Murine skin is populated by two main populations of type-2 dendritic cells, the CD11b-hi and CD11b-low DC2, which differ in their expression of multiple phenotypic markers as well as their developmental requirements. In particular the cytokine IL-13 is necessary for the normal development of CD11b-low DC2 in skin and skin-draining lymph node but does not influence the in vivo development of CD11b-hi DC2. The ability of IL-13 to support CD11b-low DC2 development in vivo can be recapitulated in vitro by supplementing Flt3L BM-DC cultures with IL-13.
We have carried out a scRNAseq characterization of CD11b-hi and CD11b-low DC2 from the skin and skin-draining lymph nodes of wild-type mice and mice that are defective in IL-13 production. We used RNA velocity and trajectory analysis to infer the developmental progression of each DC2 subset into mature phenotypes and to identify specific markers to enable their differentiation by flow cytometry. We also compared the transcriptomic changes of each DC2 subset following immunization with different antigens. Together, these studies provide evidence for developmentally distinct DC2 subsets, each with unique properties and functional characteristics.