Post challenge inhibition of C3 and CD14 attenuates Escherichia coli-induced inflammation in human whole blood

Combined inhibition of CD14 and complement, two main inducers of the inflammatory response, have proved particularly effective in attenuating Gram-negative bacteria-induced inflammation. Approaching possible clinical relevance, we investigated the effect of such inhibition in a post-challenge setting. Human whole blood was anti-coagulated with lepirudin. Anti-CD14, compstatin (C3 inhibitor) and the combination thereof were added 5 min prior to or 5, 15 or 30 min after adding Escherichia coli. Total incubation time with Escherichia coli was 120 min. Cytokines, myeloperoxidase (MPO) and the terminal complement complex (TCC) were measured using multiplex technology and ELISA. Delayed combined inhibition significantly attenuated the inflammatory response. IL-1β, IL-8 and TNF-α were significantly inhibited in the range of 20–40%, even when adding the inhibitors with up to 30 min delay. IL-6 was significantly inhibited with 15 min delay, and MIP-1α and MPO with 5 min delay. Complement activation (TCC) was block...