20-valent pneumococcal capsular polysaccharide antigens (PCV20 antigens)

The 20-valent pneumococcal capsular polysaccharide antigens are a collection of purified polysaccharides derived from twenty specific serotypes of Streptococcus pneumoniae (FDA, 2021). These serotypes include 1, 3, 4, 5, 6A, 6B, 7F, 8, 9V, 10A, 11A, 12F, 14, 15B, 18C, 19A, 19F, 22F, 23F, and 33F (Pfizer, 2023). In the bacteria, these polysaccharides form a capsule that serves as a major virulence factor by protecting the pathogen from host phagocytosis (CDC, 2023). When used in vaccines, these antigens are conjugated to a carrier protein like CRM197 to enhance their immunogenicity, particularly by inducing a T-cell dependent immune response (Essink et al., 2021). This process leads to the production of serotype-specific opsonophagocytic antibodies that facilitate the destruction of the bacteria by immune cells. The primary therapeutic goal of targeting these antigens is to provide broad protection against invasive pneumococcal disease, pneumonia, and otitis media. These 20 serotypes were selected based on their prevalence in causing severe disease and their contribution to antibiotic resistance globally (CDC, 2023). Clinical efficacy is typically monitored through opsonophagocytic activity (OPA) assays and IgG antibody levels.

Other names

Streptococcus pneumoniae capsular polysaccharides (20 serotypes)PCV20 serotypesPneumococcal capsular polysaccharides20-valent pneumococcal conjugate vaccine antigens

Induction of active immunity through the production of opsonophagocytic antibodies against specific Streptococcus pneumoniae serotypes (FDA, 2021).