Survival advantage of mice treated with 14E11 in peritoneal sepsis. Mice treated with the anti-FXI antibody 14E11 have a survival advantage after large bowel perforation. Kaplan-Meier survival curves showing survival of 2- to 4-month-old age-matched male C57Bl/6 mice treated with 14E11 (4 mg/kg), APC (6 mg/kg), or vehicle (PBS) at (A) 0 hours, (B) 6 hours, and (C) 12 hours after cecal ligation and puncture (n = 10-30 animals per time point). Vehicle data are combined (n = 50), as there was no significant difference in survival when administering vehicle at different time points (P = .93). Combined data from all experiments are shown in panel D, with total number of mice shown in parentheses. Combined survival curves were compared by log-rank test and showed a significant survival advantage for 14E11-treated mice (**P < .01) and a significant increase in death after APC treatment.