An accumulation of two populations of dendritic cells in skin-draining lymph nodes in response to the expression of thymic stromal lymphopoietin in the skin.

Thymic stromal lymphopoietin (TSLP) acts on dendritic cells (DCs), which prime helper T (Th) cells to become type 2 cytokine producing cells. Recently, a different set of populations of TSLP-responsive DCs has been discovered. Here, we identified two populations of CD103loEpCAMhi migratory DCs (fraction I and fraction II) that accumulated in skin-draining lymph nodes in response to TSLP expressed in the mouse skin. Fraction I DCs with CD11b+PDL2hi expression primed naïve Th cells to differentiate into cells secreting IFN-γ, IL-17A and IL-22, while fraction II DCs with CD11bloPDL2+ expression primed naïve Th cells to differentiate into cells secreting IL-4, IL-5, IL-9, IL-13 and IL-10. Fraction I DCs migrated from the skin via IL-4Rα signaling pathway, whereas fraction II DCs migrated partially via TSLPR signaling pathway. All suggest that at least two populations of CD103loEpCAMhi DCs with distinct functions and pathways could migrate in response to TSLP expression in the skin.