Adherence of transduced LAD CD34⁺ cells to HUVEC. Untransduced LAD CD34⁺ cells, transduced and sorted LAD CD34⁺ cells, and normal CD34⁺cells were expanded for 21 days, labeled with calcein, and allowed to bind to HUVEC. Basal represents the basal or background level of cell adherence. PMA indicates cells stimulated with 100 ng/mL PMA. 60.3 PMA indicates cells incubated with anti-CD18 MoAb 60.3 and stimulated with PMA.