A20 deficient alveolar macrophages are hyperresponsive to IAV infection. Alveolar macrophages isolated from A20myel-KO and wild type (A20myel-WT) mice were mock treated or infected with IAV (moi 1) for 18 hours. TNF, MCP-1 (ccl2), KC (cxcl1) and IFNα4 mRNA expression was determined by qPCR (A). Cell culture supernatant was analyzed for TNF, MCP-1 and KC protein levels by ELISA and multiplexing technologies (B). Error bars represent mean values (+/− SEM) of 2–3 samples. Results are representative for 2 independent experiments. *p<0.05; **p<0.01; ***p<0.001.