Chlamydial lipopolysaccharide

Chlamydiae are obligatory intracellular parasites which are responsible for various acute and chronic diseases in animals and humans. The outer membra ne of the chlamydial cell wall, contains a truncated lipopolysaccharide (LP S) antigen, which harbors a group-specific epitope being composed of a tris accharide of 3-deoxy-D-manno-oct-2-ulosonic (Kdo) residues of the sequence alpha-Kdo-(2-->8)-alpha-Kdo-(2-->4)-alpha-Kdo. The chemical structure was e stablished using LPS of recombinant Escherichia coli and Salmonella enteric a strains after transformation with a plasmid carrying the gene encoding th e multifunctional chlamydial Kdo transferase. Oligosaccharides containing t he Kdo region attached to the glucosamine backbone of the lipid A domain ha ve been isolated or prepared by chemical synthesis, converted into neoglyco proteins and their antigenic properties with respect to the definition of c ross-reactive and chlamydia-specific epitopes have been determined. The low endotoxic activity of chlamydial LPS is related to the unique structural f eatures of the lipid A, which is highly hydrophobic due to the presence of unusual, long-chain fatty acids. (C) 1999 Elsevier Science B.V. All rights reserved.