PrP^c expression in human erythroid cells cultured in vitro. (A) Erythroblasts were harvested on days 6, 8, and 11 of culture. After seeding overnight onto poly-L-lysine–coated slips, cells were fixed and permeabilized and then incubated with PrP mAb ICSM18 and subsequently with goat anti-mouse FITC. Scale bars equal 10 μm. (B) Day-6 erythroblasts were fixed and permeabilized. Dual staining of cells with PrP mAb ICSM18 show in green, and ER marker calnexin (i), Golgi marker giantin (ii), and lysosomal marker LAMP-1 (iii) shown in red. Bottom row (iv) shows PrP mAb (red) dual stained with CD63 mAb (green). Colocalization is highlighted in the grayscale image. Scale bars equal 10 μm.