Capsular polysaccharide of Streptococcus pneumoniae serotype 22F (CPS 22F)

The capsular polysaccharide of Streptococcus pneumoniae serotype 22F is a high-molecular-weight acidic polymer that constitutes the outermost layer of the bacterium [1.4.1, 1.4.3]. It functions as a critical virulence factor by shielding the pathogen from the host's innate immune system, primarily by inhibiting opsonophagocytosis and complement deposition [1.3.1, 1.4.3]. Serotype 22F has become increasingly prevalent as a cause of invasive pneumococcal disease (IPD) and community-acquired pneumonia, particularly following the widespread use of vaccines that target other serotypes [1.1.1, 1.2.1]. Consequently, it is included as a target antigen in modern pneumococcal vaccines, such as the 15-valent (PCV15), 20-valent (PCV20), and 21-valent (PCV21) conjugate vaccines [1.2.2, 1.5.2]. These vaccines stimulate the production of serotype-specific antibodies that bind to the 22F polysaccharide, facilitating bacterial clearance by immune cells [1.2.1, 1.2.2]. This immune response is essential for preventing severe clinical manifestations including meningitis, sepsis, and bacteremia [1.1.1, 1.1.2].

Other names

Streptococcus pneumoniae type 22F capsular polysaccharide antigenPneumococcal polysaccharide serotype 22FPn22F CPS22F CPSType 22F pneumococcal polysaccharide

Active immunization; induction of serotype-specific antibodies (IgG) that facilitate opsonophagocytic killing of Streptococcus pneumoniae serotype 22F [1.2.1, 1.3.1].