Construction And Biological Characteristic Determination Of A Serotpye O Attenuated Foot-and-Mouth Disease Virus

Foot-and-mouth disease (FMD), caused by foot-and-mouth disease virus (FMDV), is a fulminating infections disease mainly infects cloven animals such as cattle, sheep and swine. Currently, FMD inactivated vaccine is of great importance in FMD prevention and control campaign of FMD epidemic countries. FMD inactivated vaccine must be manufactured in at least biosafety level-3facilities with high secure leak prevention system against escape of the virulent FMDV. Despite all this, outbreak caused by virus escape from the manufacture happened sometimes, leading to great economic losses. Therefore, without safe and effective novel FMD vaccine, it is necessary to decrease or stop using virulent FMDV for vaccine production, possibly by substitute virlent virus with middle virulent or attenuated virus in the vaccine production, to resolve the potential virus escape crisis fundamentally.In this research, by inserting the structure protein gene VP1, VP2and VP3of serotype O FMD vaccine seed virus, PanAsia strain originated from swine, into a vector which is Lpro and structure protein coding region deleted and modified with cloning sites SspI and SgrAl, we constructed an infectious cDNA and succesfully rescued the chimeric attenuated FMDV v4-LL, and explored its biological characteristic. We found that v4-LL could be cultured well both in adherent cells and suspension cells and was lethal to mouse, but its pathogenicity to guinea pig was obviously low, and inoculating swine with107LD50dose of virus could not lead to clinical signs of FMD. These results provide basic experiment data for using this chimeric attenuated virus as seed virus to produce inactivated vaccine and shed light on applying this attenuated FMDV vector system to make seed virus for inactivated vaccine production to explore new ways to resolve the virus leak potential risk in current FMD inactivated vaccine production.