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In Vitro Assay of Bacterial Adhesion onto Mammalian Epithelial Cells
05:57

In Vitro Assay of Bacterial Adhesion onto Mammalian Epithelial Cells

Published on: May 16, 2011

Role of carbohydrate-mediated adherence in cytopathogenic mechanisms of Acanthamoeba

Z Cao1, D M Jefferson, N Panjwani

  • 1New England Eye Center, Tufts University School of Medicine, Boston, Massachusetts 02111, USA.

The Journal of Biological Chemistry
|June 23, 1998
PubMed

Insights

Acanthamoeba keratitis is a serious eye infection. This study shows that blocking Acanthamoeba adhesion with mannose-based sugars inhibits parasite-induced eye damage and proteinase secretion.

Area of Science:

  • Ophthalmology
  • Microbiology
  • Cell Biology

Background:

  • Acanthamoeba keratitis is a severe corneal infection that can lead to vision loss.
  • The mannose-binding protein of Acanthamoeba is crucial for parasite adhesion to host cells.
  • Understanding Acanthamoeba's cytopathic mechanisms is vital for developing effective treatments.

Purpose of the Study:

  • To characterize the carbohydrate-binding properties of the Acanthamoeba lectin.
  • To investigate the role of the lectin in Acanthamoeba-induced cytopathic effect (CPE).
  • To identify the specific proteinases involved in Acanthamoeba-mediated corneal cell damage.

Main Methods:

  • Sugar inhibition assays were used to determine the lectin's carbohydrate binding affinities.
  • In vitro cytopathic assays assessed the impact of saccharides on amoeba adhesion and CPE.
  • Zymography identified proteinases secreted by Acanthamoeba during co-culture with host cells.

Main Results:

  • The Acanthamoeba lectin exhibits high affinity for alpha-Mannose and Man(alpha1-3)Man units.
  • Mannose-based saccharides inhibited both amoeba adhesion to corneal cells and Acanthamoeba-induced CPE.
  • N-acetyl-D-glucosamine (GlcNAc) inhibited CPE but not adhesion, and also reduced metalloproteinase and serine proteinase secretion.
  • A contact-dependent metalloproteinase was implicated in Acanthamoeba-induced cytolysis.

Conclusions:

  • Lectin-mediated adhesion is a prerequisite for Acanthamoeba-induced cytolysis.
  • Specific carbohydrates can inhibit both adhesion and CPE, suggesting therapeutic potential.
  • Metalloproteinases play a key role in the cytopathogenic mechanisms of Acanthamoeba.

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