[Eosinophil chemotaxis assay using novel device EZ-TAXIScan].
Eosinophils are major effector cells in the pathogenesis of allergic inflammation such as bronchial asthma, and eosinophil migration to sites of inflammation is an important step. To date, several approaches have been developed to study eosinophil chemotaxis. Among them, the Boyden chamber method has been widely used, although this system requires a relatively large number of cells, and it usually provides no longitudinal information. In this study, we investigated real-time eosinophil chemotaxis using EZ-TAXIScan, a novel horizontal microchannel device. Eosinophils were isolated from subjects with mild eosinophilia by modified CD16-negative selection. Eosinophil chemotaxis and migration speed induced by various chemoattractants including eotaxin, RANTES, PAF, and prostaglandin (PGD2) were measured by EZ-TAXIScan. We also determined the time course of chemotaxis using Boyden chambers. By using EZ-TAXIScan, rapid (a few minutes after stimulation) and fast (20-30 microm/min) eosinophil chemotactic responses were observed by stimulation with PAF or PGD2, although eosinophils stimulated with eotaxin or RANTES showed relatively late (60 minutes after stimulation) and slow (15 microm/min) responses. In contrast, using a Boyden Chamber, the chemotactic responses we tested showed a similar time course peaking at 20-60 min. The availability of EZ-TAXIScan for investigation of eosinophil chemotaxis was confirmed. However, it should be noted that EZ-TAXIScan showed a different response to certain chemoattractants compared with the conventional method.