Adhesion of transiently transfected CHO cells to immobilized fibrinogen. ⁵¹Cr-labeled CHO cells transfected with vector alone (Mock), mutant GPIIb and normal GPIIIa cDNA constructs (Patient LW), and wild-type GPIIb and GPIIIa cDNA constructs (WT) were added to microtiter wells precoated with fibrinogen (100 μL of 20 μg/mL). Cells were incubated with buffer (□) or MoAbs specific for α_vβ₃ (LM609) (▪),30 GPIIb/IIIa + α_vβ₃(c7E3) (□),28 and GPIIb/IIIa (10E5) (▧).26The number of cells per well was calculated according to the specific activity of a 50-μL aliquot of cells sampled at the beginning of the experiment, as previously described.19 Data are presented as mean ± SD of 4 data points obtained from two separate experiments.