Enhancing Immunogenicity of VLV-Based Vaccines for Treatment of Chronic HBV

项目摘要/摘要 在急性感染患者中，宿主T细胞对乙肝病毒的反应是强烈的和多特异性的 病毒，但它很弱，更狭隘地集中在那些成为慢性感染者。 因此，尽管人类的免疫反应能够消除感染，但它往往无法消除 就这么做吧。治疗性免疫以诱导足以控制病毒的免疫反应是一种 治疗慢性乙型病毒性肝炎的可能新方法然而不幸的是，目前的乙肝疫苗 对治疗性疫苗接种无效。尽管它会引起强烈的中和抗体反应 为了预防感染，目前的疫苗不能诱导强大的CD8 T细胞反应 感染后清除病毒。向前迈出的重要一步是发展免疫疗法。 在接种疫苗的个体中同时诱导CD8细胞免疫和有效抗体的方法。 正在开发的VLV技术创新能够诱导出一种强大的抗体 应对乙肝病毒需求的应答以及多特异性CD8 T细胞应答 免疫疗法。我们之前发现，反向工程平台的改进版本 它会产生含有VSV-G但没有其他病毒结构蛋白是安全的“病毒样小泡”(VLV)， 在基因上是稳定的，在老鼠身上缺乏神经毒性。利用这种进化的VLV载体 表达乙肝病毒中表面包膜糖蛋白(MHBs)已发现其可诱导CD8T细胞 小鼠的反应幅度更大，特异性更广，比其他方法获得的反应更大 免疫策略，包括重组蛋白和DNA。加强优质加强免疫 幼稚小鼠的CD8 T细胞反应和该方案在转基因小鼠中诱导的乙肝病毒特异性CD8 T细胞 小鼠慢性乙型肝炎感染模型。我们合理地设计和设计了一种VLV疫苗， 包含乙肝病毒基因组的多种抗原，并表明这种多聚体疫苗诱导CD8- 单次免疫中的特异性T细胞。我们进一步改造了这些多蛋白，使其能够分泌。我们 现在将测试非分泌型VLV-多抗原结构的分泌版本的假设 不仅会促进细胞免疫和抗体免疫，而且还会增加广度 与单抗原MHBs抗原构建物相比，这些反应的大小。至 评估我们的假设，我们将实现三个具体目标。首先，我们将描述免疫系统的特征 正常小鼠对VLV-多抗原载体的应答。第二，我们将开发和优化素数- Boost策略，以增强对这些载体的免疫应答。最后，我们将建立 第二阶段开发的里程碑。提出研究具有重要意义，因为一种有效的治疗方法 治疗慢性乙肝的疫苗将对预防乙肝病毒相关疾病产生重大影响 慢性肝病。

PROJECT SUMMARY/ABSTRACT The host T cell response to HBV is vigorous and multi-specific in acutely infected patients who clear the virus, but it is weak and more narrowly focused in those who become chronically infected. Therefore, although the human immune response is capable of eliminating the infection, it often fails to do so. Therapeutic immunization to induce an immune response sufficient to control the virus is a possible new approach for treating chronic hepatitis B. Unfortunately however the current HBV vaccine is not effective for therapeutic vaccination. Although it elicits a strong neutralizing antibody response that prevents infection, the current vaccine does not induce the potent CD8 T cell response needed to eliminate the virus after infection. An important step forward would be to develop immune therapy approaches that induce both CD8 cellular immunity and effective antibodies in vaccinated individuals. The VLV technological innovation under development is capable of inducing both a robust antibody responses as well as multi-specific CD8 T-cell responses addressing the need for HBV immunotherapy. We have previously found that an improved version of the reverse-engineered platform that generates “virus-like vesicles” (VLVs) containing VSV-G but no other viral structural proteins are safe, are genetically stable and lack neurovirulence in mice. Employing this evolved VLV vector engineered to express the HBV middle surface envelope glycoprotein (MHBs) we have found that it induces CD8 T cell responses in mice that were greater in magnitude and broader in specificity than those obtained with other immunization strategies, including recombinant protein and DNA. A prime-boost immunization enhanced CD8 T cell responses in naïve mice and that regimen induced HBV-specific CD8 T cells in a transgenic mouse model of CHB infection. We have rationally designed and engineered a VLV vaccine that encompasses multiple antigens of the HBV genome and show that this multimeric vaccine induces CD8- specific T cells in a single immunization. We have further engineered these polyproteins to be secreted. We will now test the hypothesis that the secreted versions of the non-secreted VLV-Multi-Antigen constructs will not only drive both a superior cell-mediated and antibody immunity but would also increase the breadth and magnitude of these responses when compared to a single antigen MHBs antigen construct. To evaluate our hypothesis, we will carry out three specific aims. First, we will characterize the immune response to the VLV-Multi-Antigen vectors in normal mice. Second, we will develop and optimize a prime- boost strategy in order to enhance the immune responses to these vectors. Finally, we will establish milestones for phase II development. The propose research is significant because an effective therapeutic vaccine that cures chronic HBV would have a substantial impact on the prevention of HBV-associated chronic liver diseases.