CHLAMYDIAL LIPOPOLYSACCHARIDE - CHEMICAL AND ANTIGENIC STRUCTURE, BIOSYNTHESIS AND BIOMEDICAL APPLICATION

The obligate intracellular gram-negative bacterium Chlamydia contains as a major surface antigen a lipopolysaccharide (LPS) which harbours i n its saccharide moiety a genus-specific epitope composed of a linear trisaccharide of 3-deoxy-D-manno-octulopyranosonic acid (Kdo) of the s equence alpha Kdo-(2->8)-cuKdo-(2->4)-alpha Kdo. The structure was est ablished on LPS of recombinant E. coli bacteria transformed with a pla smid carrying the gene for the chlamydial Kdo transferase which is a m ultifunctional glycosyl transferase. The structure was determined on d eacylated and dephosphorylated LPS as well as on deacylated LPS by qua litative, quantitative and methylation analyses, fast-atom-bombardment mass spectrometry, and H-1-,C-13, and P-31-NMR spectroscopy, and conf irmed by chemcial synthesis. Artificial glycoconjugate antigens were s ynthesized and used for the preparation of murine monoclonal antibodie s which had higher affinities than those prepared against the natural counterpart. These artificial antigens were also used as solid-phase a ntigens in an enzyme-immune assay which was proven to be useful in the diagnosis of human chlamydial infections.