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

描述（由申请人提供）：在E1或E1， E3区域缺失的当前一代腺病毒（Ad）载体疫苗已经产生了对多种传染病（如HIV）进行免疫的实验潜力。这些Ad载体允许基因的传递，表达刺激免疫系统的蛋白质。先进一代的Ad载体具有独特的E1和E2b区域缺失（E2b编码病毒DNA聚合酶（pol）和前端蛋白（pTP））。这些遗传区域的缺失使Ad5 [E1-， E2b-]病毒完全无法复制。新的人Ad5 [E1-，E2b-]载体具有几个优点。阿尔茨海默病病毒DNA复制显著减少，去除E2b区域导致阿尔茨海默病晚期基因产物的产生减少10,000倍，进一步降低了阿尔茨海默病编码病毒蛋白影响宿主免疫反应的潜力。此外，使用Ad5 [E1-， E2b-]载体已被证明具有降低的细胞毒性。Ad5 [E1-， E2b-]载体也可以增加插入的转基因的数量和持续表达。这些特征表明Ad5 [E1-， E2b]载体优于Ad5 [El-]载体。鉴于这些优势，我们的战略是采用Ad5 [E1-， E2b-]载体作为基于疫苗的载体的新平台。具体来说，我们选择使用这种新的Ad5平台作为HIV-1的疫苗平台。

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.