TSLP and TGF-β induce the differentiation of blood BDCA-1⁺ DCs into LCs. (A) Representative flow cytometry density dot plots of CD207 and CD1a surface expression by human blood and tonsillar BDCA-1⁺ and BDCA-3⁺ DCs after 24-hour treatment with and without TSLP and TGF-β. Blood CD14⁺ monocyte-derived LCs after treatment with GM-CSF, IL-4, and TGF-β and CD34⁺ hematopoietic progenitor-derived LCs after treatment with Flt3-L, TNF-α, GM-CSF, and TGF-β are shown as positive controls of the staining. Quadrants were adjusted to the matching correspondent isotype controls. Numbers represent the percentage of viable cells. (B) Quantification of CD207⁺, CD1a⁺, and CD1a⁺CD207⁺ cells for all the conditions. Data are presented as percentage of viable cells. Blood CD14⁺ monocytes were treated with IL-4, GM-CSF (IL4+GM), and TGF-β; CD34⁺ hematopoietic progenitors were treated with Flt3-L, TNF-α, GM-CSF (FL+TNF+GM), and TGF-β. Each dot represents an independent experiment. *P ≤ .05; **P ≤ .005; ***P ≤ .0005, Wilcoxon nonparametric paired test. Bars represent medians. (C) (Upper) Representative flow cytometry density plots of TSLP receptor and IL-7 receptor α chains by human blood and tonsillar BDCA-1⁺ and BDCA-3⁺ DCs. Quadrants were adjusted to the matching correspondent isotype controls. Numbers represent the percentage of viable cells. (Right) Percentage of viable cells expressing both chains of TSLP receptor. Each symbol corresponds to 1 donor. (Lower) Representative histograms of CD80 expression by human blood and tonsillar BDCA-1⁺ and BDCA-3⁺ DCs after 24-hour culture with and without TSLP. Plain histograms represent the matching correspondent isotype controls and numbers represent specific median fluorescence intensities (MFIs). Below, quantification of MFIs for CD80 for 4 independent donors. Paired Student t test was used: *P ≤ .05; **P ≤ .005.