A. Sfakianakis et al., Actinobacillus actinomycetemcomitans-induced expression of IL-1 alpha and IL-1 beta in human gingival epithelial cells: role in IL-8 expression, EUR J OR SC, 109(6), 2001, pp. 393-401
Gingival epithelial cells (GEC) are the first cells of the host that encoun
ter the periodontal pathogens, and therefore their role in the initiation o
f the inflammatory response is critical. We aimed to: 1) characterize the e
xpression of interleukin (IL)-1 alpha and IL-1 beta in human gingiva and cu
ltured GEC; 2)demonstrate the ability of A. actinomycetemcomitans extracts
to upregulate IL-1 alpha, IL-1 beta and IL-8 expression in GEC in vitro; an
d 3) characterize the role of IL-1 alpha and IL-1 beta in the induction of
IL-8 expression in GEC in vitro. Ten gingival biopsies (5 inflamed and 5 co
ntrols) and cultured GEC were examined for IL-1 alpha and IL-1 beta using i
mmunohistochemical techniques. GEC were also challenged with A. actinomycet
emcomitans extracts or IL-1. and secretion of IL-1 and IL-8 was determined
by ELISA. In vivo, IL-1 alpha and IL-1 beta were localized in the gingival
epithelium and the infiltrating leukocytes. In vitro, A. actinomycetemcomit
ans extracts induced a time-dependent expression of IL-1 alpha, IL-1 beta a
nd IL-8 in GEC. IL-1 inhibitors did not affect A. actinomycetemcomitans-ind
uced IL-8, although they inhibited IL-8 induced by IL-1 alpha or IL-1 beta.
In conclusion, GEC are a major source of IL-1 alpha and IL-1 beta in the p
eriodontium, which in turn induce additional inflammatory mediators such as
IL-8. Therefore GEC can be a potential target for therapeutic intervention
in the future.