Structure, serological specificity, and synthesis of artificial glycoconjugates representing the genus-specific lipopolysaccharide epitope of Chlamydia spp.

The human bacterial pathogens Chlamydia spp. possess a genus-specific lipopolysaccharide as a major surface antigen, the structure of which has been determined by analytical chemistry as Kdop alpha 2-8-Kdop alpha 2-4-Kdop alpha 2-6GlcNp beta 1-6-GlcNol (Kdo, 3-deoxy-D-manno-2-octulosonic acid). Immunochemical studies on this pentasaccharide and the chemically synthesized partial structures Kdop alpha 2-8-Kdop alpha 2-4-Kdop alpha 2-6GlcNp beta, Kdop alpha 2-8-Kdop alpha 2-4-Kdop alpha, Kdop alpha 2-4-Kdop alpha, Kdop alpha 2-8-Kdop alpha, and Kdop alpha using artificial glycoconjugate antigens and monoclonal antibodies showed that fatty acids and phosphoryl groups (as present in native lipopolysaccharide) are dispensable for constitution of the genus-specific epitope and that the minimal structure to exhibit chlamydia specificity is the Kdo trisaccharide moiety.