Protective efficacy of CAP18106-138-immunoglobulin G in sepsis.

Naturally present antibacterial proteins play an important role in innate host defense. A synthetic peptide mimicking the C-terminal lipopolysaccharide (LPS)-binding domain of rabbit cathelicidin CAP18 was coupled to immunoglobulin (Ig) G to create CAP18(106-138)-IgG, a construct that, in concentrations equimolar to those of peptide alone, binds and neutralizes LPS and kills multiple gram-negative bacterial strains. The protective efficacy of CAP18(106-138)-IgG was evaluated in a model of cecal ligation and puncture in mice.

Bacterial peptidoglycan-associated lipoprotein is released into the bloodstream in gram-negative sepsis and causes inflammation and death in mice.

Gram-negative bacterial sepsis commonly causes organ dysfunction and death in humans. Although circulating bacterial toxins trigger inflammation in sepsis, little is known about the composition of bacterial products released into the blood during sepsis or the contribution of various bacterial components to the pathogenesis of sepsis. We have shown that diverse Gram-negative bacteria release bacterial peptidoglycan-associated lipoprotein (PAL) into serum.