Non-Integrating Lentiviral Vectors: Potential as Vaccines

描述（由申请人提供）：尽管在艾滋病毒-1治疗方面取得了重大进展，但艾滋病毒-1/艾滋病流行病继续增长，突出表明需要开发有效的疫苗。尽管具有复制能力的减毒HIV-1疫苗存在不可接受的风险，但先前对SIV减毒株的研究已经在灵长类动物模型中得出了一些关于疫苗效力的重要观察结果。在病毒感染的情况下，慢性呈现低水平的病毒抗原提供了保护。在逆转录病毒感染期间，高水平的未整合染色体外DNA （E-DNA）在受感染细胞中积累，除了负责产生新病毒子代的整合原病毒外。E- DNA已被证明在体内即使没有可检测到的血浆病毒血症也能持续存在。我们以及其他人已经证明，E-DNA在体外非分裂细胞中是稳定的，并且在转录上具有活性，可以产生功能性病毒蛋白。然而，尽管产生病毒蛋白，E-DNA不能维持病毒复制。该建议的中心假设是，从HIV-1 E-DNA持续产生病毒蛋白是一种有效和安全的表达病毒蛋白和诱导免疫反应的方法。病毒蛋白是在感染周期的背景下呈现的，其安全特征包括缺乏复制病毒的产生和缺乏整合。为了验证这一假设，我们将测试整合酶缺陷慢病毒载体在包括树突状细胞（DC）在内的专业抗原提呈细胞（APC）中产生病毒E-DNA和蛋白质的效率。这些转导细胞被效应t细胞识别和诱导应答的能力也将被评估。最后，我们将使用小鼠模型来确定肌内传递的in缺陷载体的E-DNA和病毒蛋白产生的动力学，并确定其表达是否与可测量的免疫反应相关。这些可行性研究将确定是否应利用有蛋白缺陷的载体开发疫苗。

DESCRIPTION (provided by applicant): Despite major advancements in HIV-1 therapeutics, the HIV-1/AIDS epidemic continues to grow, highlighting the need for the development of an effective vaccine. Although an attenuated replication competent HIV-1 vaccine presents unacceptable risks, prior work with attenuated strains of SIV has led to several important observations concerning vaccine efficacy in the primate model. Chronic presentation of low levels of viral antigens in the setting of a viral infection provides protection. During retroviral infection, high levels of unintegrated extrachromosomal DNA (E-DNA) accumulate in the infected cells in addition to integrated provirus responsible for production of new viral progeny. E- DNA has been shown to persist in vivo even in the absence of detectable plasma viremia. We, as well as others, have shown that E-DNA is stable in vitro in non-dividing cells and is transcriptionally active producing functional viral proteins. However, despite the production of viral protein, E-DNA does not sustain viral replication. The central hypothesis of this proposal is that sustained viral protein production from HIV-1 E-DNA is an efficient and safe way to express viral proteins and induce an immune response. Viral proteins are presented in the context of an infectious cycle with the safety features including the lack of production of replicating virus and the absence of integration. To test this hypothesis, we will test the efficiency of integrase defective lentiviral vectors to produce viral E-DNA and proteins in professional antigen presenting cells (APC) including dendritic cells (DC). The ability of these transduced cells to be recognized by and induce a response in effector T-cells will be evaluated as well. Finally we will use a murine model to determine the kinetics of E-DNA and viral protein production from IN-defective vectors delivered intramuscularly as well as determine if the expression is associated with a measurable immune response. These feasibility studies will establish whether IN-defective vectors should be exploited for vaccine development.