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Antigenic properties of HpaA and Omp18, two outer membrane proteins of Helicobacter pylori

Petra Voland1, Nadia Hafsi, Marco Zeitner

  • 1Department of Medicine and Gastroenterology, Technical University of Munich, Munich, Germany.

Infection and Immunity
|June 24, 2003
PubMed

Insights

Two Helicobacter pylori outer membrane proteins, HpaA and Omp18, are recognized by human dendritic cells. These proteins stimulate immune responses, indicating their antigenic potential in humans.

Area of Science:

  • Immunology
  • Microbiology
  • Proteomics

Background:

  • Outer membrane proteins (OMPs) of Helicobacter pylori are crucial for bacterial function and virulence.
  • Surface-exposed OMPs can elicit immune responses and are potential antigens.
  • Previous studies identified HpaA and Omp18 as serologically reactive H. pylori OMPs.

Purpose of the Study:

  • To investigate the immunogenic and antigenic potential of H. pylori OMPs HpaA and Omp18 in humans.
  • To determine the effect of HpaA and Omp18 on human antigen-presenting cells.

Main Methods:

  • Detection of HpaA and Omp18 encoding DNA using PCR across H. pylori strains.
  • Cloning and expression of recombinant HpaA (rHpaA) and rOmp18 in human kidney cells.
  • Incubation of recombinant proteins with human peripheral blood mononuclear cells, monocytes, and dendritic cells (DCs).
  • Analysis of cytokine secretion (IL-12, IL-10, IL-8) and expression of surface markers (MHC Class II, CD83) on immune cells.

Main Results:

  • HpaA and Omp18 DNA were detected in all tested H. pylori strains.
  • Recombinant HpaA and Omp18 elicited positive serological reactions only in sera from infected individuals.
  • rHpaA and rOmp18 induced significant secretion of IL-12 and IL-10 from DCs.
  • rHpaA and rOmp18 strongly stimulated MHC Class II and CD83 expression on DCs, indicating maturation and enhanced antigen presentation.
  • No significant IL-8 secretion was observed from monocytes upon stimulation with rHpaA and rOmp18.

Conclusions:

  • HpaA and Omp18 are recognized by human dendritic cells.
  • These H. pylori OMPs induce DC maturation and enhance antigen presentation.
  • HpaA and Omp18 possess specific antigenic potential in humans, contributing to the host immune response against H. pylori infection.

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