Lipid A-associated proteins from periodontopathogenic bacteria induce interleukin-6 production by human gingival fibroblasts and monocytes

FEMS Immunol Med Microbiol. 1995 Apr;11(2):137-44. doi: 10.1111/j.1574-695X.1995.tb00100.x.


The aim of this study was to determine whether lipid A-associated proteins (LAP) from two periodontopathogenic species of bacteria were able to stimulate interleukin-6 (IL-6) release from human gingival fibroblasts and myelomonocytic cells. LAP and lipopolysaccharide (LPS) were extracted from Porphyromonas gingivalis and Prevotella intermedia and added to cultures of human gingival fibroblasts and mono-mac-6 monocytic cells. Release of IL-6 into the culture supernatants was determined by ELISA. LAP and LPS from Por. gingivalis, but not from Prev. intermedia, stimulated IL-6 release from both cell types in a dose-dependent manner although LPS was less potent than LAP in inducing IL-6 release from the fibroblasts. IL-6 was detectable in cultures of both cell types following stimulation with LAP from Por. gingivalis at a concentration as low as 10 ng/ml. In response to LAP from Prev. intermedia, IL-6 was produced by mono-mac-6 cells but not by fibroblasts. Our results show that bacterial cell wall components other than LPS can induce IL-6 release from cells of the periodontium in vitro. The production of such potent immunomodulatory agents in vivo may contribute to the connective tissue breakdown characteristic of chronic periodontitis.

Publication types

  • Comparative Study

MeSH terms

  • Bacterial Proteins / chemistry
  • Bacterial Proteins / isolation & purification
  • Bacterial Proteins / pharmacology*
  • Cells, Cultured
  • Dose-Response Relationship, Immunologic
  • Electrophoresis, Polyacrylamide Gel
  • Endotoxins / chemistry
  • Endotoxins / isolation & purification
  • Endotoxins / pharmacology*
  • Fibroblasts / immunology
  • Gingiva / cytology
  • Gingiva / immunology*
  • Humans
  • Interleukin-6 / biosynthesis*
  • Lipid A / chemistry
  • Lipid A / isolation & purification
  • Lipid A / pharmacology*
  • Lipopolysaccharides / isolation & purification
  • Lipopolysaccharides / pharmacology
  • Monocytes / immunology
  • Porphyromonas gingivalis / immunology*
  • Prevotella intermedia / immunology*


  • Bacterial Proteins
  • Endotoxins
  • Interleukin-6
  • Lipid A
  • Lipopolysaccharides
  • lipid A-associated protein, Bacteria