Flow cytometric analyses of CXCR4 and CCR5 on 97% CD34⁺ HPCs. (A) Unstained control for evaluation of HPC physical parameters. (B) HPCs stained with PE- or FITC-conjugated control antibodies. Cells were double-labeled with an FITC-conjugated anti-CD34 along with CXCR4-PE MoAb (C) or CD34-PE along with anti–CCR5-FITC MoAb (clone 45502.111) (D) as described in Materials and Methods.