Modified C-reactive protein interacts with platelet glycoprotein Ibα

Abstract Herein, we investigated the possible mechanisms by which recombinant modified CRP (m r CRP) modulates blood platelet function. Modified CRP could activate blood platelets and stimulate their adhesion and aggregation in the absence of any other physiological stimuli. Pre-incubation of isolated blood platelets with m r CRP at a concentration as low as 2 µg/ml resulted in significant platelet degranulation (fraction of CD62-positive platelets increased 2-fold, p vs. 2.9 ± 0.2% in control). Furthermore, m r CRP (100 µg/ml) strongly augmented spontaneous and ADP-induced fibrinogen binding to platelets (p r CRP. Binding of m r CRP to GPIbα and C1q was also observed by ELISA, irrespective of the immobilized ligand. These outcomes strongly support a role of the GPIb-IX-V complex in the interactions of m r CRP with blood platelets.