Comparative Analysis of Integration Sites of Reticuloendotheliosis Virus 5′LTR in 12 Fowl Pox Vaccine Strains

KONG Xiang-wei;WANG Dan;WANG Shi-xin;WANG Hai-ming;YANG Shu-qing;SUN Shu-hong;Animal Science and Technology College,Shandong Agricultural University;

fowl pox vaccine;;reticuloendothliosis virus;;5′LTR

To study the integration sites of avian reticuloendothliosis virus(REV)5'long terminal repeat(LTR)in fowl pox virus(FPV)vaccine strains in recent years,12 different batches of FPV vaccines in different regions from 2012 to 2014were collected for study.All vaccines were diluted and inoculated into chicken embryo fibroblast(CEF),DNA was extracted for the amplification and sequencing of REV relating genes.(Result)The results showed that both REV-5′LTR and FPV fragments existed in the 12 FPV vaccine strains.To be specific,745 bp in the 2abroad vaccine strains and 485 bp in the other 10 domestic vaccine strains.By DNA-Star analysis,446 bp as almost the entire REV-LTR were integrated in the 2abroad vaccine strains,while,apart of the REV-LTR fragment about 194 bp were integrated in the 10 domestic vaccine strains.The integrated REV-LTR sequence among the 12 FPV vaccine strains had 70.3%-82.6% homology with the Chinese reference strain HA1101.But it had as high as 98.6%-100% homology with REVLTR in the published abroad PFV strain AY255632.The results suggested that the phenomenonof the integration of REV-LTR sequence in FP vaccine is common at home and abroad.In our study,the 12 fowl pox vaccine strains were all integrated with REV-LTR sequence,part of the FPV vaccine strains were integrated with the complete REV-LTR sequence.While the fragment in most FPV vaccine strains was relatively small,and these sequences have a closer homology to the abroad FPV.