Yang Deqiang, Zhang Lixia, Duan Jinkun, Huang Qiang, Yu Yao, Zhou Jungang, Lu Hong
State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, 2005 Songhu Road, Shanghai 200438, China.
Shanghai Engineering Research Center of Industrial Microorganisms, 2005 Songhu Road, Shanghai 200438, China.
Vaccines (Basel). 2021 Dec 7;9(12):1443. doi: 10.3390/vaccines9121443.
Infectious bursal disease (IBD), caused by the infectious bursal disease virus (IBDV), is a highly contagious and immunosuppressive disease in chickens worldwide. The novel variant IBDV (nvIBDV) has been emerging in Chinese chicken farms since 2017, but there are no available vaccines that can provide effective protection. Herein, the capsid protein VP2 from nvIBDV strain FJ-18 was expressed in with the aim to produce nvIBDV subviral particles (SVPs). Two recombinant strains constructed for expression of nvIBDV VP2 (nvVP2) and His-tagged VP2 (nvHVP2) formed two types of nvIBDV subviral particles (SVPs), namely nvVP2-SVPs and nvHVP2-SVPs. TEM scans showed that both SVPs were about 25 nm in diameter, but there was a large portion of nvVP2-SVPs showing non-spherical particles. Molecular dynamics simulations indicate that an N-terminal His tag strengthened the interaction of the nvHVP2 monomer and contributed to the assembly of SVPs. Vaccination of chicks with the nvHVP2-SVPs provided 100% protection against novel variant IBDV infection when challenged with the FJ-18 strain, as well as the classical strain BC6/85. By contrast, vaccination with the nvVP2-SVPs only provided 60% protection against their parent FJ-18 strain, suggesting that the stable conformation of subviral particles posed a great impact on their protective efficacy. Our results showed that the nvHVP2-SVPs produced by the recombinant strain is an ideal vaccine candidate for IBDV eradication.
传染性法氏囊病（IBD）由传染性法氏囊病病毒（IBDV）引起，是一种在全球范围内鸡群中具有高度传染性和免疫抑制性的疾病。自2017年以来，新型变异IBDV（nvIBDV）在中国养鸡场中不断出现，但尚无可用疫苗能提供有效保护。在此，为了生产nvIBDV亚病毒颗粒（SVPs），在[具体表达系统]中表达了来自nvIBDV毒株FJ-18的衣壳蛋白VP2。构建的两个用于表达nvIBDV VP2（nvVP2）和His标签化VP2（nvHVP2）的重组菌株形成了两种类型的nvIBDV亚病毒颗粒（SVPs），即nvVP2-SVPs和nvHVP2-SVPs。透射电镜扫描显示，两种SVPs直径均约为25nm，但有很大一部分nvVP2-SVPs呈现非球形颗粒。分子动力学模拟表明，N端His标签增强了nvHVP2单体的相互作用并有助于SVPs的组装。用nvHVP2-SVPs对雏鸡进行免疫接种，当用FJ-18毒株以及经典毒株BC6/85进行攻毒时，能提供100%针对新型变异IBDV感染的保护。相比之下，用nvVP2-SVPs进行免疫接种仅对其亲本FJ-18毒株提供60%的保护，这表明亚病毒颗粒的稳定构象对其保护效力有很大影响。我们的结果表明，由重组[具体菌株]产生的nvHVP2-SVPs是根除IBDV的理想疫苗候选物。
