TLR4 and infection: In this work, mRNA levels of TLR3, TLR4, TLR7, MyD88, NF-κB p65 and RIG-1 in the murine lung tissue from the control infected group were significantly increased compared with the control uninfected group at days 3 and 7 post-infection, suggesting influenza virus activated the TLR3, TLR4, TLR7 and RIG-1 signaling pathways after infection.