Lupiani B, Hunt H, Silva R, Fadly A
Avian Disease and Oncology Laboratory, Agricultural Research Service, East Lansing, Michigan 48823, USA.
Virology. 2000 Oct 10;276(1):37-43. doi: 10.1006/viro.2000.0539.
Three recombinant avian leukosis subgroup J viruses, ADOL 5701A, ADOL 5701ADelta, and ADOL 6803A, carrying a subgroup A envelope have been isolated and characterized. These viruses were identified by their ability to replicate in DF-1/J, a recombinant chicken embryo fibroblast (CEF) cell line expressing the subgroup J envelope that is resistant to subgroup J replication. Flow cytometric analysis of DF-1/J cells infected with ADOL 5701 and ADOL 6803, two subgroup J isolates, indicated cross-reactivity with subgroup A chicken polyclonal serum. Based on published sequences of subgroups A and J isolates, we designed a series of primers to PCR amplify the envelope and LTR of these viruses. PCR products were obtained when the forward primer was specific for subgroup A gp85 envelope protein gene and the reverse primer was specific for subgroup J LTR. Sequence analysis of the PCR products indicated that these viruses had a subgroup A gp85, a subgroup E gp37, and a subgroup J LTR. Interestingly, these viruses had previously been propagated in CEF from the alv6 chicken line, a line that carries a replication defective recombinant endogenous virus expressing a subgroup A envelope (RAV 0-A(1)). Sequence analysis of RAV 0-A(1) gp85 and gp37 envelope proteins indicated that they were almost identical to those of the recombinants ADOL 5701A and ADOL 6803A. These results indicate that these three recombinant viruses arose by recombination between exogenous subgroup J isolates and a recombinant defective endogenous virus with subgroup A envelope.
三种携带A亚群包膜的重组禽白血病J亚群病毒，ADOL 5701A、ADOL 5701ADelta和ADOL 6803A，已被分离和鉴定。这些病毒通过它们在DF-1/J细胞中的复制能力来鉴定，DF-1/J是一种表达对J亚群复制具有抗性的J亚群包膜的重组鸡胚成纤维细胞（CEF）系。对感染了两种J亚群分离株ADOL 5701和ADOL 6803的DF-1/J细胞进行流式细胞术分析，结果表明其与A亚群鸡多克隆血清存在交叉反应。基于已发表的A亚群和J亚群分离株的序列，我们设计了一系列引物，用于通过PCR扩增这些病毒的包膜和长末端重复序列（LTR）。当正向引物对A亚群gp85包膜蛋白基因具有特异性，反向引物对J亚群LTR具有特异性时，获得了PCR产物。对PCR产物的序列分析表明，这些病毒具有A亚群gp85、E亚群gp37和J亚群LTR。有趣的是，这些病毒此前是在alv6鸡系的CEF中传代的，该鸡系携带一种表达A亚群包膜的复制缺陷型重组内源性病毒（RAV 0-A(1)）。对RAV 0-A(1) gp85和gp37包膜蛋白的序列分析表明，它们与重组病毒ADOL 5701A和ADOL 6803A的几乎相同。这些结果表明，这三种重组病毒是由外源性J亚群分离株与具有A亚群包膜的重组缺陷型内源性病毒之间的重组产生的。
