Escherichia coli O157 O-antigen (O157 O-antigen)

The Escherichia coli O157 O-antigen is a complex polysaccharide component of the lipopolysaccharide (LPS) found on the outer membrane of the O157:H7 serotype [PubMed: 11520922]. It serves as a primary surface antigen and is a critical determinant of the bacterium's serological identity and virulence [Wikipedia: Escherichia coli O157:H7]. Biologically, the O-antigen protects the bacterium from host immune defenses, such as the complement system, and contributes to environmental survival [Journal of Bacteriology: 181(24)]. In clinical medicine, it is a major target for diagnostic assays and the development of glycoconjugate vaccines, such as O157-rEPA, aimed at preventing enterohemorrhagic E. coli (EHEC) infections and the life-threatening Hemolytic Uremic Syndrome (HUS) [NIH: ClinicalTrials.gov]. While most current treatments for O157:H7 infection are supportive, therapeutic strategies targeting the O-antigen focus on active immunization to generate protective antibodies that prevent bacterial colonization and systemic complications [CDC: E. coli O157:H7]. The O-antigen's unique structure, consisting of repeating tetrasaccharide units, allows for highly specific targeting, minimizing cross-reactivity with commensal flora [ScienceDirect: Carbohydrate Research]. Research into monoclonal antibodies targeting this antigen also explores passive immunity as a post-exposure prophylactic or treatment option [Journal of Infectious Diseases: 183(1)]. Its role as a biomarker is also significant, as detection of the O157 antigen in clinical samples is a standard method for identifying outbreaks [FDA: Foodborne Pathogens].

Other names

O157 lipopolysaccharideO157 LPSSomatic O157 antigenE. coli O157:H7 O-specific polysaccharide

Induction of neutralizing and opsonizing antibodies against the O-antigen to prevent bacterial colonization and promote clearance [PubMed: 11520922].