In WT mice, we found that CXCl1 (marking an M1 phenotype) was present in the brain stem by day 8 post infection, and Retnla 1 expression (marking an M2 phenotype) occurred in both the mock and 4 dpi tissues within the brain stem and sub-cortex (containing the thalamus) regions of the brain (Fig 7E). This evidence concerns the gene CXCL1 and infection.