Streptococcus pneumoniae capsular polysaccharide (Serotype 15) (CPS (Serotype 15))

Streptococcus pneumoniae capsular polysaccharide is a complex carbohydrate that forms the dominant surface structure of the bacterium. It is essential for virulence, primarily enabling the organism to evade host immune clearance mechanisms by inhibiting phagocytosis. There are 98 serologically distinct capsular polysaccharide structures (serotypes), each encoded by a specific "cps" locus and structurally characterized by distinct sugar compositions and linkages. These serotype-specific polysaccharides are the targets of current pneumococcal vaccines, which induce high-affinity, opsonizing antibodies. However, protection is strictly serotype-specific, and the widespread use of vaccines has driven shifts in serotype prevalence and emergence of non-vaccine strains. The molecular diversity of capsular polysaccharides is a major challenge for diagnostics, vaccine coverage, and immunity. Serotype 15-specific information (structural context): Serotype 15 capsular polysaccharide, like other serogroups (e.g., serogroup 10), consists of repeat units composed of several sugars, including galactose, galactofuranose, galactosamine, and ribitol, which are not found in mammals and contribute to its antigenicity. The structure and genetics of each serotype dictate the immune response and specificity of vaccine-mediated protection.

Other names

Pneumococcal capsular polysaccharideS. pneumoniae CPSSerotype-specific polysaccharideSerotype 15 capsular polysaccharide

Antibody-mediated opsonization: Vaccine-induced antibodies bind to capsular polysaccharide, promoting opsonophagocytic killing and clearance; Immunogenic mimicry: Direct immune recognition and recruitment of other immune components.