Effects of interleukin (IL)-3 and IL-5 on human eosinophil degranulation induced by complement components C3a and C5a.
It is suggested that eosinophils (Eos) play an important role in the pathogenesis of bronchial asthma by releasing cytotoxic cationic eosinophil granule proteins and damaging bronchial epithelial cells. However, the exact nature of the actual inducer of eosinophil degranulation in vivo is unclear. We examined eosinophil cationic protein (ECP) release from human Eos in response to soluble agonists such as C5a, C3a, platelet-activating factor, and FMLP with or without interleukin (IL)-3 or IL-5 priming. Eosinophil degranulation induced by these soluble agonists required the pretreatment of Eos by cytochalasin B even in IL-3 priming. Among four agonists, C5a was the most effective stimulus of ECP release either with or without IL-5 priming. IL-3 and IL-5 remarkably enhanced ECP release in Eos triggered by C3a and C5a. The enhancement of ECP release by IL-3 and IL-5 occurred at 0.1-0.3 ng/ml and became maximal at 10-30 ng/ml, concentration-dependently. The enhancement of ECP release by cytokines became optimal at an interval of 10 min. Our data support the importance of complement components and cytokines in eosinophil degranulation in vivo.
Takafuji
S
S
Department of Medicine and Physical Therapy, Faculty of Medicine, University of Tokyo, Japan.
Tadokoro
K
K
Ito
K
K
D001798:Blood Proteins / Q000378:metabolism; D015550:Cell Degranulation; D015926:Complement C3a / Q000819:agonists; D015936:Complement C5a / Q000819:agonists; D003571:Cytochalasin B / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D047091:Eosinophil Granule Proteins; D004804:Eosinophils / Q000276:immunology* / Q000502:physiology*; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology*; D015848:Interleukin-5 / Q000494:pharmacology*; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000819:agonists; D010972:Platelet Activating Factor / Q000819:agonists; D012260:Ribonucleases
D001798:Blood Proteins; D047091:Eosinophil Granule Proteins; D007377:Interleukin-3; D015848:Interleukin-5; D010972:Platelet Activating Factor; D003571:Cytochalasin B; D009240:N-Formylmethionine Leucyl-Phenylalanine; D015926:Complement C3a; D015936:Complement C5a; D012260:Ribonucleases