Adenovirus Vectors for Respiratory Syncytial Virus Vaccination

描述(申请人提供)：呼吸道合胞病毒(RSV)是导致幼儿下呼吸道疾病和住院的主要病毒原因，长期以来一直被认为是疫苗的优先疾病。呼吸道合胞病毒对疫苗效力提出了许多挑战。自从福尔马林灭活RSV疫苗失败以来的近40年里，在理解用于保护和免疫增强的适当免疫反应方面取得了长足的进步。针对RSV引起的下呼吸道疾病的疫苗诱导保护必须包括抗体和CD8+细胞溶解T细胞。同等或更重要的是，疫苗不得刺激IL-4和IL-5，这是TH2 CD4+反应的指标。IL-4已被证明具有免疫增强作用，而与TH1相关的细胞因子干扰素-γ和CD8+T细胞在没有增强肺部病理的情况下具有保护作用。因此，我们认为，如果对一个关键的RSV抗原诱导平衡的辅助和杀伤T细胞反应，疫苗接种将是有效的。腺病毒载体(侵袭者)已显示出作为传染病疫苗的前景。针对HIV的高效表达编码抗原的复制缺陷平流子疫苗的临床前和临床测试正在进行中， 埃博拉、流感和其他疾病。Advectors能够刺激Th1辅助反应和细胞溶解CD8+反应，并中和针对载体抗原的抗体。这项SBIR应用的总体目标是测试RSV新的候选平流子疫苗免疫是否能刺激中和抗体和病毒特异性Th1、CD4+和CD8+T细胞，而不是Th2 CD4+。我们将构建高效表达RSV F蛋白的新型重组腺病毒载体。GenVec拥有基于不同血清型腺病毒构建侵染子的细胞系，它提供了可用于Prime-Boost方案的侵染子，并绕过了先前存在的抗媒介免疫。这些相同的细胞系有助于构建表达具有细胞毒性或抑制平流层复制的转基因的平流层。此外，GenVec的细胞系已被用作细胞底物，用于生产和制造基于平流子的艾滋病毒疫苗，该疫苗目前处于第二阶段临床测试。侵袭者将接受对RSV的免疫反应模式、对抗RSV攻击的有效性以及肺组织病理学的测试。棉鼠和小鼠模型将被用来充分表征RSV的保护、安全性和免疫反应。在这项建议的第一阶段，将产生关键的免疫学和安全性数据，以支持进入第二阶段的决策。在第二阶段部分，将选择先导腺载体进行额外的临床前疗效测试、临床前安全性测试和临床准备制造 测试。 公共卫生相关性：呼吸道合胞病毒(RSV)是导致幼儿下呼吸道疾病和住院的主要病毒原因，长期以来一直被认为是疫苗的优先疾病。我们提出了一种疫苗接种方法，该方法将诱导针对RSV的抗体和平衡的辅助和杀伤T细胞反应，而不会导致疾病增强。在第一阶段，我们将产生表达F蛋白的新型复制缺陷腺病毒载体，并测试它们的安全性，产生适当的免疫反应，以及对RSV的保护。

DESCRIPTION (provided by applicant): Respiratory syncytial virus (RSV) is the leading viral cause of lower respiratory illness and hospitalization in young children and has long been recognized as a priority disease for a vaccine. RSV presents many challenges for vaccine efficacy. Over the nearly 40 years since the failed formalin-inactivated RSV vaccine great strides have been made in understanding the appropriate immune responses for protection versus immunopotentiation. Vaccine-evoked protection against RSV-induced disease of the lower respiratory system must include antibody and CD8+ cytolytic T- cells. Of equal or greater importance, the vaccine must not stimulate interleukin (IL)-4 and IL-5, indicators of a TH2 CD4+ response. IL-4 has been shown to immunopotentiate while the TH1-associated cytokine interferon-gamma and CD8+ T-cells have been correlated with protection without enhanced lung pathology. Thus, we propose that vaccination will be effective if there is induction of balanced helper and killer T-cell responses to a key RSV antigen. Adenovirus vectors (advectors) have shown promise as vaccines for infectious diseases. Preclinical and clinical testing of replication-defective advector vaccines with potent expression of the encoded antigen is underway for HIV, Ebola, Influenza, and other diseases. Advectors are capable of stimulating Th1 helper and cytolytic CD8+ responses and neutralizing antibody to the vectored antigen. The overall goal of this SBIR application is to test whether immunization with novel advector vaccine candidates for RSV stimulate neutralizing antibody and virus-specific Th1 CD4+ and CD8+ T-cells without Th2 CD4+. We will build novel recombinant adenovirus vectors that express the RSV F protein to high levels. GenVec has cell lines to construct advectors based on different serotypes of adenovirus, which provides advectors that can be used in prime-boost regimens and circumvent pre-existing anti-vector immunity. These same cell lines facilitate the construction of advectors that express transgenes that are cytotoxic or inhibit advector replication. Additionally, GenVec's cell line has been used as the cell substrate for the generation and manufacturing of an advector-based HIV vaccine that is now in phase II clinical testing. The advectors will be tested for the pattern of immune response evoked to RSV, for efficacy against RSV challenge, and for lung histopathology. Both cotton rat and murine models will be used to fully characterize RSV protection, safety, and the immune response. From the phase I portion of this proposal key immunological and safety data will be generated to enable decision-making for advancement to phase II. In the phase II portion, lead adenovectors will be chosen for additional preclinical efficacy testing, preclinical safety testing, and manufacturing in preparation for clinical testing. PUBLIC HEALTH RELEVANCE: Respiratory syncytial virus (RSV) is the leading viral cause of lower respiratory illness and hospitalization in young children and has long been recognized as a priority disease for a vaccine. We propose a method of vaccination that will induce an antibody and balanced helper and killer T-cell response against RSV without causing enhanced disease. In phase I we will generate novel replication-deficient adenovirus vectors that express F protein and test them for safety, generation of appropriate immune responses, and protection against RSV.