No impairment of differentiation of DCs from BM of SIRPα MT mice in vitro. (A) BM cells from WT or SIRPα MT mice were cultured with GM-CSF (10 ng/mL) for 7 days in 24-well plates, after which the total number of BM-derived DCs was determined with a Burker-Turk counting chamber. Data are means ± SE from 3 independent experiments. (B) Cells cultured as in panel A were incubated with a biotin-conjugated mAb to CD11c (open traces) or control mAb (filled traces) and were also stained with PE-conjugated streptavidin and PI. The expression of CD11c on PI-negative cells was analyzed by 2-color flow cytometry. The relative number of CD11c⁺ cells is expressed as a percentage of all PI-negative cells on each plot. Data are representative of 3 independent experiments. (C) BM cells from WT or SIRPα MT mice were cultured with Flt3 ligand (200 ng/mL) for 7 days, after which the total number of BM-derived DCs was determined with a Burker-Turk counting chamber. Data are means ± SE from 3 independent experiments. (D-E) Cells cultured as in panel C were incubated with a biotin-conjugated mAb to CD11b and also stained with an FITC-conjugated mAb to CD24, PE-conjugated streptavidin, an APC-conjugated mAb to CD11c, an APC-Cy7–conjugated mAb to B220, and PI. The expression of CD11c and B220 on PI-negative cells (D) or that of CD11b and CD24 on cDCs (E) was analyzed by 5-color flow cytometry (left panels). The relative numbers of CD11c⁺ B220⁻ cells (cDCs) and CD11c^int B220⁺ cells (pDCs; D) or those of CD24^low CD11b^high (CD11b^hi) and CD24^high CD11b^low (CD24^hi) cDCs (E) are expressed as a percentage of all PI-negative cells (D) or of cDCs (E) on each plot. The percentages of cDCs or pDCs (D) and those of CD11b^hi or CD24^hi subsets (E) among PI-negative cells were also determined (right panels); data are means ± SE from 3 independent experiments.