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Media type:
E-Article
Title:
A Cyanobacterial Lipopolysaccharide Antagonist Inhibits Cytokine Production Induced byNeisseria meningitidisin a Human Whole-Blood Model of Septicemia
Description:
<jats:title>ABSTRACT</jats:title><jats:p>Septicemia caused by<jats:italic>Neisseria meningitidis</jats:italic>is characterized by increasing levels of meningococcal lipopolysaccharide (Nm-LPS) and cytokine production in the blood. We have used an in vitro human whole-blood model of meningococcal septicemia to investigate the potential of CyP, a selective Toll-like receptor 4 (TLR4)-MD-2 antagonist derived from the cyanobacterium<jats:italic>Oscillatoria planktothrix</jats:italic>FP1, for reducing LPS-mediated cytokine production. CyP (≥1 μg/ml) inhibited the secretion of the proinflammatory cytokines tumor necrosis factor alpha, interleukin-1β (IL-1β), and IL-6 (by >90%) and chemokines IL-8 and monocyte chemoattractant protein 1 (by ∼50%) induced by the treatment of blood with pure Nm-LPS, by isolated outer membranes, and after infection with live meningococci of different serogroups. In vitro studies with human dendritic cells and TLR4-transfected Jurkat cells demonstrated that CyP competitively inhibited Nm-LPS interactions with TLR4 and subsequent NF-κB activation. These data demonstrate that CyP is a potent antagonist of meningococcal LPS and could be considered a new adjunctive therapy for treating septicemia.</jats:p>