Treatment of platelets with 9012.2 causes loss of platelet surface GP VI. Washed platelets (3 × 10⁸/mL) were labeled with FITC-conjugated streptavidin alone (black lines) or biotinylated-convulxin and FITC-streptavidin (gray lines) as indicated. Platelets were resting (light gray) or treated with 25 μg/mL mAb 9012.2 (dark gray) at 37°C for 45 minutes. Samples were fixed in 1% paraformaldehyde, diluted to 1 × 10⁷/mL, labeled for 1 hour with biotinylated-convulxin (50 ng/mL), and stained with fluorescein-streptavidin before analysis. Data were collected and analyzed using a FACScan flow cytometer and CELLQuest software. Results shown are representative of 3 independent experiments.