O-polysaccharide of Salmonella Typhimurium

The O-polysaccharide of Salmonella Typhimurium is the serotype-defining, variable polysaccharide component that extends from the outer membrane lipopolysaccharide (LPS) of the bacterium. It is formed by repeat oligosaccharide units whose precise sugar composition and modifications (such as O-acetylation and glucosylation) define antigenic specificity and serotype. The O-polysaccharide is both a major virulence factor and a protective antigen, mediating resistance to host immune clearance—especially complement activation—and facilitating systemic dissemination of Salmonella in vivo. As a highly variable surface structure, it is the target of serological typing and candidate for conjugate vaccine development. Antibody-mediated recognition of the O-polysaccharide can overcome bacterial resistance and provide immunity to infection, making the O-polysaccharide a prime target for novel therapeutic interventions such as polysaccharide-protein conjugate vaccines.

Other names

O-antigen of S. TyphimuriumO-specific polysaccharideOPSO-antigen capsule

Antibodies bind O-polysaccharide, facilitate opsonization and complement-mediated killing, and neutralize pathogen. Glycoconjugate vaccines stimulate protective anti-O-polysaccharide antibody response.