Cellular Location And Infection Related Function Of Duck Enteritis Virus US2 Protein

Duck viral enteritis (DVE), also known as duck plague (DP), which is an acute, febricity and septic infection disease in infected birds of Anseriformes(ducks, geese and swans). The disease has been epidemic in many countries and regions, and been responsible for considerable economic loss of the commercial duck industry. The pathogeny of the disease was DEV, which was assigned as member of family Herpesviridae, unclassified virus. Herpesvirus us2 gene is unnecessary for replication, but inhibits the process of viral invasion and cell-to-cell spread. US2 proteins combines with the major histocompatibility complex-specific specifically to induce its degradation thereby inhibiting antigen to be presented to T lymphocytes. Therefore, the research of US2 proteins function has significance in further understanding the mechanism of viral infection.In this study, us2 ORF was amplified by PCR with duck enteritis virus (DEV) C-KCE genomic DNA as template. Then detailed bioinformatics of US2 protein was analyzed by software, including amino acid sequence, protein structure and antigenicity.46KDa recombinant protein was gained by E. coli expression system pET32a (+) (E. coli Rosetta). The purified protein was used to immunize rabbits to prepare the rabbit anti-US2 polyclonal antibody, serum potency determined by agar diffusion was 1:8. The antibody has good responsiveness to the DEV US2 protein by western blot and indirect immunofluorescence assay analysis.The rabbit anti DEV-US2 antibody has been used to characterize cellular localization of the proteins by indirect immunofluorescence. Then it was observed by confocal laser scanning microscope that specific staining was found mainly in plasma membrane and vicinity of nucleus.Anti-US2 antibodies were added into cell culture fluid when DEV inoculation in chicken embryo fibroblast culture in order to determine the role of US2 protein in adsorption, penetration, cell-to-cell spread (CTCS) directly. The results showed that comparing with control group, viral penetration rate and formation of plaque size of the experimental group had significant differences. But the adsorption rate had barely difference. In conclusion, DEV US2 protein may be involved in invasion and intercellular virus transmission process.