Streptococcus pneumoniae type 23F capsular polysaccharide

**Streptococcus pneumoniae type 23F capsular polysaccharide** is a complex carbohydrate polymer that constitutes the outermost layer, or capsule, of Streptococcus pneumoniae serotype 23F. It is composed of repeating tetrasaccharide units containing D-glucose, D-galactose, L-rhamnose, glycerol, and phosphate[1]. This capsule is the major virulence factor of the bacterium, providing resistance to phagocytosis by host immune cells and enabling persistence and invasion during infection[3][7]. The 23F capsular polysaccharide defines the serotype for diagnostic, vaccine, and epidemiological tracking purposes and is a key component and antigen in pneumococcal vaccines[7]. Its immunogenicity underlies both natural and vaccine-induced immunity, making it a validated therapeutic and preventative target[3][7]. The unique biochemical structure of the 23F polysaccharide determines its antigenicity and resistance to immune clearance, and it is directly implicated in the diseases caused by S. pneumoniae, including pneumonia, meningitis, sepsis, and otitis media[6][7]. Vaccines comprising purified or conjugated 23F polysaccharide are used widely to prevent invasive pneumococcal disease[3][7].

Other names

Pneumococcal type 23F capsular polysaccharideS. pneumoniae serotype 23F capsuleSerotype 23F capsule

Induces specific antibody responses that mediate opsonophagocytic killing of Streptococcus pneumoniae; Conjugation to carrier proteins in vaccines elicits T cell-dependent immunity