Apoptosis Induced By Avian Newcastle Disease Virus (NDV) In Chicken Embryo Fibroblasts

Avian Newcastle Disease Virus (NDV) is the causative agent of chicken NewcastleDisease, an acute, highly contagious viral septic disease. Replication of NDV in chickenembryo fibroblasts (CEF) causes extensive cytopathic effect (CPE), leading to destructionof the entire cell monolayer and the death of infected cells. Now it sure that NDV caninduce apoptosis by interferon system and TNF-mediated responses. But the mechanism ofinfected cell apoptosis in chicken embryo fibroblasts is poorly documented. In this report,we show that NDV can induce CEF apoptosis. Then apoptosis of CEF induced byNDV-Mukteswar Strain was observed at 48hour post infection when 200 TCID50 was used.We show that infection of CEF with the NDV-Mukteswar strain induced caspase-dependentapoptosis. Caspase-dependent apoptosis, as characterized by chromosomal condensation,DNA fragmentation was detected in NDV-infected cells. In addition the general caspaseinhibitor Z-VAD fmk was added to the culture medium showed inhibition of the hallmarkof apoptosis at 48h postinfection. And the inhibitor of caspase-8, caspase-9 can blockedNDV-induced apoptosis too, but inhibitor of caspase-3, caspase-10 cannot inhibitNDV-induced apoptosis. At the same time, we found NDV-Clone30 strain cannot induceapoptosis in CEF. The study adds one more example to the growing list of animal virus thatinduces apoptosis through a caspase-dependent pathway.