Morphology of hESC-derived cells and expression of lactoferrin mRNA. (A) Wright-Giemsa staining of the day-7 cells (i) revealed that they were morphologically myeloblasts and promyelocytes. On days 9 (ii) and 11 (iii), myelocytes and metamyelocytes were predominant, and on day 13 (iv; hESC-Neu), 70% to 80% of the cells appeared to be stab and segmented neutrophils. Original magnification, ×1000. (Bi) 97.3% plus or minus 1.5% of hESC-Neu's were myeloperoxidase positive. (ii) The neutrophil alkaline-phosphatase score in hESC-Neu's was 284 plus or minus 8.6. Values represent mean plus or minus SD. Original magnification, ×1000. (C) Microstructure of hESC-Neu's. Similar to steady-state neutrophils separated from peripheral blood (i), segmented nuclei and cytoplasmic granules were observed in hESC-Neu's (ii). Original magnification, ×8000. (D) Lactoferrin (LTF) mRNA was expressed in hESC-derived cells on day 7 (D7), peaked on day 10 (D10), and was weakly positive on day 13 (D13). Bone marrow mononuclear cells (BM) were strongly positive for LTF mRNA, but PB-Neu's (PB1 and 2) were negative, although faint bands were detected in PB-Neu's prepared from some donors (data not shown). As a negative control, peripheral blood mononuclear cells (MNCs) were used.