Binding of LIBS antibodies to platelets treated with PT25-2. Washed platelets were either untreated or incubated with T6 (10 μM), PT25-2 (15 μg/mL), eptifibatide (10 μM), or EDTA (10 mM) for 10 minutes at 22°C. Then, LIBS mAbs were added: AP5 (A), LIBS1 (B), or LIBS6 (C). After 30 minutes at 22°C, the platelets were washed and analyzed by flow cytometry. To normalize for differences between donor platelets, the geometric mean fluorescence of the sample incubated with eptifibatide was defined as 100%, and all other values were expressed as a percentage of the eptifibatide value. Data are presented as mean ± standard deviation. The data for AP5 and LIBS1 are from 3 separate experiments, and the data for LIBS6 are from 4 separate experiments.