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Fc-binding components: a virulence factor in Actinobacillus actinomycetemcomitans?
1Institute of Microbiology, University of Oslo, Norway.
Oral Microbiology and Immunology
|December 1, 1991
Summary
Actinobacillus actinomycetemcomitans releases Fc-binding components that interfere with immune responses. These components can hinder phagocytosis and potentially contribute to periodontal disease by disrupting granulocyte and B-cell functions.
Area of Science:
- Microbiology
- Immunology
- Periodontal Disease Pathogenesis
Background:
- Actinobacillus actinomycetemcomitans produces components binding to the Fc region of Immunoglobulin G (IgG).
- These Fc-binding components are found in whole bacteria, capsular material, and culture medium.
Purpose of the Study:
- To investigate the presence and function of Fc-binding components from Actinobacillus actinomycetemcomitans.
- To determine the impact of these components on phagocytosis and immune system interactions.
Main Methods:
- Separation of Fc-binding components using SDS-PAGE.
- Immunoblotting with Fc-fragments and myeloma proteins.
- Phagocytosis assays with human granulocytes and antibody-opsonized erythrocytes.
Main Results:
- Fc-binding components were identified in various bacterial preparations.
- Protein A significantly reduced phagocytosis of opsonized erythrocytes.
- Bacterial medium components enhanced antibody opsonization, likely via Fc-binding component-mediated aggregation of IgG.
Conclusions:
- Released Fc-binding components from Actinobacillus actinomycetemcomitans can interfere with granulocyte phagocytosis and complement system activity.
- These bacterial components may contribute to periodontal lesions by modulating immune cell functions and potentially affecting B-cell responses.