Group B Streptococcus alpha-like protein N-terminal fusion protein (GBS-NN fusion protein)

The GBS-NN fusion protein is a recombinant antigen designed as a vaccine candidate to prevent invasive infections caused by Group B Streptococcus (GBS), a leading cause of neonatal sepsis globally. GBS-NN consists of the N-terminal domains of Alpha C and Rib proteins, major members of the alpha-like protein (Alp) family found on the surface of GBS cells[2][1][4][10][8]. The Alp-N domains protrude from the bacterial surface and are broadly distributed among clinical isolates, making them strategic vaccine targets. GBS-NN elicits placentally transferable IgG1 and IgA antibodies, mediating opsonophagocytic killing of homotypic and heterotypic GBS strains and preventing their invasion of human epithelial cells[2][10]. The protein is physically stable as a monomer but can self-assemble irreversibly at elevated temperatures, with a phase transition around 61°C[1][4][5][7]. Preclinical and early clinical studies demonstrate strong immunogenicity and a favorable safety profile, supporting its use in maternal immunization to provide neonatal protection[2][8][10]. GBS-NN is not a natural biological target but a protective antigen used in vaccines; listing it as a canonical molecular therapeutic target (receptor, enzyme, etc.) would be incorrect.

Other names

GBS-NN antigenGBS-NN vaccine antigenGroup B Streptococcus alpha-like fusion protein

As a vaccine antigen: Elicits production of specific antibodies (IgG1, IgA) that: - Opsonize GBS bacteria for phagocytic killing[2] - Prevent invasion of host epithelial cells[2] - Transfer maternal antibodies across placenta in pregnant women, providing passive immunity to neonates[2][8][10]