Capsular polysaccharide of Streptococcus pneumoniae serotype 14 (Pn14PS)

The capsular polysaccharide of Streptococcus pneumoniae serotype 14 is a complex, branched carbohydrate polymer that forms the outermost layer of the bacterium. It serves as a critical virulence factor by shielding the pathogen from host immune recognition and inhibiting opsonophagocytosis by neutrophils and macrophages (NIH, PMC6423111). Serotype 14 is historically one of the most prevalent strains causing invasive pneumococcal disease (IPD) globally, including life-threatening conditions such as pneumonia, meningitis, and bacteremia (ResearchGate, 350144444). Because of its high clinical relevance, this polysaccharide is a key component in both unconjugated (PPSV23) and protein-conjugated (PCV13, PCV15, PCV20) pneumococcal vaccines (Medscape, 343153). Vaccination induces the production of serotype-specific antibodies that bind to the capsule, facilitating bacterial clearance through the complement system and phagocytic cells. The use of conjugate vaccines has significantly reduced the incidence of serotype 14 infections, although monitoring for serotype replacement remains essential in public health (StatPearls, NBK554593).

Other names

Pneumococcal polysaccharide serotype 14S. pneumoniae type 14 capsular polysaccharidePn14 polysaccharideStreptococcus pneumoniae type 14 CPS

The capsular polysaccharide acts as an antigen that induces active immunity. In conjugate vaccines, it is covalently linked to a carrier protein (such as CRM197) to stimulate a T-cell dependent immune response, leading to the production of high-affinity IgG antibodies and B-cell memory (NIH, PMC4941368). These antibodies bind to the bacterial capsule, promoting opsonization and subsequent phagocytosis and killing by host immune cells such as neutrophils (StatPearls, NBK554593).