CXCL9 and infection: By looking at the expression of these two chemokines over the course of infection, we found that, although Cxcl9 and Cxcl10 signals were heavily enriched in the top half of the lamina propria during homeostasis, their expression was strongly induced after infection in C3-expressing fibroblasts (complement fibroblasts or adventitia fibroblasts), which are located at the bottom of the muscularis, creating a second potential attraction point for Cxcr3-expressing CD8 T cells (Fig. 4a,b).