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.