Neutralization of endotoxin in vitro and in vivo by a human lactoferrin-derived peptide

Infect Immun. 1999 Mar;67(3):1353-8. doi: 10.1128/IAI.67.3.1353-1358.1999.

Abstract

Endotoxin (lipopolysaccharide [LPS]) is the major pathogenic factor of gram-negative septic shock, and endotoxin-induced death is associated with the host overproduction of tumor necrosis factor alpha (TNF-alpha). In the search for new antiendotoxin molecules, we studied the endotoxin-neutralizing capacity of a human lactoferrin-derived 33-mer synthetic peptide (GRRRRSVQWCAVSQPEATKCFQWQRNMRKVRGP; designated LF-33) representing the minimal sequence for lactoferrin binding to glycosaminoglycans. LF-33 inhibited the coagulation of the Limulus amebocyte lysate and the secretion of TNF-alpha by RAW 264.7 cells induced by lipid A and four different endotoxins with a potency comparable to that of polymyxin B. The first six residues at the N terminus of LF-33 were critical for its antiendotoxin activity. The endotoxin-neutralizing capacity of LF-33 and polymyxin B was attenuated by human serum. Coinjection of Escherichia coli LPS (125 ng) with LF-33 (2.5 microg) dramatically reduced the lethality of LPS in the galactosamine-sensitized mouse model. Significant protection of the mice against the lethal LPS challenge was also observed when LF-33 (100 microg) was given intravenously after intraperitoneal injection of LPS. Protection was correlated with a reduction in TNF-alpha levels in the mouse serum. These results demonstrate the endotoxin-neutralizing capability of LF-33 in vitro and in vivo and its potential use for the treatment of endotoxin-induced septic shock.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cell Line
  • Female
  • Galactosamine / toxicity
  • Lactoferrin / pharmacology*
  • Lactoferrin / therapeutic use
  • Limulus Test
  • Lipopolysaccharides / antagonists & inhibitors*
  • Mice
  • Molecular Sequence Data
  • Peptide Fragments / pharmacology*
  • Peptide Fragments / therapeutic use
  • Shock, Septic / drug therapy
  • Tumor Necrosis Factor-alpha / metabolism

Substances

  • Lipopolysaccharides
  • Peptide Fragments
  • Tumor Necrosis Factor-alpha
  • Galactosamine
  • Lactoferrin