Pneumococcal capsular polysaccharide serotype 9V (Pn9V)

Pneumococcal capsular polysaccharide serotype 9V is a complex carbohydrate polymer that forms the protective outer capsule of Streptococcus pneumoniae serotype 9V. This polysaccharide is a critical virulence factor that enables the bacterium to evade the host's innate immune system by inhibiting opsonophagocytosis [2, 4]. It is included as a primary antigen in several multi-valent pneumococcal vaccines, such as PCV13, PCV15, PCV20, and PPSV23, to provide protection against invasive diseases [3, 5]. Upon vaccination, the immune system generates serotype-specific antibodies (IgG and IgM) that recognize the 9V polysaccharide, leading to bacterial opsonization and clearance by phagocytic cells [2, 3]. The structure of the 9V polysaccharide is characterized by repeating units containing glucose, galactose, and O-acetylated N-acetylmannosamine, with the O-acetylation playing a role in its antigenic properties [1, 3]. Effective targeting of this polysaccharide has led to a substantial decrease in the prevalence of serotype 9V-associated infections, including pneumonia, meningitis, and bacteremia [4, 5].

Other names

Streptococcus pneumoniae serotype 9V capsular polysaccharidePn9V capsular polysaccharide9V polysaccharideCPS9V

Induction of serotype-specific opsonophagocytic antibodies