Transitional dendritic cells are distinct from conventional DC2 precursors and mediate proinflammatory antiviral responses

By combining single cell transcriptomics and proteomics approaches, with lineage tracing and adoptive transfer experiments, we next demonstrate that tDC originate from a bone marrow precursor shared with plasmacytoid DCs (pDCs). Using new lineage tracing mouse models, we evaluated tDC plasticity and reveal their acquisition of Esamhi conventional DC type 2 (cDC2) features. Finally, we present tDC capacity to quickly response to stimulation and potently activate antigen-specific naïve T cells, demonstrating that these cells harbor functions of differentiated DCs. Our findings clarify tDC nature and reveal these cells as a unique lineage of DCs related developmentally to pDCs. Splenic DCs from 2 mice were CD135-enriched and counted. The sample was split in two: 30% was stained and DC subsets were sorted fresh; 70% was resuspended at 10x106/mL and stimulated with the LPRC adjuvant cocktail [LPS 100ng/mL, Poly(I:C) 25ug/mL, Resiquimod 2.5ug/mL and CpG-A (ODN 2216) 6ug/mL] for 3h before staining and sorting. RNA was extracted from immediately after sorting using the NucleoSpin RNA XS kit (Takara Bio) according to manufacturer’s instructions.