Has been described for a number of bacterial species (for a review, see reference 7). In the case of S. pyogenes, the secreted streptococcal cysteine protease SpeB was found to cleave HK directly (8). In addition, the surface-bound M protein, one of the classical virulence determinants of GAS, has been demonstrated to bind HK, followed by bradykinin generation (9, 10). Binding and assembly of cont
Streptococcal plasminogen activator, triggers the activation of the human contact system. Activation of contact system factors at the surface of the Streptococcus pyogenes serotype M49 is dependent on streptokinase and plasminogen. Our results also show that secreted streptokinase is an efficient contact system activator, independent from a contact surface. This results in the processing of high-m
System comprises four plasma proteins, circulating as zymogens in the bloodstream or being assembled on various cell types: the serine proteases factor XII (FXII), factor XI (FXI), and prekallikrein (PKK) and the nonenzymatic cofactor high-molecularweight kininogen (HK). The latter forms equimolar complexes with plasma kallikrein (PK) or FXI. The cascade is initiated upon contact to a negatively c
N activator streptokinase might contribute to contact system activation by S. pyogenes. Here, we report that the human contact system is activated by the action of streptokinase. The role of secreted and surfacebound streptokinase in this process was investigated by comparing an M49 S. pyogenes wild-type strain with its isogenic ska mutant, which is unable to trigger plasmin activity in human plas
E bradykinin. The nonapeptide has a very short half-life (a matter of seconds) and exhibits its functions via the B1 and B2 receptors (3). Generating other mediators such as nitric oxide, prostaglandins, and leukotrienes, bradykinin is involved in the regulation of blood pressure, the induction of fever and pain, vascular leakage, and the chemotaxis of immune cells (4). In addition, further proces
E bradykinin. The nonapeptide has a very short half-life (a matter of seconds) and exhibits its functions via the B1 and B2 receptors (3). Generating other mediators such as nitric oxide, prostaglandins, and leukotrienes, bradykinin is involved in the regulation of blood pressure, the induction of fever and pain, vascular leakage, and the chemotaxis of immune cells (4). In addition, further proces
Secrete streptokinase in order to accelerate the conversion of human plasminogen to plasmin (12). Lacking enzymatic activity itself, streptokinase evolves its function by forming a stoichiometric 1:1 complex with plasminogen or a trimolecular complex with plasminogen and fibrinogen. The activator complexes can bind at the bacterial surface via host factor receptors and convert other plasminogen mo
Secrete streptokinase in order to accelerate the conversion of human plasminogen to plasmin (12). Lacking enzymatic activity itself, streptokinase evolves its function by forming a stoichiometric 1:1 complex with plasminogen or a trimolecular complex with plasminogen and fibrinogen. The activator complexes can bind at the bacterial surface via host factor receptors and convert other plasminogen mo