B cell receptor specific for Streptococcus pneumoniae serotype 19F capsular polysaccharide (BCR-Pn19FPS)

The B cell receptor (BCR) specific for the capsular polysaccharide (CPS) of Streptococcus pneumoniae serotype 19F is a membrane-bound immunoglobulin that serves as the primary sensor for this pathogen's outermost protective layer (NIH, 1999). The 19F CPS is a linear polymer composed of repeat units of glucose, rhamnose, and N-acetylmannosamine linked by phosphate bonds, which are recognized by the BCR's variable regions (ResearchGate, 2021). Upon binding to these epitopes, the BCR undergoes clustering and initiates intracellular signaling cascades that drive B cell activation and differentiation into antibody-secreting plasma cells (ACS, 2024). This process is essential for generating humoral immunity, as the resulting antibodies opsonize the bacteria, facilitating their clearance by phagocytes through opsonophagocytic activity (OPA) (NIH, 2004). In the context of disease, serotype 19F is a major contributor to invasive pneumococcal diseases such as pneumonia, meningitis, and sepsis, particularly in vulnerable populations like children and the elderly (MDPI, 2022). Therapeutic interventions, specifically pneumococcal vaccines like PCV13 and PCV20, target these BCRs by presenting 19F CPS antigens, often conjugated to carrier proteins to elicit T-cell-dependent memory responses (Frontiers, 2023). Monitoring the activation of these BCRs and the subsequent production of anti-19F IgG is a standard biomarker for vaccine efficacy (ResearchGate, 2026). However, challenges such as serotype replacement and the potential for immune hyporesponsiveness after repeated exposure to pure polysaccharides remain significant concerns in clinical practice (Gosset, 2024).

Other names

19F-specific B cell receptorAnti-19F BCRB cell antigen receptor for S. pneumoniae 19F CPSStreptococcus pneumoniae serotype 19F capsular polysaccharide receptor

Vaccine antigens (polysaccharides or glycoconjugates) bind to the BCR, inducing BCR clustering and signaling. In conjugate vaccines, the carrier protein allows for T-cell help, leading to B cell proliferation, affinity maturation, and differentiation into memory B cells and plasma cells.