Escherichia coli O18A antigen (O18A)

The Escherichia coli O18A antigen is a specific O-polysaccharide component of the lipopolysaccharide (LPS) located on the outer membrane of certain extraintestinal pathogenic Escherichia coli (ExPEC) strains (PMID: 31541016). It functions as a major virulence factor by protecting the bacteria from the host's innate immune response, specifically providing resistance against complement-mediated lysis and opsonophagocytosis (PMID: 28807909). Strains expressing the O18 antigen are among the most common causes of neonatal meningitis and are frequently implicated in sepsis and urinary tract infections (PMID: 25153483). Consequently, the O18A antigen is a key target in the development of multivalent conjugate vaccines, such as ExPEC9V, which aim to elicit protective IgG antibodies (PMID: 33157438). These antibodies facilitate the clearance of the bacteria by the immune system, providing a prophylactic approach to managing invasive E. coli diseases. Targeting this surface carbohydrate is essential for addressing antibiotic-resistant ExPEC clones that pose a significant global health threat.

Other names

E. coli O18 antigenO18 lipopolysaccharideO18 LPSEscherichia coli O18 O-antigenO18 polysaccharide

Induction of O-antigen-specific IgG antibodies that mediate opsonophagocytic killing and complement-dependent bactericidal activity.