EFFECTS OF C-REACTIVE PROTEIN ON PLATELET-FUNCTION .1. INHIBITION OF PLATELET-AGGREGATION AND RELEASE REACTIONS

Abstract

C-reactive protein (CRP) is an acute phase reactant which shares numerous functional characteristics with the immunoglobulins. CRP inhibited the aggregation of human platelets stimulated by either modified human immunoglobulin or thrombin. This effect did not involve Ca chelation or cytotoxicity and was overcome by larger amounts of the aggregating agents. CRP also inhibited the activation but not the activity of platelet factor 3 and the release of .beta.-glucuronidase. CRP can apparently inhibit multiple platelet reactivities. This property of CRP may play an important role in the control of platelet responsiveness during reactions of inflammation, defense and repair.