Effect of inhibition of thrombin, fibrin(ogen), or platelet function upon endotoxin mortality. Effects of thrombin inhibition (A) or lack of fibrinogen (B) or platelets (C) on endotoxin mortality. Wild-type C57BL/6 female mice treated with hirudin (5 mg/kg intraperitoneally), antiplatelet serum, and/or FTY720 (0.1 mg/kg intraperitoneally) and Fib^–/– or Nf-E2^–/– (both 50% C57BL/6, 50% 129SVJ) mice and appropriate vehicle- or nonimmune serum-injected or littermate controls were injected intraperitoneally with high- or low-dose LPS and monitored for 26 or 72 hours as indicated. P values as determined by log-rank test are shown when less than .05. For littermate studies, P value refers to comparison between knockouts and wild types.