × 107 A549 cells were pretreated with 5 mM N-acetyl-L-cysteine (NAC) or 500 nM dexamethasone (DEX). After 1 hr the pretreated cells were either stimulated with TNFα (100 ng/ml) or infected with RSV (MOI = 1) for 2 hr. Nuclear extracts (3 μg) were prepared and assessed for Rel A (p65, solid bars) or NF-κB1 (p50, open bars) binding activity using a Trans-AM™ transcription factor assay kit from Active Motif (Carlsbad, CA) as per the manufacturer's instructions. Graph shows the NF-κB activation results (OD450nm) from A549 cells stimulated with TNFα (A) or infected with RSV (B). An excess of either wildtype (wt) or mutant (mut) NF-κB oligonucleotide provided by the kit was included in the binding reactions to demonstrate NF-κB binding specificity. Note that NAC and DEX inhibits RSV induced p65 and p50 whereas the inhibitors had no effect on TNFα induced NF-κB binding activity.