Acute viral necrosis virus(AVNV)was reported as the causative agent responsible for summer mass mortality of adult Zhikong scallop(Chlamys farreri),which is widely cultured along northern China coast.In this study,the open reading frame(ORF)86 of AVNV was successfully amplified based on the specific primers designed according to the complete genome sequences of AVNV.The gene encoded by ORF86 in AVNV was named IAP-86 in this study,since the homology of ORF 86 was firstly identified as encoding inhibitor of apoptosis protein(IAP)in baculovirus.We subcloned the amplified PCR fragments of IAP-86 into the prokaryotic expression vector pET32a(+),and obtained the recombinant plasmid pET32a-IAP86 through the linking of IAP-86 gene to pET32a(+)plasmid.Then the recombinant plasmids were transformed into E.coil BL21(DE3)strain and expressed under the induction of IPTG.The SDS-PAGE analysis showed that the molecular mass of the induced recombinant protein was about 40 ku.The expressed protein was verified through the Western-blotting and mass spectrometry analysis.Then the recombinant protein was purified with Co²⁺ purification column and marked with FITC.We found IAP-86 could combine with the nucleus and the cytoplasm and inhibit the apoptosis of blood lymphocyte cell of C.farreri through coincubation of them.The cell apoptosis was inhibited by the recombinant of IAP-86 according to the result of apoptosis experiment,and the rate of apoptosis inhibition was about 7%.IAP-86 was successfully expressed through the prokaryotic expression system in our study,and the expressed protein was found to be able to inhibit cell apoptosis of blood lymphocyte of C.farreri.These results provide theoretical and experimental basis for studying the infection mechanism of AVNV.