title: Modulation of O-antigen chain length by the wzz gene in Escherichia coli O157 influences its sensitivities to serum complement.
abstract: Escherichia coli O157 strains belonging to a distinct lineage and expressing different O-antigen (Oag) lengths were isolated. Although the function of wzz in E. coli has not been adequately investigated, this gene is known to be associated with regulation of Oag length. Using E. coli O157:H7 ATCC43888 (wild-type), several wzz mutants of E. coli O157, including a wzz deletion mutant, were generated and the relationship between the length of Oag modulated by the wzz gene and sensitivities to serum complement investigated. SDS-PAGE, immunoblot analyses and sensitivity tests to human serum complement were performed on these strains. The lengths of the O157-antigen could be modulated by the wzz gene mutations and were classified into long, intermediate and short groups. The short chain mutant was more serum sensitive than the wild-type strain and the other wzz mutants (P < 0.001). In conclusion, Oag chain length modulated by the wzz gene in E. coli O157 influences its sensitivities to serum complement. The present findings suggest that E. coli O157 strains with intermediate or long length Oag chains might show greater resistance to serum complement than those with short chains.
authors.affiliation: Division of Infectious Diseases, Department of International Health, Kobe University Graduate School of Health Sciences, Kobe; Indonesia-Japan Collaborative Research Center for Emerging and Re-emerging Infectious Diseases, Institute of Tropical Disease.
authors.forename: Kayo
authors.initials: K
authors.lastname: Osawa
authors.forename: Katsumi
authors.initials: K
authors.lastname: Shigemura
authors.forename: Atsushi
authors.initials: A
authors.lastname: Iguchi
authors.forename: Hiroki
authors.initials: H
authors.lastname: Shirai
authors.forename: Toru
authors.initials: T
authors.lastname: Imayama
authors.forename: Kazuko
authors.initials: K
authors.lastname: Seto
authors.forename: Dadik
authors.initials: D
authors.lastname: Raharjo
authors.forename: Masato
authors.initials: M
authors.lastname: Fujisawa
authors.forename: Ro
authors.initials: R
authors.lastname: Osawa
authors.forename: Toshiro
authors.initials: T
authors.lastname: Shirakawa
mesh_terms: D003165:Complement System Proteins / Q000276:immunology*; D004927:Escherichia coli Infections / Q000276:immunology* / Q000382:microbiology; D019453:Escherichia coli O157 / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D019081:O Antigens / Q000737:chemistry* / Q000276:immunology
chemical_list: D029968:Escherichia coli Proteins; D019081:O Antigens; C489586:wzzB protein, E coli; D003165:Complement System Proteins
keywords: Escherichia coli O157; O antigen; wzz