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Heterogeneous expression of CD23 epitopes by eosinophils from patients. Relationships with IgE-mediated functions
M Capron1, M J Truong, D Aldebert
1Centre d'Immunologie et de Biologie Parasitaire, Unité Mixte INSERM U 167-CNRS 624, Institut Pasteur de Lille, France.
Insights
Human eosinophils express a CD23-related molecule that binds Immunoglobulin E (IgE). This molecule participates in IgE-dependent eosinophil functions, suggesting a role in allergic responses.
Area of Science:
- Immunology
- Cell Biology
Background:
- The receptor for IgE (Fc epsilon RII) on human eosinophils shares characteristics with CD23, a B cell differentiation marker.
- Eosinophils play a role in allergic inflammation and immune responses.
Purpose of the Study:
- To evaluate the expression and function of CD23 epitopes on human eosinophils from patients with eosinophilia.
- To investigate the role of a CD23-related molecule in IgE-dependent eosinophil functions.
Main Methods:
- Flow cytometry was used to assess CD23 epitope expression on purified eosinophils.
- Monoclonal antibodies (mAbs) against CD23 were employed to study IgE binding and functional inhibition.
- Northern blot analysis was performed to detect CD23 transcripts in eosinophil RNA.
Main Results:
- A correlation was observed between myeloma IgE binding and the binding of a specific anti-CD23 mAb (mAb 135) to eosinophils.
- Low expression of certain CD23 epitopes was detected on eosinophils from eosinophilic patients.
- CD23 transcripts were found in a subset of eosinophils expressing membrane CD23.
- All tested anti-CD23 mAbs inhibited IgE-mediated cytotoxicity and IgE binding to eosinophils.
Conclusions:
- A CD23-related molecule is present on human eosinophils and participates in IgE-dependent functions.
- This finding suggests a potential role for CD23 in IgE-mediated eosinophil responses and allergic diseases.
Abstract:
The receptor for IgE (Fc epsilon RII) on human eosinophils presents some common characteristics with CD23, a differentiation marker of B cells. We have used flow cytometry for evaluating the expression of various epitopes of CD23 on purified eosinophils from patients with eosinophilia. A correlation was found between the binding of myeloma IgE protein and the binding of a monoclonal antibody (mAb 135), directed against the IgE-binding site of B cell CD23. Using two additional anti-CD23 mAb, directed (8-30) or not (3-5) against the IgE-binding site, a low expression of these CD23 epitopes was observed on eosinophils from different eosinophilic patients. Northern blot analysis of eosinophil RNA with the cDNA probe of CD23 revealed a low-abundance transcript in three of the six patients expressing membrane CD23. The inhibition by all anti-CD23 mAb of IgE-mediated cytotoxicity and IgE binding to eosinophils clearly indicated the participation of a CD23-related molecule in IgE-dependent eosinophil functions.