Chemical characterization and biologic properties of lipopolysaccharide from Bacteroides gingivalis strains W50, W83, and ATCC 33277.

Abstract

The chemistry and selected biological activity of lipopolysaccharide (LPS) from Bacteroides gingivalis strains W50, W83, and ATCC 33277 were compared, as well as the role of this molecule as a mediator of selected inflammatory responses. Chemically, the LPSs consisted of 47-58% Lipid A, 5-10% carbohydrate, 0.05% 3-deoxy 2-octulosonic acid, 0.3% heptose, 3.8-5.2% hexosamine, and 2% phosphate. Rhamnose represented the dominant sugar (26-36%), with lesser amounts of glucose (18-34%), galactose (18-25%), mannose (9-12%), glucosamine (7-11%), and galactosamine (2-5%). The major fatty acids were: 13-methyl-tetradecanoate (42-45%), 3-OH-heptadecanoate (21-23%), hexadecanoate (16-19%), and 12-methyl-tetradecanoate (6-8%). SDS-PAGE and sodium deoxycholate-PAGE revealed the LPS to be a smooth chemotype. Differences in migration patterns between the virulent and avirulent strain LPSs also occurred. C3H/HeN macrophages (Mø) exposed to 1 microgram/ml of LPS released 3.2-4.2 ng of prostaglandin E (PGE)/ml of supernatant, representing 236-278% of control. Interleukin-1 (IL-1) activity in C3H/HeN and C3H/HeJ Mø exposed to 50 micrograms of LPS/ml was 382-724% and 270-300% of control, respectively; similar Mø exposed to 10 micrograms of LPS/ml released 1.6-2.0 ng and 0.3-0.5 ng of tumor necrosis factor (TNF)/ml of supernatant, respectively. Maximum TNF release in C3H/HeN Mø occurred in response to 50 micrograms of LPS/ml, and was sustained for up to 96 hours. These results suggest that LPS from the B. gingivalis strains stimulate cytokine production from Mø which, in turn, may play a role in orchestrating the inflammatory response for the development of periodontal diseases.