Shigella sonnei O-antigen lipopolysaccharide and associated outer membrane components (S. sonnei O-Ag LPS)

Shigella sonnei O-antigen lipopolysaccharide (LPS) and associated outer membrane components, such as the Group 4 capsule (G4C) and invasion plasmid antigens (Ipa proteins), constitute the primary surface interface between the pathogen and the human host [2, 12, 19]. The O-antigen is a unique repeating polysaccharide unit essential for the bacterium's survival and virulence, providing a protective shield against complement-mediated lysis and phagocytosis [1, 3]. In S. sonnei, this O-antigen is present both as part of the LPS and as a high-molecular-weight capsule, a feature that distinguishes it from other Shigella species [13, 15]. These components are critical for the pathogenesis of shigellosis, as they modulate the invasion of intestinal epithelial cells and the subsequent inflammatory response [9, 16]. Due to the existence of only one S. sonnei serotype, the O-antigen is a premier target for vaccine candidates, including glycoconjugates, generalized modules for membrane antigens (GMMA), and live attenuated strains [5, 7, 20]. Therapeutic interventions, such as monoclonal antibodies and vaccines, aim to elicit O-antigen-specific antibodies that neutralize the bacteria and promote immune clearance [17, 18]. However, the lipid A component of the LPS poses safety challenges due to its potent endotoxic activity, necessitating detoxification or genetic modification in vaccine design [4, 11].

Other names

Shigella sonnei O-specific polysaccharideS. sonnei O-antigenS. sonnei LPSGroup 4 capsuleG4CS. sonnei outer membrane componentsS. sonnei O-AgInvasion plasmid antigens (Ipa proteins)

Induction of protective serum IgG and mucosal IgA antibodies against the O-antigen to neutralize bacterial invasion and promote complement-mediated killing.