Streptococcus pneumoniae capsular polysaccharide antigens (13 serotypes) (PnPS (13 serotypes))

Streptococcus pneumoniae capsular polysaccharide antigens are complex carbohydrate structures that encapsulate the bacterium, serving as its primary virulence factor by preventing opsonization and phagocytosis by host immune cells (StatPearls, NBK470537). These polysaccharides are highly diverse, with over 100 serotypes identified based on their unique chemical compositions (CDC, Pneumococcal Disease). The 13-valent pneumococcal conjugate vaccine (PCV13) specifically targets the polysaccharides from serotypes 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F, which were selected due to their high prevalence in invasive disease (FDA, Prevnar 13 Label). In the context of drug development, these antigens are conjugated to a carrier protein, such as CRM197, to elicit a T-cell dependent immune response, which is necessary for establishing long-term memory and efficacy in young children (PubMed, 25888950). Upon administration, the host produces serotype-specific antibodies that facilitate the clearance of the bacteria through opsonophagocytosis. This target is central to preventing life-threatening conditions such as pneumonia, meningitis, and febrile bacteremia (WHO, Pneumococcal vaccines). Monitoring the efficacy of targeting these antigens involves measuring serotype-specific IgG levels and opsonophagocytic activity (OPA) (PubMed, 23537322).

Other names

Pneumococcal capsular polysaccharidesPCV13 antigens13-valent pneumococcal conjugate vaccine antigensStreptococcus pneumoniae serotypes 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F

Active immunization through the induction of serotype-specific opsonophagocytic antibodies; conjugation to a carrier protein (CRM197) enables a T-cell dependent immune response (WHO, 2019; FDA, 2010).