Capsular polysaccharide of Streptococcus pneumoniae serotype 33F (CPS 33F)

The capsular polysaccharide of Streptococcus pneumoniae serotype 33F is a complex carbohydrate polymer that encapsulates the bacterial cell wall. It functions as the primary virulence factor for the pathogen by providing a physical barrier that inhibits host-mediated opsonization and subsequent phagocytosis by immune cells (Source: PubMed, PMID: 26101254). Serotype 33F is clinically significant as it is frequently associated with invasive pneumococcal disease, including bacteremia and meningitis, particularly in the era following the introduction of earlier conjugate vaccines that did not cover this serotype (Source: CDC, Pneumococcal Disease Surveillance). In the context of pharmacology, this polysaccharide serves as a key antigenic component in multi-valent pneumococcal conjugate vaccines (PCVs), such as PCV20 and PCV21 (Source: FDA, Prevnar 20 and Capvaxive Package Inserts). These vaccines utilize the purified polysaccharide conjugated to a carrier protein to stimulate a T-cell dependent immune response, leading to the production of high-affinity antibodies and immunological memory. By targeting this specific polysaccharide, vaccines provide protection against severe infections and reduce the carriage of the 33F serotype in the population.

Other names

Pneumococcal polysaccharide serotype 33FS. pneumoniae serotype 33F capsular polysaccharide33F CPSStreptococcus pneumoniae serogroup 33F polysaccharide

Induction of active immunity through the production of serotype-specific opsonizing antibodies that facilitate phagocytosis and killing of the bacteria.