Single-cell sorting of four subpopulations of CD34⁺ cord blood cells. Cord blood MNCs were stained with FITC-conjugated anti-CD34 MoAb, APC-conjugated anti-CD38 MoAb, and PE-conjugated anti–c-kit MoAb. As negative controls, FITC-, APC-, and PE-conjugated mouse IgG1 were used. (A) The lymphoblastic region (R1) was gated on the basis of FSC and SSC. (B) The gate (R2) was set on CD34⁺ cells. (C) The expressions of CD38 and c-kit on CD34⁺cells were examined. The single-cells in the R3, R4, R5, or R6 region were sorted as CD34⁺CD38⁺c-kit⁺, CD34⁺CD38⁺c-kit^-, CD34⁺CD38⁻c-kit⁺, or CD34⁺CD38⁻ c-kit^- cells, respectively, using an automatic cell deposition unit equipped with the FACStar^plus flow cytometer, as described in Materials and Methods.