Microarray analysis of C. rodentium infected colons

Defense against attaching and effacing (A/E) bacteria requires the sequential generation of IL-23 and IL-22 to induce protective mucosal responses. While the critical source of IL-22 has been identified as CD4+ and Nkp46+ innate lymphoid cells (ILCs), the precise source of IL-23 is unclear. Here, we use genetic techniques to deplete specific classical dendritic cell (cDC) subsets and analyze immunity to the A/E pathogen Citrobacter rodentium. We find that Zbtb46+ cDCs, and specifically Notch2-dependent intestinal CD11b+ cDCs, but not Batf3-dependent CD103+ cDCs, are required for IL-23 production and immunity against C. rodentium. Notch2 controls cDC differentiation at a terminal step mediated by lymphotoxin signaling. Importantly, these results provide the first demonstration of a non-redundant function of CD11b+ cDCs in vivo. Analysis of genes differentially expressed between WT, Batf3 KO and Notch2 KO colons following C. rodentium infection. Mice were infected with 2 x 10^9 C. rodentium and colons harvested at either Day 4 or Day 9.