The host specific NS3 glycosylation pattern reflects the virulence of Ibaraki virus in different hosts

•We compared the growth and release efficiency of infectious Ibaraki virus in HmLu (hamster) and C6/36 (mosquito) cells.•A significant difference was observed in release efficiency: C6/36 could release synthesized virus particles more efficiently than HmLu.•Severe cytopathic effect was observed and virus nonstructural protein NS3 was heavily glycosylated in HmLu.•It was possible that this observation reflects the virus pathogenesis in vivo and NS3 glycosylation contributes to the regulation of Ibaraki virus virulence.

The non-structural protein NS3 was investigated in Ibaraki virus (IBAV), an epizootic hemorrhagic disease virus, serotype 2. Degree of NS3 glycosylation, cytopathic effect, and virus release efficiency were compared between mammalian and insect cells. The molecular weight of synthesized NS3 was compared in Western blot analysis following the removal of the glycochain by PNGase F treatment and revealed that glycosylation of NS3 occurred only in mammalian cells. Also, it was revealed that the amount of infectious IBAV in the extracellular fraction continued to increase for insect cells even after 60 h post infection without disrupting cells. These results suggested that glycosylation of NS3 controls pathogenicity of IBAV in host cells to protect vector insects by altering the release pathway of assembled progeny viruses.