Streptococcus pneumoniae serotype 15B capsular polysaccharide (CPS15B)

Streptococcus pneumoniae serotype 15B capsular polysaccharide is a complex carbohydrate polymer that constitutes the outermost protective layer of the S. pneumoniae bacterium. It serves as a primary virulence factor by inhibiting host phagocytosis and complement-mediated killing, thereby facilitating the survival and spread of the pathogen within the host. Chemically, the 15B polysaccharide is characterized by a repeating pentasaccharide unit containing glucose, galactose, rhamnose, and N-acetylglucosamine, with specific O-acetylation and glycerol-2-phosphate substituents. This molecule is a critical target in the development of pneumococcal vaccines, where it is used as an antigen to stimulate the production of serotype-specific opsonizing antibodies. It is included in several multivalent vaccines, such as the 20-valent pneumococcal conjugate vaccine (Prevnar 20) and the 21-valent vaccine (Capvaxive), to prevent invasive diseases like pneumonia, meningitis, and bacteremia. The inclusion of this serotype in modern vaccines addresses its increasing prevalence as a cause of disease following the implementation of earlier, less-inclusive vaccine formulations.

Other names

Pneumococcal polysaccharide serotype 15BS. pneumoniae type 15B capsular polysaccharideCPS15BPnPs15BStreptococcus pneumoniae serogroup 15 polysaccharide

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