The Macrophage activation and cytotoxicity of cell components of Gram-negative Bacteroides gingivalis and Gram-positive Actinomyces viscosus, which are considered to be closely connected with the etiology of periodontal diseases, were examined. Veillonella parvula, Streptococcus mutans, and Lactobacillus casei were also evaluated in addition to the above two species. The bacteria were cultured by routine procedures, and the whole bacteria were collected, sonicated, and centrifuged, and the

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... natant was fractioned by gel-filtration using Sephadex G-200. Each of these cell components was added to the macrophage and bone-powder culture system, and the glucose consumption and osteolytic activity of macrophages, and the lactate dehydrogenase (LDH) level increase in the culture supernatant were determined daily. Bacteroides gingivalis increased, but Actinomyces viscosus reduced, the glucose consumption of the macrophage and bone-powder system. Similar changes were observed also in the osteolytic action. The LDH level in the culture supernatant was markedly increased by the addition of cell components of Veillonella parvula, suggesting cytotoxicity of the bacteria. Among the gelfiltration fractions of the supernatant of sonicated Bacteroides gingivalis, those near the protein peak increased the glucose consumption. Most of the gel-filtration fractions of Veillonella parvula increased the LDH level.