Tfh dysfunction in HIV and Aging

通过有效的抗逆转录病毒治疗，艾滋病毒感染者可以接近正常寿命，但发病率正在上升。 与普通人群相比，更早发生的合并症和混合感染更为常见。 潜在的炎症被认为是合并症的一个主要因素，但人们对 相关的免疫缺陷，即使在持久的病毒学控制后仍然存在，使艾滋病毒携带者 (PWH)患流感的风险较大，建议接种流感疫苗。除了降低风险之外 流感病毒感染后，流感疫苗可作为检测宿主免疫能力的一种方法 在这项提案和之前的一个项目(AI108472)中，我们可以将威斯康星医院的免疫力分类 参与者为疫苗应答者(VR)和疫苗无应答者(VNR)。我们观察到衰老和 HIV对疫苗的应答率有负面影响。在研究VNR的免疫缺陷机制时，我们 外周T滤泡辅助细胞(PTfh)的数量和质量缺陷已确定，这是一个亚群 对疫苗诱导的抗体(Ab)反应至关重要的CD4T细胞。PTfh显示了一个 从有利的IL-21分泌表型向有害的IL-2分泌表型倾斜的极化 Th1表型，再加上大量的炎症标志物，导致pTfh无法提供B 具有分泌抗体所需辅助信号的细胞。我们的中心假设是扭曲的极化 PTfh远离有利的IL-21分泌表型而转向其中一种IL-2且炎症是有害的， 随着年龄或艾滋病毒的增加而恶化，但可通过体外和体内操作而改变。我们将招募艾滋病毒感染者 阴性和病毒抑制的HIV+人群解决以下抗体应答的关键问题 季节性流感疫苗接种。该项目有三个目标：目标1将研究pTfh的细胞固有属性 在年龄、艾滋病毒感染和记忆B细胞生成的背景下影响其功能的细胞。 Aim 2将通过对细胞和分子的研究来研究VNR，以确定pTfh功能障碍的机制 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 将测试注射大剂量流感疫苗是否能改善所有组的VNR的免疫反应 并将调查受影响的免疫机制。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在内的多种技术组合的感兴趣人群， 细胞RNA测序、曲线谱测序、单抗产生和细胞共培养获得高 分辨率数据集。我们的方法将获得pTfh细胞在衰老和 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的机械评估 系统。考虑到我们在所述技术方面的专业知识，这些研究是可行的，可以获得所需的 生物信息学和数据整合的人口和资源。我们希望对以下方面提供新的见解 免疫紊乱，将有助于在老龄化人口中制定疫苗方法的战略。

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.