For subcellular proteome and secretome analysis (Fig. 1A) human primary macrophages were first infected with influenza A virus for 6 h, 12 h and 18 h (intracellular fractions) or 6 h, 9 h and 12 h (secretome). After this the cells were fractionated into mitochondrial, cytoplasmic and nuclear fractions, and macrophage growth media were collected for secretome analysis. The enrichment of mitochondrial, cytoplasmic and nuclear proteins into different fractions was confirmed with Western blots (Fig. 1B) .