A basal level phosphorylation of NFkB was also observed in 3D/4 pig macrophages, and was further enhanced upon H1N1pdm infection, indicating that the NFkB pathway was activated as well in infected pig macrophages (Fig. 4C) . When the cells were pre-treated with specific inhibitors of NFkB (10 nM) or IKK (10 mM), the phosphorylation/activation of NFkB was effectively decreased or diminished.