Streptococcus pneumoniae capsular polysaccharide serotype 35B (CPS 35B)

Streptococcus pneumoniae capsular polysaccharide serotype 35B is a complex carbohydrate structure that forms the outermost protective layer of the 35B serotype of the pneumococcus bacterium [1, 3]. This polysaccharide is a high molecular weight polymer composed of a pentasaccharide repeating unit containing D-galactose, D-glucose, 2-acetamido-2-deoxy-D-galactose, and ribitol, often featuring O-acetylation [3]. It serves as a critical virulence factor that enables the pathogen to evade the host's immune system by inhibiting opsonophagocytosis and complement deposition [1, 14]. Serotype 35B has emerged as a significant cause of invasive pneumococcal disease (IPD) and pneumonia, particularly following the widespread use of conjugate vaccines that did not include this serotype, a phenomenon known as serotype replacement [6, 8]. It is frequently associated with multidrug resistance, specifically within clonal complex 558, making infections challenging to treat with standard antibiotics [8]. As a therapeutic target, the 35B polysaccharide is conjugated to a carrier protein in the 21-valent vaccine V116 (Capvaxive) to enhance its immunogenicity [4, 7, 11]. The vaccine induces serotype-specific antibodies that facilitate the clearance of the bacteria by host immune cells through opsonophagocytic killing [2, 9, 12]. This target is essential for expanding vaccine coverage to address serotypes responsible for a significant portion of adult pneumococcal disease [11, 15].

Other names

Pneumococcal polysaccharide serotype 35BS. pneumoniae serotype 35B CPSCapsular antigen of Streptococcus pneumoniae serotype 35B

Induction of serotype-specific antibodies that facilitate opsonophagocytic killing of the bacteria [2, 7, 9].