FLOW CYTOMETRIC ANALYSIS OF CHANGES IN CYTOSKELETAL PROTEINS DURING PLATELET DESTRUCTION AND ACTIVATION USING A MONOCLONAL-ANTIBODY AGAINSTPLATELET MYOSIN

We developed a new monoclonal antibody directed against platelet myosi n (NNKY6-19). Using this antibody, we analyzed platelet cytoskeletal c hanges related to stimulation with thrombin and to long-term storage. Immunoelectron microscopy showed increased binding of NNKY6-19 to pseu dopods and the open canalicular system during treatment with thrombin (0.1 U/ml) and during storage for 7 days. Flow cytometry also showed i ncreased binding to platelets by NNKY6-19 and an antiactin monoclonal antibody during storage. The binding of NNKY6-19 showed an increase gr eater than that with the antiactin antibody after storage of platelets for 7 days and after thrombin treatment. These findings indicated tha t the increased binding of NNKY6-19 had some relationship to changes i n intracellular myosin and platelet morphology. Thus use of NNKY6-19 a llowed analysis of subtle changes related to platelet activation, whic h differed from those detected by antibodies against platelet glycopro teins or by the antiactin antibody. This antibody appears to provide a simple method for studying changes in platelet cytoskeletal and surfa ce proteins. (C) 1993 Wiley-Liss, Inc.