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Entamoeba histolytica Induces Host Cell Death in Amebic Liver Abscess by a Non-Fas-Dependent, Non-Tumor Necrosis Factor Alpha-Dependent Pathway of Apoptosis

1998; American Society for Microbiology; Volume: 66; Issue: 6 Linguagem: Inglês

10.1128/iai.66.6.2980-2983.1998

1098-5522

Karl B. Seydel, Samuel L. Stanley,

Neonatal Health and Biochemistry

ABSTRACT Amebic liver abscess is characterized by extensive areas of dead hepatocytes that form cavities surrounded by a thin rim of inflammatory cells and few Entamoeba histolytica trophozoites. E. histolytica produces pore-forming proteins and proteinases, but how trophozoites actually kill host cells has been unclear. Here, we report that E. histolytica induces apoptosis in both inflammatory cells and hepatocytes in a severe combined immunodeficient (SCID) mouse model of amebic liver abscess. By studying infection in C57/BL6.lpr and C57/BL6.gld mice, we found that E. histolytica -induced apoptosis does not require the Fas/Fas ligand pathway of apoptosis, and by using mice with a targeted deletion of the tumor necrosis factor receptor I gene, we have shown that E. histolytica -induced apoptosis is not mediated by tumor necrosis factor alpha. Our data indicate that apoptosis plays a prominent role in the host cell death seen in amebic liver abscess in a mouse model of disease and suggest that E. histolytica induces cell death without using two common pathways for apoptosis.