Background: Eosinophils are important cells in host immunity to infections by parasitic worms. Tissue-invasive helminthic parasites have been known to induce apoptosis of immune cells for their successful establishment in vivo. We have previously found that high doses of excretory-secreted products (ESP) secreted by lung fluke Paragonimus westermani newly excysted metacercariae (PwNEM), which cause pulmonary or extrapulmonary paragonimiasis in human beings, accelerate eosinophil cell death. However, little is known about the mechanism of eosinophil apoptosis induced by the Paragonimus-derived products. Objective: We examined involvement of caspase 3 activation in eosinophil cell death induced by ESP produced by PwNEM. Methods: Eosinophils were isolated from the peripheral blood of healthy donors by CD16-negative immunomagnetic selection. We examined the inhibitory effect of pan-caspase inhibitor on ESP-triggered phosphatidylserine (PS) externalization on the outer surface of eosinophils and intracellular activation of caspase 3 in cell lysates treated with the ESP. Results: When ESP secreted by PwNEM were incubated for up to 3 h with eosinophils, they increased surface exposure of PS on eosinophils in a time- and dose-dependent manner. This proapoptotic effect of the ESP on eosinophils was significantly inhibited by pretreatment of cells with pan-caspase inhibitor z-VAD-fmk, and was completely abolished by heat inactivation of ESP at 56°C. The activated forms of caspase 3 were also clearly detected in eosinophils incubated with ESP. Moreover, ESP potently inhibited prolonged survival of eosinophils induced by cytokines such as IL-5, IL-3, and GM-CSF. Conclusion: These results suggest that ESP secreted by PwNEM contain biological active factors causing caspase-3-mediated apoptosis of human eosinophils, thereby enabling the larvae to evade and to subvert the tackle by eosinophils during the early phase of the infection.

1.
Weller PF: Eosinophils: Structure and functions. Curr Opin Immunol 1994;6:85–90.
2.
Wardlaw AJ, Moqbel R, Kay AB: Eosinophils: Biology and role in disease. Adv Immunol 1995;60:151–266.
3.
Gleich GJ: Mechanisms of eosinophil-associated inflammation. J Allergy Clin Immunol 2000;105:651–663.
4.
Kankaanranta H, Lindsay MA, Giembycz MA, Zhang X, Moilanen E, Barnes PI: Delayed eosinophil apoptosis in asthma. J Allergy Clin Immunol 2000;106:77–83.
5.
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;85:312–326.
6.
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.
7.
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.
8.
Alam R, Forsythe P, Stafford S, Fukuda Y: Transforming growth factor beta abrogates the effects of hematopoietins on eosinophils and induces their apoptosis. J Exp Med 1994;179:1041–1045.
9.
Wedi B, Raap U, Lewrick H, Kapp A: IL-4-induced apoptosis in peripheral blood eosinophils. J Allergy Clin Immunol 1998;102:1013–1020.
10.
Walsh GM, Williamson ML, Symon FA, Willars GB, Wardlaw AJ: Ligation of CD69 induces apoptosis and cell death in human eosinophils cultured with granulocyte-macrophage colony-stimulating factor. Blood 1996;87:2815–2821.
11.
Blaylock MG, Sexton DW, Walsh GM: Ligation of CD45 and the isoforms CD45RA and CD45RB accelerates the rate of constitutive apoptosis in human eosinophils. J Allergy Clin Immunol 1999;104:1244–1250.
12.
Matsumoto K, Schleimer RP, Saito H, Iikura Y, Bochner BS: Induction of apoptosis in human eosinophils by anti-Fas antibody treatment in vitro. Blood 1995;86:1437–1443.
13.
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.
14.
Stern M, Savill J, Haslett C: Human monocyte-derived macrophage phagocytosis of senescent eosinophils undergoing apoptosis. Mediation by alpha v beta 3/CD36/thrombospondin recognition mechanism and lack of phlogistic response. Am J Pathol 1996;149:911–921.
15.
Fadok VA, Bratton DL, Konowal A, Freed PW, Westcott JY, Henson PM: Macrophages that have ingested apoptotic cells in vitro inhibit proinflammatory cytokine production through autocrine/paracrine mechanisms involving TGF-β, PGE2, and PAF. J Clin Invest 1998;101:890–898.
16.
Voll RE, Herrmann M, Roth EA, Stach C, Kalden JR, Girkontaite I: Immunosuppressive effects of apoptotic cells. Nature 1997;390:350–351.
17.
McDonald PP, Fadok VA, Bratton D, Henson PM: Transcriptional and translational regulation of inflammatory mediator production by endogenous TGF-β in macrophages that have ingested apoptotic cells. J Immunol 1999;163:6164–6172.
18.
Chung YB, Yang HJ, Kang SY, Kong Y, Cho SY: Activities of different cysteine proteases of Paragonimus westermani in cleaving human IgG. Korean J Parasitol 1997;35:139–142.
19.
Shin MH, Kita H, Park HY, Seoh JY: Cysteine protease secreted by Paragonimus westermani attenuates effector functions of human eosinophils stimulated with immunoglobulin G. Infect Immun 2001;69:1599–1604.
20.
Culley FJ, Brown A, Conoy DM, Savroe I, Pritchard DI, Williams TJ: Eotaxin is specifically cleaved by hookworm metalloproteases preventing its action in vitro and in vivo. J Immunol 2000;165:6447–6453.
21.
Elsner J, Hochstetter R, Kimmig D, Kapp A: Human eotaxin represents a potent activator of the respiratory burst of human eosinophils. Eur J Immunol 1996;26:1919–1925.
22.
