Investigating graft-versus-host clearance of HIV-infected cells in vivo

描述(申请人提供)：人类免疫缺陷病毒(HIV)仍然是全球发病率、死亡率和医疗费用的主要来源。仅在2011年，就有3400万艾滋病毒携带者，新增感染者250万人，死亡170万人。虽然抗逆转录病毒疗法(ART)可以显著减少HIV患者的病毒血症，但ART必须终生持续，否则病毒会从潜伏感染的细胞中反弹。如果没有治愈方法， 终身坚持抗逆转录病毒疗法的必要性带来了成本、毒性、不良相互作用和耐药性的挑战。最近，有几例HIV患者接受了骨髓移植(BMT)，在停止ART后显示出缺乏病毒反弹。柏林的一名患者接受了抗艾滋病毒CCR5delta32突变纯合子捐赠者的异基因骨髓移植，波士顿的两名患者接受了CCR5野生型捐赠者的异基因骨髓移植。这些患者可能治愈的机制尚未建立，但一个重要的相似之处是，他们都接受了来自无关捐赠者的异基因骨髓移植。在癌症研究中，异基因骨髓移植和供者淋巴细胞输注(DLI)已被证明可以降低白血病患者的复发率，这可能是由于移植物抗白血病效应，即供者免疫细胞识别和清除宿主的白血病细胞。柏林和波士顿患者的一个主要假设是，类似的移植物抗宿主 发生的效果是供者免疫细胞识别和清除宿主的艾滋病毒感染细胞，从而导致根除艾滋病毒的蓄积物和治愈。这份提案概述了具体的 目的是利用我们实验室开发的人源化BLT小鼠模型来验证这一假说。BLT小鼠通过重建人类造血细胞而被“人性化”，它们概括了艾滋病毒感染、发病机制、抑制和潜伏期的关键特征，就像在人类中看到的那样。因此，BLT小鼠是研究HIV感染细胞清除的极佳模型，我将直接用同种异体人DLI检测移植物抗宿主效应。这些实验将(1)评估同种异体人DLI在已经人源化的BLT小鼠中的植入以及现有人类细胞，特别是CD4+T细胞(主要的HIV靶细胞)和静止的CD4+T细胞(主要的潜伏感染细胞)的清除情况，以及(2)评估同种异体人DLI对已经人源化的HIV感染的BLT小鼠中HIV感染细胞的影响。如果获得资金，该项目将研究治愈艾滋病毒的潜在机制，并将为治疗策略的未来发展提供信息，使用先进的人性化小鼠模型来执行在人类受试者身上不切实际或不道德的实验和分析。加上北卡罗来纳大学教堂山的一流环境，加西亚博士的出色指导，以及全面的培训计划，这项研究将为我继续进行博士前培训，成为免疫学和传染病领域的内科科学家奠定坚实的基础。

DESCRIPTION (provided by applicant): The human immunodeficiency virus (HIV) remains a major source of morbidity, mortality, and healthcare costs worldwide. In 2011 alone, 34 million people were living with HIV, with 2.5 million new infections and 1.7 million deaths. Although antiretroviral therapy (ART) can drastically reduce viremia in HIV patients, ART must be continued throughout life, or else the virus rebounds from latently infected cells. Without a cure, the necessity of lifelong adherence to ART presents challenges of cost, toxicity, adverse interactions, and resistance. Recently, there have been several cases of HIV patients who underwent bone marrow transplant (BMT) and have shown a lack of viral rebound after discontinuing ART. One patient in Berlin received an allogeneic BMT from a donor who was homozygous for the HIV-resistant CCR5delta32 mutation, and two patients in Boston received allogeneic BMTs from CCR5-wildtype donors. The mechanism of possible cure in these patients has not been established, but an important similarity is that they all received allogeneic BMTs from unrelated donors. In cancer research, allogeneic BMTs and donor lymphocyte infusions (DLI) have been shown to reduce incidence of relapse in leukemia patients, likely due to a graft-versus-leukemia effect in which the donor immune cells recognize and clear the host's leukemic cells. One leading hypothesis in the Berlin and Boston patients is that a similar graft-versus-host effect occurred in which the donor immune cells recognized and cleared the host's HIV-infected cells, thus resulting in eradication of the HIV reservoir and cure. This proposal outlines specific aims to test this hypothesis using the humanized BLT mouse model developed in our laboratory. BLT mice are "humanized" by reconstitution with human hematopoietic cells, and they recapitulate key features of HIV infection, pathogenesis, suppression, and latency as seen in humans. The BLT mouse is thus an excellent model to investigate clearance of HIV-infected cells, and I will examine the graft-versus-host effect directly with allogeneic human DLI. These experiments will (1) evaluate the engraftment of allogeneic human DLI in already-humanized BLT mice and the clearance of existing human cells, particularly CD4+ T cells (primary HIV target cells) and resting CD4+ T cells (primary latently infected cells), and (2) evaluate the effet of allogeneic human DLI on HIV-infected cells in already-humanized HIV-infected BLT mice. If funded, this project will investigate a potential mechanism for curing HIV and will inform the future development of cure strategies, using an advanced humanized mouse model to perform experiments and analyses that would be impractical or unethical in human subjects. Along with the superb environment at UNC Chapel Hill, excellent mentoring by Dr. Garcia, and a well-rounded training plan, this research will provide a solid foundation on which I can continue my predoctoral training toward a career as a physician-scientist in the fields of immunology and infectious disease.