Induction of interleukin-1β in human monocytes by lipopolysaccharides from periodontal pathogens

differential effect of a synthetic lipid A precursor IVa (LA-14-PP)

Abstract

Lipopolysaccharides (LPS) from periodontal pathogens, Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Actinobacillus actinomycetemcomitans (Aa) were tested for their ability to induce the production of interleukin-1β (IL-1β) in human monocytes. Pg-LPS induced IL-1β production in a serum dependent manner. IL-1β production induced by 1.0-10 ng/ml of each LPS was the following order, E. coli-LPS>Aa-LPS>Pg-LPS>Pi-LPS. The IL-1β production by each LPS was abolished by the preincubation of LPS with polymyxin B and was blocked by anti-CD14 antibody, indicating that human monocytes utilized CD14 to recognize every LPS. IL-1β production by the cells stimulated with E. coli- or Aa-LPS (0.1-10 ng/ml) was blocked by the preincubation of the cells with LA-14-PP (100 ng/ml) but IL-1β response induced by Pg- or Pi-LPS was not.
These results suggest that to respond to Pg- or Pi-LPS, monocytes utilize a class of signaling molecule (transducer) that is not blocked by LA-14-PP.