C-reactive protein: a predominant LPS-binding acute phase protein responsive to Pseudomonas infection.
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.
Ng
Patricia M L
PM
Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore.
Jin
Zhenxiao
Z
Tan
Sandra S H
SS
Ho
Bow
B
Ding
Jeak L
JL
D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D002097:C-Reactive Protein / Q000096:biosynthesis* / Q000276:immunology*; D018076:DNA, Complementary / Q000032:analysis; D006458:Hemolymph; D006737:Horseshoe Crabs / Q000276:immunology*; D008070:Lipopolysaccharides / Q000276:immunology* / Q000633:toxicity*; D008969:Molecular Sequence Data; D011552:Pseudomonas Infections / Q000276:immunology*; D011550:Pseudomonas aeruginosa / Q000472:pathogenicity*; D012323:RNA Processing, Post-Transcriptional; D015854:Up-Regulation
D018076:DNA, Complementary; D008070:Lipopolysaccharides; D002097:C-Reactive Protein