Streptococcus pneumoniae capsular polysaccharide serotype 14 (CPS14)

The Streptococcus pneumoniae capsular polysaccharide serotype 14 is a surface-localized polysaccharide that forms a thick capsule essential for bacterial virulence in Gram-positive pathogen S. pneumoniae, which causes pneumonia, sepsis, and other infections primarily in children and the elderly. Its repeating unit structure is →3)-β-D-Galp-(1→4)-β-D-Glcp-(1→6)-[β-D-Galp-(1→4)]-β-D-GlcpNAc-(1→, synthesized via the Wzy-dependent pathway involving glycosyltransferases, flippase Wzx, and polymerase Wzy, with covalent attachment to peptidoglycan via a direct 1,6 glycosidic bond at the reducing-end glucose to GlcNAc.[1][2][3][4] This capsule shields the bacterium from host phagocytosis by inhibiting opsonization, complement activation, immunoglobulin binding, and neutrophil extracellular traps, while aiding nasopharyngeal colonization, epithelial adhesion, and biofilm formation.[2][4][6] As a major vaccine antigen, serotype 14 CPS is included in conjugate vaccines like PCV13, PCV20, and PPSV23, which elicit protective opsonophagocytic antibodies but demand serotype-specific formulations due to structural diversity across 98 S. pneumoniae serotypes.[2][4][6] Targeting this CPS disrupts bacterial survival in host environments, positioning it as a key therapeutic focus for preventing invasive pneumococcal disease.[2][4]

Other names

Serotype 14 capsular polysaccharidePneumococcal capsular polysaccharide type 14

Induction of opsonophagocytic antibodies, Serotype-specific immunization