Tfh dysfunction in HIV and Aging

通过有效的抗逆转录病毒疗法，艾滋病毒感染者可以获得接近正常的寿命，但发病率增加 合并症和合并感染发生较早，比一般人群更频繁。 基础炎症被认为是合并症的主要因素，但不太清楚的是， 相关的免疫缺陷，即使在持久的病毒学控制后仍然存在，使艾滋病毒感染者 (PWH)患流感的风险更大，因此建议接种流感疫苗。除了降低风险， 流感疫苗可以作为检测宿主免疫能力的探针， 在本建议书及先前评估威尔斯亲王医院免疫力的计划（AI 108472）中，我们可将 疫苗应答者（VR）和疫苗无应答者（VNR）。我们观察到， 艾滋病毒对疫苗反应有负面影响。在研究VNR中免疫缺陷的机制时，我们 确定了外周T滤泡辅助细胞（pTfh）的定量和定性缺陷，这是一个子集 CD 4 T细胞是疫苗诱导的抗体（Ab）反应所必需的。pTfh显示 从有利的IL-21分泌表型向有害的IL-2分泌表型倾斜极化 Th 1表型，加上大量的炎症标志物，导致pTfh不能提供B 具有Ab分泌所需的辅助信号的细胞。我们的中心假设是， pTfh从有利的IL-21分泌表型向IL-2和炎症中的一种转变是有害的， 随着年龄或HIV的增长而变化，但可通过体外和体内操作进行改变。我们将招募艾滋病毒感染者 阴性和病毒抑制的HIV+人群，以解决以下关于Ab应答的关键问题 季节性流感疫苗。本项目有3个目标：目标1研究pTfh的细胞内特性 这些细胞在年龄、HIV感染和记忆B细胞生成的背景下影响其功能。 目的2通过对pTfh功能障碍的细胞和分子机制的研究，探讨VNR的作用机制 影响pTfh功能的相互作用，并将测试体外干预以逆转pTfh功能障碍。目标3 将测试给予高剂量流感疫苗是否能改善所有组VNR的免疫应答 并将研究受影响的免疫机制。在这个项目中，我们将评估免疫细胞 使用包括多参数流式细胞术、单次流式细胞术、流式细胞仪和流式细胞仪的技术组合， 细胞RNA测序，库测序，单克隆抗体生成和细胞共培养，以获得高 分辨率数据集。我们的方法将获得pTfh细胞在衰老过程中免疫扰动的快照， 艾滋病毒感染。用纯化的细胞亚群进行的体外研究将允许对免疫调节的机制进行评估。 系统这些研究是可行的，鉴于我们在所描述的技术方面的专业知识， 生物信息学和数据整合的人口和资源。我们希望能提供新的见解， 免疫扰动，这将有助于在老龄化人口中制定疫苗方法。

With effective ART, HIV infected persons can achieve a near normal life span but have increasing incidence of comorbidities and co-infections that occur earlier, are more frequent than the general population. Underlying inflammation is considered to be a major factor for comorbidities, but less well appreciated is the associated immune deficiency that persist even after durable virologic control, putting people living with HIV (PWH) at greater risk for influenza, for which flu vaccinations are recommended. Besides decreasing risk for influenza infection, flu vaccines can serve as probes for testing host immune competence an approach used in this proposal and in a previous project (AI108472) for assessing immunity in PWH and we could classify participants as vaccine responders (VR) and vaccine non-responders (VNR). We observed that aging and HIV had a negative effect on vaccine response. In studying mechanisms of immune defects in VNR, we identified quantitative and qualitative defects in peripheral T follicular helper cells (pTfh), which are a subset of CD4 T cells that are essential for vaccine-induced antibody (Ab) responses. The pTfh displayed a skewed polarization away from a favorable IL-21 secreting phenotype towards a detrimental IL-2 secreting Th1 phenotype, coupled with abundance of inflammatory markers, resulting in failure of pTfh to provide B cells with the helper signals required for Ab secretion. Our central hypothesis is that skewed polarization of pTfh away from a favorable IL-21 secreting phenotype towards one of IL-2 and inflammation is detrimental, worsens with age or HIV but is amenable to change by ex-vivo and in-vivo manipulation. We will recruit HIV negative and virally suppressed HIV+ populations to address key questions on Ab response following seasonal influenza vaccination. The project has 3 aims: Aim 1 will investigate cell-intrinsic properties of pTfh cells that influence their function in the context of age, HIV infection and the generation of memory B cells. Aim 2 will investigate VNR to define mechanism of pTfh dysfunction via study of cellular and molecular interactions affecting pTfh function and will test in-vitro interventions to reverse the pTfh dysfunction. Aim 3 will test whether administering high dose flu vaccine improves immune response in VNR from all groups and will investigate the immune mechanisms affected. In this project we will evaluate immune cell populations of interest using a combination of technologies including multi-parameter flow cytometry, single cell RNA sequencing, repertoire sequencing, monoclonal Ab generation and cell co- cultures to gain high resolution datasets. Our approach will obtain a snapshot of immune perturbation of pTfh cells in aging and HIV infection. In vitro studies with purified cell subsets will allow for mechanistic evaluation of the immune system. These studies are feasible, given our expertise in the technologies described, access to desired population and resources for bioinformatics and data integration. We expect to provide novel insights into immune perturbations that will help in strategizing vaccine approaches in aging populations.