Because WNV is controlled in part, by cytolytic and IFN-γ secreting CD8+ T cells that clear infection from peripheral and CNS tissues [58], [59], [60], [61], [62], we evaluated whether the severe clinical phenotype after infection in IRF-1-/- mice was explained in part, by a failure of antigen-specific cells to expand and migrate to infected tissues. This evidence concerns the gene IRF1 and infection.