Capsular polysaccharide of Streptococcus pneumoniae serotype 10A (CPS10A)

The capsular polysaccharide of Streptococcus pneumoniae serotype 10A is a complex carbohydrate polymer that forms the outermost protective layer of the bacterium. It serves as a primary virulence factor by shielding the pathogen from the host's innate immune system, specifically by inhibiting opsonophagocytosis and preventing clearance by neutrophils and macrophages (NIH, 2020). Serotype 10A is a significant contributor to the global burden of invasive pneumococcal disease (IPD), including life-threatening conditions such as pneumonia, meningitis, and bacteremia, as well as non-invasive infections like otitis media (Pfizer, 2023). Due to its clinical relevance and association with antibiotic resistance, this polysaccharide is utilized as a target antigen in several multi-valent vaccines, including the 23-valent pneumococcal polysaccharide vaccine (PPSV23) and newer conjugate vaccines such as the 20-valent (PCV20) and 21-valent (PCV21) formulations (FDA, 2023; Merck, 2024). In conjugate vaccines, the polysaccharide is chemically linked to a carrier protein, such as CRM197, to induce a T-cell dependent immune response that is effective across all age groups, including infants and the elderly. Vaccination with these products stimulates the production of serotype-specific antibodies that promote the opsonization and subsequent destruction of the bacteria by the host immune system (EMA, 2023).

Other names

Pneumococcal polysaccharide serotype 10APn10A capsular polysaccharideStreptococcus pneumoniae type 10A capsular polysaccharide antigenPn10A CPS

Induces active immunization by stimulating the production of serotype-specific IgG antibodies and opsonophagocytic activity (OPA), which facilitate the clearance of the bacteria by the host immune system.