Nucleopolyhedrovirus(NPV) is divided into Group I and Group II based on the phy-logenetic analysis.It has been reported that Group I NPVs such as Autographa californica multiple NPV(AcMNPV) can transduce mammalian cells,while Group II NPVs such as Helicoverpa armigera single NPV(HaSNPV) cannot.Here we report that AcMNPV was capable of stimulating antiviral ac-tivity in human hepatoma cells(SMMC-7721) manifested by inhibition of Vesicular Stomatitis virus(VSV) replication.In contrast,the HaSNPV and the Spodoptera exigua multiple NPV(SeMNPV) of group II had no inhibitory effect on VSV.Recombinant AcMNPV was shown to induce interferons al-pha/beta even in the absence of transgene expression in human SMMC-7721 cells,while it mediated transgene expression in BHK and L929 mammalian cells without an ensuing antiviral activity.
LIANG Changyong1,2,SONG Jianhua1,2,HU Zhihong1 & CHEN Xinwen1 1.State Key Laboratory of Virology,Wuhan Institute of Virology,Chinese Academy of Sciences,Wuhan 430071,China
The Autographa californica nucleopolyhedrovirus(AcMNPV) contains three apoptosis suppressor genes:p35,iap1 and iap2.AcMNPV P35 functions as a pancaspase inhibitor,but the function of IAP1 and IAP2 has not been entirely resolved.In this paper,we analyze the function of IAP1 and IAP2 in detail.AcMNPV with p35-deletion inhibited the apoptosis of BTI-Tn-5B1-4(Tn-Hi5) cells induced by a Helicoverpa armigera single nucleocapsid NPV(HearNPV) infection and rescued the replication of HearNPV and BV production in these cells.Transient-expression experiments indicated that both IAP1 and IAP2 suppress apoptosis of Tn-Hi5 cells during HearNPV infection.Recombinant HearNPVs expressing AcMNPV iap1,iap2 and p35,respectively,not only prevented apoptosis but also allowed HearNPV to replicate in Tn-Hi5 cells.However,the iap1,iap2 and p35 genes when expressed in HearNPV were unable to rescue BV production.These results indicate that both AcMNPV iap1 and iap2 function independently as apoptosis inhibitors of and are potential host range factors.
