Characterization and immunobiologic activities of lipopolysaccharides from periodontal bacteria.

lacterial surface structures play a critical role in the initiation of infectious diseases. Various surface ^ components of pathogenic bacteria have been reported to be involved in host injury. There is a great deal of evidence incriminating certain Gram-negative, anaerobic bacteria present in the gingival crevice as etiologic agents of human periodontal diseases. We have isolated endotoxic cellular components from suspected periodontopathic bacteria and examined their immunobiological activities. Lipopolysaccharides (LPS) and lipidassociated proteoglycans (LPG) were prepared from whole cells by the phenol-water and butanol-water procedures, respectively. LPS from Bacteroides gingivalis, B. intermedius, B. oralis, and B. loescheii, Fusobacterium nudeatum and F. necrophorum, and Actinobacillus (Haemophilus) actinomycetemcomitans were found to possess biological activities comparable with those of LPS from E. coli K235 in terms of activation of Limulus lysate, Bcell mitogenicity, polyclonal B-cell activation, induction of bone resorption, and IL-1 production by macrophages. These LPS contained mainly sugars, amino sugars, and fatty acids. No heptose or 2-keto-3-deoxyoctonate (KDO) was detected in the Bacteroides LPS, while LPS from Actinobacillus and Fusobacterium species contained significant amounts of heptose as well as small quantities of KDO. Bacteroides LPS were clearly mitogenic for spleen cells of C3H/HeJ mice, which are non-responsive to LPS from E. coli, A. actinomycetemcomitans, and Fusobacterium species. Furthermore, polymyxin B was found to abrogate the mitogenic activity of LPS from E. coli, Actinobacillus, and Fusobacterium species, but not those from Bacteroides species. Spleen cells from both C3H/HeN and C3H/HeJ mice responded to all butanol-water-extracted LPG preparations, including those from E. coli, A. actinomycetemcomitans, and Fusobacterium species. It may be concluded that LPS and LPG isolated from suspected periodontopathic bacteria possess marked immunobiological potencies on lymphoreticular and bone cells.