Epstein-Barr virus antigen design and characterisation

爱泼斯坦-巴尔病毒(EBV)是一种人类疱疹病毒，感染上皮细胞和B淋巴细胞，并使B细胞保持潜伏并可自发重新激活。该病毒感染了90%以上的成年人，在大多数情况下不会引起任何问题或相对轻微的症状(典型的传染性单核细胞增多症，也称为腺热)。然而，在一小部分感染者中，EBV与多发性硬化症或某些癌症的发展有关。这些疾病往往与预后不佳有关，往往需要昂贵的治疗干预，对社会构成重大问题。事实上，英国癌症研究中心的数据表明，EBV感染每年导致20万新的癌症病例，导致每年超过14万人死亡。因此，迫切需要设计一种有效的疫苗来预防EBV感染，从长远来看，目的是减少这些更严重的EBV相关病理的发生。到目前为止，还没有批准的EBV候选疫苗，部分原因是无法选择合适的抗原来诱导强大的中和抗体来阻止感染。最近，对EBV疫苗开发的支持和研究一直在增加，莫德纳已经启动了针对四个关键EBV包膜糖蛋白Gh、g1、g42和gp220的mRNA候选的第一阶段试验。这位主管的团队采取了一种不同的方法来靶向III类FusoGen蛋白-糖蛋白B(GB)，这种蛋白对于介导膜融合到上皮细胞和B淋巴细胞都是至关重要的。然而，gB蛋白非常迅速地将构象从融合前状态(病毒膜上的自然构象)转换到融合后结构。预聚变状态的高分辨率结构尚未建立。确定gB的融合前状态将在很大程度上促进其作为疫苗抗原的使用。该项目将使用gB突变体库来确定蛋白质中的哪些残基参与融合前构象的稳定，从而尝试设计融合前稳定的蛋白质形式。据推测，稳定的融合前GB可以在免疫后引发更强的免疫反应，类似于针对SARS-CoV-2的2P疫苗。此外，该项目可以进一步深入了解驱动GB融合从而EBV感染的分子结构和动力学。

The Epstein-Barr virus (EBV) is a human herpesvirus that infects epithelial cells and B lymphocytes; and transforms B cells to remain latent and can spontaneously reactivate. The virus infects over 90% of adults, and in most cases causes no problems or relatively mild symptoms (typically infectious mononucleosis, also known as glandular fever). In a small minority of those who are infected, however, EBV is associated with the development of multiple sclerosis or certain cancers. These diseases are often associated with poor prognoses and often require expensive treatment interventions, posing a significant issue to society. Indeed, data from Cancer Research UK suggests that EBV infection accounts for 200,000 new cases of cancer each year resulting in more than 140,000 deaths yearly. Therefore, there is an urgent need to design an efficacious vaccine that prevents EBV infection with the aim in the long run to reduce the onset of these more severe EBV associated pathologies. To date there is no approved EBV vaccine candidate, in part due to the inability to select an appropriate antigen that elicits robust neutralising antibodies to block infection. Recently there has been increasing support and research towards EBV vaccine development, with Moderna having initiated Phase I trials of their mRNA candidate targeting four key EBV envelope glycoproteins gH, gL, gp42 and gp220. The supervisor's group have taken a different approach in targeting the class III fusogen protein, glycoprotein B (gB), which is crucial for mediating membrane fusion to both epithelial cells and B lymphocytes. However, the gB protein very rapidly switches conformation from a pre-fusion state (natural conformation on the viral membrane) towards a post-fusion structure. A high-resolution structure of the pre-fusion state has not yet been established. Defining the pre-fusion state of gB would largely promote its use as a vaccine antigen.The project will use a library of gB mutants to establish which residues within the protein are involved in the stability of the pre-fusion conformation, and hence to attempt to design a pre-fusion stabilised form of the protein. It is hypothesised that a stabilised pre-fusion gB could elicit stronger immune responses upon immunisation, analogous to the 2P-based vaccines that target SARS-CoV-2. Furthermore, this project could provide further insight into the molecular architecture and dynamics that drive gB fusion and thus EBV infection.