West Nile virus (WNV) is an emerging flavivirus capable of infecting the central nervous system (CNS) and mediating neuronal cell death and tissue destruction. The processes that promote
inflammation and
encephalitis within the CNS are important for control of WNV disease but, how inflammatory signaling pathways operate to control
CNS infection is not defined. Here, we identify IL-1β signaling and the NLRP3
inflammasome as key host restriction factors involved in viral control and
CNS disease associated with
WNV infection. Individuals presenting with acute
WNV infection displayed elevated levels of IL-1β in their plasma over the course of
infection, suggesting a role for IL-1β in WNV immunity. Indeed, we found that in a mouse model of
infection, WNV induced the acute production of IL-1β in vivo, and that animals lacking the
IL-1 receptor or components involved in
inflammasome signaling complex exhibited increased susceptibility to WNV pathogenesis. This outcome associated with increased accumulation of virus within the CNS but not peripheral tissues and was further associated with altered kinetics and magnitude of
inflammation, reduced quality of the effector CD8(+) T cell response and reduced anti-viral activity within the CNS. Importantly, we found that
WNV infection triggers production of IL-1β from cortical neurons. Furthermore, we found that IL-1β signaling synergizes with type I IFN to suppress WNV replication in neurons, thus implicating
antiviral activity of IL-1β within neurons and control of virus replication within the CNS. Our studies thus define the NLRP3
inflammasome pathway and IL-1β signaling as key features controlling
WNV infection and immunity in the CNS, and reveal a novel role for IL-1β in
antiviral action that restricts virus replication in neurons.