Streptococcus pneumoniae Polysaccharide (Multiple Serotypes) (PnPs)

The *Streptococcus pneumoniae* polysaccharide refers to the capsular polysaccharides that form the outermost layer of the bacterium. This capsule is a polymeric, surface-exposed carbohydrate structure that encapsulates each bacterial cell. The capsule is the major virulence factor, protecting bacteria from host immune responses. There are 98 recognized capsular polysaccharide serotypes. These serotypes are targets for pneumococcal vaccines, including polysaccharide-only and conjugate vaccines. Protection conferred by these vaccines is serotype-specific. Widespread vaccine use has led to serotype replacement.

Other names

Pneumococcal PolysaccharideS. pneumoniae Capsular PolysaccharideCapsular PolysaccharideStreptococcus pneumoniae polysaccharide serotypes

Vaccines stimulate the production of serotype-specific antibodies that promote opsonophagocytosis and complement-mediated killing of Streptococcus pneumoniae. Antibodies bind to the capsular polysaccharide, facilitating phagocytosis and destruction of the bacteria by immune cells.