Expression of c-kit and CD15 on cultured cells grown by various combinations of SCF, TPO, and FL. CD34⁺ BM cells (5 × 10³) were plated per well containing various combinations of 10 ng/mL of SCF, 10 ng/mL of TPO, and 50 ng/mL of FL. After the numbers of viable cells were counted at 3 weeks of culture, the cells were stained with PE-conjugated anti–c-kit MoAb and FITC-conjugated anti-CD15 MoAb. (A) The viable cell region (R1) was gated on the basis of FSC and SSC. (B) As negative controls, PE- and FITC-conjugated mouse IgG1 were used. The c-kit⁺CD15⁻ cells (R2) were identified as mast cells, and the c-kit⁻CD15⁺ cells (R3) as myeloid cells. Stimulation with (C) SCF + TPO, (D) SCF + FL, (E) TPO + FL, and (F) SCF + TPO + FL.