The innate capacity of human T cells to respond to Mycobacterium tuberculosis

描述（由申请人提供）：人对结核分枝杆菌（Mtb）的免疫反应允许建立潜伏期，并且在某些个体中，随后的再激活和疾病。宿主与病原体之间的相互作用阻碍了灭菌免疫的产生，但人们对这种相互作用的了解并不充分。新兴研究表明，在Mtb-naïve宿主中，存在与保护性免疫相关的具有效应功能的mmb反应性先天T细胞。此外，人类naïve T细胞能够使用toll样受体（TLR），即通常与先天免疫相关的分子，直接接收来自Mtb配体的共刺激信号。我们假设Mtb反应性先天T细胞和naïve具有功能性先天共刺激受体的T细胞是Mtb感染初始阶段促炎介质（如IFN-γ）的来源。这种早期产生的IFN-γ和其他效应分子可能会增强Mtb感染的巨噬细胞的抗菌反应，以及Mtb感染的树突状细胞产生的IL-12。确定和描述Mtb反应性先天T细胞和naïve具有功能性TLR的T细胞的全部功能，是开发疫苗和免疫疗法的重要第一步，这些疫苗和免疫疗法可以扩大这些细胞，以加强针对Mtb的无菌免疫反应。本提案的目的是表征Mtb反应性先天T细胞以及naïve T细胞亚群（包括调节性T细胞）的表型、频率、效应潜力和基因表达谱，这些T细胞亚群利用TLR对Mtb配体做出反应，在Mtb-naïve宿主中从出生到成年。这一建议的具体目的是研究先天T细胞对Mtb的反应在抗原经验不足的新生儿和Mtb幼稚婴儿和成人。我们将使用一种新的检测方法来鉴定和量化不同年龄供体中的非经典限制性mtb反应性T细胞，并结合流式细胞术、多重细胞因子阵列、无机质谱和基因表达谱来描述它们的表型、功能能力和分子谱。我们将对新生儿、婴儿和成人中响应tlr介导的共刺激的naïve T细胞亚群的表型、功能能力、基因表达谱和T细胞受体多样性进行表征。我们还将确定年龄是否会影响tlr介导的调节性T细胞抑制功能的改变。我们的方法将允许我们确定tlr反应性naïve T细胞是否从没有抗原的宿主（如新生儿）中分离出来，代表了先天T细胞的一个独特子集。了解先天T细胞的个体发生和T细胞利用先天受体改变其激活和功能的能力，将促进我们对T细胞发育途径的全部潜力的理解，以及它们对宿主免疫防御的贡献。此外，由于新生儿和婴儿非常容易受到来自传染性病原体的严重疾病表型的影响，因此确定其T细胞对诸如结核分枝杆菌之类的病原体作出反应的先天能力，可用于为下一代疫苗和婴儿使用的治疗方法的开发提供信息。

DESCRIPTION (provided by applicant): The human immune response to Mycobacterium tuberculosis (Mtb) permits establishment of latency and in some individuals, subsequent reactivation and disease. The host-pathogen interactions that prevent sterilizing immunity are not well understood. Emerging research demonstrates that among Mtb-naïve hosts, Mtb-reactive innate T cells with effector functions associated with protective immunity are present. Moreover, human naïve T cells are capable of using Toll-like receptors (TLR), molecules typically associated with innate immunity, to directly receive co-stimulatory signals from Mtb ligands. We hypothesize that Mtb-reactive innate T cells, and naïve T cells with functional innate co-stimulatory receptors, are a source of pro-inflammatory mediators such as IFN-γ during the initial stages of Mtb infection. This early production of IFN-γ and other effector molecules may augment antimicrobial responses by Mtb-infected macrophages, as well as IL-12 production by Mtb- infected dendritic cells. Defining and characterizing the repertoire of Mtb-reactive innate T cells, and naïve T cells with functional TLR, is an essential first step in the development of vaccines and immune-based therapeutics that expand these cells in order to bolster sterilizing immune responses against Mtb. The objectives of this proposal are to characterize the phenotype, frequency, effector potential, and gene expression profile of Mtb-reactive, innate T cells, as well as naïve T cell subsets (including regulatory T cells), that utilize TLR to respond o Mtb ligands, among Mtb-naïve hosts from birth to adulthood. The specific aims of this proposal are focused on investigating innate T cell responses to Mtb among antigen-inexperienced neonates and Mtb-naive infants and adults. We will use a novel assay to identify and quantify non-classically restricted Mtb-reactive T cells among donors of different ages, and a combination of flow cytometry, multiplex cytokine arrays, inorganic mass spectrometry, and gene expression profiling to delineate their phenotypes, functional capabilities, and molecular profiles. We will characterize the phenotype, functional capabilities, gene expression profiles, and T cell receptor diversity of naïve T cell subsets responsive to TLR-mediated co-stimulation among neonates, infants, and adults. We will also determine if age impacts TLR-mediated alterations of the suppressive functions of regulatory T cells. Our approach will allow us to determine if TLR-responsive naïve T cells isolated from antigen-inexperienced hosts, such as newborns, represent a unique subset of innate T cells. Understanding the ontogeny of innate T cells and the capacity of T cells to utilize innate receptors to alter their activation and functio, will advance our understanding of the full potential of T cell developmental pathways, as well as their contribution to host immune defense. In addition, as neonates and infants are exquisitely vulnerable to severe disease phenotypes from infectious pathogens, defining the innate capacity of their T cells to respond to a pathogen such as Mtb, can be used to inform the development of next generation vaccines and therapeutics utilized in infancy.