Effects of Notch ligand-dependent activation on differentiation of primary hematopoietic progenitors. Purified CD34⁺ were seeded on NIH3T3pBABE and NIH3T3pBABE-J2 at a density of 0.1 × 10⁶/mL in IMDM supplemented with 10% FCS and FLT-3 L. At different time points cells were detached from the 3T3 layer, washed, and labeled with FITC- and PE-conjugated MoAbs directed to CD34, CD11b, or CD14. The top panel of contour plots shows fluorescence intensity of the cultured CD34⁺ cells stained with control antibodies (IgG1-FITC and IgG1-PE) at day 14. The middle panel shows fluorescence intensity of the cultured CD34⁺ cells stained with anti-CD34 antibody at day 7; CD34 intensity of fluorescence is expressed on the x-axis, and forward scatter on the y-axis. The bottom panel shows two-color flow cytometric analysis of cultured CD34⁺ cells at day 14; anti-CD11b antibody fluorescence intensity is shown on the x-axis, and anti-CD14 antibody fluorescence intensity on the y-axis.