Bacillus anthracis Interacts with Plasmin(ogen) to Evade C3b-Dependent Innate Immunity
Figure 3
Spore-bound PLG is activated by uPA.
(A) Plasmin activity of bound PLG after uPA activation. Spores (5×107) were incubated with PLG and washed, and 20 units of uPA and plasmin substrate VLK-pNA were added. After incubation for 15 min at room temperature, the absorbance was measured at 405 nm. (B) Effect of lysine analogues on spore-bound PLG/plasmin activity. Spores (5×107) were incubated with PLG (2 µg) in the presence of 50 mM amino acids, and assayed as described in panel A. (C) Binding affinity of PLG and plasmin to spores. PLG and plasmin were incubated with spores (2.4×107) and the amount of bound proteins was assayed by the colorimetric method described in panel B. The amount of plasmin was determined using a standard activity curve.