Streptococcus pneumoniae capsular polysaccharide serotype 8 (Spn8 CPS)

Streptococcus pneumoniae capsular polysaccharide serotype 8 is a complex carbohydrate polymer that serves as the outermost layer and a primary virulence factor for the serotype 8 pneumococcus bacterium. This polysaccharide is composed of a linear tetrasaccharide repeating unit containing D-galactose, D-glucose, and D-glucuronic acid, which provides a protective shield against the host's immune system by inhibiting opsonization by C3b (Geno et al., 2015; Jones, 2005). Clinically, serotype 8 is highly significant as it is frequently associated with invasive pneumococcal disease (IPD), particularly bacteremic pneumonia, and has shown a high propensity for causing outbreaks in adult populations (Ladhani et al., 2018). In the context of pharmaceutical intervention, this polysaccharide is used as a purified antigen in the 23-valent pneumococcal polysaccharide vaccine (PPSV23) and as a protein-conjugated antigen in the 20-valent pneumococcal conjugate vaccine (PCV20) (FDA, 2021; CDC, 2023). Administration of these vaccines triggers a specific immune response, leading to the production of opsonizing antibodies that facilitate the recognition and destruction of the pathogen by neutrophils and macrophages.

Other names

Serotype 8 pneumococcal polysaccharidePn8 polysaccharidePneumococcus type 8 capsular polysaccharideCPS8Pn8

Induces active immunity by stimulating the production of serotype-specific opsonizing antibodies (IgG) that target the bacterial capsule for phagocytosis and clearance.