Immunostaining of transfected cells. WT BHK cells transfected with normal GPIIIa and GPIIb cDNAs displayed immunostainable GPIIb and GPIIb/IIIa detected with monoclonal antibodies against GPIIb (SZ22) and GPIIb/IIIa (10E5 and AP2). Cells containing GPIIb-del.20 exhibited faint staining with the 3 antibodies, and GPIIb-alt.25 cells exhibited more conspicuous staining with AP2 and SZ22 but not with 10E5. Control BHK cells were transfected with GPIIIa cDNA and pCEP4. Original magnification, × 200.