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

Background: Adhesion molecules may play an important role in eosinophilic a ctivation as well as adherence of extracellular matrix (ECM) including fibr onectin (FN) in the inflamed focus. Tissue eosinophils expressed intercellu lar adhesion molecule-1 (ICAM-1, CD54), whereas peripheral blood eosinophil s did not. The molecular mechanisms of ICAM-1 expression on eosinophils are not clear. We immunologically examined the effect of adherence to FN on th e expression of adhesion molecules in an eosinophilic cell line (EoL-1). Me thods: EoL-1 cells, suspended at a concentration of 2 x 10(6) cells/ml, wer e cultured at 37 degrees C in BSA or FN-coated 24-well plates. After 4 h, t he cells were removed by pipetting, and the expression of adhesion molecule s was evaluated by immunofluorescence. Results: Adherence of EoL-1 to FN en hanced 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 molec ules on EoL-1 (CD11a, CD18, CD49d), the expression was not significantly au gmented by adherence to FN. Conclusions: We concluded that the signal via a dhesion of FN regulates the expression of ICAM-1 on eosinophilic cells. Thi s study suggests that eosinophilic adhesion to ECM via adhesion molecules p lays an important role in the pathogenesis of allergic inflammation through eosinophilic functional changes, including regulation of expressive adhesi on molecules such as ICAM-1.