The development and pre-clinical assessment of novel HCV vaccines to generate T and B cell immunity

项目摘要 丙型肝炎病毒（HCV）感染超过7100万人，并导致肝脏瘢痕和癌症。有效 迫切需要预防感染的疫苗。这应该是一个可以实现的目标，因为25%的人 自发地解决（SR）原发性感染，产生抗病毒免疫。有效的疫苗可能需要 以模拟与SR相关的免疫应答，包括诱导抗HCV中和 抗体（NAb）和HCV特异性T细胞。实现这一点的一种方法是通过使用病毒载体， 疫苗（包括黑猩猩腺病毒[ChAd]和改良的安卡拉牛痘[MVA]）， 作为产生针对编码的免疫原（包括HCV）的免疫应答的有力工具。然而，在这方面， 病毒遗传多样性是开发HCV疫苗的主要挑战，至少有八种不同的基因。 基因型（gt）和多种亚型之间和HCV感染的人。最近，一种病毒载体 编码单一gt-1b序列的疫苗未能预防慢性感染，这突出了开发 新的方法与新的HCV免疫原，产生NAb和T细胞对多种gts。项目5 测试了优化的病毒载体HCV疫苗策略可以产生抗HCV nAb的假设， 交叉反应性T细胞为了验证这一假设，我们将追求三个具体目标。Aim 1使用生物信息学 分析并产生在ChAd和MVA中编码的新型T细胞免疫原，其被设计用于产生广泛的T 在近交系、远交系和（HLA-2）人源化小鼠中评估了所有HCV gt的细胞覆盖率。最有前途的 然后T细胞免疫原将进展到目标2。目的2将增加病毒载体疫苗产生的T细胞 使用遗传佐剂（包括II类不变链的变体）的应答，并评估替代方案 腺病毒载体以克服可能存在于人类中的潜在抗载体免疫。目标3将 开发新的疫苗策略，以产生抗HCV抗体和T细胞。完成这项工作的方法是 评估：i）病毒载体疫苗中编码的不同B细胞免疫原（在项目2和3中鉴定）; ii）将有希望的T细胞疫苗候选物与设计用于产生bNAb（包括病毒抗体）的策略组合 来自项目3的呈递HCV包膜（E2）或具有ChAd的样颗粒（VLP）或纳米颗粒 表达E蛋白;和iii）开发编码最佳E蛋白的单一“二价”病毒载体疫苗， B细胞和T细胞免疫原。重要的是，该项目还将考虑到合作伙伴的调查结果， 项目应确定与SR相关的T细胞图谱（项目1）或病毒序列基序（项目4）。 这些目标将有助于开发一种优化的病毒载体HCV疫苗策略， 在恒河猴中进行评估，以便将来进行人体临床试验。

PROJECT SUMMARY Hepatitis C virus (HCV) infects more than 71 million people and causes liver scarring and cancer. An effective vaccine to prevent infection is urgently required. This should be an achievable goal, since 25% of individuals spontaneously resolve (SR) primary infection generating anti-viral immunity. An effective vaccine may need to mimic the immune responses associated with SR including the induction of anti-HCV neutralizing antibodies (NAbs) and HCV-specific T cells. One method to achieve this, is through the use of viral vectored vaccines (both chimpanzee Adenoviral [ChAd] and modified vaccinia Ankara [MVA]), which have emerged as powerful tools to generate immune responses against an encoded immunogen, including HCV. However, viral genetic diversity is a major challenge for the development of HCV vaccines, with at least eight distinct genotypes (gt) and multiple subtypes between and within HCV infected people. Recently, a viral vectored vaccine encoding a single gt-1b sequence failed to prevent chronic infection, highlighting the need to develop new approaches with novel HCV immunogens that generate NAbs and T cells against multiple gts. Project 5 tests the hypothesis that an optimized viral vectored HCV vaccine strategy can generate anti-HCV nAbs and cross-reactive T cells. To test this hypothesis, we will pursue three specific aims. Aim 1 uses bioinformatic analysis and generates novel T cell immunogens encoded in ChAd and MVA, designed to generate broad T cell coverage to all HCV gts assessed in inbred, outbred and (HLA-2) humanised mice. The most promising T cell immunogen(s) will then progress to aim 2. Aim 2 will increase viral vectored vaccine generated T cell responses using genetic adjuvants (including variants of class II invariant chain) and assess alternative adenovirus vectors to overcome potential anti-vector immunity, that may be present in humans. Aim 3 will develop new vaccine strategies to generate both anti-HCV Abs and also T cells. This will be achieved through assessing: i) Different B cell immunogens (identified in project 2 and 3) encoded in viral vectored vaccines; ii) Combining promising T cell vaccine candidates with strategies designed to generate bNAbs including Viral Like Particles (VLP) or nanoparticles that present the HCV envelope (E2) from Project 3 or with a ChAd expressing E proteins; and iii) developing a single ‘bivalent’ viral vectored vaccine that encodes the optimal B cell and T cell immunogens together. Importantly, the project will also take account of findings in partner projects should T cell profiles (project 1) or viral sequence motifs (project 4) linked to SR be identified. Together the aims will contribute to developing an optimized viral vectored HCV vaccine strategy for assessment in Rhesus monkeys with a view to future human clinical trials.