Salmonella Typhi Vi Capsular Polysaccharide (Vi polysaccharide)

The Vi capsular polysaccharide is a surface-expressed linear homopolymer found on *Salmonella enterica* serovar Typhi, the causative agent of typhoid fever. It is a critical virulence factor and the antigenic component used in current typhoid vaccines. The polysaccharide is composed of α-1,4-linked N-acetylgalactosaminuronic acid residues, variably O-acetylated at the C3 position. It enables S. Typhi to evade host immune responses and is a key component in vaccines against typhoid fever. Immunogenicity depends heavily on O-acetyl groups present on the polymer surface.

Other names

Vi antigenVi capsule

The Vi polysaccharide itself doesn't have a mechanism of action related to drug targeting. Vaccines containing the Vi polysaccharide induce antibodies that confer protective immunity against Salmonella Typhi.