Nonhuman adenoviral vectors for gene therapy

描述(由申请人提供)： 尽管人腺病毒(HAD)载体作为基因治疗和疫苗应用的递送系统具有许多优点，但与这些载体相关的主要缺点之一是载体免疫。这是由于在大多数人类群体中存在预先存在的HAD特异性免疫，以及在第一次接种后产生了媒介特异性免疫反应。HAD特异性免疫显著降低HAD载体的摄取效率，从而显著降低转基因表达的水平和持续时间。与HAD载体相关的另一个主要问题是由天然免疫激活引起的急性炎症反应和肝毒性。我们的假设是，HAd5、牛腺病毒3型(BAd3)和猪腺病毒3型(PAD3)的主要受体是不同的，因此这些腺病毒载体转导的细胞类型将是不同的。这项建议解决了通过顺序给药人和非人腺病毒载体来逃避媒介免疫的核心问题。这将避免毒性，并允许减少每次接种的媒介剂量，而不会影响治疗效果。在特定目标1下，将评估非人腺病毒载体用于基因治疗的效果。特别是，转导效率、载体的水平和持久性以及载体基因/S的表达将被确定。特定目的2阐述已知腺病毒受体和辅助受体在非人腺病毒载体内化中的作用。随后，将进行一系列体内实验，以评估连续给药人和非人腺病毒载体在规避载体特异性免疫反应和毒性方面的有效性(特定目标3)。这些体内实验将在正常免疫能力小鼠和主要组织相容性复合体(MHC)I类缺陷小鼠身上进行，以确定细胞毒性T细胞在限制载体转导、持久性和生物分布中的作用。还将在乳腺癌的小鼠模型上进行额外的实验，以确定静脉接种和肿瘤内接种后基因表达和毒性是否存在差异。该项目的成功完成将为规避腺病毒载体的免疫和基因治疗应用中的毒性提供有效的策略。

DESCRIPTION (provided by applicant): In spite of a number of advantages of human adenovirus (HAd) vectors as a delivery system for a variety of gene therapy and vaccine applications, the vector immunity is one of the major disadvantages associated with these vectors. This is due to the presence of preexisting HAd-specific immunity in the majority of the human population and the development of a vector-specific immune response following the first inoculation. HAd-specific immunity significantly lowers the efficiency of HAd vector uptake following readministration of the same vector and thus drastically reduces the levels and duration of transgene expression. Another major concern associated with HAd vectors is an acute inflammatory response and hepatotoxicity caused by activation of innate immunity. Our hypothesis is that the primary receptors for HAd5, bovine adenovirus type 3 (BAd3) and porcine adenovirus type 3 (PAd3) are distinct, and therefore, the repertoire of cell types transduced by these adenoviral vectors will be different. This proposal addresses the core issue of eluding vector immunity by sequential administration of human and nonhuman adenoviral vectors. This will avoid toxicity and allow a reduction of the vector dose per inoculation without compromising the therapeutic effect. Under Specific Aim 1, the efficacy of nonhuman adenoviral vectors for gene therapy will be evaluated. In particular, transduction efficiency, the level and persistence of the vector and expression of the vector gene/s will be determined. Specific Aim 2 addresses the role of known adenoviral receptors and co-receptors in internalization of nonhuman adenoviral vectors. Subsequently, a series of in vivo experiments will be conducted to evaluate the usefulness of sequential administration of human and nonhuman adenoviral vectors in circumventing the vector-specific immune response and toxicity (Specific Aim 3). These in vivo experiments will be done in normal immunocompetent mice and major histocompatibility complex (MHC) class I-deficient mice to determine the role of cytotoxic T cells in limiting vector transduction, persistence and biodistribution. Additional experiments will be carried out in a mouse model of breast cancer to determine if differences in gene expression and toxicity occur following intravenous vs. intratumoral inoculation. The successful completion of this project should provide an effective strategy for circumvention of adenoviral vector immunity and toxicity for gene therapy applications.