Isolatation And Identify Of Four PRV Strains From Hunan Province And The Study Of High Titer PRV Culturing

Four wild-type pseudorabies virus (PRV) strains were detected from porcine brain tissues, which collected from four farms of Pingjiang?Miluo?Liuyang and Changsha in Hunan province during 2012-2014. The four PRV strains were isolated by inoculating porcine brain tissues to the PK-15 cells, identified by PCR tests and animal inoculation, and named PRV-XiangA?PRV-GA?PRV-YY and PRV-LY, respectively. The results showed the nucleotide homology among the four strains was 99.8%-100%, by aligning the immunity (gB?gG?gH?gI?gL?gM)and virulence genes(gE?PK?TK) of the four PRV strains, which indicated these strains display almost no differences. Results of nucleotide alignment between the four strains and main strains isolated from China and abroad showed that the four strains have a high homology with PRV main strains isolated from China, with displaying nucleotide identity was 99.8%-100% to BJ-YT and TJ strains, which revealed that the epidemic PRV strains in China has a little variation currently.After tested the virus titer of 4 PRV strains isolated from Hunan Province, a PRV strain(PRV-YY) of high virus titer cultured by MDBK cell be screened and the virus titer reached 107.41 TCIDso/0.1mL. The virus titer of PRV-YY cultured by MDBK-1(a monoclonal cell) selected from bank of MDBK monoclonal cell lines can reached 1071 TCID50/0.1mL. When PRV-YY strain passaged from MDBK-1 monoclonal cell by end point dilution method, the virus titer of PRV-YY strains above 107.5 TCIDso/0.1mL. Average virus titer of PRV-YY strains can be 107.692 TCID50/0.1mL. As a result, the virus titer of PRV-YY strain was about 2 times higher than before. This research build a good foundation for produce inactivated vaccine of wild-type pseudorabies virus strains.