CD4 and viral encephalitis: Flow cytometric analysis of CD45high cells isolated from the forebrain of wild-type (WT) WNV-infected mice at 7 (peak encephalitis), 25 (early recovery), and 52 (late recovery) DPI indeed revealed a significant increase in percentages of CD4+ and CD8+ T cells expressing CXCR6 at 25 and 52 DPI compared to 7 DPI (Fig. 2c, Additional file 1: Fig. S3a,c).