Background: Eosinophils play a central role in the induction and perpetuation of allergic inflammatory responses. The present study was performed to investigate the effects of reactive oxygen intermediates on constitutive apoptosis as well as on interleukin (IL)-5 afforded human eosinophil survival. Methods: Peripheral blood eosinophils were isolated by CD16-negative selection to >99% purity and were cultured for 48 h. The number of apoptotic eosinophils in the culture was assessed by flow cytometric analysis of relative DNA content in propidium-iodide-stained cells, annexin-V binding or by morphological analysis. Apoptosis was confirmed by the appearance of a typical ladder pattern in the DNA fragmentation assay by agarose gel electrophoresis. Results: Exogenous H2O2 reversed IL-5-afforded eosinophil survival by inducing apoptosis. Constitutive eosinophil apoptosis was inhibited by a reduction of intracellular levels of H2O2 by catalase. Exogenous H2O2 increased the rate of constitutive apoptosis. Conclusions: Our results suggest that H2O2 may play a role in the downregulation of eosinophilic inflammation by inducing eosinophil apoptosis.

1.
Barnes PJ, Pedersen S, Busse WW: Efficacy and safety of inhaled corticosteroids. New developments. Am J Respir Crit Care Med 1998;157:S1–S53.
2.
Seminario MC, Gleich GJ: The role of eosinophils in the pathogenesis of asthma. Curr Opin Immunol 1994;6:860–864.
3.
Simon HU, Blaser K: Inhibition of programmed eosinophil death: A key pathogenic event for eosinophilia? Immunol Today 1995;16:53–55.
4.
Simon HU, Yousefi S, Schranz C, Schapowal A, Bachert C, Blaser K: Direct demonstration of delayed eosinophil apoptosis as a mechanism causing tissue eosinophilia. J Immunol 1997;158:3902–3908.
5.
Walsh GM: Mechanism of human eosinophil survival and apoptosis. Clin Exp Allergy 1997;27:482–487.
6.
Stern M, Savill J, Haslett C: Human monocyte-derived macrophage phagocytosis of senescent undergoing apoptosis. Mediation by αvβ3/CD36/thrombospondin recognition mechanism and lack of phlogistic response. Am J Pathol 1996;149:911–921.
7.
Yamaguchi Y, Suda T, Ohta S, Tominaga K, Miura Y, Kasahara T: Analysis of the survival of mature human eosinophils: Interleukin-5 prevents apoptosis in mature human eosinophils. Blood 1991;78:2542–2547.
8.
Stern M, Meagher L, Savill J, Haslett C: Apoptosis in human eosinophils. Programmed cell death in the eosinophil leads to phagocytosis by macrophages and is modulated by IL-5. J Immunol 1992;148:3543–3549.
9.
Tai PC, Sun L, Spry CJ: Effects of IL-5, granulocyte/macrophage colony-stimulating factor (GM-CSF) and IL-3 on the survival of human blood eosinophils in vitro. Clin Exp Immunol 1991;85:312–316.
10.
Kankaanranta H, Lindsay MA, Giembycz MA, Zhang X, Moilanen E, Barnes PJ: Delayed eosinophil apoptosis in asthma. J Allergy Clin Immunol 2000;106:77–83.
11.
Wedi B, Raap U, Lewrick H, Kapp A: Delayed eosinophil programmed cell death in vitro: A common feature of inhalant allergy and extrinsic and intrinsic atopic dermatitis. J Allergy Clin Immunol 1997;100:536–543.
12.
Giembycz MA, Lindsay MA: Pharmacology of the eosinophil. Pharmacol Rev 1999;51:213–340.
13.
Wedi B, Straede J, Wieland B, Kapp A: Eosinophil apoptosis is mediated by stimulators of cellular oxidative metabolisms and inhibited by antioxidants: Involvement of a thiol-sensitive redox regulation in eosinophil cell death. Blood 1999;94:2365–2373.
14.
Hansel TT, Pound JD, Pilling D, Kitas GD, Salmon M, Gentle TA, Lee SS, Thompson RA: Purification of human blood eosinophils by negative selection by using immunomagnetic beads. J Immunol Methods 1989;122:97–103.
15.
Kankaanranta H, De Souza PM, Barnes PJ, Salmon M, Giembycz MA, Lindsay MA: SB 203580, an inhibitor or p38 mitogen-activated protein kinase, enhances constitutive apoptosis of cytokine-deprived human eosinophils. J Pharmacol Exp Ther 1999;290:621–628.
16.
Kankaanranta H, De Souza PM, Giembycz MA, Lindsay MA: Human eosinophil isolation and the measurement of apoptosis; in Chung KF, Adcock IM (eds): Methods in Molecular Medicine. Ashma: Mechanisms and Protocols. Totowa, Humana Press Inc., 2000, vol 44, pp 99–110.
17.
Barnes PJ, Chung KF, Page CP: Inflammatory mediators of asthma: An update. Pharmacol Rev 1998;50:515–596.
18.
Hansson M, Asea A, Ersson U, Hermodsson S, Hellstrand K: Induction of apoptosis in NK cells by monocyte-derived reactive oxygen metabolites. J Immunol 1996;156:42–47.
19.
Teramoto J, Tomita T, Matsui H, Ohga E, Matsuse T, Ouchi Y: Hydrogen-peroxide-induced apoptosis and necrosis in human lung fibroblasts: Protective roles of glutathione. Jpn J Pharmacol 1996;79:33–40.
20.
Kasahara Y, Iwai K, Yachie A, Ohta K, Konno A, Seki H, Miyawaki T, Taniguchi N: Involvement of reactive oxygen intermediates in spontaneous and CD95 (Fas/APO-1)-mediated apoptosis of neutrophils. Blood 1997;89:1748–1753.
21.
Meagher LC, Cousin JM, Seckl JR, Haslett C: Opposing effects of glucocorticoids on the rate of apoptosis in neutrophilic and eosinophilic granulocytes. J Immunol 1996;156:4422–4428.
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