group b streptococcus capsular polysaccharide serotype ib conjugated to CRM197

Group B streptococcus capsular polysaccharide serotype Ib conjugated to CRM197 is a glycoconjugate vaccine component developed by Pfizer as an integral part of its hexavalent GBS vaccine candidate, PF-06760805 (also known as GBS6). This entity consists of the capsular polysaccharide (CPS) of *Streptococcus agalactiae* (Group B Streptococcus) serotype Ib covalently linked to CRM197, a non-toxic recombinant mutant of the diphtheria toxin. The conjugation of the polysaccharide to a carrier protein like CRM197 is a critical design feature that converts the T-cell independent polysaccharide antigen into a T-cell dependent antigen. This transformation enables the induction of high-affinity IgG antibodies and the establishment of immunological memory, which is particularly vital for maternal immunization strategies. The primary clinical goal is to vaccinate pregnant women to facilitate the transplacental transfer of protective antibodies to the fetus, thereby preventing invasive GBS disease (such as neonatal sepsis, meningitis, and pneumonia) in infants during the first months of life. As part of the GBS6 formulation, this component is currently in Phase 3 clinical development.

Other names

GBS serotype Ib-CRM197 conjugateGBS Ib-CRM197Group B Streptococcus serotype Ib capsular polysaccharide-CRM197 conjugate