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Peptides that mimic Candida albicans-derived beta-1,2-linked mannosides
T Jouault1, C Fradin, F Dzierszinski
1Laboratoire de Mycologie Fondamentale et Appliquée, INSERM EPI 9915, Université de Lille II, Faculté de Médecine H. Warembourg, Pôle Recherche, Place Verdun, 59037 Lille Cedex, France.
Abstract:
Beta-1,2-linked mannosides from Candida albicans phosphopeptidomannan (PPM) bind to macrophages through a receptor independent from the macrophage alpha-linked mannose receptor and stimulate these cells to secrete immune mediators. Anti-beta-1,2-linked mannoside but not anti-alpha-linked mannoside antibodies produced after immunization with neoglycoproteins protect animals from disseminated candidiasis. In this study, peptides that mimic beta-1,2-linked mannosides were isolated using phage display methodology. A phage library expressing random peptides was panned with an anti-beta-1,2-linked mannoside monoclonal antibody (mAb). After three rounds of biopanning, the isolated phages were able to inhibit recognition of C. albicans by the mAb. Sixty percent of the phages had an identical DNA insert corresponding to the peptide sequence FHENWPS that was recognized specifically by the mAb. Injection of KLH-coupled peptide into mice generated high titers of polyclonal antibodies against C. albicans yeast cell walls. The anti-FHENWPS antibodies bound to C. albicans PPM and were inhibited by soluble beta-1,2-mannotetraose. Together, these data provide evidence for mimotopic activity of the peptide selected by biopanning with the anti-beta-1,2-oligomannoside mAb.
Insights
Researchers identified a peptide that mimics Candida albicans beta-1,2-linked mannosides, crucial for immune cell binding and protection against candidiasis.
Area of Science:
- Immunology
- Microbiology
- Biochemistry
Background:
- Beta-1,2-linked mannosides from Candida albicans phosphopeptidomannan (PPM) interact with macrophages via a distinct receptor, stimulating immune responses.
- Antibodies targeting these beta-1,2-linked mannosides, but not alpha-linked ones, confer protection against candidiasis.
Purpose of the Study:
- To isolate peptides that mimic beta-1,2-linked mannosides using phage display.
- To characterize the mimotopic activity of selected peptides.
Main Methods:
- Phage display methodology was employed to screen a random peptide library.
- Biopanning was performed using an anti-beta-1,2-linked mannoside monoclonal antibody (mAb).
- Peptide specificity was confirmed by antibody binding assays and inhibition studies.
Main Results:
- A specific peptide sequence, FHENWPS, was identified and recognized by the anti-beta-1,2-linked mannoside mAb.
- Antibodies generated against the FHENWPS peptide bound to C. albicans PPM.
- These antibodies demonstrated inhibition by soluble beta-1,2-mannotetraose, confirming mimotopic activity.
Conclusions:
- The peptide FHENWPS effectively mimics Candida albicans beta-1,2-linked mannosides.
- This mimetic peptide can elicit protective immune responses against candidiasis.
- Phage display is a viable method for discovering functional peptide mimics of microbial carbohydrates.