COMPLEMENT-DEPENDENT PLATELET INJURY BY STAPHYLOCOCCAL PROTEIN A

Complement-dependent Platelet Injury by Staphylococcal Protein A

A new example of complement-mediated platelet injury has been described. Staphylococcal protein A (SPA) causes rabbit platelet injury as manifested by release of platelet 5-hydroxytryptamine (5HT). This reaction is complement-dependent and occurs over a very small range of SPA concentration, larger amounts being inhibitory. Complement fixation by SPA demonstrates the same narrow SPA concentrati...

Complement - Dependent Platelet Injury

Blood platelets are involved in a number of immune reactions and, by release of vasoactive amines and thromboplastic factor(s), may contribute to vascular injury and deposition of fibrin (1, 2). Platelet injury can be induced by bacterial endotoxins (3, 4) and immune complexes (5-7), both of which require complement, and by membrane-active bacterial toxins such as streptolysins O and S and stap...

A molecular insight into complement evasion by the staphylococcal complement inhibitor protein family.

Staphylococcus aureus possesses an impressive arsenal of complement evasion proteins that help the bacterium escape attack of the immune system. The staphylococcal complement inhibitor (SCIN) protein exhibits a particularly high potency and was previously shown to block complement by acting at the level of the C3 convertases. However, many details about the exact binding and inhibitory mechanis...

Inhibitor Protein Family Evasion by the Staphylococcal Complement A Molecular Insight into Complement

Crystallization of human complement component C3b in the presence of a staphylococcal complement-inhibitor protein (SCIN).

Staphylococcus aureus secretes a number of small proteins that effectively attenuate the human innate immune response. Among these, the staphylococcal complement-inhibitor protein (SCIN) disrupts the function of the complement component 3 (C3) convertase that is initiated through either the classical or the alternative pathway and thereby prevents amplification of the complement response on the...