A peptide, ALTTE, within the fimbrial subunit protein from Porphyromonas gingivalis, induces production of interleukin 6, gene expression and protein phosphorylation in human peripheral blood mononuclear cells.

Porphyromonas gingivalis 381 fimbriae and a synthetic peptide composed of residues 69-73 (ALTTE) of the fimbrial subunit protein, FP381(69-73), function in the induction of interleukin 6 (IL-6) production, IL-6 mRNA expression, and tyrosine and serine/threonine phosphorylation of several proteins in human peripheral blood mononuclear cells (PBMC). Herbimycin A and H-7, inhibitors of tyrosine kinases and protein kinase C (PKC), markedly inhibited IL-6 production, gene expression, and tyrosine and serine/threonine phosphorylation of proteins. An inactive analog of synthetic peptide replaced alanine to glycine at position 69 in FP381(69-73), GLTTE, exhibited an antagonistic effect on the IL-6 production induced by the fimbriae. These results suggest that the peptide ALTTE functions as an agent in inflammatory reactions and immune responses in the inflamed gingival and periodontal tissues, in which the participation of protein phosphorylation by tyrosine kinases and PKC in signal transduction may be considered.