Nanocapsule-mediated topical delivery of VLP-generating Dengue DNA vaccine

描述（由申请人提供）：本项目的最终目标是开发一种安全有效的登革热病毒（DENV）局部疫苗。据估计，DENV每年在全世界造成3000万至5000万例衰弱性发热，导致超过20，000人死亡。基于DNA的疫苗具有对抗DENV的巨大潜力，因为它们可以更快地产生平衡的免疫应答，生产成本更低，并且具有比目前临床试验中的DENV候选疫苗更高的温度稳定性。然而，DNA疫苗历来具有低免疫原性。我们提出的疫苗是经过设计的，可以通过三种关键方式克服这种成功的障碍。首先，美国疾病控制和预防中心（CDC）疫苗结合了将体液免疫从非保护性和潜在致病性抗体的产生重新定向到增加有效中和和保护性抗体的产生的进展。第二，疫苗通过GeneSegues（GSI）局部施用的亚50纳米（s50）胶囊直接递送到皮肤中的免疫效应细胞网络。第三，s50包封疫苗利用有效的、大小敏感的脂筏摄取途径直接运输到免疫效应细胞的细胞核，解决了DNA递送的主要障碍。在这项1期研究中，我们建议通过专注于血清型2（DENV-2）开发局部DENV DNA疫苗，具有四个特定目标。首先，我们将建立在试验性体内s50 DENV-2疫苗递送研究的基础上，以确定小鼠模型中的最佳局部递送部位参数。其次，对于所选的递送和应用部位，我们将通过比较早期效应细胞转染和抗原表达百分比与随后的中和抗体应答和持久性，从机械上评估差异佐剂和给药参数。第三，使用目标1和2中鉴定的两种最佳s50候选疫苗，我们将通过检查DENV-2特异性免疫记忆的建立和持久性来表征细胞介导的免疫应答。第四，在单独的研究组中，我们将在一组半固体媒介物（洗剂和/或凝胶）中复合s50 DENV-2 DNA疫苗以获得最大和均匀的剂量递送，并在小鼠中用最佳复合候选物进行原理验证研究，关键目标是实现与通过电穿孔和通过肌内注射递送的裸DNA相比相等或上级保护性中和抗体滴度。未来的工作将扩展和过渡到其余三种登革热血清型（DENV-1，-3和-4），并确定最佳配方，以在两到三个月内引发四价平衡，保护和持久的免疫力。将通过使用DENV疫苗和疾病AG 129小鼠模型评估疫苗有效性和安全性，包括致死攻击和亚致死抗体依赖性感染增强研究。我们还将进行生产规模扩大和其他必要的任务，以推进IND提交和人体临床试验。

DESCRIPTION (provided by applicant): The ultimate goal of this project is to develop a safe and effective topical vaccine against the dengue virus (DENV). DENV causes an estimated 30 to 50 million cases of debilitating fever leading to over 20,000 deaths worldwide every year. DNA-based vaccines have great potential against DENV because they can more quickly generate a balanced immune response, are less expensive to produce, and have greater temperature stability than current DENV vaccine candidates in clinical trial. However, DNA vaccines have historically suffered from low immunogenicity. The vaccine that we propose is engineered to overcome this barrier-to- success in three key ways. First, the US Centers for Disease Control and Prevention (CDC) vaccine incorporates advances that redirect humoral immunity away from the production of non-protective and potentially pathogenic antibodies to increase the production of potently neutralizing and protective antibodies. Second, the vaccine is delivered directly to the network of immune effector cells in the skin via GeneSegues' (GSI's) topically administered sub-50 nanometer (s50) capsules. Third, the s50 encapsulated vaccine exploits the efficient, size-sensitive lipid raft uptake pathway to traffic directly to the nucleusof immune effector cells, addressing a major hurdle to DNA delivery. In this Phase 1 study, we propose to develop a topical DENV DNA vaccine by focusing on serotype-2 (DENV-2), with four specific aims. First, we will build upon pilot in vivo s50 DENV-2 vaccine delivery studies to determine optimal topical delivery site parameters in a mouse model. Second, for the selected delivery and application site, we will mechanistically assess differential adjuvants and dosing parameters, by comparing early percent effector cell transfection and antigen expression with subsequent neutralizing antibody response and persistence. Third, using the two best s50 vaccine candidates identified in Aims 1 and 2, we will characterize cell-mediated immune responses by examining the establishment and persistence of DENV-2 specific immunological memory. Fourth, in a separate study arm, we will compound the s50 DENV-2 DNA vaccine in a panel of semisolid vehicles (lotions and/or gels) to obtain maximum and uniform dose delivery, and execute a proof-of-principle study in mice with the best compounded candidate, with a key goal of achieving equivalent or superior protective neutralizing antibody titers vs. naked DNA delivered via electroporation and via intramuscular injection. Future work will expand and transition to the three remaining dengue serotypes (DENV-1, -3 and -4) and determine the optimum formulation to elicit tetravalent balanced, protective, and long lasting immunity within two to three months. Vaccine efficacy and safety will be assessed by using the DENV vaccine and disease AG129 mouse model, including lethal challenge and sublethal antibody-dependent enhancement of infection studies. We will also conduct manufacturing scale-up and other tasks necessary to progress to IND submission and human clinical trials.