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Complement resistance of pathogenic Entamoeba histolytica mediated by trypsin-sensitive surface component(s)
C Hamelmann1, B Urban, B Foerster
1Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.
Infection and Immunity
|May 1, 1993
Summary
Pathogenic and nonpathogenic Entamoeba histolytica resist the alternative complement pathway (AP) by inhibiting AP amplification. However, pathogenic strains require intact membrane mobility and trypsin-sensitive surface components for AP resistance.
Area of Science:
- Immunology
- Parasitology
- Cell Biology
Background:
- Pathogenic Entamoeba histolytica (E. histolytica) temporarily resists the alternative complement pathway (AP), while nonpathogenic forms exhibit stable AP resistance.
- Understanding the distinct mechanisms of AP resistance is crucial for developing therapeutic strategies against amoebiasis.
Purpose of the Study:
- To elucidate the differing mechanisms underlying alternative complement pathway resistance in pathogenic versus nonpathogenic Entamoeba histolytica.
Main Methods:
- Comparative analysis of C3 product binding on amebae exposed to AP activity.
- Enzymatic treatments (e.g., trypsin) to identify surface components involved in resistance.
- Inhibition of membrane mobility using cytochalasin B and glutaraldehyde fixation.
Main Results:
- Both resistant pathogenic and nonpathogenic E. histolytica bound significantly less C3 products than sensitive strains, indicating inhibition of AP amplification.
- Mechanisms of AP inhibition differed: pathogenic E. histolytica required intact membrane mobility and trypsin-sensitive surface components, unlike nonpathogenic forms.
Conclusions:
- Entamoeba histolytica employs distinct strategies to resist complement-mediated lysis.
- Pathogenic E. histolytica's AP resistance is dependent on dynamic membrane processes and specific surface molecules, offering potential targets for intervention.