title: Serological identification and prevalence of a novel O-antigen epitope linked to 3- and 4-O-acetylated rhamnose III of lipopolysaccharide in Shigella flexneri.
abstract: Shigella flexneri is the major cause of shigellosis in developing countries. All serotypes except for serotype 6 share an O-antigen backbone composed of a → 2)-α-L-Rhap(III)-(1 → 2)-α-l-Rhap(II)-(1 → 3)-α-l-Rhap(I)-(1 → 3)-β-D-GlcpNAc-(1 → tetrasaccharide repeat. It can be modified by the addition of a glucosyl group to one or more sugar residues and/or an O-acetyl group to Rha(I) and/or a phosphoethanolamine to Rha(II) and/or Rha(III). These modifications give rise to type I-, IC-, II-, IV-, and V- and to group 6-, 7,8-, and MASF IV-1-specific antigenic determinants, which comprise the current serotyping scheme of S. flexneri. Recently, another O-antigen modification created by adding an O-acetyl group to Rha(III) at position 3 or 4 (3/4-O-acetylation) has been found in S. flexneri serotypes 1a, 1b, 2a, 5a, Y, and 6. A new O-acyltransferase gene named oacB has been shown to mediate the 3/4-O-acetylation in serotypes 1a, 1b, 2a, 5a, and Y but not in 6. In this work, we studied the distribution of the 3/4-O-acetylation in S. flexneri and the antigenicity that resulted from this modification. PCR screening of the oacB gene in clinical isolates of S. flexneri demonstrated that the oacB-mediated 3/4-O-acetylation is widespread in serotypes 1a, 1b, 2a, 5a, and Y. Serological analysis indicated that this modification confers the host with a novel antigenic determinant that is provisionally named group O factor 9. These findings enhance our understanding of the varieties of O-antigenic determinants related to O-antigen modification in S. flexneri and will assist epidemiological studies and vaccine development.
authors.affiliation: 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 Prevention, China CDC, Changping, Beijing, China.
authors.forename: Jianping
authors.initials: J
authors.lastname: Wang
authors.affiliation: School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia.
authors.forename: Ruiting
authors.initials: R
authors.lastname: Lan
authors.affiliation: N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation.
authors.forename: Yuriy A
authors.initials: YA
authors.lastname: Knirel
authors.affiliation: 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 Prevention, China CDC, Changping, Beijing, China.
authors.forename: Xia
authors.initials: X
authors.lastname: Luo
authors.affiliation: N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation.
authors.forename: Sof'ya N
authors.initials: SN
authors.lastname: Senchenkova
authors.affiliation: N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation.
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Shashkov
authors.affiliation: 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 Prevention, China CDC, Changping, Beijing, China.
authors.forename: Jianguo
authors.initials: J
authors.lastname: Xu
authors.affiliation: 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 Prevention, China CDC, Changping, Beijing, China sunqiangzheng@icdc.cn.
authors.forename: Qiangzheng
authors.initials: Q
authors.lastname: Sun
mesh_terms: D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D000939:Epitopes / Q000032:analysis* / Q000276:immunology; D006801:Humans; D008070:Lipopolysaccharides / Q000737:chemistry* / Q000276:immunology*; D019081:O Antigens / Q000032:analysis* / Q000276:immunology; D016133:Polymerase Chain Reaction; D015995:Prevalence; D012210:Rhamnose / Q000378:metabolism; D012763:Shigella flexneri / Q000737:chemistry* / Q000145:classification / Q000276:immunology* / Q000302:isolation & purification
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D000939:Epitopes; D008070:Lipopolysaccharides; D019081:O Antigens; D000217:Acyltransferases; D012210:Rhamnose