Streptococcus pneumoniae serotype 14 capsular polysaccharide

The Streptococcus pneumoniae serotype 14 capsular polysaccharide is a high-molecular-weight carbohydrate polymer that forms the outermost layer ("capsule") surrounding the bacterium S. pneumoniae type 14 cells. This capsule is composed of repeating units with a defined structure—specifically, →3)-β-D-Gal p-(1→4)-β-D-Glu p-(1→6)-[β-D-Gal p-(1→4)] -β-D-Glu pNAc-(1→—and its integrity can be confirmed by NMR spectroscopy. The capsule serves as a major virulence factor by protecting bacteria from phagocytosis and complement-mediated killing, thereby enabling colonization and infection in humans. The type-specific nature of this capsular structure makes it an effective target for vaccines; antibodies generated against this molecule confer protection against invasive pneumococcal disease caused by serotype 14 strains. As such, purified or conjugated forms of this polysaccharide are included in licensed pneumococcal vaccines to induce immunity through T cell-dependent or independent mechanisms depending on formulation [conjugate vs plain]. The presence and amount of anti-serotype 14 CPS antibodies serve as biomarkers for assessing vaccine efficacy. There are no major safety concerns unique to this molecule beyond general considerations associated with bacterial carbohydrate antigens used in vaccines. In summary, the Streptococcus pneumoniae serotype 14 capsular polysaccharide is a well-characterized bacterial surface antigen essential for virulence and targeted effectively by current pneumococcal vaccines.

Other names

S. pneumoniae serotype 14 CPSPneumococcal serotype 14 capsular polysaccharideSerotype 14 capsule (S. pneumoniae)

Induces production of specific anti-capsular antibodies that promote opsonization and clearance of S. pneumoniae by the immune system