The role of T regulatory cells in cigarette smoke-induced susceptibility to tuberculosis

香烟烟雾（CS）损害宿主对结核分枝杆菌（MTB）的保护性免疫反应。 然而，一个被忽视的方面是CS或尼古丁如何驱动免疫抑制细胞增加， 对MTB的敏感性。调节性T细胞（Tlymphocytes，Tlymphocytes）是免疫抑制细胞， 动物和人类感染结核病CS或尼古丁不仅增加了Tcl 4向肺部的流入，而且还诱导了Tcl 4向肺部的流入。 细胞表面信号分子-程序性死亡-1（PD-1）和细胞毒性T淋巴细胞相关蛋白 4（CTLA-4）-增强其免疫抑制活性。我们的中心假设是CS增强了 通过诱导PD-1和CTLA-4来发挥TGF 1 α免疫抑制功能， 活性在损害MTB感染的控制中起关键作用。我们将采取双管齐下的办法， 使用体内鼠模型和使用原代人细胞的离体模型。首先，我们将采用 将相同数量的暴露于空气或CS的T细胞转移到CS未处理的小鼠中，然后用 MTB，以确定CS暴露的结核分枝杆菌的转移是否比空气暴露的结核分枝杆菌的转移更易导致MTB感染 你好第二，我们将利用原代人肺泡巨噬细胞（AM）+THP的共培养物， 暴露于单独的培养基、CS或尼古丁的睾酮，以及PD-1和CTLA-4的药理学拮抗剂， 建立CS/尼古丁增加Treg活性以损害抗TB免疫的机制。 目的1：在体内小鼠模型中建立CS暴露的TdR在MTB易感性中的作用。 假设：我们预测CS诱导的Treg活性的上调是CS 易患结核病因此，与接受暴露于空气中的TdR的小鼠相比，接受CS暴露的TdR的小鼠 更容易感染结核病，表现为宿主保护性M1巨噬细胞和TH 1细胞减少， MTB负担加重、肺部病理学恶化和生存率降低。方法：我们将采用相同的 从暴露于空气或CS的供体小鼠到未接触CS的小鼠的T细胞数量，用MTB感染受体小鼠， 并确定微生物和免疫学结果。 目的2：确定暴露于CS的TdR在损害人类MTB AM控制中的作用。假设： CS或尼古丁将增加TGFAP上PD-1和CTLA-4的表达，并且在与AM共培养中，增加TGFAP上PD-1和CTLA-4的表达。 通过增加的免疫抑制细胞因子水平证明TdR对AM的抑制作用， 宿主保护性细胞因子水平降低，吞噬体-溶酶体（P-L）融合和自噬减少，以及 更好地恢复MTB。阻断PD-1或CTLA-4将消除这些作用。进近：空中、CS或 暴露于尼古丁的THBE将与未处理AM共培养，用PD-1或CTLA-4的MTB ±抑制剂感染， 并分析MTB负荷、细胞因子、P-L融合和自噬。 本项目将阐明TdR在介导CS诱导的结核病易感性中所起的作用。的结果 这些研究可以为开发独特的免疫调节方法来治疗结核病提供基础。

Cigarette smoke (CS) impairs host-protective immune responses to Mycobacterium tuberculosis (MTB). However, an overlooked aspect is how CS or nicotine may drive immunosuppressive cells to increase susceptibility to MTB. T regulatory cells (Tregs) are immunosuppressive cells that predispose laboratory animals and humans to TB. CS or nicotine not only increases the influx of Tregs to the lungs but also induces cell surface signaling molecules – programmed death-1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) – that enhance their immunosuppressive activity. Our central hypothesis is that CS enhances the immunosuppressive function of Tregs via induction of PD-1 and CTLA-4, and that this upregulation of Treg activity plays a pivotal role in impairing control of MTB infection. We will undertake a two-pronged approach, using both an in vivo murine model and an ex vivo model using primary human cells. First, we will adoptively transfer equal number of air- or CS-exposed Tregs into CS-naïve mice and then infect the recipient mice with MTB to determine if transfer of CS-exposed Tregs aggravates MTB infection more than transfer of air-exposed Tregs. Second, we will utilize co-cultures of primary human alveolar macrophages (AM) + Tregs with only the Tregs exposed to medium alone, CS, or nicotine, and pharmacologic antagonists to PD-1 and CTLA-4 to establish the mechanism by which CS/nicotine increases Treg activity to impair anti-TB immunity. Aim 1: Establish the role CS-exposed Tregs play in predisposing to MTB in an in vivo murine model. Hypothesis: We predict that CS-induced upregulation of Treg activity is a pivotal mechanism by which CS predisposes to MTB. Thus, compared to mice receiving air-exposed Tregs, mice receiving CS-exposed Tregs will be more susceptible to TB, demonstrated by fewer host-protective M1 macrophages and TH1 cells, greater burden of MTB, worse lung pathology, and reduced survival. Approach: We will adoptively transfer the same number of Tregs from air- or CS-exposed donor mice to CS-naïve mice, infect the recipient mice with MTB, and determine microbiological and immunological outcomes. Aim 2: Establish the role CS-exposed Tregs play in impairing human AM control of MTB. Hypothesis: CS or nicotine will increase PD-1 and CTLA-4 expression on Tregs, and in co-cultures with AM, augment the suppressive effect of Tregs on AM, demonstrated by increased levels of immunosuppressive cytokines, decreased levels of host-protective cytokines, reduced phagosome-lysosome (P-L) fusion and autophagy, and greater recovery of MTB. Blocking PD-1 or CTLA-4 will abrogate these effects. Approach: Air-, CS-, or nicotine-exposed Tregs will be co-cultured with naïve AM, infected with MTB ± inhibitors to PD-1 or CTLA-4, and analyzed for MTB burden, cytokines, P-L fusion, and autophagy. This project will clarify the role played by Tregs in mediating CS-induced susceptibility to TB. Findings from these studies can provide the foundation for developing unique immunomodulatory approaches to treat TB.