Streptococcus pneumoniae capsular polysaccharide antigens (15 serotypes) (PCV15 antigens)

Streptococcus pneumoniae capsular polysaccharide antigens are complex carbohydrates that form the outermost layer of the pneumococcus bacterium, serving as its primary virulence factor by preventing opsonization and phagocytosis by host immune cells (CDC, 2023). The 15 serotypes included in this target set (1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, 22F, 23F, and 33F) are specifically selected due to their high prevalence in causing invasive pneumococcal disease (IPD), such as meningitis and bacteremia, as well as community-acquired pneumonia (FDA, 2022). In pharmaceutical applications, these polysaccharides are utilized as the active components in conjugate vaccines like Vaxneuvance (PCV15) (Merck, 2022). By conjugating these polysaccharides to a carrier protein like CRM197, the vaccine induces a T-cell dependent immune response, which is crucial for generating long-term immunological memory and high-affinity antibodies (StatPearls, 2023). This mechanism allows the host's immune system to effectively identify and neutralize the bacteria, providing protection against the specific serotypes covered (PubMed, 2021). The use of these antigens has significantly decreased the incidence of pneumococcal infections and associated mortality worldwide (WHO, 2021).

Other names

Pneumococcal capsular polysaccharidesS. pneumoniae CPS15-valent pneumococcal conjugate vaccine antigensPCV15 polysaccharides

Active immunization through the induction of serotype-specific opsonophagocytic antibodies and memory B-cell responses via a T-cell dependent mechanism facilitated by conjugation to a carrier protein (FDA, 2022; StatPearls, 2023).