Flow cytometric analysis of integrin α_vβ₃ expression on human CD34⁺ PB cells. For cell activation study, purified human CD34⁺ PB cells were incubated in the absence or presence of IL-3 (5 ng/mL), IL-6 (20 ng/mL), or SCF (100 ng/mL) for 48 hours. Flow cytometric analysis was performed by staining for both CD34 and integrin α_vβ₃ simultaneously as described in the Materials and Methods. First, CD34⁺ PB cells were gated, and the expression of integrin α_vβ₃on gated CD34⁺ PB cells was shown.