TLR3 and viral infectious disease: Poly(I:C) activates toll-like receptor 3 (TLR3) signalling via TRIF-dependent pathways and culminating in the activation of the interferon (IFN) response transcription factor IFN regulatory factor-3 and a number of IFN-β-dependent genes, as well as other pro-inflammatory cytokines in the periphery and CNS (Fernandez-Lizarbe et al, 2009), which are normally involved in the acute symptoms of viral infections.