Mechanisms of the mAb ALB6(CD9) induced human platelet activation: comparison with thrombin.
A CD9 monoclonal antibody described to aggregate human platelets was studied on different platelet functions in order to determine its mechanism of action. After a lag phase of 35 sec the mAb ALB6 induced a transient decrease in 32P-polyphosphoinositides, synthesis of 32P-phosphatidate (PA), phosphorylation of myosin light chain (P20) and of 43 KDa protein (P43) and the release reaction. Final biological and metabolic effects of ALB6 thus appear similar to that of thrombin but three differences bring additional information: (i) the lag phase, (ii) the kinetic of ALB6-induced release is identical for all granules whereas the release of dense granules is faster when induced by thrombin. (iii) no external Ca++ is required for ALB6 induced-activation.
D000911:Antibodies, Monoclonal; D001792:Blood Platelets / Q000187:drug effects / Q000276:immunology / Q000502:physiology; D001798:Blood Proteins / Q000378:metabolism; D002118:Calcium / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D010716:Phosphatidylinositols / Q000097:blood*; D010766:Phosphorylation; D010974:Platelet Aggregation; D012701:Serotonin / Q000097:blood; D013917:Thrombin / Q000502:physiology*; D013931:Thromboxanes / Q000097:blood
D000911:Antibodies, Monoclonal; D001798:Blood Proteins; D010716:Phosphatidylinositols; D013931:Thromboxanes; D012701:Serotonin; D013917:Thrombin; D002118:Calcium