Effect of PSGL-1 MoAb on human neutrophil and leukemia cell line rolling on L-selectin and P-selectin. Neutrophils (1 × 10⁶/mL) and the leukemia cell lines HL-60, U937, and SKW3 (0.5 × 10⁶/mL) were treated with either MoAb KPL1 (10 μg/mL) or KPL1 ascites (1:500) and allowed to bind to purified L-selectin (1:5; 170 sites/μm²) (A) or P-selectin (1:60; 270 sites/μm²) (B) under static conditions for 90 seconds, followed by initiation of flow at a wall shear stress of 1 dyne/cm². Mean ± SEM of bound cells/mm² in multiple fields from three independent experiments.