Research On The Expression Of IL-2、IL-12-B、IFN-γ In DEF And Ducklings After DHAV-1Infection

Duck hepatitis A virus (DHAV) was classified as a member of a novel genus Avihepatovirus in the family Picornaviridae. DHAV-1causes duck viral hepatitis(DVH) which is a cute and fatal disease in ducklings often associated with liver necrosis, hemorrhage and high mortality. DHAV-1is distributed worldwide and become the most economic importance to all duck-growing farms.In this study, duck embryo fibroblast cells(DEF),4-day and21-day old ducklings were infected by DHAV-1. We detected the quantity of virus and the mRNA expression of IL-2, IL-12-B, IFN-y when DEF was infected with DHAV-1at0h,6h,12h,24h,48h,72h. We observed the CPE at24h post-infection in DEF. The RT-qPCR results showed that the amount of virus arose in6h post-infection, reached the peak in48h post-infection and then declined. We also observed DHAV-1virionsas spherical with30nm diameter formation in DEF cytoplasm at24h post-infection using transmission electron microscope. In conclusion, we established the DHAV-1infection model of DEF successfully. The expression of cytokines IL-2, IL-12-B and IFN-y in DEF were up-regulated until72h post-infection, down-regulated in96h post-infection and at24h post-infection there were both statistically significant differences.4-day and21-day old ducklings were infected with DHAV-1and then they were killed atOh,6h,12h,24h,48h,72h,96hpsot-infection. Liver, spleen,thymus and bursa of4-day and21-day old ducklings were used for analysis the expression of IL-2, IL-12-B, IFN-y. Gross anatomy and the results of PT-qPCR demonstrated that the animal model of DHAV-1infection was successful. The results showed as follows:in liver, the quantity of virus of4-dayold ducklings were higher than21-day old ducklings’and the quantity of virus in both of them first arose and then declined. In spleen, the quantity of virus of4-day and21-day old ducklings were similar and they first arose, reached the peak at24h or48h post-infection then declined. In thymus and bursa, the quantity of virus in both of them were unstable.In4-dayold ducklings, IL-2up-regulated in Liver,thymus and bursa while up-regulated at6h and12h post-infection and down-regulated at24h,48h,72h and96h post-infection. IL-12-B always up-regulated. IFN-y was irregular.In21-day old ducklings, IL-2down-regulated in Liver,thymus and spleen at24h and48h post-infection and up-regulated at other time points. In bursa, IL-2down- regulated at72h post-infection and up-regulated at other time points. IL-12-B down-regulated at72h post-infection and up-regulated at other time points. IFN-γ was irregular.We established the DHAV-1infection model of DEF successfully and detected the quantity of virus and expression of cytokines IL-2, IL-12-B and IFN-y in DEF, liver, spleen,thymus and bursa in our study. The results showed that the regulate of cytokinesassociated with viral multiplication and disease progression.