Flow cytometric analysis of isolated LP CD34⁺ cells (purity 98%) from a representative experiment; indirect single-color immunofluorescence staining was performed with specific antibodies raised against the human chemokine receptor subtypes CCR-1, CCR-4, and CCR-5 as described in Materials and Methods. Control cells were stained with secondary FITC-linked antibody only. Chemokine receptor expression was analyzed in a uniformly set lymphocyte gate comprising 20,375, 21,503, and 21,659 cells in the CCR-1, CCR-4, and CCR-5 experiments, respectively. Overlay plots of the histograms (cell number against MFI) for the different chemokine receptors and the control are shown.