Extraintestinal pathogenic Escherichia coli O-polysaccharide antigen (ExPEC O-antigen)

Extraintestinal pathogenic Escherichia coli (ExPEC) O-polysaccharide antigens are the distal, highly variable carbohydrate components of the lipopolysaccharide (LPS) found on the outer membrane of ExPEC strains (Poolman et al., 2020). These antigens play a critical role in bacterial survival within the host by providing resistance to serum-mediated killing and escaping phagocytosis (Vila et al., 2016). ExPEC is a leading cause of invasive infections, including urinary tract infections (UTIs), sepsis, and neonatal meningitis, with a small number of O-serotypes (such as O1, O2, O6, and O25B) accounting for the majority of clinical cases (Johnson et al., 2003). As surface-exposed molecules, these polysaccharides are primary targets for glycoconjugate vaccines designed to elicit protective opsonophagocytic antibodies (Huttner et al., 2017). Current clinical development focuses on multivalent vaccines, such as ExPEC9V and ExPEC24V, that combine several prevalent O-antigen serotypes to provide broad protection against ExPEC-associated diseases (Janssen Biotech, 2023).

Other names

ExPEC O-antigenEscherichia coli O-polysaccharideO-specific polysaccharideLPS O-antigenO-antigen

Induction of opsonophagocytic antibodies to promote immune-mediated bacterial clearance