Immunobiological activities of a chemically synthesized lipid A of Porphyromonas gingivalis

A synthetic lipid A of Porphyromonas gingivalis strain 381 (compound PG-381 ), which is similar to its natural lipid A, demonstrated no or very low end otoxic activities as compared to Escherichia coli-type synthetic lipid A (c ompound 506). On the other hand, compound PG-381 had stronger hemagglutinat ing activities on rabbit erythrocytes than compound 506. Compound PG-381 al so induced mitogenic responses in spleen cells from lipopolysaccharide (LPS )-hyporesponsive C3H/HeJ mice, as well as LPS-responsive C3H/HeN mice. The addition of polymyxin B resulted in the inhibition of mitogenic activities, however, compound 506 did not show these capacities, Additionally, compoun d PG-381 showed a lower level of activity in inducing cytokine production i n peritoneal macrophages and gingival fibroblasts from C3H/MeN mice, but no t C3H/HeJ mice, in comparison to compound 506. Thus, this study demonstrate s that the chemical synthesis of lipid A, mimicking the natural lipid A por tion of LPS from P. gingivalis, confirms its low endotoxic potency and immu nobiological activity. (C) 2000 Federation of European Microbiological Soci eties. Published by Elsevier Science B.V. All rights reserved.