Development in the Concept of Bacterial Polysaccharide Repeating Unit-Based Antibacterial Conjugate Vaccines

Abstract

The surface of cells is coated with a dense layer of glycans, known as the cell glycocalyx. The complex glycans in the glycocalyx are involved in various biological events, such as bacterial pathogenesis, protection of bacteria from environmental stresses, etc. Polysaccharides on the bacterial cell surface are highly conserved and accessible molecules, and thus they are excellent immunological targets. Consequently, bacterial polysaccharides and their repeating units have been extensively studied as antigens for the development of antibacterial vaccines. This Review surveys the recent developments in the synthetic and immunological investigations of bacterial polysaccharide repeating unit-based conjugate vaccines against several human pathogenic bacteria. The major challenges associated with the development of functional carbohydrate-based antibacterial conjugate vaccines are also considered.

A Fluorinated Sialic Acid Vaccine Lead Against Meningitis B and C

“…Carbohydrates are known to produce a short-lived and comparatively weak immune response, as they elicit a T-cell-independent response. , Therefore, to enable T-cell-dependent B-cell activation and impart long-term immunity, glycans are frequently conjugated to a carrier protein. , Consequently, fluorinated disialoside 2 (DisAF) was covalently conjugated to CRM197, a commonly used and FDA-approved protein in glycoconjugate vaccines, and Porin A, a specific protein from N. meningitidis serogroup B .…”

Synthesis and immunogenicity evaluation of oligosaccharide epitopes for the development of a glycoconjugate vaccine against Streptococcus pneumoniae serotype 3

“…13 Recently, the fully synthesized and structurally well-defined oligosaccharide fragments of bacterial polysaccharides have demonstrated considerable potential as candidate antigens for the development of oligosaccharide-based antibacterial conjugate vaccines. [14][15][16][17][18][19] Therefore, several groups have focused on the synthesis of ST3 CPS oligosaccharide fragments and the discovery of immunogenic epitopes to develop ST3 oligosaccharide-based glycoconjugate vaccines. [20][21][22][23][24][25] Vliegenthart's group prepared a series of neoglycoproteins using the synthesized ST3 CPS oligosaccharides with chain lengths varying from di-to tetra-saccharide.…”

Effect of Side-Chain Functional Groups in the Immunogenicity of Bacterial Surface Glycans

“…Carbohydrates are the crucial constituent on the surface of many bacterial species, mainly present as capsular polysaccharides (CPSs), glycoproteins, and glycolipids (like lipopolysaccharide, LPS) [1]. These molecules have unique characteristics attributed to specific bacteria and different bacterial serotypes (STs) [2].…”