Reyes R A, Cockerell G L
Department of Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins 80523-1671, USA.
J Virol. 1996 Aug;70(8):4961-5. doi: 10.1128/JVI.70.8.4961-4965.1996.
The correlation between bovine leukemia virus (BLV) unintegrated DNA, viral expression, and stage of disease was determined in cattle naturally infected with BLV. The concomitant presence of unintegrated BLV DNA with viral transcriptional activity was observed in 53% (18 of 34) of hematologically normal, BLV-seropositive cattle and in 100% (10 of 10) of BLV-seropositive cattle with the preneoplastic syndrome persistent lymphocytosis. In vitro studies suggested that accumulation of unintegrated BLV DNA resulted from a process of reinfection rather than intracellular reverse transcription of newly synthesized BLV RNA. Interestingly, unintegrated BLV DNA was not detected in tumor cells from cattle with BLV-associated lymphocytic leukemia/malignant lymphoma despite viral transcriptional activity in 100% (eight of eight) of these cattle. Thus, the presence of unintegrated BLV DNA differentiated nonneoplastic from neoplastic conditions in BLV-infected cattle. These results demonstrate that unintegrated viral DNA serves as a marker of disease progression in BLV-infected cattle but is not necessarily associated with induction or maintenance of the neoplastic state.
在自然感染牛白血病病毒（BLV）的牛中，确定了BLV未整合DNA、病毒表达与疾病阶段之间的相关性。在血液学正常的BLV血清阳性牛中，53%（34头中的18头）以及在患有肿瘤前综合征持续性淋巴细胞增多症的BLV血清阳性牛中，100%（10头中的10头）观察到未整合的BLV DNA与病毒转录活性同时存在。体外研究表明，未整合的BLV DNA积累是由再感染过程导致的，而非新合成的BLV RNA的细胞内逆转录。有趣的是，尽管在100%（8头中的8头）患有BLV相关淋巴细胞白血病/恶性淋巴瘤的牛的肿瘤细胞中检测到病毒转录活性，但未检测到未整合的BLV DNA。因此，未整合的BLV DNA的存在区分了BLV感染牛的非肿瘤性与肿瘤性状况。这些结果表明，未整合的病毒DNA是BLV感染牛疾病进展的标志物，但不一定与肿瘤状态的诱导或维持相关。
