title: Constitutive production of IL-4 and IL-10 and stimulated production of IL-8 by normal peripheral blood eosinophils.
abstract: To study the capacity and regulation of cytokine production by normal peripheral blood eosinophils, we isolated eosinophils from healthy individuals and stimulated them with immobilized Ig or TNF-alpha, with or without exogenous IL-5. By reverse transcription-PCR, uncultured, freshly isolated eosinophils constitutively expressed mRNA for IL-4, IL-10, and TGF-beta1. Eosinophils stimulated by immobilized secretory IgA, immobilized IgA, immobilized IgG, or TNF-alpha for 3 h expressed mRNA encoding IL-3, IL-4, IL-8, IL-10, granulocyte-macrophage CSF, TNF-alpha, TGF-beta, and RANTES. The mRNA for IL-2, IL-5, or IFN-gamma was not detected. IL-4 and IL-10 protein, but not IL-8, were measurable in lysates of fresh eosinophils or eosinophils cultured with medium alone for 24 h. Eosinophils incubated with immobilized Ig or TNF-alpha released IL-8 protein into the supernatants. In contrast, IL-4 and IL-10 proteins were not detectable. Soluble secretory IgA immune complexes also induced degranulation, as measured by eosinophil-derived neurotoxin, and IL-8 release, but not IL-4 or IL-10 release, from eosinophils. Release of IL-8 protein and storage of IL-4 and IL-10 proteins were enhanced by exogenous IL-5 and inhibited by a transcription inhibitor, actinomycin D. Degranulation of stored granule proteins was not affected by actinomycin D. Therefore, normal peripheral blood eosinophils can transcribe and synthesize several cytokines, including IL-4, IL-8, and IL-10; some are stored, and some are released. These cytokines may play important roles in modulating immune responses in diseases associated with eosinophils.
authors.affiliation: Department of Immunology, Mayo Graduate School of Medicine, Mayo Clinic and Mayo Foundation, Rochester, MN 55905, USA.
authors.forename: H
authors.initials: H
authors.lastname: Nakajima
authors.forename: G J
authors.initials: GJ
authors.lastname: Gleich
authors.forename: H
authors.initials: H
authors.lastname: Kita
mesh_terms: D001483:Base Sequence; D015550:Cell Degranulation / Q000187:drug effects; D017931:DNA Primers / Q000737:chemistry; D003609:Dactinomycin / Q000494:pharmacology; D004804:Eosinophils / Q000378:metabolism*; D015870:Gene Expression; D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000276:immunology; D016753:Interleukin-10 / Q000096:biosynthesis*; D015847:Interleukin-4 / Q000096:biosynthesis*; D016209:Interleukin-8 / Q000096:biosynthesis*; D015759:Ionomycin / Q000494:pharmacology; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D017931:DNA Primers; D007071:Immunoglobulin A, Secretory; D016209:Interleukin-8; D012333:RNA, Messenger; D016753:Interleukin-10; D003609:Dactinomycin; D015847:Interleukin-4; D015759:Ionomycin