Effect of a novel interleukin-5 receptor antagonist, YM-90709 (2,3-dimethoxy-6,6-dimethyl-5,6-dihydrobenzo(7,8)indolizino(2,3-b)quinoxal ine), on antigen-induced airway inflammation in BN rats.

摘要

Interleukin-5 (IL-5) plays an important role in the activation of eosinophils in the allergic inflammation in conditions such as asthma, rhinitis, and atopic dermatitis. A newly synthesized compound, YM-90709 (2,3-dimethoxy-6,6-dimethyl-5,6-dihydrobenzo[7,8]indolizino[2,3-b]quinoxal ine), was previously reported to inhibit the binding of IL-5 to its receptor (R) on human eosinophils and eosinophilic HL-60 clone 15 cells. However, it did not inhibit the binding of granulocyte-macrophage colony-stimulating factor (GM-CSF) to its receptor on the same cells. In this study, the intravenous injection of YM-90709 resulted in the inhibition of antigen-induced infiltration of eosinophils and lymphocytes, but not neutrophils or monocytes, into the bronchoalveolar lavage fluid (BALF) of Brown-Norway (BN) rats, with ED(50) values of 0.32 mg/kg and 0.12 mg/kg, respectively. Two glucocorticoids, dexamethasone and prednisolone, inhibited neutrophil, eosinophil, and lymphocyte infiltration into the BALF. However, bothsignificantly reduced the number of peripheral blood leukocytes and bone marrow leukocytes. In contrast, YM-90709 did not affect the peripheral blood leukocytes or the bone marrow leukocytes. These results indicate that, in this model, YM-90709, which is a novel IL-5 R antagonist, inhibits antigen-induced eosinophil and lymphocyte recruitment into the airway, without any suppressive effects on peripheral blood leukocytes or bone marrow leukocytes, in contrast to the glucocorticoids.