Animal Science Department, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Iran.
Razi Vaccine and Serum Research Institute, Agricultural Research Education and Extention Organization (AREEO), Tehran, Iran.
Vet Med Sci. 2020 Nov;6(4):730-739. doi: 10.1002/vms3.307. Epub 2020 Jun 26.
The bovine leukaemia virus (BLV) is a retrovirus responsible for enzootic bovine leukaemia (EBL) disease, the most common cattle disease leading to high annual economic losses to the cattle breeding industry. Virus monitoring among the sheep and cattle herds is usually done by vaccination. Inactivated virus vaccines can partially protect the livestock from viral challenge. However, vaccinated animals are likely to be infected. So, there is an essential need for producing vaccine by other methods. Gp60 SU, encoded by Env gene, is the surface glycoprotein of BLV detected to be the major target for the host immunity against the virus. Different stages were performed to predict the potential B and T-helper cell epitopes. The general framework of the method includes retrieving the amino acid sequence of gp60 SU, conducting the sequence alignment, getting the entropy plot, retrieving the previously found epitopes, predicting the hydropathy parameters, modelling the tertiary structure of the glycoprotein, minimizing the structure energy, validating the model by Ramachandran plot, predicting the linear and discontinuous epitopes by various servers and eventually choosing the consensus immunogenic regions. Ramachandran plot scrutiny has demonstrated that the modelled prediction is accurate and suitable. By surveying overlaps of various results, 4 and 2 immunogenic regions were selected as linear and conformational epitopes respectively. Amino acids 35-53, 67-97, 288-302 and 410-421 and those of numbers 37-58 and 72-100 were the regions selected as linear and conformational epitopes respectively. The tertiary structure of the final epitope was modelled as well. A comparison of the predicted epitopes structure with that of gp60 SU envelope, illustrated that the tertiary structure of these epitopes does not change after being separated from the primary complete one. The present achievements will lead to a better interpretation of the antigen-antibody interactions against gp60 in the designing process of safe and efficient vaccines.
牛白血病病毒（BLV）是一种逆转录病毒，负责引起地方性牛白血病（EBL）疾病，这是导致养牛业每年遭受高经济损失的最常见的牛病。对羊群和牛群的病毒监测通常通过接种疫苗来完成。灭活病毒疫苗可以部分保护牲畜免受病毒攻击。然而，接种疫苗的动物很可能会被感染。因此，迫切需要通过其他方法生产疫苗。Env 基因编码的 gp60 SU 是 BLV 的表面糖蛋白，被检测为宿主针对病毒免疫的主要靶标。进行了不同的阶段来预测潜在的 B 和 T 辅助细胞表位。该方法的总体框架包括检索 gp60 SU 的氨基酸序列、进行序列比对、获得熵图、检索先前发现的表位、预测亲水性参数、建模糖蛋白的三级结构、最小化结构能量、通过 Ramachandran 图验证模型、通过各种服务器预测线性和不连续表位，最终选择共识免疫区域。Ramachandran 图分析表明，模型预测是准确和合适的。通过对各种结果的重叠进行调查，选择了 4 个和 2 个免疫区域作为线性和构象表位。氨基酸 35-53、67-97、288-302 和 410-421 以及数字 37-58 和 72-100 分别是作为线性和构象表位选择的区域。最终的表位的三级结构也被建模。将预测的表位结构与 gp60 SU 包膜的结构进行比较，表明这些表位的三级结构在与原始完整结构分离后不会发生变化。目前的研究成果将有助于更好地解释针对 gp60 的抗原-抗体相互作用，从而设计安全有效的疫苗。
