Mesenchymal stem/stromal cells to enhance cytotoxic T cell immunity during HIV infection

多能干细胞/基质细胞(MSC)由于其强大的功能，有望成为治疗HIV感染的候选细胞。 免疫调节特性和广泛的安全边际。骨髓间充质干细胞能否逆转CD8 T细胞尚不清楚 在慢性HIV感染期间，耗尽并促进CD8 T细胞进入特权部位。因此，在那里 迫切需要确定CD8 T细胞耗竭是否可以作为MSC的治疗靶点。我们的 长期目标是确定MSC在慢性病毒感染中诱导免疫调节的机制 开发改进的治疗策略。我们在此应用程序中的总体目标是确定 MSC治疗可通过逆转慢性SIV感染患者耗尽的CD8 T细胞来增强病毒清除 猕猴。我们的中心假设是全身输注同种异体骨髓间充质干细胞可增强病毒清除。 ART-幼稚，并通过逆转在ART治疗SIV感染猕猴的ART中断时延迟病毒反弹 CD8 T细胞耗竭和特权部位的渗透。这项拟议研究的基本原理 CD8 T细胞耗尽和病毒隔离是HIV病毒持续存在的主要机制，可能 以MSC治疗为靶点。为了验证我们的假设，我们将使用SIV感染的非人类灵长类动物模型 爱滋病患者。感染SIV的动物将用ART和/或MSC和来自 在尸检过程中将采集外周血液、肠道组织和淋巴结。中心假说将 通过追求两个特定目标进行测试：1)确定MSC治疗对耗尽的CD8 T细胞的影响 长期感染SIV的恒河猴种群。我们的工作假设是MSC治疗 逆转慢性SIV感染导致的CD8 T细胞衰竭。我们将从血液、肠道中分离CD8 T细胞 组织和淋巴结，并进行单细胞RNAseq分析、多色流式细胞术和体外实验 刺激分析。2)确定MSC治疗对CD8T细胞向淋巴滤泡转运的影响 在长期感染SIV的恒河猴身上。我们的工作假设是MSC治疗慢性阻塞性肺疾病 感染SIV的猕猴增加了CXCR5+/CD8 T细胞向B细胞毛囊的转运。我们将确定 肠道组织中SIV特异性CD8 T细胞和病毒库的显微解剖分布和表型 通过原位MHC-四聚体、免疫组织化学染色和共聚焦显微镜观察淋巴结转移情况。这个 申请中提出的研究具有创新性，因为它探索了一种新的靶向治疗范式 艾滋病毒持续存在的多种机制在多个机制层面上同时存在。拟议的研究是 意义重大，因为艾滋病毒/艾滋病仍然是一种重大的全球健康危机，部分是由病毒驱动的 尽管进行了有效的抗逆转录病毒治疗和抑制了病毒复制，但这种情况仍然存在。此外，作为CD8 T细胞 精疲力竭与其他多种慢性病毒性疾病和恶性肿瘤的发病机制有关， 这项研究的发现有可能产生广泛而深刻的影响。这项研究的发现是 可直接翻译为MSC的可随时用于临床试验。

Multipotent stem/stromal cells (MSC) are promising candidate therapeutics for HIV infection, given their potent immunomodulatory properties and wide safety margins. It remains unknown if MSC can reverse CD8 T cell exhaustion and promote trafficking of CD8 T cells into privileged sites during chronic HIV infection. Thus, there is a critical need to determine whether CD8 T cell exhaustion can be therapeutically targeted by MSC. Our long-term goal is to define mechanisms of MSC-induced immune-modulation during chronic viral infections so that improved therapeutic strategies be developed. Our overall objective in this application is to determine if MSC treatment can enhance viral clearance via reversal of exhausted CD8 T cells in chronic SIV-infected macaques. Our central hypothesis is that systemic infusions of allogeneic MSC enhance viral clearance in ART-naïve, and delay viral rebound upon ART interruption in ART-treated SIV-infected macaques, via reversal of CD8 T cell exhaustion and infiltration of privileged sites. The rationale that underlies the proposed research is that CD8 T cell exhaustion and viral sequestration are major mechanisms of HIV viral persistence that may be targeted with MSC treatment. To test our hypothesis we will use the SIV-infected non-human primate model of AIDS. SIV-infected animals will be treated with a combination of ART and/or MSC and samples from peripheral blood, gut tissue, and lymph nodes will be collected during necropsies. The central hypothesis will be tested by pursuing two specific aims: 1) Determine the impact of MSC treatment on exhausted CD8 T cell populations in rhesus macaques chronically infected with SIV. Our working hypothesis is that MSC treatment reverses CD8 T cell exhaustion that is driven by chronic SIV infection. We will sort CD8 T cells from blood, gut tissue, and lymph nodes and perform single-cell RNAseq analysis, multi-color flow cytometry, and ex-vivo stimulation assays. 2) Determine the impact of MSC treatment on CD8 T cell trafficking into lymphoid follicles in rhesus macaques chronically infected with SIV. Our working hypothesis is that MSC treatment in chronic SIV-infected macaques enhances CXCR5+/CD8 T cell trafficking into B-cell follicles. We will determine the micro-anatomical distribution and phenotype of SIV-specific CD8 T cells and viral reservoirs in gut tissue and lymph nodes via in situ MHC-tetramer, and immunohistochemistry staining, and confocal microscopy. The research proposed in the application is innovative because it explores a new therapeutic paradigm of targeting multiple mechanisms of HIV persistence concurrently on multiple mechanistic levels. The proposed research is significant because HIV/AIDS remains a significant global health crisis that is partially driven by viral persistence despite effective antiretroviral therapy and suppression of viral replication. Moreover, as CD8 T cell exhaustion has been implicated in the pathogenesis of multiple other chronic viral diseases and malignancies, findings stemming from this study have the potential to impact broadly and deeply. Findings from this study are directly translatable as MSC are readily available for clinical trials.