title: CD69 is expressed by human eosinophils activated in vivo in asthma and in vitro by cytokines.
abstract: CD69 is an early activation marker for T cells and cross-linking of CD69 on platelets triggers aggregation and mediator release. Expression of a number of membrane receptors is induced on eosinophils after culture with certain cytokines. Therefore, we investigated whether cytokine-activated eosinophils expressed CD69. Unstimulated, peripheral blood eosinophils did not express CD69, as determined by immunofluorescence and flow cytometry (n = 15). CD69 expression was induced on eosinophils by granulocyte-macrophage colony-stimulating factor (GM-CSF) in a time- and dose-dependent manner. After 1 day in culture, expression was significant at concentrations of 10(-11) M and above. CD69 expression could be detected after stimulation with GM-CSF for only 1 hr, was significant after 2 hr and was sustained over 1-2 days in culture. CD69 expression was also induced by interleukin-3 (IL-3), IL-5 and interferon-gamma (IFN-gamma), but stimulation of eosinophils with platelet-activating factor (PAF) (10(-6) M) for up to 2 hr did not induce CD69 expression. Cycloheximide (10(-6) M) significantly inhibited GM-CSF-induced CD69 expression, suggesting a requirement for protein synthesis. However, unlike up-regulation of CR3 expression, GM-CSF-induced CD69 expression was not inhibited by dexamethasone. CD69 was present on eosinophils from the bronchoalveolar lavage (BAL) fluid of patients with mild asthma (5/5), suggesting that the in vitro findings may have biological relevance in vivo. Therefore, CD69 can be used as a marker of eosinophil activation by cytokines and is a candidate receptor for triggering eosinophil mediator release in the airways in asthma.
authors.affiliation: Department of Allergy and Clinical Immunology, National Heart and Lung Institute, London, U.K.
authors.forename: A
authors.initials: A
authors.lastname: Hartnell
authors.forename: D S
authors.initials: DS
authors.lastname: Robinson
authors.forename: A B
authors.initials: AB
authors.lastname: Kay
authors.forename: A J
authors.initials: AJ
authors.lastname: Wardlaw
mesh_terms: D015703:Antigens, CD / Q000032:analysis* / Q000187:drug effects; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis*; D001249:Asthma / Q000276:immunology*; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D016207:Cytokines / Q000276:immunology*; D003907:Dexamethasone / Q000494:pharmacology; D004804:Eosinophils / Q000276:immunology*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000276:immunology; D006801:Humans; D066298:In Vitro Techniques; D037181:Lectins, C-Type; D010972:Platelet Activating Factor / Q000276:immunology; D000099192:CD69 Antigens
chemical_list: D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D003513:Cycloheximide; D016207:Cytokines; D003907:Dexamethasone; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D037181:Lectins, C-Type; D010972:Platelet Activating Factor; D000099192:CD69 Antigens