Targeting HIV-specific T cell differentiation programs to enhance post-treatment control of HIV

项目摘要 全世界有近4000万人感染了艾滋病毒，这种感染无法治愈。许多策略 旨在治愈艾滋病毒的研究重点是利用艾滋病毒特异性T细胞来控制抗逆转录病毒后反弹的病毒 抗逆转录病毒疗法（ART）由于其特异性识别和杀死HIV感染细胞的能力而被停止。 然而，如果HIV特异性T细胞疗法不能克服T细胞耗竭， 发生在慢性抗原刺激的情况下。在慢性感染和癌症的小鼠模型中，T细胞 富集了干细胞记忆（TSCM）表型或干细胞样转录程序的细胞稳健地扩增， 分化为效应细胞，同时抵抗衰竭。我们已经发现， 干/记忆促进转录因子TCF-1与HIV-1的体外高增殖能力相关， 在自然控制HIV感染的个体中特异性CD 8 + T细胞和TCF-1过表达导致 体外肽刺激后更好的HIV特异性T细胞扩增。而富含干细胞的T细胞 程序在动物模型中更好地增殖和控制癌症，目前尚不清楚干细胞样T细胞是否 （相对于，例如，效应分化的T细胞）对于在ART停止后控制HIV是最佳的。的 该提案的总体目标是直接确定T细胞干细胞在促进HIV-1感染能力方面的作用， 特异性T细胞来扩增功能性效应子群体，以在停止ART后控制HIV感染。 目的1，我们将使用多模式高维单细胞表型和转录谱建立 ART上干细胞样病毒特异性CD 8 + T细胞的比例是否与其体内扩增相关 以及随后在治疗中断后控制人类中的HIV或猕猴中的SIV。在目标2中，我们将使用 具有强效抗HIV活性的包膜（Env）靶向HIV特异性CAR-T细胞（duoCAR-T细胞）作为模型， 询问精确调节干细胞水平如何影响CAR-T细胞长期抑制HIV的能力 在HIV抑制剂衍生的异种移植（PDX）小鼠模型中。在目标3中，我们将利用血液和组织 来自一项非常独特的临床试验的样本，该试验的对象是接受抗HIV duoCAR输注的艾滋病毒感染者， T细胞并经历ATI。我们假设在输注之前更像干细胞的CAR-T细胞（即，要么 总输注前产品中的CAR-T细胞或我们在输注前识别的亚群，然后跟踪 在体内输注后使用单细胞配对的α/β TCR序列作为“条形码”）将扩增更大、更少- 耗尽的效应子群体。这些研究将首次在艾滋病毒感染的背景下测试 令人信服的假设，即富含干细胞的T细胞具有更大的增殖能力和持久性， 能够产生效应T细胞，这些细胞能够更好地在体内控制艾滋病毒。我们还将全面 评估其他T细胞分化状态，可能与停止抗逆转录病毒治疗后的艾滋病毒控制有关。 这些研究的完成将使我们对HIV特异性T细胞分化状态的作用有新的认识 开发有效的基于T细胞的艾滋病治疗策略。

PROJECT SUMMARY Nearly 40 million people world-wide are infected with HIV, an infection for which there is no cure. Many strategies that aim to cure HIV focus on harnessing HIV-specific T cells to control the virus that rebounds after antiretroviral therapy (ART) is discontinued because of their ability to specifically recognize and kill HIV-infected cells. However, HIV-specific T cell therapies will not be effective if they cannot overcome the T cell exhaustion that occurs in the setting of chronic antigen stimulation. In mouse models of chronic infection and cancer, T cells enriched for a stem cell memory (TSCM) phenotype or stem-like transcriptional program robustly expand and differentiate into effector cells while resisting exhaustion. We have found that the expression of the stem/memory-promoting transcription factor, TCF-1, is associated with high in vitro proliferative capacity in HIV- specific CD8+ T cells in individuals who naturally control HIV infection and that TCF-1 overexpression leads to better HIV-specific T cell expansion after in vitro peptide stimulation. While T cells that are enriched for stemness programs proliferate and control cancer better in animal models, it is currently unknown whether stem-like T cells (versus, for example, effector-differentiated T cells) are optimal for controlling HIV after ART is stopped. The overarching goal of this proposal is to directly establish the role of T cell stemness in promoting the ability of HIV- specific T cells to expand a functional effector population to control HIV infection after discontinuation of ART. In Aim 1, we will use multi-modal high-dimensional single cell phenotypic and transcriptional profiling to establish whether the proportion of stem-like virus-specific CD8+ T cells on ART correlates with their in vivo expansion and subsequent control of HIV in humans or SIV in macaques after treatment interruption. In Aim 2, we will use envelope (Env)-targeting HIV-specific CAR-T cells with potent anti-HIV activity (duoCAR-T cells) as a model to ask how precisely tuning the level of stemness influences the ability of CAR-T cells to suppress HIV long-term in the HIV Participant-Derived Xenograft (PDX) mouse model. In Aim 3, we will leverage blood and tissue samples from a highly unique clinical trial of people with HIV on ART who receive an infusion of anti-HIV duoCAR- T cells and undergo an ATI. We hypothesize that CAR-T cells that are more stem-like prior to infusion (i.e., either the CAR-T cells in the total pre-infusion product or sub-populations that we identify pre-infusion and then track in vivo post-infusion using single cell paired α/β TCR sequences as “barcodes”) will expand a larger, less- exhausted effector population. These studies will test for the first time in the context of HIV infection the compelling hypothesis that T cells enriched for stemness have greater proliferative capacity and durability and are able to give rise to effector T cells that are better able to control HIV in vivo. We will also comprehensively evaluate other T cell differentiation states that might associate with HIV control after ART discontinuation. Completion of these studies will result in new knowledge about the role of HIV-specific T cell differentiation states in the development of effective T cell-based strategies for HIV cure.