C5 is required for leukocyte PS exposure in the flow-restricted IVC. Adhesion (A) and rolling (B) of leukocytes were investigated in C5^−/− mice and WT controls under IVC stenosis condition over 6 hours (n = 5-6; 3-4 visual fields per mouse; mean ± SD). Scale bar: 100 μm. Consecutive measurements were evaluated by 2-way ANOVA followed by Bonferroni posttests. (C) Quantification of adherent Gr-1⁺ cells 3 hours after IVC ligation. (D) PS exposure was measured in C5^−/− mice and WT controls 3 hours after flow restriction of the IVC. Fluorescence labeled Gr-1⁺ to stain myeloid cells (green) and Annexin V (AV) to identify PS⁺ cells (red) were injected prior to imaging. (E) Quantification of AV staining in C5^−/− mice and WT controls. Two to 3 visual fields per mouse were analyzed with fixed threshold, and relative fluorescence of WT is shown as mean ± SD and analyzed by Mann-Whitney U test. *P < .05. (F) Citrated whole blood was stimulated with LPS for 4 hours in the presence and absence of anti-C5 antibody, and TF cell-surface expression was measured on CD14⁺ monocytes. Data were expressed as mean ± SD; n = 3. Data were analyzed by 1-way ANOVA followed by Bonferroni posttests. ***P < .001. (G-H) Citrated whole blood was stimulated with LPS in the presence of 100 μM rutin (G), anti-C5, C7, or C9 antibody (H) for 4 hours, and the PCA was measured in cell-free plasma. Anti-TF was added to the clotting assay to demonstrate induction of TF activity in plasma from LPS-stimulated blood. Data were expressed as mean ± SD; n = 3 to 6. Data were analyzed by 1-way ANOVA followed by Bonferroni posttests. **P < .01; ***P < .001. MFI, mean fluorescence intensity; n.s., not significant; PBS, phosphate-buffered saline.