Adhesion of α_IIbβ₃ mutants to immobilized fibrinogen.

Wild-type α_IIb or each mutant α_IIb cDNA was transiently cotransfected with wild-type β₃ cDNA into 293 cells. Two days after transfection, wild-type or mutant α_IIbβ₃-transfected cells (1 × 10⁶ cells/well) were incubated with immobilized fibrinogen (FBG) in the presence of 50 μM cyclo(RGDfV) (α_vβ₃-specific antagonist) at 37°C. After washing with PBS, adherent cells were quantified with a colorimetric reaction using endogenous cellular acid phosphatase activity. Data represent the mean ± SD of triplicate measures of optical density at 415 nm. Statistical analysis (2-tailed P values for paired sample) was performed between 293 cells expressing wild-type α_IIbβ₃ and those expressing each mutant α_IIbβ₃ (**P < .01; *P < .05).