Streptococcus pneumoniae capsular polysaccharide serotype 17F (Spn17F CP)

Streptococcus pneumoniae capsular polysaccharide serotype 17F is a critical structural component of the bacterial capsule of specific pneumococcal strains, serving as a major virulence factor that enables the pathogen to evade the host immune system [4, 8, 10]. This complex polysaccharide layer covers the bacterial surface and prevents complement-mediated opsonization, thereby inhibiting phagocytosis by immune cells [10, 18]. Strains expressing serotype 17F are associated with various infections, including otitis media and life-threatening invasive pneumococcal diseases such as pneumonia, meningitis, and sepsis [1, 6, 12, 17]. To provide protection, the 17F polysaccharide is utilized as a vaccine antigen in multivalent formulations like the 23-valent pneumococcal polysaccharide vaccine (PPSV23) and the 21-valent pneumococcal conjugate vaccine (PCV21) [3, 11, 14]. These vaccines stimulate the production of serotype-specific opsonophagocytic antibodies, primarily IgG, which recognize the polysaccharide and facilitate bacterial clearance [1, 3, 20]. Clinical efficacy is typically monitored via opsonophagocytic activity (OPA) titers or serum antibody concentrations [1, 20]. Key therapeutic challenges include the management of hypersensitivity reactions and the potential for serotype replacement, where non-vaccine serotypes emerge as prominent causes of disease in the population [4, 14, 21].

Other names

Pneumococcal polysaccharide serotype 17FSerotype 17F capsular polysaccharideStreptococcus pneumoniae type 17F polysaccharide antigenPneumococcal type 17F polysaccharide

Induction of active immunity by stimulating the production of serotype-specific opsonophagocytic antibodies (primarily IgG) that facilitate the clearance of encapsulated bacteria by phagocytes.