Effects of platelet P-selectin and α_IIbβ₃ antagonists on LS174T cell adhesion to surface-adherent platelets under conditions of flow (0.8 dyn/cm²).

Platelets were isolated either from healthy volunteers or a patient with Glanzmann thrombasthenia (GT). Closed bars represent stable adherent cells (stationary for > 10 seconds) counted at the end of the 10-minute experiment, whereas open bars represent the total interacting cells counted throughout the entire 10-minute experiment. Immobilized platelets were treated with agents specific for P-selectin and α_IIbβ₃ during the 10-minute thrombin incubation. XV454 (blocking α_IIbβ₃function); AC1.2 (nonblocking anti-P-selectin mAb); AK4 or EP5C7 (blocking P-selectin function). *, **P < .05 with respect to no-treatment control. § P < .05 with respect to XV454-treated specimens. Values are mean ± SEM (n = 5-31 healthy volunteers; n = 1 GT patient performed in triplicate).