Flow cytometric analysis of changes in cytoskeletal proteins during platelet destruction and activation using a monoclonal antibody against platelet myosin

Abstract

We developed a new monoclonal antibody directed against platelet myosin (NNKY6-19). Using this antibody, we analyzed platelet cytoskeletal changes related to stimulation with thrombin and to long-term storage. Immunoelectron microscopy showed increased binding of NNKY6-19 to pseudopods and the open canalicular system during treatment with thrombin (0.1 U/ml) and during storage for 7 days. Flow cytometry also showed increased binding to platelets by NNKY6-19 and an antiactin monoclonal antibody during storage. The binding of NNKY6-19 showed an increase greater than that with the antiactin antibody after storage of platelets for 7 days and after thrombin treatment. These findings indicated that the increased binding of NNKY6-19 had some relationship to changes in intracellular myosin and platelet morphology. Thus use of NNKY6-19 allowed analysis of subtle changes related to platelet activation, which differed from those detected by antibodies against platelet glycoproteins or by the antiactin antibody. This antibody appears to provide a simple method for studying changes in platelet cytoskeletal and surface proteins.