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The interaction between Acanthamoeba polyphaga and human osteoblastic cells in vitro
Bruno da Rocha-Azevedo1, Gustavo Conde Menezes, Fernando Costa e Silva-Filho
1Programa de Bioengenharia e Biotecnologia Animal, Laboratório de Biologia da Superfície Celular, UFRJ, Instituto de Biofísica Carlos Chagas Filho, Rio de Janeiro, RJ, Brazil.
Microbial Pathogenesis
|December 6, 2005
Summary
Acanthamoeba polyphaga, a common amoeba, readily attaches to and destroys human osteoblasts, potentially causing osteomyelitis. Mannose-associated molecules on the amoeba surface facilitate this interaction.
Area of Science:
- Microbiology
- Cell Biology
- Pathology
Background:
- Acanthamoeba spp. are ubiquitous free-living amoebae.
- These microorganisms can cause human diseases, including osteomyelitis.
Purpose of the Study:
- To characterize the cellular interaction between Acanthamoeba polyphaga and human osteoblasts.
- To evaluate the cytoadherence and cytotoxicity of clinical and freshwater isolates of A. polyphaga.
Main Methods:
- Quantitative and qualitative evaluation of amoeba cytoadherence to human osteoblastic cells (HOB).
- Assessment of mannose-dependent cytoadhesion using alpha-mannose.
- Scanning electron microscopy to visualize cell interactions.
- Evaluation of cytotoxicity of A. polyphaga to HOB cells.
Main Results:
- A clinical isolate of A. polyphaga demonstrated saturable, time-dependent adherence to HOB cells.
- Mannose-associated surface glycoconjugates were partially responsible for cytoadhesion (approx. 75% reduction with alpha-mannose).
- A. polyphaga exhibited acanthapodia contacting osteoblasts, and some osteoblasts showed signs of apoptosis.
- The clinical isolate was highly toxic to HOB cells, with cytotoxicity dependent on the amoeba-cell ratio.
- Amoebae were observed ingesting HOB cells and extending projections into them.
Conclusions:
- Acanthamoeba polyphaga trophozoites attach to and destroy human osteoblasts.
- This interaction highlights a potential mechanism for Acanthamoeba-induced osteomyelitis.