Antibacterial Carbohydrate Vaccines

Carbohydrates represent the most structurally diverse class of biopolymers and are crucially involved in a plethora of biochemical and biological processes essential for every form of life. In particular, bacterial surface polysaccharides ( PSs ) can trigger bacterial adhesion and host cells infection; hence, they are key virulence factors. The seminal finding that carbohydrate-specific antibodies are predominantly responsible for protection against bacteria is the basis for carbohydrate-based vaccines development. Among them, glycoconjugate vaccines, based on pathogen-related poly- or oligosaccharides chemically conjugated to an immunogenic protein carrier, are a formidable weapon to protect public health. Despite their great success, currently, licensed glycoconjugate vaccines suffer from several drawbacks, which still pose strong limitations to their wider use in massive vaccination campaigns. There is, therefore, an urgent call for the development of improved vaccine constructs with well-defined compositions and based on more cost-effective production processes. The design of innovative carbohydrate vaccines takes advantage of diverse cutting-edge technologies developed over the last decade, and it is steered by the recent advances of modern immunology. In this chapter, the mechanism of action and the characteristics of each major component of carbohydrate-based vaccines are illustrated. In addition, we report an account of the most innovative technologies currently investigated to improve existing vaccines as well as to design novel constructs able to timely combat emerging infectious diseases and/or address unmet medical needs.