IRF3 and infection: Our observations were in line with the study comparing transcriptomes between the wildtype and Irf3-/-Irf7-/- double KO (DKO) mice infected with PR8 (H1N1), in which the upregulation of MAPK signaling pathway was observed to correlate with susceptible phenotypes of mutants such as significant weight loss, a higher mortality and a higher viral load with infection [43].