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

描述（由申请人提供）：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3 400万人感染艾滋病毒，250万人新感染，170万人死亡。虽然抗逆转录病毒疗法（ART）可以大大减少艾滋病毒患者的病毒血症，但ART必须终生持续，否则病毒会从潜伏感染的细胞中反弹。如果没有解药， 终身坚持ART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患者接受骨髓移植（BMT），并显示停止ART后缺乏病毒反弹。柏林的一名患者接受了来自HIV耐药CCR 5 δ 32突变纯合子供体的同种异体BMT，波士顿的两名患者接受了来自CCR 5野生型供体的同种异体BMT。这些患者可能治愈的机制尚未确定，但一个重要的相似之处是他们都接受了来自无关供体的同种异体BMT。在癌症研究中，同种异体骨髓移植和供体淋巴细胞输注（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，其中供体免疫细胞识别并清除宿主的白血病细胞。在柏林和波士顿患者中的一个主要假设是， 在这种情况下，供体免疫细胞识别并清除宿主的HIV感染细胞，从而根除HIV储存库并治愈。该提案概述了具体的 目的是使用我们实验室开发的人源化BLT小鼠模型来验证这一假设。BLT小鼠通过与人类造血细胞重建而“人源化”，并且它们概括了在人类中观察到的HIV感染、发病机制、抑制和潜伏期的关键特征。因此，BLT小鼠是研究HIV感染细胞清除的极好模型，我将直接用同种异体人DLI检查移植物抗宿主效应。这些实验将（1）评价同种异体人DLI在已经人源化的BLT小鼠中的植入和现有人细胞，特别是CD4+ T细胞（原代HIV靶细胞）和静息CD4+ T细胞（原代潜伏感染细胞）的清除，和（2）评价同种异体人DLI对已经人源化的HIV感染的BLT小鼠中的HIV感染细胞的影响。如果获得资助，该项目将研究治愈艾滋病毒的潜在机制，并将为未来的治愈策略提供信息，使用先进的人源化小鼠模型进行实验和分析，这些实验和分析在人类受试者中是不切实际或不道德的。随着沿着一流的环境，在圣查佩尔山，优秀的指导博士加西亚，和一个全面的培训计划，这项研究将提供一个坚实的基础上，我可以继续我的博士前培训的职业生涯作为一个医生，科学家在免疫学和传染病领域。

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.