We compared the innate immune response to a newly emerged swine-origin influenza A(H3N2) variant containing the M gene from 2009 pandemic influenza A(H1N1), termed "A(H3N2)vpM," to the immune responses to the 2010 swineorigin influenza A(H3N2) variant and seasonal influenza A(H3N2). Our results demonstrated that A(H3N2)vpMinduced myeloid dendritic cells secreted significantly lower levels of type I interferon (IFN) but produced significantly higher levels of proinflammatory cytokines and induced potent inflammasome activation. The reduction in antiviral immunity with increased inflammatory responses upon A (H3N2)vpM infection suggest that these viruses have the potential for increased disease severity in susceptible hosts.
