Interleukin 5 synthesis by eosinophils: association with granules and immunoglobulin-dependent secretion.
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.
Dubucquoi
S
S
Centre d'Immunologie et de Biologie Parasitaire, Institut Pasteur, Lille, France.
Desreumaux
P
P
Janin
A
A
Klein
O
O
Goldman
M
M
Tavernier
J
J
Capron
A
A
Capron
M
M
D003594:Cytoplasmic Granules / Q000378:metabolism; D004804:Eosinophils / Q000276:immunology / Q000378:metabolism*; D005260:Female; D006801:Humans; D007136:Immunoglobulins / Q000276:immunology; D007150:Immunohistochemistry; D015848:Interleukin-5 / Q000096:biosynthesis* / Q000378:metabolism; D008854:Microscopy, Electron; D008875:Middle Aged; D012333:RNA, Messenger / Q000378:metabolism
D007136:Immunoglobulins; D015848:Interleukin-5; D012333:RNA, Messenger