MBL-dependent C4 cleavage activity of mouse serum samples (NMRI; n = 5) at different time points after CLP and from untreated control mice was compared to an internal standard with the arbitrary activity of 1 U/ml. (A) Statistically significant reduced C4 activation in sera was determined at 10, 24, and 36 h after CLP. *, P < 0.05; **, P < 0.005. (B) MBL-dependent C4 cleavage activity 5 (n = 4), 7 (n = 4), 10 (n = 3), and 14 (n = 3) days after CLP. **, P < 0.005.