Bovine leukemia virus (BLV) causes enzootic bovine leukosis and is closely related to the human T-lymphotropic virus. Bovine major histocompatibility complex (BoLAs) are used extensively as markers of disease and immunological traits in cattle. For BLV diagnosis, proviral load is a major diagnosis index for the determination of disease progression and transmission risk. Therefore, we investigated the frequency of BoLA-DRB3 alleles, BoLA-DQA1 alleles, and haplotypes of BoLA class II isolated from the heads of 910 BLV-infected cows out of 1290 cows assessed from BLV-positive farms, in a nationwide survey from 2011 to 2014 in Japan. Our aim was to identify BoLA class II polymorphisms associated with the BLV proviral load in the Holstein cow. The study examined 569 cows with a high proviral load and 341 cows with a low proviral load. Using the highest odds ratio (OR) as a comparison index, we confirmed that BoLA-DRB3 was the best marker for determining which cow spread the BLV (OR 13.9 for BoLA-DRB3, OR 11.5 for BoLA-DQA1, and OR 6.2 for BoLA class II haplotype). In addition, DRB3*002:01, *009:02, *012:01, *014:01, and *015:01 were determined as BLV provirus associated alleles. BoLA-DRB3*002:01, *009:02, and *014:01 were determined as resistant alleles (OR > 1), and BoLA-DRB3*012:01 and *015:01 were determined as susceptible alleles (OR < 1). In this study, we showed that BoLA-DRB3 was a good marker for determining which cow spread BLV, and we found not only one resistant allele (BoLA-DRB3*009:02), but also two other disease-resistant alleles and two disease-susceptible alleles. This designation of major alleles as markers of susceptibility or resistance can allow the determination of the susceptibility or resistance of most cows to disease. Overall, the results of this study may be useful in eliminating BLV from farms without having to separate cows into several cowsheds.

中文翻译：

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与日本荷斯坦奶牛的 DQA1 多态性相比，牛白血病病毒前病毒载量与牛主要组织相容性复合体 II 类 DRB3 多态性的相关性更强

牛白血病病毒（BLV）引起地方性牛白血病，与人类嗜T淋巴细胞病毒密切相关。牛主要组织相容性复合体 (BoLA) 被广泛用作牛疾病和免疫学特征的标志物。对于 BLV 诊断，前病毒载量是确定疾病进展和传播风险的主要诊断指标。因此，我们在 2011 年的全国性调查中调查了从 BLV 阳性农场评估的 1290 头奶牛中的 910 头 BLV 感染奶牛的头部中分离的 BoLA-DRB3 等位基因、BoLA-DQA1 等位基因和 BoLA II 类单倍型的频率到 2014 年在日本。我们的目标是确定与荷斯坦奶牛 BLV 前病毒载量相关的 BoLA II 类多态性。该研究检查了前病毒载量高的 569 头奶牛和前病毒载量低的 341 头奶牛。使用最高优势比 (OR) 作为比较指标，我们确认 BoLA-DRB3 是确定哪头奶牛传播 BLV 的最佳标记（BoLA-DRB3 的 OR 为 13.9，BoLA-DQA1 的 OR 为 11.5，BoLA 的 OR 为 6.2 II 类单倍型）。此外，DRB3*002:01、*009:02、*012:01、*014:01和*015:01被确定为BLV原病毒相关等位基因。BoLA-DRB3*002:01、*009:02 和 *014:01 被确定为抗性等位基因（OR > 1），BoLA-DRB3*012:01 和 *015:01 被确定为敏感等位基因（OR < 1）。在本研究中，我们发现 BoLA-DRB3 是确定哪头牛传播 BLV 的良好标记，我们不仅发现了一个抗性等位基因 (BoLA-DRB3*009:02)，还发现了另外两个抗病等位基因和两种疾病- 易感等位基因。这种将主要等位基因指定为易感性或抗性标志物可以确定大多数奶牛对疾病的易感性或抗性。总的来说，这项研究的结果可能有助于从农场中消除 BLV，而不必将奶牛分成几个牛棚。