Apoptosis is induced by hantaviruses in cultured cells

Hantaviruses replicate in primary and cultured animal cells with little or no cytopathic effect. We report here that the cultured Vero E6 cells infect ed by the Hantaan or by the Prospect Hill viruses exhibited characteristic features of apoptosis, including condensation and segmentation of nuclei an d internucleosomal cleavage of nuclear DNA. Apoptosis was not seen in the c ells adsorbed by UV-inactivated virus, indicating that the viral replicatio n is required for the induction of apoptosis. Furthermore, level of the pro to-oncogenic Bcl-2 protein was significantly reduced, whereas its mRNA leve l remained unchanged in Hantaan virus-infected cells, suggesting possible i nvolvement and posttranscriptional regulation of this antiapoptotic protein in the process. (C) 1999 Academic Press.