Inhibitory effect of ibudilast (KC-404) on the expression of the beta(2) integrin family on an eosinophilic cell line (EoL-1)

Background: Adhesion molecules are thought to play a key role in inflammato ry processes in bronchial asthma. We previously observed an increased expre ssion of the beta(2)-integrin family on an eosinophilic cell line (EoL-1) b y platelet-activating factor (PAF). Objective: In the present study, we examined the effect of ibudilast (KC-40 4), a novel anti-asthma agent, on beta(2) integrin expression induced by PA F. Material and Methods: EoL-1 cells (1 x 10(6)/mL) were incubated in the pres ence or absence of 10(-6)M ibudilast (KC-404), then cells were cultured in the presence or absence of PAF (10(-7)M) for 45 minutes. Flow cytometric an alysis for CD11a, CD11b, and CD18 expression was examined. Results: Ibudilast had an inhibitory effect on beta(2) integrin expression induced by PAF [CD11a: 84.8% versus 73.1% (preincubation with ibudilast), C D11b: 35.8% versus 26.2%, CD18 74.9% versus 65.6%]. Conclusions: Ibudilast: (KC-404) has anti-inflammatory activities through i ts inhibitory effect on the expression of adhesion molecules on eosinophils .