Determination of proviral load in bovine leukemia virus-infected cattle with and without lymphocytosis
Determination of proviral load in bovine leukemia virus-infected cattle with and without lymphocytosis
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DOI：
10.2460/ajvr.68.11.1220
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发表时间：
2007-11-01
影响因子：
1
通讯作者：
Ceriani, Carolina
中科院分区：
文献类型：
--
作者：
Juliarena, Marcela A.;Gutierrez, Silvina E.;Ceriani, Carolina
测定牛白血病病毒（BLV）感染的牛中的前病毒载量（有或没有持续的淋巴细胞增多症），以评估传播病毒的可能性。动物-6个奶牛群中的牛。方法-以6个月的间隔对来自感染牛的血样进行3次评价，以通过PCR测定前病毒载量，通过ELISA测定血清学结果，结果感染牛分为淋巴细胞性和非淋巴细胞性两组。淋巴细胞性牛在外周血白细胞中始终具有> 100，000拷贝的整合前病毒/μ g DNA（即，高前病毒载量）。针对BLVgp 51和BLVp 24的抗体的滴度指示强的免疫应答。非淋巴细胞牛包括2个亚组：一组具有高前病毒载量和强免疫应答，另一组具有较弱免疫应答，主要针对BLVp 24，并且前病毒载量< 100拷贝/μ g DNA（即，低前病毒载量）。结论和临床相关性-结果强调了在根除计划期间表征非淋巴细胞BLV感染牛的重要性。从非淋巴细胞牛传播BLV感染的风险可能因前病毒载量而异。在标准饲养条件下，前病毒负荷高的非淋巴细胞牛可能是有效的发射器（与淋巴细胞牛一样有效），而前病毒负荷低的非淋巴细胞牛可能是无效的发射器。由于大多数前病毒载量低的牛不会产生抗BLVp 24抗体，因此似乎缺乏抗BLVp 24抗体应答可能是这种情况的良好标志。
Objective-To determine proviral load in bovine leukemia virus (BLV)-infected cattle with and without persistent lymphocytosis to assess the potential of transmitting the virus.Animals-Cattle in 6 dairy herds.Procedures-Blood samples from infected cows were evaluated 3 times at 6-month intervals for determination of proviral load via PCR assay, serologic results via ELISA, and hematologic status via differential cell counts.Results-Infected cattle were classified into lymphocytotic and nonlymphocytotic groups. Lymphocytotic cattle consistently had > 100,000 copies of integrated provirus/mu g of DNA (ie, high proviral load) in peripheral blood leukocytes. Titers of antibodies against BLVgp51 and BLVp24 indicated a strong immune response. Nonlymphocytotic cattle comprised 2 subgroups: a group with high proviral load and strong immune response, and a group with a weaker immune response, mostly against BLVp24, and a proviral load of < 100 copies/mu g of DNA ie, low proviral load).Conclusions and Clinical Relevance-Results emphasized the importance of characterizing nonlymphocytotic BLV-infected cattle during eradication programs. The risk of transmitting BLV infection from nonlymphocytotic cattle may differ depending on the proviral load. Nonlymphocytotic cattle with high proviral load could be efficient transmitters (as efficient as lymphocytotic cattle), whereas nonlymphocytotic cattle with low proviral load could be inefficient transmitters under standard husbandry conditions. Because most cattle with low proviral load do not develop anti-BLVp24 antibodies, it appears that lack of an anti-BLVp24 antibody response may be a good marker of this condition.