Salmonella Typhimurium O:4 O-antigen polysaccharide (O:4 O-Ag)

Salmonella Typhimurium O:4 O-antigen polysaccharide is a critical component of the lipopolysaccharide (LPS) found on the outer membrane of Salmonella enterica serovar Typhimurium. It consists of a repeating oligosaccharide unit typically composed of abequose, rhamnose, mannose, and galactose, where the O:4 serospecificity is determined by the abequose residue (1.2.3). This polysaccharide plays a vital role in bacterial virulence by providing resistance to the host's serum bactericidal activity and facilitating evasion of the innate immune system (1.3.1, 1.3.3). As a primary surface-exposed antigen, it is a major target for the development of glycoconjugate vaccines and therapeutic monoclonal antibodies aimed at preventing and treating invasive nontyphoidal Salmonella (iNTS) infections (1.1.2, 1.3.4). Structural variations, such as O-acetylation (which creates the O:5 epitope) and glucosylation, can significantly influence the immunogenicity and protective efficacy of these medical interventions (1.2.2, 1.3.4). The induction of high-titer bactericidal antibodies against this target is a key strategy for achieving protective immunity against salmonellosis and associated systemic complications (1.1.1, 1.5.5).

Other names

O:4 antigenO-specific polysaccharideOPSSomatic antigenGroup B O-antigenSalmonella Typhimurium O-polysaccharide

Induction of protective bactericidal antibodies and opsonophagocytosis