Degranulation of human eosinophils induced by Paragonimus westermani-secreted protease.
Eosinophil degranulation is considered to be a key effector function for the killing of helminthic worms and tissue inflammation at worm-infected lesion sites. However, relatively little data are available with regard to eosinophil response after stimulation with worm-secreted products which contain a large quantity of cysteine proteases. In this study, we attempted to determine whether the degranulation of human eosinophils could be induced by the direct stimulation of the excretory-secretory products (ESP) of Paragonimus westermani, which causes pulmonary paragonimiasis in human beings. Incubation of eosinophils for 3 hr with Paragonimus-secreted products resulted in marked degranulation, as evidenced by the release of eosinophil-derived neurotoxin (EDN) in the culture supernatants. Moreover, superoxide anion was produced by eosinophils after stimulation of the ESP. The ESP-induced EDN release was found to be significantly inhibited when the ESP was pretreated with protease inhibitor cocktail or the cysteine protease inhibitor, E-64. These findings suggest that human eosinophils become degranulated in response to P. westermani-secreted proteases, which may contribute to in vivo tissue inflammation around the worms.
Shin
Myeong Heon
MH
Department of Parasitology, Institute of Tropical Medicine, and Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 120-752, Korea. myeong@yumc.yonsei.ac.kr
Chung
Young-Bae
YB
Kita
Hirohito
H
D000818:Animals; D015550:Cell Degranulation; D003546:Cysteine Endopeptidases / Q000378:metabolism / Q000502:physiology*; D047208:Eosinophil-Derived Neurotoxin / Q000378:metabolism; D004804:Eosinophils / Q000502:physiology*; D006801:Humans; D048492:Paragonimus westermani / Q000201:enzymology*; D013481:Superoxides / Q000378:metabolism; D013997:Time Factors
D013481:Superoxides; D047208:Eosinophil-Derived Neurotoxin; D003546:Cysteine Endopeptidases