A Pneumococcal Protein That Elicits interleukin-8 From Pulmonary Epithelial Cells

J Infect Dis. 2000 Apr;181(4):1330-6. doi: 10.1086/315388. Epub 2000 Apr 13.


To understand how neutrophils are recruited to the lung in pneumococcal pneumonia, the ability of pneumococcal components to elicit the chemokine interleukin (IL)-8 from monolayers of cultured human type II cells was assessed. Heat-killed clinical and laboratory strains of Streptococcus pneumoniae and secreted proteins from exponentially growing pneumococci elicited significant quantities of IL-8 from A549 cells. All strains that elicited IL-8 production secreted a protein ( approximately 90 kDa) that comigrated on SDS-PAGE with a C3-binding protein previously identified in S. pneumoniae. As little as 7 pmol of the purified 90-kDa protein readily elicited levels of IL-8 production equivalent to those obtained with 1 U of IL-1alpha. Supernatant proteins and heat-killed cells of an isogenic mutant that failed to produce the C3-binding protein elicited significantly less IL-8 than did supernatant proteins or heat-killed cells of the parent strain. These results implicate the C3-binding protein of S. pneumoniae in a novel pathway of pulmonary inflammation.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Bacterial Proteins / pharmacology*
  • Carrier Proteins / metabolism*
  • Cells, Cultured
  • Electrophoresis, Polyacrylamide Gel
  • Epithelial Cells / metabolism
  • Humans
  • Interleukin-8 / biosynthesis*
  • Lung / metabolism*
  • Molecular Weight
  • Pneumonia, Pneumococcal / metabolism*
  • Streptococcus pneumoniae / metabolism


  • Bacterial Proteins
  • Carrier Proteins
  • Interleukin-8