Adhesion molecules may play an important role not only in adherence of inflammatory cells (particularly eosinophils) to an inflamed focus but also in activation of these cells. It is therefore of interest to evaluate eosinophil activation via intercellular adhesion molecule-1 (ICAM-1) and the beta 2-integrin family, namely CR3 (Mac-1), lymphocyte function-associated antigen (LFA)-1 alpha and LFA-1 beta, which are ligands for ICAM-1. Reactive oxygen species generated by eosinophils have also been considered capable of causing airway injury at the inflamed focus. This study examined the effect of recombinant soluble ICAM-1 and its ligands on eosinophil-induced radical oxygen products in terms of luminol-dependent chemiluminescence. Recombinant soluble ICAM-1 augmented eosinophil oxidative metabolism. It was concluded that signaling via adhesion molecules might play an important role in the pathogenesis of allergic inflammation through activation of eosinophils, e.g. an increase in oxidative metabolism.