LPS from Actinobacillus actinomycetemcomitans and the expression of beta 2integrins and L-selectin in an ex vivo human whole blood system

Actinobacillus actinomycetemcomitans is assumed to be an important etiologi cal agent in localized juvenile periodontitis (LJP) and to have the ability to invade periodontal tissues. This bacterium has also been noted for its potential to cause serious extraoral infections. In this study, the effect of lipopolysaccharides (LPS) extracted from A. actinomycetemcomitans on the expression of the leukocyte adhesion molecules CD11a/CD18, CD11b/CD18, CD1 1c/CD18 and L-selectin (CD 62L) were measured in an ex vivo whole blood sys tem by use of fluorescent antibodies followed by flow cytometry. LPS from E scherichia coil, which is known to elicit a strong inflammatory response wa s used as a reference. The expression of the gz integrins CD11a/CD18, CD11b /CD18, and CD11c/CD18 were significantly upregulated in granulocytes and mo nocytes. This expression was dose-dependent. The baseline levels of L-selec tin was high on all three types of leukocytes, but on granulocytes and mono cytes it decreased dramatically after stimulation with LPS. The LPS from A. actinomycetemcomitans was equally potent as LPS from E. coli in its abilit y to affect the expression of the leukocyte integrins and L-selectin.