Effect of Cysteinyl Leukotriene Receptor Antagonists on Leukotirene D4-Induced Chemotaxis of Human Eosinophilc Cell Line, Eol-1 Cells

Many reports have shown that cysteinyl leukotrienes (CysLTs) contribute to tissue accumulation of eosinophils in allergic airway inflammation, because CysLT1 antagonists such as montelukast and pranlukast reduce the number of eosinophils in allergic aiway mucosa. To date, only a few reports have shown chemotactic activity of CysLTs on human eosinophils in vitro. The purpose of this study was to investigate whether CysLTs had chemotactic activity on human eosinophilic cell line. A human eosinophilic cell line, EoL-1 cells differentiated into mature eosinophil-like cells when incubated with butyric acid and cytokines (IL-3, IL-5 and GM-CSF). Chemotactic activity of the differentiated EoL-1 cells was assessed using the commercial cell migration assay kit (CytoSelectTM). The migratory cells which passed through PET membrane inserts were then dissociated from the membrane and subsequently detected by CyQuantTM GR dye. The level of migrated EoL-1 cells was measured by using fluorescence plate reader. LTD4 caused a dose-related chemotactic activity of the differnciated EoL-1 cells in the range of 1-100nM. The chemotactic activity generated by LTD4 (10nM) was strongly inhibited by montelukast (100nM). By contrast, montelukast was completely unable to inhibit the chemotactic activity generated with PAF 10nM. This in vitro model may be useful for clarify the mechanism of CysLTs-induced tissue eosinophilia.