Viral Infectious Diseases Unit, RIKEN, Wako, Saitama, 351-0198, Japan.
Photonics Control Technology Team, RIKEN Center for Advanced Photonics, Wako, Saitama, 3510198, Japan.
Retrovirology. 2019 May 16;16(1):14. doi: 10.1186/s12977-019-0476-z.
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-DRB3002:01, *009:02, and 014:01 were determined as resistant alleles (OR > 1), and BoLA-DRB3012:01 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-DRB3009:02), 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.
牛白血病病毒 (BLV) 引起地方性牛白血病，与人类 T 淋巴细胞嗜病毒密切相关。牛主要组织相容性复合体 (BoLAs) 被广泛用作牛疾病和免疫性状的标记。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，我们从 2011 年至 2014 年在日本全国范围内对来自 BLV 阳性农场的 1290 头奶牛中检测出的 910 头 BLV 感染奶牛的头部分离的 BoLA-DRB3 等位基因、BoLA-DQA1 等位基因和 BoLA 类 II 单倍型的频率进行了调查。我们的目的是鉴定与荷斯坦奶牛 BLV 前病毒载量相关的 BoLA 类 II 多态性。该研究检查了 569 头高前病毒载量的奶牛和 341 头低前病毒载量的奶牛。使用最高优势比 (OR) 作为比较指标，我们证实 BoLA-DRB3 是确定哪种奶牛传播 BLV 的最佳标记物（BoLA-DRB3 的 OR 为 13.9，BoLA-DQA1 的 OR 为 11.5，BoLA 类 II 单倍型的 OR 为 6.2）。此外，确定 DRB3*002:01、*009:02、*012:01、*014:01 和 015:01 为与 BLV 前病毒相关的等位基因。BoLA-DRB3002:01、*009:02 和 014:01 被确定为抗性等位基因（OR >1），而 BoLA-DRB3012:01 和 015:01 被确定为易感等位基因（OR <1）。在这项研究中，我们表明 BoLA-DRB3 是确定哪种奶牛传播 BLV 的良好标记物，我们不仅发现了一个抗性等位基因（BoLA-DRB3009:02），还发现了另外两个抗性等位基因和两个易感等位基因。将主要等位基因指定为易感性或抗性标记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在不将奶牛分为几个牛舍的情况下从农场中消除 BLV。
