IL-21 from high-affinity CD4 T cells drives differentiation of brain-resident CD8 T cells during persistent viral infection

To investigate IL-21 producing CD4 T cells, we infected IL21-VFP reporter mice with mouse polyomavirus and compared VFP+ (IL-21+) CD4 T cells to VFP- (IL-21-) CD4 T cells in the brains and spleens. Comparative gene expression profiling analysis of RNA-seq data for VFP+ and VFP- CD4 T cells derived from the brains or spleens of IL21-VFP reporter mice at 15 day post Mouse Polyomavirus infection (dpi).