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Human eosinophils express and release IL-13 following CD28-dependent activation.
Gaetane Woerly1, Paige Lacy, Amena Ben Younes
1Centre d'Immunologie et Biologie Parasitaire, Unité INSERM U547 and IFR17, Institut Pasteur, Lille, France.
Journal of Leukocyte Biology
|October 16, 2002
Summary
Human eosinophils synthesize and store interleukin-13 (IL-13), a key cytokine in allergic inflammation. Eosinophil-derived IL-13 influences B cells and may contribute to T helper cell type 2 responses in allergies.
Area of Science:
- Immunology
- Cell Biology
Background:
- Human eosinophils are known to produce immunoregulatory cytokines.
- Eosinophils store and release interleukin-4 (IL-4), crucial in allergic inflammation.
- IL-4 and IL-13 share similar biological functions, prompting investigation into IL-13 synthesis by eosinophils.
Purpose of the Study:
- To investigate whether human eosinophils synthesize and store IL-13.
- To determine the cellular localization and release mechanisms of IL-13 in eosinophils.
- To assess the biological effects of eosinophil-derived IL-13 on other immune cells.
Main Methods:
- Flow cytometry and immunocytochemistry were used to detect IL-13 synthesis and localization.
- Subcellular fractionation and electron microscopy identified IL-13 within eosinophil granules.
- Experiments involving CD28 ligation and immunoglobulin A complexes assessed IL-13 release.
Main Results:
- Eosinophils were confirmed to synthesize and store IL-13.
- IL-13 was localized to the dense cores of bicompartmental secondary granules within eosinophils.
- Eosinophil-derived IL-13 was shown to induce CD23 expression on B cells, with release modulated by CD28 and IgA signaling.
Conclusions:
- Human eosinophils possess the capacity to synthesize, store, and release IL-13.
- Eosinophil-derived IL-13 can exert biological effects on B cells.
- Eosinophils may play a significant role in the development and maintenance of T helper cell type 2 responses characteristic of allergic diseases.