Primate Model Towards HIV Eradication Strategies

描述(由申请人提供)：该项目的长期目标是制定和评估从感染者身上根除艾滋病毒-1的战略。这些研究将通过动物模型进行，该模型能够全面分析HAART期间的病毒库和复制动力学。该模型利用感染了含有HIV-1逆转录酶(RT)的SIVmac239嵌合病毒的恒河猴来代替SIV RT(RT-Shiv)。在这个模型中，在人类中广泛使用的三种药物组合[efavirenz+(-)-FTC+PMPA]在病毒载量(VL)抑制和停止药物治疗后反弹方面模拟了HIV-1感染者的HAART。为了研究RT-Shiv/猕猴模型中的根除策略，我们建立了一种灵敏的VL检测方法，其极限是每毫升血浆中检测到1-2个拷贝的病毒RNA(VRNA)，还建立了灵敏的RT-PCR和PCR方法来检测组织中的vRNA和病毒DNA(VDNA)。该项目的目标是评估增强型HAART的组合，这些组合可以更充分地将血浆和组织VLS抑制到低于我们灵敏的PCR分析检测的水平。由于目前抗逆转录病毒治疗的一个潜在限制是药物可以进入关键的储存组织，我们还将确定目标组织中的药物水平，并利用这些信息来优化药物方案。除了病毒学终点，这些药物组合的影响将在RT-SHV感染的静止CD4+淋巴细胞群体中进行评估。重要的是，高度可操作的RT-SHIV/猕猴模型能够通过确定在停止治疗时延迟或减少病毒反弹的效果来评估潜在的临床影响。我们建议的药物组合旨在评估：i)四种有效核苷类似物(NRTI)与Eefavirenz(NNRTI)或整合酶抑制剂Raltegravir的组合优化DNA链终止；ii)最有效的NRTI与Eefavirenz和Raltegravir的组合；以及iii)加强最有效的药物与蛋白酶抑制剂或CCR5拮抗剂的组合。该项目的总体假设是，强化的HAART方案有可能从受感染的猕猴身上消除RT-SHV。这些研究将提供对完全抑制病毒在组织和特定细胞类型以及血浆中复制的要求的洞察。因此，该项目旨在确定用抗病毒药物组合抑制残留病毒血症是否存在限制，以及根除是否还需要重新激活潜伏病毒的“诱导”策略。与公共卫生相关：从感染者身上根除艾滋病毒-1很可能需要在完全抑制疗法期间充分抑制病毒复制和重新激活潜伏病毒。该项目的重点是消除细胞和组织中残留的病毒复制。这些结果将为HAART期间病毒复制和其他潜伏病毒的重新激活对残留病毒血症的相对贡献，组织和特定细胞类型中的药物浓度与病毒抑制的关系，以及加强治疗对静息CD4+T淋巴细胞潜伏库的影响提供重要信息。这项研究的结果也将有助于未来研究消除潜伏的HIV-1的静止记忆T细胞库的策略。这种诱导策略的成功很可能取决于完全抑制HAART以防止重新激活的病毒复制的能力。

DESCRIPTION (provided by applicant): The long-term goal of this project is to develop and evaluate strategies for eradication of HIV-1 from infected individuals. These studies will be performed with an animal model that enables comprehensive analyses of viral reservoirs and replication dynamics during HAART. This model utilizes rhesus macaques infected by a chimeric virus of SIVmac239 containing the HIV-1 reverse transcriptase (RT) in place of the SIV RT (RT-SHIV). In this model a three-drug combination that is widely used in humans [efavirenz + (-)-FTC + PMPA] mimics HAART in HIV- 1-infected humans with respect to virus load (VL) suppression and rebound upon cessation of drug therapy. In order to study eradication strategies in the RT-SHIV/macaque model, we have developed a sensitive VL assay with a limit of detection of 1-2 copies of viral RNA (vRNA) per ml of plasma, and have also developed sensitive RT-PCR and PCR assays to measure vRNA and viral DNA (vDNA) in tissues. The goal of this project is to evaluate enhanced HAART in combinations that may more fully suppress plasma and tissue VLs to levels below detection with our sensitive PCR assays. Because a potential limitation of current antiretroviral therapy is access of drugs to key reservoir tissues, we will also determine levels of drugs in target tissues and use that information to optimize drug regimens. In addition to virological endpoints, the impact of these drug combinations will be evaluated in RT-SHIV-infected resting CD4+ lymphocyte populations. Importantly, the highly manipulatable RT-SHIV/macaque model enables assessment of potential clinical impact by determining effects on delay or reduction of viral rebound upon cessation of therapy. The drug combinations we propose are designed to evaluate: i) optimization of DNA chain termination with combinations of four potent nucleoside analogs (NRTI) in combination with efavirenz (NNRTI) or an integrase inhibitor, raltegravir; ii) combinations of the most effective NRTIs with both efavirenz and raltegravir; and iii) enhancement of the most potent drug combination with a protease inhibitor or a CCR5 antagonist. The overall Hypothesis of this project is that an intensified HAART regimen has the potential to eliminate RT-SHIV from infected macaques. These studies will provide insight on the requirements for complete suppression of virus replication in tissues and specific cell types as well as in plasma. Thus, this project aims to determine whether there is a limitation to suppression of residual viremia with antiviral drug combinations and whether eradication will also require "induction" strategies for reactivation of latent virus. PUBLIC HEALTH RELEVANCE: It is likely that eradication of HIV-1 from infected individuals will require both full suppression of virus replication and the reactivation of latent virus during fully suppressive therapy. The focus of this project is elimination of residual virus replication in cells and tissues. The results will provide important information about the relative contributions of virus replication and other reactivation of latent virus to residual viremia during HAART, the relationship between drug levels and virus suppression in tissues and specific cell types, and the effect of enhanced therapy on latent reservoirs in resting CD4+ T lymphocytes. The results of this study will also contribute to future studies of strategies for eliminate the resting memory T cell reservoir of latent HIV-1. The success of such induction strategies will likely be dependent on the ability of fully suppressive HAART to prevent replication of reactivated virus.