[The roles of adhesion molecules, cytokines, and chemokines in eosinophil activation during allergic inflammation].
Patients with hypereosinophila have at least two subpopulation of eosinophils: "normodense" and "hypodense". Hypodense eosinophils can be distinguished by their increased expression of various membrane receptors including IL-5 receptors (J Exp Med 172: 1347) and by the expression of particular proteins (J Immunol 142: 4416). Recently, adhesion molecules have also been found to play an important role in the inflammatory processes in allergic disease. 1) Adhesion molecules were found to be strongly expressed on eosinophils from patients with asthma. 2) Platelet activating factor and induced the expression of adhesion molecules as did the supernatant of mononuclear cells from mite-allergic patients with asthma stimulated either with mite allergen or with a combination of recombinant IL-3, GM-CSF, and IL-5 (Immunol, Lett. 42: 25, '94, & 46: 241, '95). 3) Patients with bronchial asthma had a high level of soluble ICAM-1) (Lancet. 343: 1108, '94). Moreover, the presence of a large variety of membrane receptors and the identification of cytotoxic molecules (mainly granule basic proteins) indicate that eosinophils should be considered effector cells. Therefore the release of granule proteins in response to ICAM-1 and its ligands was studied. The concentrations of eosinophil cationic protein and eosinophil-derived neurotoxin in supernatants of eosinophils were significantly greater in the presence of recombinant soluble ICAM-1 than in its absence (p < 0.05). These results suggest that signals from ICAM-1 and its ligands induce eosinophil activation and are involved in degranulation of eosinophil granule proteins. In addition, reactive oxygen species generated by eosinophils have also been considered capable of causing airway injury at sites of inflammation. The effect of recombinant soluble ICAM-1 and its ligands on eosinophil-induced radical oxygen products was studied. Recombinant soluble ICAM-1 augmented eosinophil oxidative metabolism. Therefore, signaling via adhesion molecules might play an important role in the pathogenesis of allergic inflammation. Specifically, it may activate eosinophils and increase oxidative metabolism or cause degranulation of eosinophil granule proteins.
Chihara
J
J
Department of Clinical and Laboratory Medicine, Akita University School of Medicine, Japan.
D015550:Cell Degranulation; D018925:Chemokines / Q000502:physiology*; D016207:Cytokines / Q000502:physiology*; D004802:Eosinophilia / Q000209:etiology; D004804:Eosinophils / Q000502:physiology*; D006801:Humans; D006967:Hypersensitivity / Q000209:etiology*; D007249:Inflammation / Q000209:etiology*; D018799:Intercellular Adhesion Molecule-1 / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction
D018925:Chemokines; D016207:Cytokines; D017382:Reactive Oxygen Species; D018799:Intercellular Adhesion Molecule-1