Pneumococcal capsular polysaccharide serotype 23F (CPS23F)

Pneumococcal capsular polysaccharide serotype 23F is a complex carbohydrate polymer that forms the outermost protective layer of Streptococcus pneumoniae serotype 23F (Richards & Perry, 1988). This capsule is a critical virulence factor that enables the bacterium to evade the host immune system by inhibiting opsonophagocytosis (García et al., 2000; Weinberger et al., 2009). Serotype 23F is historically one of the most prevalent serotypes causing invasive pneumococcal diseases, such as pneumonia, meningitis, and bacteremia, and is frequently associated with multi-drug resistance (Jedrzejas, 2001). As a therapeutic target, this polysaccharide is utilized as an antigen in both pneumococcal polysaccharide vaccines (PPSV) and pneumococcal conjugate vaccines (PCV) (Paton & Trappetti, 2019). These vaccines work by inducing the production of serotype-specific antibodies that bind to the capsule, thereby facilitating the recognition and destruction of the bacteria by host phagocytes (MIMS, 2025). While highly effective, the use of vaccines targeting this serotype has led to the phenomenon of serotype replacement, where non-vaccine serotypes increase in clinical prevalence (Weinberger et al., 2009).

Other names

Streptococcus pneumoniae serotype 23F capsular polysaccharidePn23F polysaccharideType 23F pneumococcal polysaccharide

Induction of serotype-specific opsonophagocytic antibodies that facilitate bacterial clearance by the host immune system (MIMS, 2025; Drugs.com, 2025).