Survival of PAR-deficient mice after endotoxin challenge: single knockouts. (A) Par1^–/– (top panels), Par2^–/– (middle panels), and Par4^–/– (bottom panels) mice and strain- (about 97.5% C57BL/6, about 2.5% 129SVJae), age-, and sex-matched controls were injected intraperitoneally with LPS and monitored for 26 (high-dose LPS) or 72 (low-dose LPS) hours. (B) Comparisons that showed trends toward differences in panel A were repeated in littermate-controlled studies. These were in the same strain background as in panel A, except for PAR2, which was 50% C57BL/6, 50% 129SVJae. (C) Pooled low-dose data from panels A-B. The top panel compares wild-type responses. In all panels, high-dose LPS was 60 mg/kg for both sexes; low dose was 30 mg/kg for females and 20 mg/kg for males. These dosing conventions were maintained for all subsequent studies. P values as determined by log-rank test are shown when < .05.