Immunization Strategies for Autologous HIV Immunotherapy

描述(申请人提供)：艾滋病毒的多样性是开发有效的艾滋病毒免疫疗法的主要障碍。最近的几项研究表明，细胞免疫在预防和控制艾滋病毒感染方面发挥着重要作用。在灵长类和人类疫苗和免疫治疗研究中，HIV特异性免疫失败与“CTL逃避”有关。有效的CTL介导的免疫应答的建立和维持通常依赖于CD4+T细胞帮助的存在，而Th1型应答对于诱导和维持细胞介导的免疫至关重要。树突状细胞(DC)在免疫的发生和控制中起着重要作用。除了是最强大的抗原提呈细胞(APC)外，它们还决定免疫反应的性质和大小，并在先天性免疫和获得性免疫之间提供重要的联系。这里提出的研究将建立在我们以前的努力的基础上，利用编码自体患者来源的HIV抗原的DNA表达构建体和新的DC转染法来解决有效的HIV免疫治疗的主要障碍。具体地说，我们建议在体内对皮肤树突状细胞进行基因工程，以有效地呈递患者特定的Nef和GAG抗原，并表达增强的DC1型极化免疫刺激功能，这对HIV感染者Th1T细胞的最佳激活至关重要。这一建议将开发基于编码HIV-1抗原的颗粒和DNA制剂的新型体内抗原递送系统，以：1)推动转基因(TG)抗原在DC中的表达；2)有利于将TG Ag多肽呈递给CD8+CTL和CD4+Th细胞；3)诱导Th1极化DC功能。我们将测试这样的假设，即自体树突状细胞，通过基因工程，在Th1扭曲共刺激功能的背景下呈现转基因患者来源的HIV抗原，将诱导有效的Th1型患者特异性HIV免疫反应。这将通过使用小鼠模型和我们开发的便于转化为临床试验的独特的原位人类皮肤模型来实现。除了验证这一假设外，我们提出的研究还有可能克服现有艾滋病毒免疫疗法的主要局限性，并确定能够遏制或根除慢性感染患者感染的免疫策略。重要的是，我们建议的研究包括作为人类临床试验的直接前奏而设计的转化性临床前模型。与公共卫生的相关性：艾滋病毒的多样性是开发有效的艾滋病毒免疫疗法的主要障碍。我们将检验这样一种假设，即在Th1偏斜佐剂的背景下，以向树突状细胞递送自体抗原为靶点的DNA免疫策略将诱导有效的Th1型患者特异性HIV-1免疫反应。这将通过使用小鼠模型和我们开发的便于转化为临床试验的独特的原位人类皮肤模型来实现。我们提出的研究有可能克服现有艾滋病毒免疫疗法的主要局限性，并确定能够遏制或根除慢性感染患者感染的免疫策略。我们建议的研究包括作为人类临床试验的直接前奏而设计的翻译临床前模型。

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.