Impaired thrombus formation in C3- and C5-deficient mice. C3^−/− mice have less thrombus weight (A) and length (B) compared with C3^+/+ controls 48 hours after IVC stenosis (n = 9-11; mean ± standard deviation [SD]; Mann-Whitney U test). *P < .05; **P < .01. C5^−/− mice have less thrombus weight (C) and length (D) compared with C5^+/+ controls 48 hours after IVC stenosis (n = 11-12; mean ± SD; Mann-Whitney U test). Adherent (E) and rolling (F) leukocytes, and adherent (G) and transient (H) platelets following IVC low restriction were compared between C3^−/− mice and WT controls by intravital imaging over 6 hours (n = 6; mean ± SD); 2-way ANOVA for multiple groups with time scale observations followed by Bonferroni posttest; *P < .05, **P < .01, ***P < .001. h, hour; n.s., not significant. Red circles represent WT; blue squares represent knock-out.