Stx induces cellular activation and injury to endothelium resulting in the expression of MBL2 ligand and recognized by MBL2. MBL2 binds, activates the lectin complement pathway and results in C3d deposition. MBL2 complex, which has thrombin-like activity, cleaves fibrinogen to fibrin, leading to cross-linked fibrin formation. Stx, Shiga toxin; MBL, mannose binding lectin 2; MASPs, MBL/ficolin-associated serine proteases.