Construction of designer glycoconjugate vaccines with size-specific oligosaccharide antigens and site-controlled coupling.

Coupling of carbohydrate antigens to protein carriers is a typical approach to enhancing the immunogenicity of carbohydrate-based vaccines. Glycoconjugates with well-defined structures are needed for studies defining the structural variables that govern antibody responses. We report a chemical strategy for preparation of an array of glycoconjugates containing saccharides of desired molecular sizes by selective depolymerization of bacterial polysaccharides and chemically controlled site-specific coupling. As an example, we synthesized and evaluated an oligosaccharide-based vaccine against type III group B Streptococcus.