Regulation of eosinophil cell death by adhesion to fibronectin.

Fibronectin is an extracellular matrix (ECM) that binds to very late antigen-4 (a beta 1 integrin molecule) expressed by eosinophils. To investigate the effect of adherence to fibronectin on regulation of eosinophil cell death, survival of eosinophils was examined by trypan blue exclusion and Fas antigen expression on the cell surface using an eosinophilic cell line (EoL-1). Adhesion to fibronectin resulted in prolongation of eosinophil survival (fibronectin vs. bovine serum albumin (BSA), 62.9 +/- 5.10 vs. 53.9 +/- 4.30% viability at 72 h) and the decreasement of Fas antigen expression on EoL-1 (fibronectin vs. BSA, 24.3 +/- 2.15 vs. 74.5 +/- 8.25% positive). These findings suggest that eosinophil adhesion to ECM via adhesion molecules plays an important role in the pathogenesis of allergic inflammation, which involves eosinophil accumulation at the inflammatory site, through regulation of eosinophil cell death.