Journal of Medical Virology 73:323–331 (2004) SARS Coronavirus Induces Apoptosis

Severe acute respiratory syndrome (SARS) is an emerging infectious disease. Its etiological agent has been convincingly identified as a new member of family Coronaviridae (SARS-CoV). It causes serious damage to the respiratory system yet themechanism is not clear. Infection-induced apoptosis or necrosis is suspected but no direct evidence for this yet exists. To date, Vero E6 cells are the only cell line that could be used to replicate the virus with obvious CPE (cytopathic effect) in vitro. It is known for some viruses (includingmembersof familyCoronaviridae) that CPE can be caused either by virus-induced apoptosis (active death) or cell necrosis (passive death). In this study, we examined the apoptosis in the SARS-CoV infected Vero E6 cells. Indeed, the results do show that the CPE was induced by apoptosis rather than necrosis, shown by typical DNA fragmentation, through the existence of apoptotic bodies and swollenmitochondria. This observation has some implications for the SARS-CoVpathogenicity: SARS-CoVdoes induce apop-tosis in cell cultures and might have the same effect in vivo, responsible for the severe damage of the respiratory system. J. Med. Virol