POSSIBLE RELEASE OF EOSINOPHIL GRANULE PROTEINS IN RESPONSE TO SIGNALING FROM INTERCELLULAR-ADHESION MOLECULE-1 AND ITS LIGANDS

The presence of a large variety of membrane receptors and the identification of cytotoxic molecules (mainly granule basic proteins) have indicated that eosinophils should be considered as effector cells. It has recently been suggested that adhesion molecules, particularly intercellular adhesion molecule-1 (ICAM-1), play an important role in allergic inflammation, for example in bronchial asthma. This study therefore investigated the possible release of granule protein in response to signaling from ICAM-1 and its ligands. The concentrations of eosinophil cationic protein and eosinophil-derived neurotoxin in supernatants of eosinophils were significantly greater (p < 0.05) in the presence of recombinant soluble ICAM-1 than without it. These results suggest that signaling from ICAM-1 and its ligands might induce eosinophil activation and might be involved in degranulation of eosinophil granule proteins, e.g. eosinophil cationic protein and eosinophil-derived neurotoxin.