Cutting edge: repurification of lipopolysaccharide eliminates signaling through both human and murine toll-like receptor 2.
Toll-like receptor (TLR) 2 has recently been associated with cellular responses to numerous microbial products, including LPS and bacterial lipoproteins. However, many preparations of LPS contain low concentrations of highly bioactive contaminants described previously as "endotoxin protein," suggesting that these contaminants could be responsible for the TLR2-mediated signaling observed upon LPS stimulation. To test this hypothesis, commercial preparations of LPS were subjected to a modified phenol re-extraction protocol to eliminate endotoxin protein. While it did not influence the ability to stimulate cells from wild-type mice, repurification eliminated the ability of LPS to activate cells from C3H/HeJ (Lpsd) mice. Additionally, only cell lines transfected with human TLR4, but not human or murine TLR2, acquired responsiveness to both re-extracted LPS and to a protein-free, synthetic preparation of lipid A. These results suggest that neither human nor murine TLR2 plays a role in LPS signaling in the absence of contaminating endotoxin protein.
Hirschfeld
M
M
Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84132, USA.
Ma
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Weis
J H
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Vogel
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Weis
J J
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D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D029721:Drosophila Proteins; D004340:Drug Contamination; D005786:Gene Expression Regulation / Q000187:drug effects / Q000276:immunology; D005822:Genetic Vectors / Q000235:genetics / Q000276:immunology; D006801:Humans; D008050:Lipid A / Q000302:isolation & purification / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000302:isolation & purification* / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D051379:Mice; D008809:Mice, Inbred C3H; D019800:Phenol; D011956:Receptors, Cell Surface / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology*; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D014162:Transfection; D014407:Tumor Cells, Cultured
D029721:Drosophila Proteins; D008050:Lipid A; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; C495342:TLR2 protein, human; C495345:TLR4 protein, human; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D019800:Phenol