N-acetyl-D-galactosamine inhibits TNF-alpha gene expression induced in mouse peritoneal macrophages by fimbriae of Porphyromonas (Bacteroides) gingivalis, an oral anaerobe.

Adherence to host cells is an essential step in the initiation of most infectious diseases. It is well known that bacterial fimbriae may be involved in the adherence. Porphyromonas (Bacteroides) gingivalis is a pathogenic organism of adult periodontitis which is a chronic inflammatory disease. Using an experimental system for fimbria-induced TNF-alpha gene expression in mouse peritoneal macrophages, we examined the role of sugar moieties in the adhesion of P. gingivalis fimbriae to these cells. The fimbriae strongly induced TNF-alpha gene expression in the macrophages, and marked TNF activity toward fibroblasts was observed in culture supernatants of the fimbria-treated cells. The potent expression of TNF-alpha was inhibited by N-acetyl-D-galactosamine, but not inhibited by D-mannose, alpha-lactose, and alpha-L-rhamnose, D-galactose, and N-acetyl-D-glucosamine.