Siglec-H is expressed specifically on pDC precursors in FACS analyses. (A) Single-cell suspensions of bone marrow (BM), spleen, and lymph node (LN) from μH gene-deficient mice were stained sequentially with MB15, biotinylated mouse anti-rat IgG2a, and streptavidin-PE. Cells were counterstained with CD11c-FITC and B220-APC. About 50 000 events were acquired for each sample. (B) Single-cell suspensions from bone marrow (BM), spleen, and blood were stained with FITC-labeled sheep anti–Siglec-H pAb in combination with the indicated mAbs. The percentages of cells relative to total live cells are shown in the quadrants. About 200 000 events were acquired for each sample.