Plasminogen (Pg) binds <i>L. interrogans</i> enolase and activates plasmin.

<p><u>The error bars indicate the standard deviations from three independent experiments performed in triplicate</u>. * <i><u>P</u></i><u> < 0.05</u>. (A) <u>Pg binds to <i>L. interrogans</i> in a concentration-dependent manner. Microtiter plates were coated with fixed cells and incubated with various concentrations of human plasminogen (hPg)</u>. (B) <u><i>L. interrogans</i> converts Pg into plasmin in the presence of tissue plasminogen (tPA). Well-bound <i>L. interrogans</i> cells were incubated with hPg (1µg) and a chromogenic substrate (D-valyl-L-lysyl-<i>p</i>-nitroaniline hydrochloride) in the presence or absence of tPA and a known Pg inhibitor, a lysine analogue, ε-ACA</u>. (C) <u>A Pg inhibitor</u> blocks <i>L. interrogans</i>-hPg interaction. Microtiter plates were coated with fixed <i>L. interrogans</i> and increasing concentrations (0 to 100 mM) of ε-ACA were incubated with a fixed amount (1µg) of hPg. (D) Fibrinolytic activity of Pg-bound <i>L. interrogans</i>. Panels represent <i>L. interrogans</i> cells in the presence or absence of hPg and tPA. Arrow denotes fibrinolytic activity of spirochetes only in the presence of both hPg and tPA.