 IRF-3-knockdown cells express viral protein and produces low levels of infectious virions.IRF-3 controls the fate of the SeV-infected cells by triggering apoptosis and preventing persistence establishment; therefore its knock down allows persistence to occur.It was also reported that during SeV infection replication defective viral genomes (DVG) are forming and selectively protect a sub-population of host cells from death, therefore promoting the establishment of persistent infections.