Incomplete regulation of NF-kappaB by IkappaBalpha during respiratory syncytial virus infection in A549 cells.

Respiratory syncytial virus (RSV) infection of airway epithelial cells results in persistent NF-kappaB activation and NF-kappaB-mediated interleukin-8 production. Previous studies in airway epithelial cells demonstrated that tumor necrosis factor alpha (TNF-alpha)-induced NF-kappaB activation is transient due to regulation by IkappaBalpha. However, during RSV infection, IkappaBalpha has only a partial inhibitory effect on NF-kappaB activation. Studies presented here demonstrate that neither increased IkappaBalpha production which occurs as a result of RSV-induced NF-kappaB activation nor inhibition of proteasome-mediated IkappaBalpha degradation results in a reversal of RSV-induced NF-kappaB activation. Thus, while manipulation of IkappaBalpha results in reversal of TNF-alpha-induced NF-kappaB activation, manipulation of IkappaBalpha does not result in a reversal of RSV-induced NF-kappaB activation.