Different adhesive characteristics and VLA-4 expression of CD34() progenitors in G0/G1 versus SG2/M phases of the cell cycle

We identified the cell cycle status of CD341 cells of steady-state bone marrow (BM) and peripheral blood (PB) obtained from healthy volunteers, and those of apherasis PB samples collected from healthy donors who had been administered granulocyte colony-stimulating factor (G-CSF). More than 10 % of CD341 cells in BM were in S1G2/M phase. In contrast, regardless of whether G-CSF treatment was performed, less than 2 % of CD341 cells in PB were cycling. BM CD341 cells showed greater VLA-4 expression and adherence to stromal cells than PB CD341 cells. In addition, when cycling and dormant BM CD341 cells were analyzed separately, the cells in S1G2/M phase expressed more VLA-4 and adhered to the stromal cell monolayer more efficiently than the cells in G0/G1 phase. Furthermore, this adhesion of CD341 cells to the stromal cell layer was almost completely inhibited b