A novel endotoxin antagonist attenuates tumor necrosis factor-alpha secretion.
Twenty-seven amino acid peptides with sequences corresponding to a proposed endotoxin binding region of bactericidal permeability increasing protein (BPI):1) inhibit lipopolysaccharide induced macrophage tumor necrosis factor-alpha (TNF-alpha) secretion, 2) have bactericidal activity against gram-negative bacteria, and 3) protect mice from a lethal lipopolysaccharide (LPS) challenge. Unfortunately, peptides have a short halflife in vivo. Therefore, we have chemically conjugated the BPI based peptide, BG38, to a larger carrier protein, keyhole limpet hemocyanin (KLH), and characterized its ability: 1) to inhibit LPS induced macrophage TNF-alpha secretion and 2) to decrease plasma endotoxin and TNF-alpha levels following an i.v. injection of E. coli 0111:B4 LPS. BG38-KLH inhibited cultured macrophage TNF-alpha secretion in response to LPS derived from four pathogenic strains of gram-negative bacteria in a dose dependent manner (>90% inhibition at 50 microgram/ml, P < 0.05 Student's t test). BG38-KLH also decreased serum endotoxin (>90%, P < 0.05 Student's t test) and peak TNF-alpha levels (>30% inhibition, P < 0.05 Student's t test) following E. coli LPS challenge in a murine gram-negative bacterial sepsis model. Novel endotoxin antagonists based upon a small domain of BPI represent promising reagents for the treatment of serious gram-negative bacterial infections.
Dahlberg
P S
PS
Department of Surgery, University of Minnesota, Minneapolis 55455, USA.
Acton
R D
RD
Battafarano
R J
RJ
Uknis
M E
ME
Ratz
C A
CA
Johnston
J W
JW
Haseman
J R
JR
Gray
B H
BH
Dunn
D L
DL
D000818:Animals; D023181:Antimicrobial Cationic Peptides; D001770:Blood Bactericidal Activity; D001798:Blood Proteins / Q000737:chemistry / Q000494:pharmacology*; D002460:Cell Line; D004731:Endotoxins / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004926:Escherichia coli; D006090:Gram-Negative Bacteria; D006801:Humans; D007711:Klebsiella pneumoniae; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects / Q000502:physiology*; D008565:Membrane Proteins; D051379:Mice; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa; D012706:Serratia marcescens; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*
D023181:Antimicrobial Cationic Peptides; D001798:Blood Proteins; D004731:Endotoxins; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D010446:Peptide Fragments; D014409:Tumor Necrosis Factor-alpha; C021623:bactericidal permeability increasing protein