Isolated mitochondrial, cytoplasmic and nuclear fractions from influenza A virus infected and untreated macrophages were dissolved in Laemmli sample buffer. Equal amount of protein from each sample was loaded into an SDS-PAGE gel and transferred onto PVDF-membrane. Membranes were blocked with 5% nonfat milk, stained with different Abs overnight and detected by ECL. The primary antibodies used in this study were cathepsin B (Calbiochem), caspase-3 and HSP90 (Cell Signaling), IFIT3 (BD Transduction Laboratories), actin, annexin A1, b-Amyloid, APOE, caspase-1, cathepsin D, cathepsin Z, cytochrome c, galectin-3, GAPDH, histone H1, HMGB1, LAMP-1, P2X7 receptor, S100-A9 and VDAC1 (Santa Cruz Biotechnology Inc.). IL-18 and influenza A virus (H3N2) antibodies have been previously described [4, 40] .