title: Ultrastructural observation of human neutrophils during apoptotic cell death triggered by Entamoeba histolytica.
abstract: Neutrophils are important effector cells against protozoan extracellular parasite Entamoeba histolytica, which causes amoebic colitis and liver abscess in human beings. Apoptotic cell death of neutrophils is an important event in the resolution of inflammation and parasite's survival in vivo. This study was undertaken to investigate the ultrastructural aspects of apoptotic cells during neutrophil death triggered by Entamoeba histolytica. Isolated human neutrophils from the peripheral blood were incubated with or without live trophozoites of E. histolytica and examined by transmission electron microscopy (TEM). Neutrophils incubated with E. histolytica were observed to show apoptotic characteristics, such as compaction of the nuclear chromatin and swelling of the nuclear envelop. In contrast, neutrophils incubated in the absence of the amoeba had many protrusions of irregular cell surfaces and heterogenous nuclear chromatin. Therefore, it is suggested that Entamoeba-induced neutrophil apoptosis contribute to prevent unwanted tissue inflammation and damage in the amoeba-invaded lesions in vivo.
authors.affiliation: Department of Parasitology, Institute of Tropical Medicine, and Brain Korea 21 for Medical Science, Yonsei University College of Medicine, Seoul 120-752, Korea.
authors.forename: Seobo
authors.initials: S
authors.lastname: Sim
authors.forename: Kyeong Ah
authors.initials: KA
authors.lastname: Kim
authors.forename: Tai-Soon
authors.initials: TS
authors.lastname: Yong
authors.forename: Soon-Jung
authors.initials: SJ
authors.lastname: Park
authors.forename: Kyung-il
authors.initials: KI
authors.lastname: Im
authors.forename: Myeong Heon
authors.initials: MH
authors.lastname: Shin
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D004748:Entamoeba histolytica / Q000502:physiology*; D006790:Host-Parasite Interactions / Q000502:physiology; D006801:Humans; D066298:In Vitro Techniques; D009504:Neutrophils / Q000502:physiology / Q000648:ultrastructure*