C-reactive protein: a predominant LPS-binding acute phase protein responsive to Pseudomonas infection

J Endotoxin Res. 2004;10(3):163-74. doi: 10.1179/096805104225004833.


As a structural component of the outer membrane of Gram-negative bacteria, endotoxin, also known as lipopolysaccharide (LPS) exhibits strong immunostimulatory properties, rendering it a pivotal role in the pathogenesis of Gram-negative septicaemia. Our attempt to identify LPS-binding proteins from the hemolymph of the horseshoe crab led to the isolation and identification of Creactive protein (CRP) as the predominant LPS-recognition protein during Pseudomonas infection. CRP is an evolutionarily ancient member of a superfamily of 'pentraxins'. It is a major protein in acute phase of infection in humans. Our investigation of CRP response to Pseudomonas aeruginosa unveiled a robust innate immune system in the horseshoe crab, which displays rapid suppression of a dosage of 10(6) CFU of bacteria in the first hour of infection and effected complete clearance of the pathogen by 3 days. Such a high dose would have been lethal to mice. Full-length CRP cDNA was cloned. Analysis of the untranslated regions suggests their crucial role in post-transcriptional regulation of CRP transcript levels. Northern blot analysis demonstrated an acute up-regulation of CRP by about 60-fold in 6-48 h of Pseudomonas infection. Taken together, our results provide new insights into the importance of CRP as a conserved molecule for pathogen recognition.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Blotting, Northern
  • C-Reactive Protein / biosynthesis*
  • C-Reactive Protein / immunology*
  • DNA, Complementary / analysis
  • Hemolymph
  • Horseshoe Crabs / immunology*
  • Lipopolysaccharides / immunology*
  • Lipopolysaccharides / toxicity*
  • Molecular Sequence Data
  • Pseudomonas Infections / immunology*
  • Pseudomonas aeruginosa / pathogenicity*
  • RNA Processing, Post-Transcriptional
  • Up-Regulation


  • DNA, Complementary
  • Lipopolysaccharides
  • C-Reactive Protein