Flow cytometric characteristics of platelets produced in culture. Culture-produced platelets were defined as CD41⁺elements with the same scatter properties as blood platelets. (A) Scatter properties of blood platelets after FITC-TAB (anti-CD41b) labeling. (B) Scatter properties of culture platelets labeled in the same conditions and the gate chosen for the analysis. Black points are CD41⁻ elements, grey points CD41⁺ elements. (C) CD41 expression of platelets produced in culture before (---) and after (—) thrombin activation. The isotype control (....) is shown. (D) Forward scatter height of platelets produced in culture before (---) and after (—) thrombin activation. (E) Side scatter height of platelets produced in culture before (---) and after (—) thrombin activation.