Staphylococci-induced Human Platelet Injury Mediated by Protein A and Immunoglobulin G Fc Fragment Receptor

Abstract

A B S T R A C T Bloodstream infections with staphylococci are accompanied by thromboembolic complications. We have studied the mechanism of the interaction of staphylococci with human blood platelets.Staphylococci

Human alveolar macrophage cytophilic immunoglobulin G-mediated phagocytosis of protein A-positive staphylococci.

“…Interestingly, injury to human platelets by S. aureus has recently been shown also to involve interactions of cell wall protein A, IgG, and platelet Fc receptors (46).…”

Platelet-Bacterial Interactions as Therapeutic Targets in Infective Endocarditis

“…aureus predominantly uses multiple cell wall surface proteins to interact with platelets to trigger their activation. Early studies by Hawiger et al demonstrated that S. aureus cell wall protein A acts as a receptor for specific anti-staphylococcal antibodies which in turn bind FcγRIIa on platelets (Hawiger et al, 1979). This interaction triggers an intracellular signal that leads to granule release and platelet aggregation.…”

Modulation of human platelet protein kinase C by endotoxic lipid A.

“…Platelet-rich plasma (PRP) was loaded with [14C]serotonin (0.05 MCi/ml) and then platelets radiolabeled with serotonin were separated from free amine and from plasma proteins as described previously (26). Secretion of ['4C]serotonin was measured at 370C with stirring for the specified times in the presence of imipramine (1.5 Mg/ml).…”

“…The reaction was stopped by chilling the platelets on ice and adding 0.3% p-formaldehyde in 2 mM EDTA before centrifugation in a microcentrifuge for 15,000 g for 2 min (27). Secretion was calculated as previously described (26).…”