Adhesion to fibronectin regulates expression of intercellular adhesion molecule-1 on eosinophilic cells

Background: Adhesion molecules may play an important role in eosinophilic activation as well as adherence of extracellular matrix (ECM) including fibronectin (FN) in the inflamed focus. Tissue eosinophils expressed intercellular adhesion molecule-1 (ICAM-1, CD54), whereas peripheral blood eosinophils did not. The molecular mechanisms of ICAM-1 expression on eosinophils are not clear. We immunologically examined the effect of adherence to FN on the expression of adhesion molecules in an eosinophilic cell line (EoL-1). Methods: EoL-1 cells, suspended at a concentration of 2 x 10(6) cells/ml, were cultured at 37 degrees C in BSA or FN-coated 24-well plates. After 4 h, the cells were removed by pipetting, and the expression of adhesion molecules was evaluated by immunofluorescence. Results: Adherence of EoL-1 to FN enhanced ICAM-1 (CD54) expression on EoL-1. (FN vs. BSA: 84.76 +/- 17.90 vs. 43.73 +/- 7.60, mean fluorescent intensity). Regarding other adhesion molecules on EoL-1 (CD11a, CD18, CD49d), the expression was not significantly augmented by adherence to FN. Conclusions: We concluded that the signal via adhesion of FN regulates the expression of ICAM-1 on eosinophilic cells. This study suggests that eosinophilic adhesion to ECM via adhesion molecules plays an important role in the pathogenesis of allergic inflammation through eosinophilic functional changes, including regulation of expressive adhesion molecules such as ICAM-1.