On day 6 post-infection, the increase in the total number of inflammatory monocytes, resident macrophages, and microglia, as previously described in Figures 4A–C, was accompanied by a rise in the number of cells from these same populations expressing iNOS (Figures 5A–C), and producing IL-1β (Figures 5D–F) or TNF (Figures 5G–I). Here, IL1B is linked to infection.