CD8α+ Dendritic Cells Are an Obligate Cellular Entry Point for Productive Infection by Listeria monocytogenes

CD8α+ dendritic cells (DCs) prime cytotoxic T lymphocytes during viral infections and produce interleukin-12 in response to pathogens. Although the loss of CD8α+ DCs in Batf3−/− mice increases their susceptibility to several pathogens, we observed that Batf3−/− mice exhibited enhanced resistance to the intracellular bacterium Listeria monocytogenes. In wild-type mice, Listeria organisms, initially located in the splenic marginal zone, migrated to the periarteriolar lymphoid sheath (PALS) where they grew exponentially and induced widespread lymphocyte apoptosis. In Batf3−/− mice, however, Listeria organisms remain trapped in the marginal zone, failed to traffic into the PALS, and were rapidly cleared by phagocytes. In addition, Batf3−/− mice, which lacked the normal population of hepatic CD103+ peripheral DCs, also showed protection from liver infection. These results suggest that Batf3-dependent CD8α+ and CD103+ DCs provide initial cellular entry points within the reticuloendothelial system by which Listeria establishes productive infection. ► Batf3−/− mice, lacking CD8α+ and CD103+ DCs, are resistant to Listeria infection ► Listeria migration from the splenic marginal zone to the PALS requires CD8α+ DCs ► Splenic CD8α+ DCs are eliminated during Listeria infection