Bacterial polysaccharides as major surface antigens: interest in O-acetyl substitutions
Polysaccharides represent essential, although highly structurally diverse, components on microbial cell surfaces. They are the primary interface with the host and play critical roles in survival strategies. Acting as shields against environmental assaults, they are actively investigated as attractive vaccine components. Contributing to a tremendous structural diversity, a subtle but nonetheless essential microbial polysaccharide modification is O-acetylation. Focusing on bacterial capsular polysaccharides (CPS), this chapter provides some highlights on this widespread substitution. CPS O-acetylation is discussed first from a genetic and biochemical perspective, then in view of its implication in the host-pathogen crosstalk and ability to modulate CPS biological properties in a context-dependent manner. Lastly, the chapter addresses CPS O-acetylation in the context of antibacterial vaccine development.