IL-5 as a strong secretagogue for human eosinophils.
The ability of IL-5 to induce eosinophil degranulation was investigated. Peripheral blood eosinophils from patients with mildly allergic individuals were isolated with CD16- selection method. Eosinophils were then incubated with interleukin-5 (IL-5) (0.1-100 ng/ml) for 1-48 h and EPX in the supernatants were measured with RIA. We found that IL-5 induced significant amount of eosinophil protein X in a concentration-dependent manner at 24 h. Eosinophil viability was about 90% either in the presence or absence of IL-5 at 24 h. Eosinophils stimulated with IL-5 adhered to the plate. Anti-CD18 mAb blocked adhesion and degranulation induced by IL-5. Dexamethasone and TGFbeta significantly inhibited degranulation in a concentration-dependent manner. These results suggest that IL-5 may be a strong secretagogue for eosinophils, that adhesion via beta2 integrin is a requisite for degranulation, and that the anti-inflammatory effect of corticosteroids and TGFbeta may be exerted at least in part, through the inhibition of eosinophil degranulation.
Fujisawa
T
T
Department of Pediatrics, Mie National Hospital, Japan.
Terada
A
A
Atsuta
J
J
Iguchi
K
K
Kamiya
H
H
Sakurai
M
M
D018821:CD18 Antigens; D002448:Cell Adhesion; D015550:Cell Degranulation; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004804:Eosinophils / Q000166:cytology / Q000187:drug effects*; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology*; D006969:Hypersensitivity, Immediate / Q000276:immunology*; D015848:Interleukin-5 / Q000494:pharmacology*
D018821:CD18 Antigens; D015848:Interleukin-5