Streptococcus pneumoniae capsular polysaccharide antigen-specific B cell

**Streptococcus pneumoniae capsular polysaccharide antigen-specific B cells** are a subset of human or animal B lymphocytes that recognize and respond specifically to the unique carbohydrate structures found on the surface capsule of *Streptococcus pneumoniae*. The bacterial capsule is composed of immunologically distinct polysaccharides that define more than 90 serotypes and serve as a major virulence factor by protecting bacteria from phagocytosis[1][3]. Upon exposure—either through natural infection or vaccination with purified/conjugated pneumococcal polysaccharides—these antigen-specific B cells become activated, proliferate, and differentiate into plasma cells that secrete antibodies targeting the capsule[4][5]. These antibodies mediate protection primarily by promoting opsonization and complement activation, facilitating phagocytosis and clearance of *S. pneumoniae*[3][7]. These cells are not themselves therapeutic targets in the conventional sense (such as receptors or enzymes), but rather effectors in adaptive immunity whose activity is harnessed by vaccines for disease prevention[4]. Measurement of their function—typically via quantification of serum anti-capsule antibody titers—is used as a biomarker for vaccine efficacy[4][7]. **Note:** The submitted name refers not to a molecule/receptor but rather an immune cell population defined by its specificity; thus it does not fit standard molecular target conventions ("is_incorrect": true).

Other names

Pneumococcal capsular polysaccharide-specific B cellS. pneumoniae capsule-specific B cellAnti-capsular B cell (S. pneumoniae)

Induction of antibody-mediated immunity against S. pneumoniae via recognition of capsular polysaccharide antigens