Induction of apoptosis in HT-29 cells infected with SA-11 rotavirus

Rotavirus infection is associated both in vivo and in vitro with a series of subcellular pathological alterations leading to cell lysis. It has been suggested that these modifications can play a key role in the pathogenesis of rotavirus-associated diarrheal disease. We describe the effects of SA-11 rotavirus infection in HT-29 cells, a human enterocyte-like cell line. Cytological analyses suggested that the viral-induced cytopathic process, including chromatin clumping, can be referred to as apoptosis, the cell death pathway alternative to necrosis. A time course of the process was performed to investigate whether rotavirus-associated cell death showed specific injury signs. HT-29-infected cells were analyzed by scanning and transmission electron microscopy and features of apoptosis such as blebbing of the plasma membrane, peripheral condensation of chromatin, and fragmentation of the nucleus were observed. Specific changes occurring in cell-substrate adhesion and in some organelles relevant for viral maturation, i.e., rough endoplasmic reticulum, were detected. These findings indicate a role for apoptosis in the rotavirus infection process and its related cytopathology, and also suggested that specific histological alterations such as derangement of enterocytes are associated with the pathogenesis of rotavirus-induced diarrheal disease and could be a direct consequence of viral-triggered apoptosis.