禽痘疫苗病毒中网状内皮组织增生病病毒5'LTR整合位点序列分析

参照国外发表的禽网状内皮组织增生病病毒（REV）5’长末端重复序列（LTR）在禽痘病毒（FPV）疫苗株基因组上的整合位点及相关序列，合成一对来自FPV的引物，从国内5个不同厂家生产的禽痘疫苗中经PCR均扩增到REV-5’LTR。通过序列比较发现，我国5个FPV疫苗毒株中REV-5’LTR整合位点与美国和澳大利亚的天然重组禽痘疫苗完全一致。其中，有3个的REV-5’LTR插入序列也与美国的Vac-3-Am株和澳大利亚的Vac-M3-Au株有100％的同源性。另2个中国疫苗毒株中的REV．LTR插入序列与美国疫苗毒株Vac-1-A。中的REV-LTR插入序列有99．6％的同源性。但是，这5个中国禽痘疫苗毒株中整合的REVLTR与中国近年分离到的REV野毒株HA9901的5’LTR的同源性只有75．4％-92．4％。

Sequence analysis of integration sites of reticuloendotheliosis virus LTR in fowlpox vaccine virus genomes

By use of genomic DNA prepared from 5 fowlpox virus (FPV) vaccines made in China (from Shandong, Beijing, Liaoning, Zhejing and Shanghai respectively) as the templates, reticuloendotheliosis virus (REV) LTR was amplified in PCR with a pair of primers synthesized according to the sequences flanking the integrated REV-5'LTR in FPV genomes published in US and Australia. Sequence analysis indicated that the REV-5'LTR integration sites in genomes of all 5 Chinese PFV vaccine products were identical to American and Australian FPV vaccines with integrated REV-5' LTR. Among the 5 FPV vaccine products made in China, 3 productes Vac-B-Ch, Vac-D-Ch and Vac-E-Ch had the integrated REV-5' LTR sequences of 223bp with 100% homology to that in American vaccine Vac-3-Am and Australian vaccine Vac-M3-Au. The integrated 505bp REV-LTR sequences in another Chinese products Vac-A-Ch and Vac-C-Ch had 99.6% homology to the integrated REV-LTR of American vaccine Vac-1-Am and Australian vaccine Vac-S-Au. However, REV-5'LTR integrated in all 5 FPV vaccines made in China gave only 75.4%-91.5% homology to LTR of a Chinese field strain HA9901 of REV. Based on the above results, it is reasonable to speculate that the virus stocks for the 5 Chinese FPV vaccine products were rather originally imported with their integrated REV LTR than recombinated with LTR of REV local field strains in China.