Streptococcus pneumoniae capsular polysaccharide serotype 20 (CPS20)

Streptococcus pneumoniae capsular polysaccharide serotype 20 is a complex, surface-exposed carbohydrate polymer that serves as a critical virulence factor for the pneumococcus [6, 12]. Its primary biological function is to protect the bacterium from host immune recognition and prevent opsonophagocytic clearance by neutrophils and macrophages [6, 9, 14]. The capsule is composed of repeating oligosaccharide units, with recent research identifying distinct subtypes (20A, 20B, and 20C) that vary in their glucose side-chain patterns and O-acetylation [8, 11, 15]. Clinically, serotype 20 is a significant contributor to invasive pneumococcal disease (IPD), including life-threatening conditions such as pneumonia, meningitis, and bacteremia [3, 4, 12]. \n\nAs a therapeutic target, this polysaccharide is included as a primary antigen in several multivalent vaccines, including the 23-valent polysaccharide vaccine (Pneumovax 23), the 20-valent conjugate vaccine (Prevnar 20), and the 21-valent conjugate vaccine (Capvaxive) [1, 4, 16]. These vaccines function by inducing the production of serotype-specific IgG antibodies that facilitate bacterial clearance. In conjugate formulations, the polysaccharide is linked to a carrier protein to recruit T-cell help, ensuring a robust and durable immune response even in pediatric and high-risk populations [4, 6, 17, 19].

Other names

Streptococcus pneumoniae serogroup 20 polysaccharidePneumococcal polysaccharide serotype 20Capsular polysaccharide serotype 20S. pneumoniae CPS type 20Serotype 20 capsular antigen

Induces active immunization through the stimulation of serotype-specific IgG antibodies. In conjugate vaccines, the polysaccharide is covalently linked to a carrier protein (such as CRM197) to induce T-cell dependent B-cell activation, leading to high-affinity antibodies that mediate opsonophagocytic killing and clearance of the bacteria by the host immune system [4, 6, 17, 19].