B cell receptor specific for Group B Streptococcus serotype III capsular polysaccharide (GBS III CPS-specific BCR) (GBS III CPS-specific BCR)

B cell receptors (BCRs) specific for the Group B Streptococcus (GBS) serotype III capsular polysaccharide (CPS) are specialized surface immunoglobulins that play a pivotal role in the immune recognition of Streptococcus agalactiae (Wessels et al., J Biol Chem, 1989). Serotype III is one of the most prevalent strains causing invasive neonatal diseases, including sepsis and meningitis, and its CPS is a primary virulence factor that inhibits phagocytosis (Baker & Edwards, Vaccine, 2003). The BCRs on specific B cell clones recognize the unique sialylated carbohydrate structure of the type III capsule, triggering signaling cascades that lead to the production of protective antibodies. In clinical development, these BCRs are the primary targets of conjugate vaccines, such as the hexavalent GBS6, which link the CPS to carrier proteins like CRM197 to overcome the poor immunogenicity of polysaccharides in infants (Buurman et al., Vaccine, 2019). By stimulating these BCRs, vaccines aim to induce high titers of opsonophagocytic IgG that can be transplacentally transferred to provide passive protection to the neonate (Madhi et al., N Engl J Med, 2023). This target is central to maternal immunization strategies aimed at reducing the global burden of neonatal GBS disease.

Other names

Anti-GBS III CPS BCRGroup B Streptococcus type III capsular polysaccharide-specific B cell receptorGBS type III CPS-specific BCR

Binding of the capsular polysaccharide antigen to the B cell receptor induces receptor clustering and intracellular signaling, promoting B cell differentiation into plasma cells that secrete opsonophagocytic antibodies (Madhi et al., N Engl J Med, 2023).