Interleukin 5 (IL-5) is the main factor that promotes the terminal differentiation of eosinophil progenitors (as indicated by colony formation assays), and enhances the effector capacity of mature eosinophils. IL-5 is produced by T lymphocytes, CD4-/CD8- and mast cells and recently, messenger (m)RNA of this cytokine has been identified in eosinophils from patients with coeliac disease, asthma, or eosinophilic heart diseases. In this study, IL-5 mRNA and immunoreactive IL-5 protein were detected in tissue and blood eosinophils from patients with eosinophilic cystitis or hypereosinophilic syndromes but not in Crohn's disease. By electron microscopy associated to immunogold staining, immunoreactive IL-5 was identified in eosinophilic granules. After stimulation with IgA-, IgE-, or IgG-immune complexes, blood eosinophils were shown, by immunocytochemistry and by enzyme-linked immunosorbent assay, to secrete IL-5. These observations demonstrate that eosinophils, under physiological stimulation, can release significant amounts of IL-5, which may contribute to local eosinophil recruitment and activation.
Interleukin 5 synthesis by eosinophils: association with granules and immunoglobulin-dependent secretion.
S Dubucquoi, P Desreumaux, A Janin, O Klein, M Goldman, J Tavernier, A Capron, M Capron; Interleukin 5 synthesis by eosinophils: association with granules and immunoglobulin-dependent secretion.. J Exp Med 1 February 1994; 179 (2): 703–708. doi: https://doi.org/10.1084/jem.179.2.703
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