CDPs express TLR2, TLR4, and TLR9. The relative mRNA expression of Tlr2 (A), Tlr4 (B), and Tlr9 (C) is shown for progenitor populations (dark gray) and CDPs (blue) sorted from steady-state mouse BM, and pDCs and cDCs from the spleen (light gray). Progenitors included LSK cells containing stem cells and multipotent progenitors, CMP,⁴⁶  GMP, MEP, and CLP.⁴⁷  Populations were isolated by FACS, mRNA expression was determined by quantitative real-time PCR, and levels were normalized to Rn18s. Results on mRNA show means and SEM of 4 independent experiments, including independent cell sorts and real-time PCR runs, and they are plotted on a bilogarithmic scale (log ₂). Histograms show surface TLR2 and TLR4 protein expression, and intracellular expression of TLR9 (gray filled histograms), overlaid with isotype-matched control stains (black line) of BM CDPs and spleen pDCs and cDCs (D). The data show 1 representative experiment of 3 independent experiments.