Reovirus Activates a Caspase-Independent Cell Death Pathway

Berger, Angela K.; Danthi, Pranav

To determine whether viral genomic RNA is required for induction of cell death, we infected cells with equivalent numbers of genome-deficient (or top-component) particles and infectious virions and assessed their capacity to elicit cell death. To rule out the effect of secondary rounds of infections from the contaminating infectious particles in the top-component particle fraction, we assessed the induction of cell death at 24 h after infection (19) . We found that~35% and~20% of the cells were dead following infection with a multiplicity of infection (MOI) of 17,700 particles/ cell (equivalent of 100 PFU/cell) or 5,840 particles/cell (equivalent of 33 PFU/cell), respectively, of infectious virus (Fig. 5A ). In contrast, infection of cells with an equivalent number of topcomponent particles killed a substantially smaller amount of cells, 10% and~5%, respectively. These data indicate that viral genomic double-stranded RNA (dsRNA) is required for induction of necroptosis.