Streptococcus pneumoniae capsular polysaccharide (PnPS) (PnPS)

Streptococcus pneumoniae capsular polysaccharides are the primary virulence factors of the pneumococcus bacterium, serving as the outer protective layer that inhibits phagocytosis by host immune cells (Source: CDC, "Pneumococcal Disease"). Immunological induction against 24 specific serotypes of these polysaccharides is a therapeutic strategy designed to provide broad-spectrum protection against invasive pneumococcal disease (IPD), including pneumonia, meningitis, and sepsis (Source: GSK, "GSK completes acquisition of Affinivax"). The target consists of complex carbohydrate structures unique to each serotype, which are recognized by the immune system to produce serotype-specific IgG antibodies and activate opsonophagocytic pathways (Source: PubMed, PMID: 34415745). Vaccines targeting these 24 serotypes, such as the candidates AFX3772 and VAX-24, utilize advanced conjugation or presentation technologies to enhance both B-cell and T-cell mediated immunity (Source: Vaxcyte, "VAX-24 Phase 2 Results"). This broad coverage is intended to address the challenge of serotype replacement, where non-vaccine strains emerge as significant causes of disease following the widespread use of lower-valency vaccines. Monitoring efficacy typically involves measuring opsonophagocytic activity (OPA) titers and serotype-specific antibody concentrations in the blood (Source: FDA, "Pneumovax 23 Label").

Other names

Pneumococcal capsular polysaccharideStreptococcus pneumoniae antigen24-valent pneumococcal polysaccharidePnPS

Induction of serotype-specific IgG antibodies and opsonophagocytic activity (OPA) to facilitate bacterial clearance by the immune system.