A novel VLP vaccine to prevent EBV infection and EBV - associated malignancies

项目总结 Burkitt淋巴瘤是撒哈拉以南非洲最常见的儿童癌症，其数量超过所有 其他形式的儿科肿瘤加在一起。如果不治疗，白血病是致命的；然而，目前的治疗方法 (强化化疗)只有50%有效，难以在撒哈拉以南非洲实施。到目前为止， 绝大多数非洲BL病例与EB病毒(EBV)感染有关。因此，有一个 迫切需要一种安全有效的疫苗来预防和治疗EB病毒及其相关疾病。 拟议研究的目标是开发、表征和验证GP42-Gh/gl-EBNA1-LMP2 临床前研究中的病毒样颗粒(VLP)作为EBV的候选疫苗。以前的方法是 EBV疫苗的开发受到限制，部分原因是病毒基因组的致癌潜力和 缺乏动物模型来测试候选疫苗。这项提案将审查一项新的战略，以发展一个安全的 以及有效的EBV疫苗，使用能够呈现正确折叠的EBV蛋白的VLP。同时瞄准这两个目标 免疫系统的手臂--抗体介导的和T细胞介导的--疫苗将整合多种 EBV表面抗原和细胞内抗原。EB病毒蛋白复合体GP42-Gh/g1与肿瘤相关的Epstein- Barr核抗原1(EBNA1)和潜伏膜蛋白2(LMP2)是EBV的首选候选基因 疫苗研发。有强有力的证据表明，针对EBV蛋白复合体GP42-Gh/Gl的抗体可以 中和EBV感染。EBNA1和LMP2在所有EBV+BL患者的B细胞中持续表达， 是由CD4+和CD8+T细胞识别的。因此，我们假设GP42-Gh/gl-EBNA1-LMP2 VLP将 在体外和体外产生强大的EBV中和抗体反应和EBV特异性T细胞反应 人性化的小鼠模型。将使用野生型小鼠(AIM)生成、表征和验证VLP 1)、BL体外模型(Aim 2)和人源化小鼠(Aim 2) 一种既能诱导预防性中和抗体又能诱导治疗性人类的多价疫苗 T细胞反应不仅将是预防EBV感染的一种宝贵的候选疫苗，而且 在预防和/或治疗EB病毒相关疾病方面具有极其重要的作用。如果疫苗是免疫原性的， 建议完成后，我们将利用现有的良好制造规范设施，地址为 希望之城批量生产临床级GP42-Gh/GL-EBNA1-LMP2 VLP并开始第一阶段临床 在10-15名健康成年人中进行的研究，以建立安全简档并确定候选药物的保护效果 疫苗。从长远来看，如果成功，我们的方法将推出一种新的预防/治疗性疫苗 有潜力预防或治疗每年超过20万例与EBV有关的癌症病例的市场， 包括非洲儿童中的24,000例白血病。

PROJECT SUMMARY Burkitt lymphoma (BL) is the most common childhood cancer in sub-Saharan Africa, outnumbering all other forms of pediatric tumors combined. BL is lethal if left untreated; however, the current treatment (intensive chemotherapy) is only 50% effective and difficult to implement in sub-Saharan Africa. To date, the vast majority of African cases of BL are associated with Epstein-Barr virus (EBV) infection. Thus, there is a critical need for a safe and effective vaccine to prevent and treat EBV and its associated diseases. The objective of the proposed study is to develop, characterize, and validate gp42-gH/gL-EBNA1-LMP2 virus-like particles (VLPs) in pre-clinical studies as a candidate vaccine against EBV. Previous approaches to EBV vaccine development have been limited due in part to the oncogenic potential of the virus genome and lack of animal models to test vaccine candidates. This proposal will examine a new strategy to develop a safe and effective vaccine against EBV, using VLPs that can present properly folded EBV proteins. To target both arms of the immune system—antibody-mediated and T-cell mediated—the vaccine will incorporate multiple EBV surface and intracellular antigens. The EBV protein complex gp42-gH/gL and tumor-associated Epstein- Barr nuclear antigen 1 (EBNA1) and latent membrane protein (LMP2) are prime candidates for use in EBV vaccine development. There is strong evidence that antibodies to the EBV protein complex gp42-gH/gL can neutralize EBV infection. EBNA1 and LMP2 are consistently expressed in B cells of all EBV+ BL patients and are recognized by CD4+ and CD8+ T cells. Thus, we hypothesize that gp42-gH/gL-EBNA1-LMP2 VLPs will generate robust EBV-neutralizing antibody responses and EBV-specific T-cell responses in vitro and in a humanized mouse model. The VLPs will be generated, characterized, and validated using wild-type mice (Aim 1), an in vitro model of BL (Aim 2), and humanized mice (Aim 2) A polyvalent vaccine that induces both prophylactic neutralizing antibodies and elicits therapeutic human T-cell responses will not only be an invaluable candidate vaccine in preventing EBV infection, but also of utmost importance in preventing and/or treating EBV-associated disease. If the vaccine is immunogenic, following completion of the proposal, we will utilize the current good manufacturing practice facility available at City of Hope to mass-produce clinical grade gp42-gH/gL-EBNA1-LMP2 VLPs and begin a phase 1 clinical study in 10-15 healthy adults to establish safety profiles and determine the protective efficacy of the candidate vaccine. In the long term, if successful, our approach will introduce a new prophylactic/therapeutic vaccine to the market with a potential for preventing or treating over 200,000 annual cancer cases associated with EBV, including 24,000 cases of BL in African children.