Vi capsular polysaccharide: Synthesis, virulence, and application

Abstract

Vi capsular polysaccharide, a linear homopolymer of α-1,4-linked N-acetylgalactosaminuronate, is characteristically produced by Salmonella enterica serovar Typhi. The Vi capsule covers the surface of the producing bacteria and serves as an virulence factor via inhibition of complement-mediated killing and promoting resistance against phagocytosis. Furthermore, Vi also represents a predominant protective antigen and plays a key role in the development of vaccines against typhoid fever. Herein, we reviewed the latest advances associated with the Vi polysaccharide, from its synthesis and transport within bacterial cells, mechanisms involved in virulence, immunological characteristics, and applications in vaccine, as well as its purification and detection methods.

Keywords:

• Vi
• capsular polysaccharide
• Salmonella
• virulence
• vaccine

Acknowledgements

The authors thank Dr. Daoguo Zhou of Purdue University for critical review of this manuscript.

Disclosure statement

The authors report that they have no conflicts of interest.