Capsular polysaccharide of Streptococcus pneumoniae serotype 6A (Pn6A CPS)

The capsular polysaccharide of Streptococcus pneumoniae serotype 6A is a complex carbohydrate polymer that forms the outermost layer of the bacterium, serving as its primary virulence factor. It functions by shielding the pathogen from the host's innate immune system, specifically by preventing opsonization and subsequent phagocytosis by immune cells like neutrophils (Source: NIH, PMID: 1550500). The chemical structure of the 6A polysaccharide is characterized by a repeating unit containing galactose, glucose, rhamnose, and ribitol phosphate, which is structurally distinct from other serogroup 6 members like 6B (Source: ResearchGate, Jan 2007). As a key antigen, it is included in various pneumococcal vaccines, such as PCV13 (Prevnar 13), PCV20 (Prevnar 20), and PCV21 (Capvaxive), to elicit a protective immune response (Source: FDA, Prevnar 13 Package Insert). Vaccination induces the production of antibodies that recognize the 6A polysaccharide, enabling the immune system to identify and destroy the bacteria. This targeting is essential for preventing invasive pneumococcal diseases, including pneumonia, meningitis, and sepsis, caused by this specific serotype.

Other names

Serotype 6A capsular polysaccharidePneumococcal polysaccharide serotype 6APn6A polysaccharideStreptococcus pneumoniae type 6A capsular polysaccharide

Induction of serotype-specific opsonophagocytic antibodies (IgG) that facilitate complement-mediated phagocytosis and clearance of the bacteria.