B cell receptor specific for Group B Streptococcus serotype Ib capsular polysaccharide

B cell receptors (BCRs) specific for Group B Streptococcus (GBS) serotype Ib capsular polysaccharide are specialized transmembrane proteins on the surface of B lymphocytes that recognize and bind to the specific carbohydrate structure of the GBS serotype Ib capsule [1, 10]. GBS, or Streptococcus agalactiae, is a leading cause of invasive neonatal infections, including sepsis, pneumonia, and meningitis [6, 11]. The interaction between the CPS Ib antigen and these BCRs is the critical first step in the adaptive immune response, leading to B cell activation, differentiation into plasma cells, and the secretion of high-affinity IgG antibodies [10, 13]. These antibodies provide protection through opsonophagocytic killing of the bacteria [11, 18]. In the context of drug development, these BCRs are the primary targets of conjugate vaccines, such as Pfizer's hexavalent GBS6, which aim to elicit a robust and long-lasting memory B cell response against the Ib serotype to prevent maternal colonization and neonatal transmission [9, 15, 18].

Other names

GBS serotype Ib CPS-specific B cell receptorAnti-GBS Ib CPS BCRStreptococcus agalactiae serotype Ib capsular polysaccharide receptor

Antigen binding to the B cell receptor triggers B cell activation, clonal expansion, and differentiation into plasma cells that secrete protective IgG antibodies [10, 13].