Second-generation Langerhans cells originating from epidermal precursors are essential for CD8+ T cell priming.

Abstract In vivo studies questioned the ability of Langerhans cells (LCs) to mediate CD8+ T cell priming. To address this issue, we used intradermal immunization with plasmid DNA, a system in which activation of CD8+ T cells depends on delayed kinetics of Ag presentation. We found that dendritic cells (DCs) located in the skin at the time of immunization have limited ability to activate CD8+ T cells. This activity was mediated by a second generation of DCs that differentiated in the skin several days after immunization, as well as by lymph node–resident DCs. Intriguingly, CD8+ T cell responses were not affected following treatment with clodronate liposomes, immunization of CCR2−/− mice, or …