Capsular polysaccharides of 23 Streptococcus pneumoniae serotypes (CPS)

The capsular polysaccharide is a complex carbohydrate structure forming the outermost layer of Streptococcus pneumoniae cells, composed of repeating oligosaccharide units unique to each serotype. These capsules are the primary virulence factors, enabling immune evasion by preventing phagocytosis and defining serotype diversity. Over 100 serotypes exist, but the 23 covered by PPV23 vaccines are responsible for the vast majority of severe pneumococcal infections worldwide. The diversity of capsular polysaccharides presents challenges for vaccine design and epidemiological control, as immune protection is strictly serotype-specific. These capsular polysaccharides do not act as classical receptors or enzymes, but as antigenic targets for immune recognition and vaccine development, making them essential in infectious disease prevention and public health.

Other names

Pneumococcal capsular polysaccharideS. pneumoniae capsule antigenCPSCapsule antigen

Induction of specific anti-capsular antibodies, promoting opsonophagocytosis and clearance