Kampen GT, Stafford S, Adachi T, Jinquan T, Andrew SQ, Skov PS, Poulsen LK, Alam R: Eotaxin induces degranulation and chemotaxis of eosinophils through the activation of ERK2 and p38 mitogen-activated protein kinase. Blood 2000;95:1911–1917.
23.
Williams GT: Programmed cell death: a fundamental protective response to pathogens. Trends Microbiol 1994;2:463–464.
24.
Luder CGK, Gross U, Lopes MF: Intracellular protozoan parasites and apoptosis: Diverse strategies to modulate parasite-host interactions. Trends Parasitol 2001;17:480–486.
25.
Lockshin RA, Zakeri Z: Caspase-independent cell deaths. Curr Opin Cell Biol 2002;14:727–733.
26.
Widmann C, Gibson S, Johnson GL: Caspase-dependent cleavage of signaling proteins during apoptosis. J Biol Chem 1998;273:7141–7147.
27.
Shin MH: Excretory-secretory product of newly excysted metacercariae of Paragonimus westermani directly induces eosinophil apoptosis. Korean J Parasitol 2000;38:17–23.
28.
Shin MH, Min DY: Infection status of Paragonimus westermani metacercariae in crayfish (Cambaroides similis) collected from Bogildo (Islet), Wando-gun, Chollanam-do, Korea. Korean J Parasitol 1999;37:55–57.
29.
Heussler VT, Kuenzi P, Rottenberg S: Inhibition of apoptosis by intracellular protozoan parasites. Int J Parasitol 2001;31:1166–1176.
30.
Kephart GC, Gleich GJ, Connor DH, Gibson DW, Ackerman SJ: Deposition of eosinophil granule major basic protein onto microfilaria of Onchocerca volvulus in the skin of patients treated with diethylcarbamazine. Lab Invest 1984;50:51–61.
31.
Hamann KJ, Barker RL, Loegering DA, Gleich GJ: Comparative toxicity of purified human eosinophil granule proteins for new-born larvae of Trichinella spiralis. J Parasitol 1987;73:523–529.
32.
Rainbird MA, Macmillan D, Meeusen ENT: Eosinophil-mediated killing of Haemonchus contortus larvae: Effect of eosinophil activation and role of antibody, complement and interleukin-5. Parasite Immunol 1998;20:93–103.
33.
Sher A, Coffman RL, Hiney S, Cheever AW: Ablation of eosinophil and IgE responses with anti-IL-5 or anti-IL-4 antibodies fails to affect immunity against Schistosoma mansoni in the mouse. J Immunol 1990;145:3911–3916.
34.
Dent LA, Daly CM, Mayrhofer G, Zimmermann T, Hallett A, Bignold LP, Creaney J, Parsons JC: Interleukin-5 transgenic mice show enhanced resistance to primary infections with Nippostrongylus brasiliensis but not primary infections with Toxocara canis. Infect Immun 1999;67:989–993.
35.
Chen L, Rao KV, He YX, Ramaswamy K: Skin-stage schistosomula of Schistosoma mansoni produce an apoptosis-inducing factor that can cause apoptosis of T cells. J Biol Chem 2002;277:34329–34335.
36.
Kuroda A, Uchikawa R, Matsuda S, Yamada M, Tegoshi T, Arozono N: Up-regulation of Fas (CD95) and induction of apoptosis in intestinal epithelial cells by nematode-derived molecules. Infect Immun 2002;70:4002–4008.
37.
Chow SC, Brown A, Pritchard DI: The human hookworm pathogen Necator americanus induces apoptosis in T lymphocytes. Parasite Immunol 2000;22:21–29.
38.
Lopez-Briones S, Sciutto E, Ventura JL, Zentella A, Fragoso G: CD4+ and CD19+ splenocytes undergo apoptosis during an experimental murine infection with Taenia crassiceps. Parasitol Res 2003;90:157–163.
39.
Araujo MI, Lopez AA, Medeiros MJr, Cruz AA, Sousa-Atta L, Sole D, Calvalho EM: Inverse association between skin response to aeroallergens and Schistosoma mansoni infection. Int Arch Allergy Immunol 2000;123:145–148.
40.
Wang CC, Nolan TJ, Schad GA, Abraham D: Infection of mice with the helminth Strongyloides stercoralis suppresses pulmonary allergic responses to ovalbumin. Clin Exp Allergy 2001;31:495–503.
41.
Medeiros MJr, Figueiredo JP, Almeida MC, Matos MA, Araujo MI, Cruz AA, Atta AM, Rego MAV, de Jesus AR, Taketomi EA, Carvalho EM: Schistosoma mansoni infection is associated with a reduced course of asthma. J Allergy Clin Immunol 2003;111:947–951.
42.
Shin MH, Seoh JY, Park HY, Kita H: Excretory-secretory products secreted by Paragonimus westermani delay the spontaneous cell death of human eosinophils through autocrine production of GM-CSF. Int Arch Allergy Immunol 2003;132:48–57.
43.
Chung YB, Kong Y, Joo IJ, Cho SY, Kang SY: Excystment of Paragonimus westermani metacercariae by endogenous cysteine protease. J Parasitol 1995;81:137–142.
44.
Carmona C, Dowd AJ, Smith AM, Dalton JP: Cathepsin L proteinase secreted by Fasciola hepatica in vitro prevents antibody-mediated eosinophil attachment to newly excysted juveniles. Mol Biochem Parasitol 1993;62:9–17.
45.
Kong Y, Chung YB, Cho SY, Kang SY: Cleavage of immunoglobulin G by excretory-secretory cathepsin S-like protease of Spirometra mansoni plerocercoid. Parasitology 1994;109:611–621.
46.
Barrett AJ, Kirschke H: Cathepsin B, cathepsin H, and cathepsin L. Methods Enzymol 1981,80:535–561.
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