B-cell receptor specific for Streptococcus pneumoniae capsular polysaccharides (BCR-PnPS)

The B-cell receptor (BCR) specific for Streptococcus pneumoniae capsular polysaccharide epitopes is a membrane-bound immunoglobulin complex that serves as the primary recognition site for pneumococcal antigens (Clutterbuck et al., 2012). These receptors are predominantly found on B-1b and marginal zone B cells, which are specialized in responding to T-cell independent type 2 (TI-2) antigens (Musher et al., 2013). Upon binding to the repeating polysaccharide units found in the 23-valent pneumococcal polysaccharide vaccine (PPV23), the BCRs undergo cross-linking, which initiates intracellular signaling pathways leading to B-cell activation and differentiation into antibody-secreting plasma cells (CDC, 2021). The resulting antibodies are specific to the 23 serotypes included in the vaccine and provide protection by promoting opsonophagocytosis of the bacteria (WHO, 2022). However, because this interaction does not typically involve T-cell help, it does not induce strong immunological memory or affinity maturation, and it is ineffective in children under two years of age whose B-cell populations are immature (Pollard et al., 2009). This target is central to the efficacy of polysaccharide vaccines used to prevent invasive pneumococcal diseases such as pneumonia, bacteremia, and meningitis in high-risk populations and the elderly (NIH, 2023).

Other names

B cell receptor specific for Streptococcus pneumoniae capsular polysaccharide epitopes in PPV23Pneumococcal polysaccharide-specific B-cell receptorBCR-PnPSSurface immunoglobulin specific for S. pneumoniae

Antigen-mediated cross-linking of B-cell receptors leading to T-cell independent B-cell activation and antibody production.