Fighting infection: the role of lipopolysaccharide binding proteins CD14 and LBP.
An invading pathogen must be held in check by the innate immune system until a specific immune response is mounted. Nonclonal pattern recognition receptors like CD14 or lipopolysaccharide (LPS) binding protein (LBP) recognize ubiquitous pathogen-associated molecular patterns, e.g. LPS. LBP mediates the binding of minute amounts of LPS to membrane-bound CD14 (mCD14) triggering a proinflammatory response of macrophages, which is crucial for keeping an infection under control. Moreover, in vitro mCD14 and LBP are involved in recognition and phagocytosis of heat-killed bacteria. Living Salmonella typhimurium or Escherichia coli depend on the presence of LBP to induce the generation of reactive oxygen species in human or murine macrophages. Using LBP-deficient mice it could be demonstrated that LBP is essential to control low dose (100 CFU S. typhimurium) infection. Therefore, LPS binding proteins play a pivotal role in physiology as well as pathophysiology of Gram-negative infection.
Schütt
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Institute of Immunology and Transfusion Medicine, University of Greifswald, Germany.
D000209:Acute-Phase Proteins; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology*; D004195:Disease Models, Animal; D006801:Humans; D018950:Lipopolysaccharide Receptors / Q000502:physiology*; D008562:Membrane Glycoproteins; D051379:Mice; D018345:Mice, Knockout; D010587:Phagocytosis / Q000502:physiology*; D012481:Salmonella Infections, Animal / Q000503:physiopathology; D012486:Salmonella typhimurium / Q000472:pathogenicity; D000099231:Lipopolysaccharide-Binding Protein
D000209:Acute-Phase Proteins; D002352:Carrier Proteins; D018950:Lipopolysaccharide Receptors; D008562:Membrane Glycoproteins; D000099231:Lipopolysaccharide-Binding Protein