The enhancing effect of E₂ on the TLR-mediated responses of pDC is mediated through hematopoietic ERα. WT or ERα^−/− B6 bone marrow cells were injected into lethally irradiated CD45.1 WT female B6 mice. After 3 weeks of reconstitution, bone marrow cells were stimulated with polyU (C), R848 (D), or GpG-2216 (E). (A) Dot plots showing the frequency of WT or ERα^−/− pDCs (mPDCA1⁺CD45.1⁻). (B) Percentage of pDCs from individual mice. (C-E) Intracellular IFN-α/β staining of pDCs derived from ERα^+/+ or ERα^−/− bone marrow cells. Stimulated pDCs were stained for IFN-α/β and analyzed by flow cytometry. Results from individual mice are shown. The lines on scatter plots indicate mean values. P values were determined using the Mann-Whitney U test. Data are representative of 3 independent experiments.