Functional roles of human pulmonary DC's in the lung draining lymph nodes

项目总结/摘要 每一次呼吸，肺都暴露在一系列环境因子中，这些因子必须 被当地单核吞噬细胞（MP）区分为有害或无害。树突状细胞（DC）在 肺，MP系统的一部分，是这种识别和启动对外源性免疫应答的关键。 抗原然而，我们目前对人肺中DC的类型、功能和位置的了解是有限的。 非常有限，并且主要基于与小鼠更详细研究的类比。直接了解 人DC信号传导是开发基于人免疫的治疗剂的关键步骤。 在这项研究中，我们提出了一个详细的人肺树突状细胞的功能特性。我们 假设我们将能够鉴定两种明显分化的DC类型（这里称为hDC 1和 hDC 2）扮演不同的功能角色。基于我们实验室和其他实验室开发的小鼠模型，我们预计 hDC 1和hDC 2群体具有与抗病毒和抗真菌相关的功能特征 尽管hDC在功能上也可能与小鼠DC完全不同，但是hDC与小鼠DC在免疫力方面可能不同。更具体地说， 我们将检验hDC 1选择性吞噬死亡细胞、表达和激活的假设， 通过Toll样受体3（TLR 3）交叉呈递细胞相关抗原，促进诱导 细胞毒性CD 8 + T细胞。相比之下，预期hDC 2不能诱导凋亡细胞， 将表达不同的TLR（例如TLR 7）和C型凝集素如Mincle和Dectin 1，并且将 主要向CD 4 + T细胞呈递可溶性和颗粒性外源性抗原。 目的1：探讨人巨噬细胞对凋亡细胞的选择性获得 肺树突状细胞了解巨噬细胞DC（即交叉呈递DC）的生理重要性， 已经清楚地概述了病毒免疫，细胞内病原体和癌症。在目标2中，我们检查基因， 所提出的人肺DC的蛋白表达，包括模式识别受体 (PRR)以及对它们的连接的反应。由于携带抗原的DC需要直接由它们的抗原刺激， 同源PRR以驱动效应T细胞的分化，表征PRR，特别是TLR， 人肺DC表达的抗原将为成功激活靶肺DC提供关键信息。 DC在诱导适应性免疫应答中的作用最后，在目标3中，我们将检验这两个假设， 候选人肺DC在它们呈递外源性抗原的能力上不同，导致肺DC的免疫应答。 CD 4和CD 8 T细胞的差异诱导。这些研究的最终结果将是一个详细的功能 分析人类肺迁移DC群体--在没有真实的 体内研究，但最佳利用非病变的人肺，沿着其附着的引流淋巴 结这些研究将加深我们对人类肺部免疫系统的理解， 我们有能力开发针对多种疾病的靶向免疫疗法，如肺癌和COPD。

Project Summary/Abstract With every breath, the lung is exposed to an array of environmental agents, which must be discriminated as harmful or harmless by the local mononuclear phagocytes (MPs). Dendritic cells (DC) in the lung, part of the MP system, are key to this recognition and to the initiation of immune responses to foreign antigens. However, our current knowledge of the types, functions and locations of DCs in the human lung is extremely limited, and based largely on analogies with more detailed studies in mice. A direct understanding of human DC signaling is a critical step in developing human immune-based therapeutics. In this grant, we propose a detailed functional characterization of human pulmonary DCs. We hypothesize that we will be able to identify two clearly differentiated types of DCs (called here hDC1 and hDC2) playing separate functional roles. Based on mouse models developed in our lab and others', we expect hDC1 and hDC2 populations to have functional characteristics associated with antiviral and antifungal immunity, respectively, though hDCs may also be quite different from mouse DCs in function. More specifically, we will test the hypotheses that hDC1 selectively phagocytose dying cells, express and are activated through Toll-like receptor 3 (TLR3), cross-present cell-associated antigen, and promote the induction of cytotoxic CD8+ T cells. By contrast, hDC2 are expected to be incapable of ingesting apoptotic cells, will express different TLRs (e.g. TLR7) and C-type lectins such as Mincle and Dectin1, and will predominantly present soluble and particulate exogenous antigen to CD4+ T cells. Aim 1 is to investigate the selective acquisition of apoptotic cells (efferocytosis) by human pulmonary DCs. The physiological importance of knowing the efferocytic DC (i.e. cross-presenting DC) has been clearly outlined for viral immunity, intracellular pathogens, and cancer. In Aim 2 we examine gene and protein expression by the proposed human pulmonary DCs, including pattern recognition receptors (PRR) and responses to their ligation. Since antigen-bearing DCs need to be directly stimulated by their cognate PRR to drive the differentiation of effector T cells, characterizing the PRRs, specifically TLRs, expressed by human pulmonary DCs will provide key information for successful activation of target pulmonary DCs in induction of adaptive immune responses. Finally, in Aim 3, we will test the hypothesis that the two candidate human lung DCs differ in their ability to present exogenous antigens, resulting in the differential induction of CD4 and CD8 T cells. The net outcome of these studies will be a detailed functional analysis of the human pulmonary migratory DC populations – as complete as can be achieved without true in vivo studies, but making optimal use of non-diseased human lungs, along with their attached draining lymph nodes. These studies will heighten our understanding of the human pulmonary immune system and enhance our ability to develop targeted immune therapies for multiple diseases such as lung cancer and COPD.