Development of an Ad5 [E1-, E2b-] HIV-1 vaccine for use in Ad5 Immunized Vaccinee

描述（由申请方提供）：在E1或E1、E3区域缺失的当前一代腺病毒（Ad）载体疫苗具有免疫多种感染性疾病（如HIV）的实验潜力。这些Ad载体允许传递基因，这些基因表达刺激免疫系统的蛋白质。先前已经描述了具有E1和E2 b区域（E2 b编码病毒DNA聚合酶（pol）和前末端蛋白（pTP））的独特缺失的先进一代Ad载体。这些遗传区域的缺失使得Ad 5 [E1-，E2 b-]病毒完全不能复制。新的人Ad 5 [ E1-，E2 b-]载体具有几个优点。Ad病毒DNA复制显著减少，并且E2 b区域的去除导致Ad晚期基因产物的产生减少10，000倍，进一步降低了Ad编码的病毒蛋白影响宿主免疫应答的可能性。此外，已显示使用Ad 5 [El-，E2 b-]载体具有降低的细胞毒性。Ad 5 [E1-，E2 b-]载体还可以导致插入的转基因的数量增加和持续表达。Ad 5 [E1-，E2 b]载体的这些特征表明它们比Ad 5 [E1-]载体优越上级。鉴于这些优势，我们的策略是采用Ad 5 [E1-，E2 b-]载体作为基于疫苗的载体的新平台。具体来说，我们选择使用这个新的Ad 5平台作为HIV-1的疫苗平台。 我们研究Ad 5 [E1-，E2 b-]载体的第1阶段目标非常成功。多次免疫诱导对转基因产物的强烈免疫应答。我们观察到动物可以用一种抗原免疫，然后在Ad 5免疫存在下用第二种不同的抗原免疫。与当前一代Ad 5 [E1-]载体相比，我们的[E1-，E2 b-]载体诱导更高水平的干扰素-？而IL-2分泌淋巴细胞在Ad 5幼稚和Ad 5免疫中均为阴性。研究还表明，动物可以用Ad 5 [E1-，E2 b-] gag，nef，pol的三联体混合物进行免疫。我们对NHP中初始疫苗试验的样品进行的分析表明，在预先存在的Ad 5超免疫力的情况下，它们可以成功地对HIV gag蛋白进行免疫。 在II期，将在小鼠和NHP中进行研究，以进一步开发疫苗接种方案。II期研究的目的是（1）制备SIV和人Ad 5 [E1-，E2 b-]-gag，pol，nef疫苗平台。(2)通过研究每周、每两周和每月一次的免疫接种来确定小鼠中三联体疫苗接种的最佳频率和最佳途径，并且还将皮内、肌内、腹膜内和静脉内免疫途径与Ad 5 [E1-，E2 b-]-gag/pol/nef载体的三联体混合物进行比较。(3)确定转基因在体内表达的持续时间。(4)在Ad 5初治和Ad 5免疫NHP中测试三联疫苗的安全性和免疫原性，以及（5）对接种疫苗的NHP进行SIV攻击研究。Etubics将进行这些临床前研究，以将这种新的疫苗平台推进临床试验。公共卫生相关性：由于每天约有5，000例新的HIV-1感染发生，以及默克公司的STEP HIV疫苗试验失败，迫切需要一种可行的HIV-1疫苗。在这项研究中，我们将进一步开发我们先进的腺病毒载体递送系统的艾滋病毒疫苗。需要该系统来突破由先前患有腺病毒感染的疫苗接种者提出的障碍，其中包括世界各地的许多人。

DESCRIPTION (provided by applicant): Current generation Adenovirus (Ad) vector vaccines deleted at the E1 or the E1, E3 regions have resulted in experimental potential to immunize against a variety of infectious diseases such as HIV. These Ad vectors permit the delivery of genes, which express proteins that stimulate the immune system. An advanced generation of Ad vectors with unique deletions of the E1 and E2b region (E2b encodes the viral DNA polymerase (pol) and the preterminal protein (pTP) has previously been described. The deletion of these genetic regions renders the Ad5 [E1-, E2b-] virus completely replication incompetent. The new human Ad5 [ E1-,E2b-] vectors have several advantages. Ad viral DNA replication is significantly diminished and the removal of the E2b region results in a 10,000-fold reduction in the production of Ad late gene products, further reducing the potential of Ad encoded viral proteins from impacting host immune responses. Moreover, use of Ad5 [E1-, E2b-] vectors have been shown to have decreased cytotoxicity. The Ad5 [E1-, E2b-] vectors can also lead to an increased quantity and sustained expression of inserted transgenes. These characteristics of Ad5 [E1-, E2b] vectors suggest that they are superior to Ad5 [ El-] vectors. In light of these advantages, our strategy is to employ the use of Ad5 [E1-, E2b-] vectors as a new platform for vaccine based vectors. Specifically, we chose to use this new Ad5 platform as a vaccine platform for HIV-1. Our Phase 1 goal to investigate Ad5 [E1-, E2b-] vectors was very successful. Multiple immunizations induced robust immunologic responses to transgene products. We observed that animals could be immunized with one antigen and then subsequently immunized with a second differing antigen in the presence of Ad5 immunity. In comparison with the current generation Ad5 [E1-] vector, our [E1-, E2b-] vector induced higher levels of interferon-? and lL-2 secreting lymphocytes both in Ad5 naive and Ad5 immune. Studies also demonstrate that animals could be immunized with a triad mixture of Ad5 [E1-, E2b-] gag, nef, pol. Our analysis of samples from our initial vaccine trial in NHPs suggest that they can be successfully immunized against the HIV gag protein in the presence of pre-existing Ad5 hyper immunity. In Phase II, studies will be performed in mice and NHPs to further develop the vaccination regimen. The Aims of the Phase II study are to (1) prepare SIV and human Ad5 [E1-, E2b-]-gag, pol, nef vaccine platforms. (2) determine the optimal frequency and optimal route of triad vaccination in mice by investigating immunizations on a weekly, bi-weekly and monthly schedule and also compare intradermal, intramuscular, intraperitoneal and intravenous routes of immunization with a triad mix of Ad5 [E1-, E2b-]-gag/pol/nef vectors. (3) determine the duration of transgene expression in vivo. (4) test safety and immunogenicity of the triad vaccine in Ad5 na¿ve and Ad5 immune NHP, and (5) perform SIV challenge studies of vaccinated NHPs. Etubics will perform these pre-clinical studies to advance this new vaccine platform into clinical trials. PUBLIC HEALTH RELEVANCE: With approximately 5,000 new HIV-1 infections occurring daily and the failure of the Merck 'STEP" HIV vaccine trial, the need for a viable HIV-1 vaccine is urgent. During this study, we will further develop our advanced adenoviral vector delivery system for HIV vaccines. The system is needed to break through the barrier presented by vaccinees who have had prior adenovirus infections which includes many humans worldwide.