Flow cytometric analysis of _IIbβ₃ on the transfected cell surface. Recombinant _IIb cDNA containing the ²³³⁴A → C substitution subcloned into pcDNA3 was cotransfected with recombinant wild-type β₃ cDNA in 293 cells. The transfected cells were incubated with TP80 (_IIb-specific MoAb), AP3 (β₃-specific MoAb), or AP2 (_IIbβ₃ complex-specific MoAb) for 30 minutes on ice and washed once, and bound antibodies were detected by FITC-conjugated goat F(ab′)₂ antimouse IgG. Results are expressed as histograms of cell number (linear scale) on the ordinate versus fluorescence intensity (log scale) on the abscissa.