title: Antigenic diversity among Portuguese clinical isolates of Helicobacter pylori.
abstract: BACKGROUND
  The human gastroduodenal pathogen, Helicobacter pylori, is characterized by an unusual extent of genetic heterogeneity. This dictates differences in the antigenic pattern of strains resulting in heterogeneous human humoral immune responses. Here, we examined the antigenic variability among a group of 10 strains isolated from Portuguese patients differing in age, gender, and H. pylori-associated gastric diseases.
  
  
  METHODS
  Immunoassays were performed on two-dimensional electrophoresis gels obtained for the proteome of each strain, using a commercial pool of antibodies produced in rabbit, against the whole cell lysate of an Australian H. pylori strain. Relevant proteins were identified by mass spectrometry.
  
  
  RESULTS
  Immunoproteomes of the Portuguese strains showed no correlation between the number of antigenic proteins or the antigenic profile, and the disease to which each strain was associated. The Heat shock protein B was the unique immunoreactive protein common to all of them. Additionally, seven proteins were found to be antigenic in at least 80% of strains: enoyl-(acyl-carrier-protein) reductase (NADH); Catalase; Flagellin A; 2 isoforms of alkyl hydroperoxide reductase; succinyl-CoA transferase subunit B; and an unidentified protein. These proteins were present in the proteome of all tested strains, suggesting that differences in their antigenicity are related to antigenic variance.
  
  
  CONCLUSIONS
  This study showed evidence of the variability of antigenic pattern among H. pylori strains. We believe that this fact contributes to the failure of anti-H. pylori vaccines and the low accuracy of serological tests based on a low number of proteins or antigens of only one strain.
authors: Faculdade de Engenharia, Universidade Católica Portuguesa, Rio de Mouro, Portugal Chymiotechnon, Departamento de Química, Universidade de Coimbra, Coimbra, Portugal.
authors: Inês
authors: I
authors: Vitoriano
authors: Alexandra
authors: A
authors: Rocha-Gonçalves
authors: Teresa
authors: T
authors: Carvalho
authors: Mónica
authors: M
authors: Oleastro
authors: Cecília R C
authors: CR
authors: Calado
authors: Mónica
authors: M
authors: Roxo-Rosa
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000940:Antigenic Variation / Q000276:immunology*; D000942:Antigens, Bacterial / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D016480:Helicobacter pylori / Q000276:immunology*; D006801:Humans; D007118:Immunoassay / Q000379:methods; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D000942:Antigens, Bacterial