Department of Veterinary Biotechnology, College of Veterinary Science, P.V. Narsimha Rao Telangana Veterinary University, Hyderabad.
Onderstepoort J Vet Res. 2020 Oct 8;87(1):e1-e6. doi: 10.4102/ojvr.v87i1.1816.
Bluetongue (BT) is a vector-borne disease of ruminants caused by Bluetongue virus (BTV). Twenty-nine different serotypes of BTV are currently reported throughout the world. The main objective of this study is the development of a subunit vaccine model that could potentially be adapted to provide broad spectrum protection against multiple BTV serotypes, which the conventional vaccines fail to address. To this end, three different BTV proteins (conserved region of viral protein [VP]2, VP5 and NS1) were expressed and purified in an Escherichia coli expression system. The immunogenicity of these proteins was tested in murine models using the MontanideTM ISA 201 VG adjuvant. BALB/c mice were immunised thrice (with individual proteins and a mixture of three proteins) at two-week intervals and were monitored until Day 40 post-infection/vaccination. Protein-specific antibodies directed against the recombinant proteins were detected by indirect enzyme-linked immunosorbent assay. Neutralising antibody (Nab) titres and cross-neutralisation against a range of BTV serotypes (BTV-1, -2, -4, -5, -9, -10, -12, -16, -21, -23 and -24) were determined by serum neutralisation test. The recombinant proteins elicited higher Nab titres compared with the inactivated vaccine group, except for BTV-1, where the inactivated vaccine group elicited higher Nab titres. Additive effect of the three proteins was not observed as the Nab titres generated with a combination of conserved VP2, VP5 and NS1 was similar to those of the individual protein groups. Whilst BTV-12 could only be neutralised by serum raised against the inactivated vaccine group, BTV-5 and -24 could not be neutralised by any of the groups tested. Our cumulative data suggest that the conserved regions of VP2 (cVP2), VP5 and NS1 could play an important part in the novel vaccine design against multiple BTV serotypes. Importantly, given that VP2 was already known to elicit a serotype-specific immune response against BT, we report, for the first time, that the conserved region of VP2 has the ability to induce cross-protective immune response.
蓝舌病（BT）是一种由蓝舌病病毒（BTV）引起的反刍动物的虫媒病。目前，全世界共报告了 29 种不同的 BTV 血清型。本研究的主要目的是开发一种亚单位疫苗模型，该模型可能能够提供针对多种 BTV 血清型的广谱保护，而传统疫苗无法解决这一问题。为此，在大肠杆菌表达系统中表达和纯化了三种不同的 BTV 蛋白（病毒蛋白 [VP]2 的保守区、VP5 和 NS1）。使用 MontanideTM ISA 201 VG 佐剂在小鼠模型中测试了这些蛋白的免疫原性。BALB/c 小鼠每两周免疫一次（分别用单个蛋白和三个蛋白的混合物），并监测至感染/接种后第 40 天。通过间接酶联免疫吸附试验检测针对重组蛋白的蛋白特异性抗体。通过血清中和试验测定针对一系列 BTV 血清型（BTV-1、-2、-4、-5、-9、-10、-12、-16、-21、-23 和 -24）的中和抗体（Nab）效价和交叉中和。与灭活疫苗组相比，重组蛋白引起的 Nab 效价更高，除了 BTV-1，其中灭活疫苗组引起的 Nab 效价更高。未观察到三种蛋白的附加效应，因为用保守 VP2、VP5 和 NS1 组合产生的 Nab 效价与单个蛋白组相似。虽然 BTV-12 只能被针对灭活疫苗组的血清中和，但 BTV-5 和 -24 不能被任何测试组中和。我们的综合数据表明，VP2（cVP2）、VP5 和 NS1 的保守区可能在针对多种 BTV 血清型的新型疫苗设计中发挥重要作用。重要的是，鉴于 VP2 已经被证明对 BT 产生血清型特异性免疫反应，我们首次报告 VP2 的保守区具有诱导交叉保护免疫反应的能力。
