B-cell receptor specific for Streptococcus pneumoniae serotype 22F capsular polysaccharide (BCR-Spn22F)

B-cell receptors (BCRs) specific for Streptococcus pneumoniae serotype 22F capsular polysaccharide are specialized membrane-bound immunoglobulins that serve as the primary recognition units for the 22F antigen on the surface of B lymphocytes. Serotype 22F is a highly virulent strain of S. pneumoniae that has emerged as a significant cause of invasive pneumococcal disease (IPD) following the widespread use of earlier conjugate vaccines. The interaction between the 22F polysaccharide antigen and these specific BCRs is the fundamental step in generating a protective humoral immune response, leading to the expansion of memory B cells and the secretion of high-affinity opsonizing antibodies. Therapeutic engagement of these receptors is primarily achieved through multivalent vaccines such as PCV15 (Vaxneuvance) and PCV20 (Prevnar 20), which include the 22F polysaccharide to provide broader protection against circulating strains. Upon binding the antigen, the BCR initiates signaling through the Ig-alpha/Ig-beta (CD79a/CD79b) complex, facilitating the clearance of the bacteria via opsonophagocytosis. Monitoring the activation of these BCRs and the resulting antibody titers is a standard clinical metric for evaluating vaccine immunogenicity and the prevention of pneumonia and meningitis.

Other names

Anti-22F B-cell receptorStreptococcus pneumoniae serotype 22F-specific BCRPneumococcal serotype 22F-specific B-cell receptorBCR-22F

The vaccine-derived capsular polysaccharide antigen (or conjugate) binds to and cross-links the specific B-cell receptors, triggering an intracellular signaling cascade that leads to B-cell proliferation, differentiation into plasma cells, and the secretion of serotype-specific IgG antibodies.