Interactions of neutrophils with HL-60 cells mediated by PMPs in the presence of an anti–L-selectin antibody.
(A) Neutrophils (total volume, 6 mL) were withdrawn at 1.0 dyne/cm2 over HL-60 cells prebound to an antihuman CD43 mAb-coated glass slide. The normalized rate of neutrophil–HL-60 cell interactions was counted. Error bars represent ± SEM (standard error of the mean) (n = 3). (B) Neutrophils (total volume, 6mL) incubated with 0.4 mL PMPs and generated by the calcium ionophore A23187 were withdrawn at 1.0 dyne/cm2. The cells were withdrawn in the presence of both anti–L-selectin mAb DREG-56 to eliminate L-selectin–dependent binding to PSGL-1 and anti–P-selectin antibodies S12 (nonblocking) or G1 (blocking) or in the presence of DREG-56 together with either of the anti–PSGL-1 mAbs PL2 (nonblocking) or PL1 (blocking). Cells were withdrawn over HL-60 cells bound to an antihuman CD43 mAb-coated glass slide. The normalized rate of neutrophil–HL-60 cell interactions was counted. Error bars represent ± SEM.
