GENERATION OF THROMBOXANE-A2 AND AORTA-CONTRACTING ACTIVITY FROM PLATELETS STIMULATED WITH MODIFIED C-REACTIVE PROTEIN

  • 1 January 1982
    • journal article
    • research article
    • Vol. 47  (1) , 193-202
Abstract
The classical acute phase reactant, C-reactive protein (CRP), appears in markedly elevated concentration in the sera of individuals undergoing reactions of acute inflammation and tissue degradation. Like IgG, appropriately purified CRP was thermally modified (H-CRP) such that it enhanced platelet activation in plasma and initiated platelet responses in isolated systems. This direct platelet activation by modified CRP resulted in the secretion of both platelet dense body and .alpha.-granule constituents and was sensitive to non-steroidal anti-inflammatory drugs and the ADP-removing enzyme system creatine phosphate/creatine phosphokinase. TLC analysis of prostanoate endproducts following platelet activation with H[heat modified]-CRP revealed the formation of thromboxane B2 (the hydrated endproduct of thromboxane A2), an important endogenous platelet activator and contractor of vascular tissue; bioassay on rabbit aorta strips of supernatants obtained from platelets undergoing challenge with H-CRP supported the TLC analysis. Complexes formed between CRP and 1 major ligand, the polycation, shared certain platelet activating properties with H-CRP, as did latex-aggregated CRP. A potential agonist role for this acute phase reactant in platelet physiology was implied. The interaction of modified forms of CRP with the platelet at sites of vascular damage could have pathological significance.