The effect of SerpinPC and anti-PC/APC antibodies in a sublethal LPS model. Serum IL-6 (A) and BUN levels (B) 13 hours after WT mice were given a sublethal dose of LPS and either vehicle (PBS), 10 mg/kg SerpinPC, or 10 mg/kg control antibodies MAPC1591 or MPC1609. MPC1609 conferred lethality in this model and increased serum IL-6 and BUN levels relative to PBS-treated mice. MAPC1591 did not cause lethality but did significantly increase both markers relative to the vehicle control (IL-6, P = .0431; BUN, P = .0309). In contrast, SerpinPC reduced IL-6 relative to vehicle (P = .0309), and had no effect on serum BUN levels relative to PBS controls. Controls from mice treated with PBS and saline, instead of LPS, are included.