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Updated: Jun 30, 2026

High Resolution Electron Microscopy of the Helicobacter pylori Cag Type IV Secretion System Pili Produced in Varying Conditions of Iron Availability
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High Resolution Electron Microscopy of the Helicobacter pylori Cag Type IV Secretion System Pili Produced in Varying Conditions of Iron Availability

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Alterations in Helicobacter pylori outer membrane and outer membrane vesicle-associated lipopolysaccharides under

Jacqueline I Keenan1, Kylie A Davis, Clare R Beaugie

  • 1Department of Surgery, University of Otago, Christchurch, New Zealand. jacqui.keenan@otago.ac.nz

Innate Immunity
|September 24, 2008
PubMed

Insights

Iron availability alters lipopolysaccharide (LPS) structure and content in Helicobacter pylori outer membrane vesicles (OMVs). Iron-limited conditions reduce LPS length and Lewis antigen expression, impacting OMV composition and potentially H. pylori pathogenesis.

Area of Science:

  • Microbiology
  • Pathogenesis
  • Host-pathogen interactions

Background:

  • Helicobacter pylori outer membrane vesicles (OMVs) influence host epithelial cell responses.
  • Lipopolysaccharide (LPS) on H. pylori OMVs plays a role in pathogenesis.
  • Iron availability is a critical factor for bacterial growth and virulence.

Purpose of the Study:

  • To investigate the impact of iron availability on the quantity and structure of LPS in H. pylori and its OMVs.
  • To elucidate the basis for observed differences in LPS production under varying iron conditions.
  • To assess the implications of these changes for H. pylori pathogenesis.

Main Methods:

  • Culturing H. pylori under iron-limited and iron-replete conditions.
  • Electrophoretic, immunoblotting, and structural analyses of bacterial and OMV LPS.
  • Serological probing to determine O-chain composition (Lewis antigens).
  • Quantification of LPS content in shed OMVs.
  • Assessment of bacterial ATP levels.

Main Results:

  • Iron-limited H. pylori produced shorter LPS with reduced Lewis(y) expression compared to iron-replete counterparts.
  • OMVs from iron-replete bacteria were enriched in LPS, while those from iron-limited bacteria had significantly reduced LPS content.
  • Core oligosaccharide and lipid A structures remained similar across conditions.
  • Differences in LPS content were correlated with bacterial ATP levels.

Conclusions:

  • Iron availability significantly modulates the extent and nature of LPS expressed by H. pylori and its shed OMVs.
  • Changes in OMV LPS composition, particularly reduced LPS and altered antigenicity, may influence H. pylori's interaction with the host.
  • Host iron status could be a contributing factor in Helicobacter pylori pathogenesis.

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