H. Wang et al., A ROLE FOR FIBRINOGEN IN THE STREPTOKINASE-DEPENDENT ACQUISITION OF PLASMIN(OGEN) BY GROUP-A STREPTOCOCCI, The Journal of infectious diseases, 171(1), 1995, pp. 85-92
Acquisition of plasmin(ogen) by group A streptococci occurs by two dis
tinct pathways. In addition to the well-characterized direct interacti
on of plasmin with cell-surface receptors on group A streptococci, a s
econd pathway dependent on streptokinase and a nonplasminogen factor(s
) present in human plasma was identified. The role of streptokinase in
the second pathway was not merely as a plasminogen activator, since s
ubstitution of the plasminogen activator urokinase did not result in t
he capture of plasmin(ogen) by bacteria in the presence of plasminogen
-depleted plasma. However, if streptokinase was added to plasmin that
had been generated by treatment of plasminogen with urokinase, the abi
lity of the bacteria to capture plasmin in the presence of plasminogen
-depleted plasma was restored. Fibrinogen present in human plasma was
identified as the major factor required for streptokinase-dependent up
take of plasmin(ogen) by group A streptococci.