Escherichia coli O18A O-antigen (E. coli O18A O-antigen)

The Escherichia coli O18A O-antigen is a specific polysaccharide component of the lipopolysaccharide (LPS) found on the outer membrane of certain extraintestinal pathogenic E. coli (ExPEC) strains [1, 10]. It serves as a critical virulence factor by providing protection against host immune responses, including serum-mediated killing and phagocytosis [13, 14]. Strains carrying the O18A antigen are frequently associated with severe infections such as neonatal meningitis, sepsis, and urinary tract infections [12, 15]. Due to its surface exposure and role in pathogenesis, the O18A O-antigen is a primary target for the development of multivalent glycoconjugate vaccines, such as ExPEC9V and ExPEC10V [1, 3, 5]. These vaccines aim to elicit protective, serotype-specific antibodies that facilitate the opsonophagocytic killing of the bacteria by host immune cells [2, 7]. Targeting this antigen is particularly relevant for preventing invasive E. coli disease in vulnerable populations, including the elderly and newborns [4, 8].

Other names

E. coli O18A lipopolysaccharide O-side chainO18A antigenO18A polysaccharideO18ab antigenEscherichia coli serogroup O18A antigen

Induction of O-antigen-specific bactericidal antibodies that promote opsonophagocytic killing (OPK) of the bacteria [2, 5].