Escherichia coli O6A O-antigen (O6A O-antigen)

The Escherichia coli O6A O-antigen is a specific polysaccharide component of the lipopolysaccharide (LPS) found on the outer membrane of certain E. coli strains, particularly those belonging to the extra-intestinal pathogenic E. coli (ExPEC) group. It consists of repeating oligosaccharide units that define the O6A serotype, which is one of the most prevalent serotypes associated with clinical infections such as urinary tract infections (UTIs), bacteremia, and sepsis in humans. As a surface-exposed molecule, the O6A O-antigen serves as a critical virulence factor by protecting the bacteria from host immune defenses, including complement-mediated killing and phagocytosis. It is a primary target for the development of glycoconjugate vaccines, such as the 9-valent (ExPEC9V) and 10-valent (ExPEC10V) candidates, which aim to elicit protective opsonophagocytic antibodies. These vaccines are designed to prevent invasive E. coli disease, especially in elderly populations and those at high risk for recurrent infections. Beyond its role in immune evasion, the O-antigen has also been implicated in modulating host pain responses during infection and inducing the formation of neutrophil extracellular traps (NETs).

Other names

E. coli O6A lipopolysaccharide O-side chainO6A antigenO6A polysaccharideO6A-PSEscherichia coli serotype O6A antigen

Active immunization to induce opsonophagocytic antibodies (IgG) that target the O6A serotype, facilitating bacterial clearance by the host immune system.