Abstract
Members of the bacterial genus Chlamydia are responsible for widespread disease among humans and animals, including endemic trachoma in developing countries, venereal disease in developed countries, and a variety of other diseases such as infantile pneumonia and lymphogranuloma venereum. Although there is little genetic relatedness between and large antigenic diversity between and among the two chlamydial species, one antigenic determinant has been preserved among all serovars: the genus-specific lipopolysaccharide epitope. In this report, the tools of molecular genetics, monoclonal antibodies, and analytical and synthetic chemistry have been combined to determine the structure of this epitope. This epitope is attributed to the presence of a trisaccharide of 3-deoxy-D-manno-octulosonic acid (KDO) of the sequence KDOp-(2----8)-KDOp-(2----4)-KDO. The structure includes a unique linkage of two KDO residues through a 2.8-linkage.