RELATIVE CYTOKINE-STIMULATING ACTIVITIES OF SURFACE COMPONENTS OF THEORAL PERIODONTOPATHOGENIC BACTERIUM ACTINOBACILLUS-ACTINOMYCETEMCOMITANS

The purpose of this study was to determine whether bacterial surface c omponents other than lipopolysaccharide (LPS) could stimulate pro-infl ammatory cytokine synthesis by mesenchymal and myelomonocytic cells in vitro. LPS, lipid A-associated proteins (LAP) and saline-extractable surface-associated material (SAM) were isolated from the periodontopat hogenic bacterium Actinobacillus actinomycetemcomitans and added to cu ltures of human gingival fibroblasts (HGFs), human PBMCs and the human myelomonocytic Mono-Mac-6 cell line, Pro-inflammatory cytokine releas e into culture supernatants was determined by two-site ELISAs. Contrar y to expectation, the highly purified LPS extracted from this bacteriu m was significantly less potent than the other surface extracts in sti mulating release of IL-1 beta, IL-6 and TNF-alpha by all three cell ty pes, The SAM was the most potent cytokine-stimulating agent showing eq uivalent activity to highly purified E. coli LPS in stimulating IL-6 r elease by PBMCs, LAP also had cytokine-stimulating activity although i t was generally significantly less potent than the SAM, Thus in the ca se of this organism, which is involved in the pathology of chronic inf lammatory diseases the LPS does not appear to be the major cytokine-st imulating component. (C) 1995 Academic Press Limited.