Group B Streptococcus alpha-like surface protein Rib N-terminal domain (Rib N-domain)

The Group B Streptococcus (GBS) alpha-like surface protein Rib is a major cell-surface-associated antigen found in Streptococcus agalactiae, particularly in highly invasive strains such as those belonging to serotype III (Lindahl et al., 2005). It is a member of the alpha-like protein (Alp) family, which also includes the Alpha C, Alp1, Alp2, and Alp3 proteins. The Rib protein is characterized by a unique N-terminal domain followed by a variable number of identical tandem repeats; the N-terminal domain is specifically recognized as a potent immunogen (UniProt P0C0S1). Biologically, Rib facilitates bacterial adhesion to host tissues and provides resistance to proteases, thereby aiding in immune evasion and systemic spread. In clinical development, the N-terminal domain of Rib is utilized as a key component in multivalent vaccines, such as the hexavalent GBS6 conjugate vaccine, to elicit protective opsonophagocytic antibodies (Madhi et al., 2023). These vaccines are designed to prevent neonatal sepsis, meningitis, and pneumonia by inducing maternal immunity that is transferred to the fetus.

Other names

Surface protein RibAlp family protein RibResistance to proteases, Immunity, Bacterial adhesion proteinGBS Rib protein

Induction of opsonophagocytic antibodies that facilitate bacterial clearance by immune cells.