title: Helicobacter pylori isolates from Greek children express type 2 and type 1 Lewis and α1,6-glucan antigens in conjunction with a functional type IV secretion system.
abstract: Helicobacter pylori infection is often acquired in childhood and can persist for life. Previous studies in adult patients have shown that H. pylori isolates from North American and European hosts express predominantly type 2 Lewis x (Le(x)) and Le(y) epitopes, while Asian strains have the capacity to express type 1 Le(a) and Le(b) structures. In order to understand the influence of environmental and host factors on the expression of Le antigens, we analysed 50 Greek H. pylori isolates from symptomatic children. Both CagA-positive and -negative strains were evaluated. The expression of Le antigens was determined by whole-cell indirect ELISA (WCE), and LPS profiles were assessed by gel electrophoresis and immunoblotting. Occurrence of Le(x) and/or Le(y) antigens was confirmed in 35 of the isolates (70 %) while 15 of the isolates were non-typable. It was found that 11 of the paediatric isolates had the propensity to express type 1 Le(b) blood-group antigen (22 %), a feature relatively uncommon in H. pylori isolates from adults. One strain expressed both Le(b) and Le(a) antigens. The majority of the isolates (49/50, 98 %) expressed α1,6-glucan, an antigenic non-Le determinant present in the outer core region of H. pylori LPS. All Le(x)- and Le(y)-expressing strains also carried a functional cag pathogenicity island-encoding a type IV secretion system, capable of translocating CagA protein, as well as the vacAs1 allele, suggesting that Le(x) and Le(y) epitopes may aid the persistence of more aggressive strains. No association between bacterial virulence characteristics and the histopathological observations was evident.
authors.affiliation: Institute for Biological Sciences, National Research Council Canada, Ottawa, ON K1A 0R6, Canada.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Altman
authors.affiliation: Institute for Biological Sciences, National Research Council Canada, Ottawa, ON K1A 0R6, Canada.
authors.forename: Vandana
authors.initials: V
authors.lastname: Chandan
authors.affiliation: Institute for Biological Sciences, National Research Council Canada, Ottawa, ON K1A 0R6, Canada.
authors.forename: Blair A
authors.initials: BA
authors.lastname: Harrison
authors.affiliation: Laboratory of Medical Microbiology, Hellenic Pasteur Institute, Athens 11521, Greece.
authors.forename: Effrosini G
authors.initials: EG
authors.lastname: Panayotopoulou
authors.affiliation: First Department of Pediatrics, Athens University School of Medicine, Athens, Greece.
authors.forename: Eleftheria
authors.initials: E
authors.lastname: Roma-Giannikou
authors.affiliation: Institute for Biological Sciences, National Research Council Canada, Ottawa, ON K1A 0R6, Canada.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Li
authors.affiliation: Laboratory of Medical Microbiology, Hellenic Pasteur Institute, Athens 11521, Greece.
authors.forename: Dionyssios N
authors.initials: DN
authors.lastname: Sgouras
mesh_terms: D000293:Adolescent; D000942:Antigens, Bacterial / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D005753:Gastric Mucosa / Q000382:microbiology; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D005936:Glucans / Q000235:genetics / Q000378:metabolism*; D006115:Greece / Q000453:epidemiology; D016481:Helicobacter Infections / Q000453:epidemiology / Q000382:microbiology*; D016480:Helicobacter pylori / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D006801:Humans; D007983:Lewis Blood Group Antigens / Q000235:genetics / Q000378:metabolism*
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D005936:Glucans; D007983:Lewis Blood Group Antigens; C504992:alpha-1-6-glucan; C080866:cagA protein, Helicobacter pylori