Biochemistry (Moscow)

, Volume 80, Issue 7, pp 901–914 | Cite as

O-Antigen modifications providing antigenic diversity of Shigella flexneri and underlying genetic mechanisms

  • Y. A. KnirelEmail author
  • Qiangzheng SunEmail author
  • S. N. Senchenkova
  • A. V. Perepelov
  • A. S. Shashkov
  • Jianguo XuEmail author


O-Antigens (O-specific polysaccharides) of Shigella flexneri, a primary cause of shigellosis, are distinguished by a wide diversity of chemical modifications following the oligosaccharide O-unit assembly. The present review is devoted to structural, serological, and genetic aspects of these modifications, including O-acetylation and phosphorylation with phosphoethanolamine that have been identified recently. The modifications confer the host with specific immunodeterminants (O-factors or O-antigen epitopes), which accounts for the antigenic diversity of S. flexneri considered as a virulence factor of the pathogen. Totally, 30 O-antigen variants have been recognized in these bacteria, the corresponding O-factors characterized using specific antibodies, and a significant extension of the serotyping scheme of S. flexneri on this basis is suggested. Multiple genes responsible for the O-antigen modifications and the resultant serotype conversions of S. flexneri have been identified. The genetic mechanisms of the O-antigen diversification by acquisition of mobile genetic elements, including prophages and plasmids, followed occasionally by gene mobilization and inactivation have been revealed. These findings further our understanding of the genetics and antigenicity of S. flexneri and assist control of shigellosis.


Shigella flexneri O-antigen O-polysaccharide structure serotype-converting bacteriophage transposon plasmid serotyping immunodeterminant 



galacturonic acid






insertion sequence








Shigella flexneri


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© Pleiades Publishing, Ltd. 2015

Authors and Affiliations

  1. 1.Zelinsky Institute of Organic ChemistryRussian Academy of SciencesMoscowRussia
  2. 2.State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and PreventionChinese Center for Disease Control and PreventionBeijingChina

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