Immunization Strategies for Autologous HIV Immunotherapy

描述（由申请人提供）：HIV病毒的多样性是开发有效HIV免疫疗法的主要障碍。最近的几项研究表明，细胞介导的免疫在预防和控制HIV感染中发挥着重要作用。在灵长类动物和人类疫苗接种和免疫治疗研究中，HIV特异性免疫的失败与“CTL逃逸”相关。有效的CTL介导的免疫应答的建立和维持通常取决于CD 4 + T细胞辅助的存在，并且Th 1型应答对于细胞介导的免疫的诱导和维持是关键的。树突状细胞（Dendritic cells，DCs）在免疫的发生和调控中起着重要作用。除了是最有效的抗原呈递细胞（APC）外，它们还决定了免疫反应的性质和程度，并在先天性和获得性免疫之间提供了重要的联系。这里提出的研究将建立在我们以前的努力，利用DNA表达构建体编码自体患者来源的HIV抗原和新的DC转染方法，以解决有效的HIV免疫治疗的主要障碍。具体地，我们提出在体内基因工程皮肤DC，以有效地呈现患者特异性Nef和Gag抗原，并表达增强的DC 1型极化免疫刺激功能，该功能对于HIV感染个体中Th 1 T细胞的最佳活化至关重要。该提议将开发基于递送编码HIV-1抗原的颗粒和DNA制剂的新型体内抗原递送系统，以：1）驱动转基因（tg）抗原在DC中的表达，2）促进tg Ag肽呈递给CD 8 + CTL和CD 4 + Th细胞，以及3）引发Th 1极化DC功能。我们将测试的假设，自体树突状细胞，基因工程目前转基因患者来源的HIV抗原的背景下，Th 1偏斜共刺激功能，将诱导有效的Th 1型患者特异性HIV免疫反应。这将使用小鼠模型和我们开发的独特的原位人皮肤模型来完成，以促进临床试验的转化。除了验证这一假设外，我们提出的研究有可能克服现有HIV免疫疗法的主要局限性，并确定一种能够遏制或根除慢性感染患者感染的免疫策略。重要的是，我们提出的研究包括翻译临床前模型，作为人体临床试验的直接前奏。公共卫生相关性：HIV病毒的多样性是开发有效的HIV免疫疗法的主要障碍。我们将测试这一假设，即基于DNA的免疫策略，靶向递送自体抗原的树突状细胞的背景下，Th 1偏斜佐剂将诱导有效的Th 1型患者特异性HIV-1免疫应答。这将使用小鼠模型和我们开发的独特的原位人皮肤模型来完成，以促进临床试验的转化。我们提出的研究有可能克服现有HIV免疫疗法的主要局限性，并确定一种能够遏制或根除慢性感染患者感染的免疫策略。我们提出的研究包括翻译临床前模型，作为人体临床试验的直接前奏。

DESCRIPTION (provided by applicant): The diversity of the HIV virus is a major obstacle to the development of an effective HIV immunotherapy. Several recent studies demonstrate an important role for cell-mediated immunity in both the prevention and control of HIV infection. Failure of HIV-specific immunity has been correlated with "CTL escape" in both primate and human vaccination and immunotherapy studies. Establishment and maintenance of effective CTL- mediated immune responses generally depends on the presence of CD4+ T-cell help, and a Th1 type response is critical for induction and maintenance of cell-mediated immunity. Dendritic cells (DCs) play critical roles in the development and control of immunity. Besides being the most potent antigen-presenting cells (APC), they determine the nature and magnitude of immune responses and provide an essential link between innate and acquired immunity. The studies proposed here will build on our previous efforts utilizing DNA expression constructs encoding autologous patient-derived HIV antigens and novel DC transfection approaches to address major obstacles to effective HIV immunotherapy. Specifically, we propose to genetically engineer skin DCs in vivo to both efficiently present patient-specific Nef and Gag antigens, and express enhanced DC1 type polarized immune-stimulatory function essential for optimal activation of Th1 T- cells in HIV infected individuals. This proposal will develop novel in vivo antigen delivery systems based on the delivery of particulate and DNA formulations encoding HIV-1 antigens to: 1) drive the expression of transgenic (tg) antigens in DCs, 2) favor presentation of tg Ag peptides to CD8+ CTL and CD4+ Th cells and 3) elicit Th1 polarizing DC function. We will test the hypothesis that autologous dendritic cells, genetically engineered to present transgenic patient-derived HIV antigens in the context of Th1 skewing costimulatory function, will induce effective Th1 type patient-specific HIV immune responses. This will be accomplished using both murine models, and unique in situ human skin models we have developed to facilitate translation to clinical trials. In addition to testing this hypothesis, the studies we propose have the potential to overcome major limitations of existing HIV immunotherapies, and to define an immunization strategy capable of containing or eradicating infection in chronically infected patients. Importantly, the studies we propose include translational preclinical models designed as a direct prelude to human clinical trials. PUBLIC HEALTH RELEVANCE: The diversity of the HIV virus is a major obstacle to the development of an effective HIV immunotherapy. We will test the hypothesis that DNA-based immunization strategies that target delivery of autologous antigen to dendritic cells in the context of Th1 skewing adjuvants will induce effective Th1 type patient-specific HIV-1 immune responses. This will be accomplished using both murine models, and unique in situ human skin models we have developed to facilitate translation to clinical trials. The studies we propose have the potential to overcome major limitations of existing HIV immunotherapies, and to define an immunization strategy capable of containing or eradicating infection in chronically infected patients. The studies we propose include translational preclinical models designed as a direct prelude to human clinical trials.