Surface-bound C9 on platelet-leukocyte complexes induced by Stx2, Stx1, Stx1B, Ol57LPS, and/or O111LPS. Incubation of whole blood with Stx2, Stx1, Stx1B, or O157LPS induced C9 deposition on platelet-monocyte (A) and platelet-neutrophil (B) complexes and to a lesser extent on unbound monocytes (C) and unbound neutrophils (D). Data are expressed as box-plots depicting the median and range regarding the percentage of the platelet-monocyte or platelet-neutrophil population or the percentage of unbound monocytes or neutrophils that were positive for C9 (n = 12 experiments). C9 deposition on complexes or unbound monocytes or neutrophils in whole blood incubated with an agonist was compared with that in PBS-treated whole blood. *P < .05; **P < .01; ***P < .001. NS indicates not significant.