Human CD34⁺ HPCs adhere to P- and E-selectins resulting in growth inhibition and apoptosis. (A) Dose-dependent adhesion of CD34⁺ HPCs to microwells coated with increasing concentrations of CD14-Fc control or E- and P-selectin–Fc. (B) BM CD34⁺ proliferation at day 7 of culture in the presence of 36GS on microwells coated with increasing concentrations of CD14-Fc (○), E-selectin-Fc (▴) or P-selectin-Fc (♦). Cells were seeded at 10⁴/mL. (C) Apoptosis of BM CD34⁺ cells at day 7 of culture in the presence of 36GS on microwells coated with increasing concentrations of CD14-Fc, E-selectin–Fc, or P-selectin–Fc. (D) Proliferation of CD34⁺ cells isolated from steady-state BM, mobilized peripheral blood (PBPC), or umbilical cord blood (UCB) on microwells coated with BSA (10 μg/mL), P-selectin (1800 sites/μm²), or E-selectin (550 sites/μm²) alone or in combination (P+E). Cells (10⁴/mL) were seeded at day 0 in the presence of 36GS and counted on day 7. *indicates statistically different (P < .05) from BSA-treated control group. (E) Apoptosis of CD34⁺ cells isolated from steady-state BM, mobilized peripheral blood, or umbilical cord blood on microwells coated as described for panel D with BSA, P- or E-selectin alone, or in combination. Cells were grown in the presence of 36GS and TUNEL assays performed on day 7. (A-C) Data are expressed as a mean ± SD of one representative experiment. (D-E) Data are expressed as mean ± SEM for 3 independent experiments on BM, peripheral blood, or umbilical cord blood CD34⁺ HPCs. * indicates statistically different (P < .05) from BSA control groups.