TLR3 and infection: Such reduction correlated positively with severity of the disease [50]; Second, infection of hepatoma cells with HCV in vitro degraded TRIF protein, an essential TLR3 adaptor, and subsequently attenuated poly I:C-induced signaling [10]; Third, the NS3/4A serine protease of hepatitis C virus (HCV) can interrupt TLR3 and/or RIG-I-mediated signal transduction by proteolytic cleavage of TRIF and/or CADIF [51–53].