Streptococcus pneumoniae serotype 4 capsular polysaccharide antigen (PPS4)

Streptococcus pneumoniae serotype 4 capsular polysaccharide antigen is a complex carbohydrate polymer that encapsulates the serotype 4 strain of the bacterium Streptococcus pneumoniae [1]. This polysaccharide is a primary virulence factor, functioning as a protective shield that prevents the host's immune system from recognizing and phagocytosing the pathogen [3]. It specifically inhibits complement deposition and protects the bacteria from being cleared by neutrophils and macrophages [3]. Serotype 4 is historically one of the most prevalent strains causing invasive pneumococcal disease, including life-threatening conditions such as meningitis, bacteremia, and severe pneumonia [1]. Consequently, this antigen is a key component in various pneumococcal vaccines, including conjugate vaccines like PCV13 and PCV20, as well as the polysaccharide vaccine PPSV23 [2]. These vaccines work by stimulating the host's B cells to produce specific antibodies that bind to the polysaccharide, facilitating opsonization and subsequent destruction of the bacteria [2]. Clinical monitoring of the response to this target is typically performed by measuring serum IgG levels or using opsonophagocytic activity assays [2]. References: [1] CDC. (2022). Pneumococcal Disease. [2] FDA. (2021). Prevnar 20 Prescribing Information. [3] Geno, K. A., et al. (2015). Streptococcus pneumoniae Capsular Polysaccharide Structure and Genetics. Microbiology and Molecular Biology Reviews.

Other names

Pneumococcal polysaccharide serotype 4Spn4 capsular polysaccharideSerotype 4 capsular antigenS. pneumoniae type 4 polysaccharide

Induction of active immunity through the production of serotype-specific opsonophagocytic antibodies that facilitate bacterial clearance [2].