Flow cytometry assessment of spleen erythroblast maturation.

Freshly dissociated wild-type mouse spleen cells were labeled with a biotin-conjugated monoclonal antibody (mAb) to CD71 and a PE-conjugated anti-Ter119 mAb, followed by APC-conjugated streptavidin. Dead cells (staining positive with propidium iodide) and anucleated red cells (with low forward scatter) were excluded from analysis. The left-hand panel illustrates a density plot of all viable spleen cells; axes indicate relative fluorescence units for PE (x-axis) and APC (y-axis). Regions I to IV were selected as indicated. The right-hand panels show May-Grunwald Giemsa–stained cytospin preparations of cells sorted from each of regions I to IV. Representative cells from 2 to 3 fields are shown for each region. These are predominantly proerythroblasts in region I, basophilic erythroblasts in region II, late basophilic and chromatophilic erythroblasts in region III, and orthochromatophilic erythroblasts in region IV. The photographs were taken at an original magnification of × 400.