Oligonucleotide aptamer ligands to reverse T cell anergy in HIV-infected patients

描述(由申请人提供)：HIV感染者的免疫谱系的特征是存在功能逐渐失调的病毒特异性CD4+和CD8+T细胞，也被称为“无能”或“疲惫”T细胞。无能T细胞不能控制病毒血症，也不能阻止疫苗诱导的保护性免疫。该项目的基本假设是：(A)逆转艾滋病毒感染患者的T细胞功能障碍将显著提高治疗性疫苗接种策略的有效性。(B)多种机制导致T细胞功能障碍，但其相对重要性尚未完全确定。(C)重新激活有效且对治疗有用的抗病毒免疫反应将需要艾滋病毒感染者体内多种共刺激和共抑制受体的同时激活。(D)开发针对免疫调节受体的更易获得和免疫原性更低的试剂，将大大便利和加快对它们的联合探索和使用。这个为期两年的项目的具体目标是开发一种新型的临床有用的试剂来阻断HIV感染患者无能T细胞表达的共抑制受体PD-1的功能，PD-1抑制剂将由一个基于寡核苷酸(ODN)的适体组成。适配子是高亲和力的核酸配体，与抗体一样，具有高度的特异性和对靶标的高亲和力。与抗体不同，适配子可以通过简单的化学过程合成，因此为临床使用提供了更直接、更具成本效益和更简单的监管批准过程。此外，基于ODN的适配子的免疫原性预计明显低于抗体。本项目的具体目标是：(1)。目的分离与表达于T细胞上的小鼠和人PD-1结合的跨物种PD-1适配子。(2)。证明PD-1结合适体可以挽救HIV感染患者的功能障碍的T细胞(3)。证明PD-1结合适配子可以逆转小鼠LCMV感染模型中的T细胞无能。越来越多的证据表明，PD-1信号并不是HIV感染患者T细胞无能的唯一机制。在这个为期两年的项目中，PD-1适配子的开发将指导跨物种适配子的开发，以对抗与T细胞无能有关的其他免疫受体，如阻断CTLA-4适配子或激动型4-1BB和CD27适配子。基于ODN的适配子代表了一种新的平台技术，使免疫受体靶向适配子的联合评估和临床探索能够调节接种HIV感染患者的抗病毒免疫。公共卫生相关性：HIV感染患者的免疫缺陷表现为免疫系统的各种功能障碍。这种功能障碍被称为“无能”，这在很大程度上是患者无法控制病毒并进展为艾滋病的原因，也限制了以免疫为基础的治疗的有效性。这项研究提案的目标是逆转艾滋病毒感染患者的无能。我们建议开发一种新的平台技术，提供有效的和临床上有用的药物，即成本效益和用户友好的药物，将艾滋病毒感染者功能失调的免疫细胞转化为能够靶向和消除艾滋病毒的活性细胞。当这些药物与旨在刺激受感染患者的艾滋病毒特异性免疫的治疗结合使用时，这些药物将特别有用，也被称为“治疗性疫苗接种”。

DESCRIPTION (provided by applicant): The immune repertoire of HIV-infected individuals is characterized by the presence of progressively dysfunctional viral-specific CD4+ and CD8+ T cells, also referred to as "anergic" or "exhausted" T cells. The anergic T cells fail to control viremia and prevent the induction of vaccine-induced protective immunity. The hypotheses underlying this project are: (a) Reversing T cell dysfunction in HIV-infected patients will significantly enhance the effectiveness of therapeutic vaccination strategies. (b) Multiple mechanisms contribute to T cell dysfunction, the relative importance of which has not been fully determined (c) Re- activation of a potent and therapeutically useful antiviral immune response will require the simultaneous engagement of multiple costimulatory and coinhibitory receptors in the HIV-infected patient. (d) Development of increasingly accessible and less immunogenic reagents targeting immune modulatory receptors will significantly facilitate and expedite their combined exploration and use. The specific goal of this 2-year project is to develop a novel and clinically useful reagent to block the function of the coinhibitory receptor PD-1 expressed by the anergic T cells of HIV infected patients, The PD-1 inhibitor will consist of an oligonucleotide (ODN)-based aptamer. Aptamers are high-affinity nucleic acid ligands which like antibodies exhibit exquisite specificity and high affinity to their targets. Unlike antibodies, aptamers can be synthesized in a simple chemical process and hence offer a more straightforward, cost effective, and vastly simpler regulatory approval process for clinical use. In addition, ODN-based aptamers are expected to be significantly less immunogenic than antibodies. The specific aims of this project are: (1). To isolate cross-species PD-1 aptamers which bind to both murine and human PD-1 expressed on T cells. (2). To demonstrate that PD-1 binding aptamers can rescue dysfunctional T cells obtained from HIV-infected patients (3). To demonstrate that the PD-1 binding aptamers can reverse T cell anergy in an LCMV infection model in mice. Accumulating evidence suggest that PD-1 signaling is not the sole mechanism for T cell anergy in HIV-infected patients. The development of PD-1 aptamers in this 2 year project will guide the development of cross-species aptamers against other immune receptors implicated in T cell anergy, such as blocking CTLA-4 aptamers or agonistic 4-1BB and CD27 aptamers. The ODN-based aptamers represent a novel platform technology enabling the combined evaluation and clinical exploration of immune receptor-targeted aptamers to modulate antiviral immunity in the vaccinated HIV-infected patients. PUBLIC HEALTH RELEVANCE: Immune defects in HIV infected patients are manifested in various dysfunctions of the immune system. This dysfunction, referred to as "anergy", is largely responsible why patients don't control the virus and progress to AIDS and also limits the effectiveness of immune-based treatments. The goal of this research proposal is to reverse anergy in HIV infected patients. We propose to develop a new platform technology which will provide effective and clinically useful, namely cost-effective and user-friendly, drugs to convert the dysfunctional immune cells of HIV-infected patients into active cells capable of targeting and eliminating HIV. These drugs will be particularly useful when used in combination with treatments designed to stimulate HIV specific immunity in the infected patients, known also as "therapeutic vaccination".