CLPs give rise to DCs in vivo.

CLPs were competitively transplanted into lethally irradiated CD45 congenic animals, together with host-type whole bone marrow (A). CD45 expression was used to gate on donor-type (CD45.1) and host-type (CD45.2) CD11c⁺-enriched, live splenocytes on day 15 after transplantation (B). Both CLP (upper panel) and host-derived (lower panel) cells were analyzed for DC phenotype by MHC class II⁺ and CD11c⁺ expression (C, contour plots). CLP-derived MHC class II⁺CD11c⁺ cells account for approximately 10% of donor-derived MHC class II⁺CD11c⁺ cells in a CD11c⁺-enriched sample. MHC class II⁺CD11c⁺ cells were further analyzed for CD8α, CD40, CD80, and CD86 expression (C). Closed hisograms represent specific staining, and open histograms represent isotype-matched controls of the MHC class II⁺CD11c⁺ cells. On day 15, 69% of CLP-derived DCs and 63% of host-derived DCs were CD8α⁺. Both CLP and host-derived DCs expressed low to intermediate levels of CD40, CD80, and CD86. Details are given in “Materials and methods.”