A novel CD4+ T cell subset associated with allergy protection

项目总结 与哮喘等过敏相关的疾病是一个日益严重的健康问题，目前还没有治愈的方法。 对常见过敏原作出反应的CD4+辅助T细胞(TH)在推动呼吸道炎症中发挥重要作用 得了哮喘。为了更好地了解T细胞亚群在过敏和哮喘中的多样性，我们分析了单个细胞 哮喘患者和非哮喘患者约50,000只尘螨变应原反应性TH细胞的转录组， 有无HDM过敏。从我们的分析来看，除了TH2、TH17和TH1等典型的细胞团外， 我们鉴定了一种新的过敏原反应性TH细胞亚群，其特征是干扰素反应基因签名 我们称之为THIFNR细胞(Seumois et al.《科学免疫学》，2020)。THIFNR细胞的比例为 与过敏性患者相比，非过敏性患者显著增加，提示有过敏原特异性 宿主特异性反应，即使在非过敏个体中也是如此。此外，唯一存在的过敏原-反应性 过敏患者中的Th2细胞提示THIFNR细胞在非过敏患者中具有保护作用(抗TH2反应) 接触过敏原的过敏性患者。这种潜在的保护作用在我们的体外研究中得到了加强 THIFNR细胞产生的肿瘤坏死因子相关的凋亡诱导配体(TRAIL)直接抑制T细胞 由TCR参与触发的激活。在后续研究中，我们发现病毒反应性THIFNR细胞 细胞指向流感或SARS-CoV2，这表明这些细胞在免疫反应中发挥了更广泛的作用。另外， 我们在一大群健康个体中发现了THIFNR细胞作为稳定的TH亚群。因为最近 自发现THIFNR细胞以来，人们对其起源、分化、表型和功能知之甚少。我们 假设这些THIFNR HDM反应性T细胞可能通过TRAIL参与抑制 过敏和哮喘中的Th2炎症。 在目标1中，我们将定义THIFNR细胞的功能特性。我们将进行共培养实验来测试 THIFNR细胞以TRAIL依赖的方式抑制TH2细胞增殖和功能的能力。在AIM 2我们将确定在体外诱导THIFNR细胞分化的最佳条件，并比较它们的 功能特性与体内产生的特性相一致。最后，在目标3中，我们将确定HDM反应性THIFNR 细胞在体内表现出持久性和可塑性。我们将对HDM反应进行单细胞TCR测序 从纵向采集的HDM血样中分离出THIFNR细胞和其他记忆CD4+T细胞亚群 过敏和非过敏受试者。通过比较纵向样本中的TCR曲目，我们将评估 THIFNR细胞在体内的持久性。总体而言，R21计划中的功能研究将提供重要的见解 转化为这个新的CD4+T细胞亚群；并形成了未来R01应用程序的基础，以进行翻译研究 把结果带到诊所。

PROJECT SUMMARY Disease associated with allergies such as asthma are a rising health problem with no current curative solutions. CD4+ helper T cells (TH) that respond to common allergens play an important role in driving airway inflammation in asthma. To better understand the diversity of T cell subsets in allergy and asthma, we analyzed the single-cell transcriptome of ~50,000 house dust mite (HDM) allergen-reactive TH cells from asthmatics and non-asthmatics, with and without HDM allergy. From our analysis, besides canonical clusters of cells such as TH2, TH17, and TH1, we identified a novel subset of allergen-reactive TH cells characterized by an IFN responsive gene signature that we called THIFNR cells (Seumois et al. Science Immunology, 2020). Proportions of THIFNR cells were significantly increased in nonallergic individuals compared to allergic patients, suggesting an allergen-specific host specific response even in non-allergic individuals. Moreover, the exclusive presence of the allergen-reactive TH2 cells in the allergic patients suggests a protective role (anti-TH2 response) of the THIFNR cells in the non- allergic patients with exposure to allergen. This potential protective role was reinforced by our in vitro studies showing that TNF-related apoptosis-inducing ligand (TRAIL) produced by THIFNR cells directly inhibits T cell activation triggered by TCR engagement. In follow-up studies, we found THIFNR cells among viral-reactive TH cells directed towards Flu or SARS-CoV2, suggesting a broader role of those cells in immune responses. Also, we found THIFNR cells as a stable TH subset in a large cohort of healthy individuals. Because of the recent discovery of THIFNR cells, very little is known about their origins, differentiation, phenotype, and function. We hypothesize that these THIFNR HDM-reactive T cells could play a role through TRAIL engagement in dampening TH2 inflammation in allergy and asthma. In Aim 1, we will define the functional properties of THIFNR cells. We will perform co-culture experiments to test the ability of THIFNR cells to inhibit proliferation and function of TH2 cells in a TRAIL-dependent manner. In Aim 2 we will determine optimal conditions to induce differentiation of THIFNR cells in vitro and compare their functional properties with those generated in vivo. Finally, in Aim 3, we will determine if HDM-reactive THIFNR cells show persistence and plasticity in vivo. We will perform single-cell TCR sequencing of HDM-reactive THIFNR cells and other memory CD4+ T cell subsets isolated from longitudinally collected blood samples of HDM allergic and non-allergic subjects. By comparing TCR repertoire in longitudinal samples, we will assess persistence of THIFNR cells in vivo. Overall, functional studies in this R21 program will provide important insights into this novel CD4+ T cell subset; and form the basis of a future R01 application to conduct studies translating findings to the clinic.