Proinflammatory activity of a cecropin-like antibacterial peptide from Helicobacter pylori.

Helicobacter pylori, the bacterial pathogen associated with gastritis and peptic ulcers, is highly successful in establishing infection in the human gastric mucosa, a process typically associated with massive infiltration of inflammatory cells. Colonization of the mucosa is suggested to be facilitated by H. pylori-produced cecropin-like peptides with antibacterial properties, giving the microbe a competitive advantage over other bacteria. We show that a cecropin-like antibacterial peptide from H. pylori, Hp(2-20), not only has a potent bactericidal effect but also induces proinflammatory activities in human neutrophils, e.g., upregulation of integrins (Mac-1), induction of chemotaxis, and activation of the oxygen radical producing NADPH-oxidase. Furthermore, we show that these effects are mediated through binding of Hp(2-20) to the promiscuous, G-protein-linked lipoxin A(4) receptor-formyl peptide-like receptor 1.