Adhesive activities of a strain of Porphyromonas gingivalis (previously classified as Bacteroides gingivalis) isolated from human with periodontitis, and 2 strains of Porphyromonas asaccharolyticus (previously classified as Bacteroides asaccharolyticus) from dogs with gingival inflammation to human and dog buccal epithelial cells and erythrocytes from various animal species, were compared in relation to their pathogenicities. The dog-derived P. asaccharolyticus strongly adhered to dog epithelial cells but not to human cells. The human-derived P. gingivalis, in contrast, strongly adhered to human cells but not to the dog cells. P. gingivalis strongly agglutinated all species of erythrocytes examined including human blood group erythrocytes A, B and O. On the other hand, P. asacchrolyticus and other Bacteroides were found to agglutinate rabbit and/or rat erythrocytes but not other species of erythrocytes examined. Lipopolysaccharide (LPS) from human-derived P. gingivalis weakly agglutinated rat erythrocytes. Hemagglutinating activity was not found in fimbrial material from the human derived P. gingivalis. Sonicated extract and LPS from dog-derived P. asaccharolyticus agglutinated only the rat erythrocytes. The results indicate that adherence activity of Porphyromonas was stronger to the epithelial cells of the original host animal specie for individual organism than that to the cells from other species. In contrast, there was no specific correlation between each organism and the original host animal specie in their hemagglutinating activity. It is suggested that the adherence activity of Porphyromonas to the epithelial cells determined the bacterial specie which could grow and colonize on oral surfaces in specific animals.
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