Innate Immune Responses to West Nile Virus Infection
Innate antiviral immunity is activated by the detection of conserved virus-associated molecular motifs by host-encoded pathogen-recognition receptors (PRRs). This phenomenon triggers the production of antiviral and proinflammatory cytokines as well as the expression of costimulatory molecules in immune cells, leading to the establishment of an antiviral state and the induction of adaptive immune responses. In this chapter we review our current understanding of the innate immune mechanisms that mediate the recognition of West Nile virus (WNV) infection. The role of innate immune cells and cytokines in WNV immunopathogenesis is also discussed. Paradoxically, although many of the innate responses induced by WNV infection are protective, others favor WNV neuroinvasion by their detrimental effect on blood–brain barrier permeability.