Streptococcus pneumoniae type 18C capsular polysaccharide (CPS 18C)

The Streptococcus pneumoniae type 18C capsular polysaccharide is a serotype-specific carbohydrate polymer that forms the outermost layer (capsule) of the bacterium S. pneumoniae. This capsule is the dominant surface structure and serves as a major virulence factor, protecting the bacterium from host immune responses, particularly by interfering with opsonophagocytic clearance mechanisms. It is a component of some pneumococcal conjugate vaccines like PCV15 (Vaxneuvance), stimulating antibody production for protection.

Other names

Pneumococcal capsular polysaccharide type 18CS. pneumoniae type 18C capsuleType 18C polysaccharide

The polysaccharide itself is not directly targeted by drugs. Rather, vaccines containing this polysaccharide stimulate the production of antibodies that recognize and bind to the capsule, promoting opsonization and phagocytosis of the bacteria.