Modulation of Immune Defenses in Pathobiology of Chronic Infections

描述（由申请人提供）： 新型隐球菌是一种常见的和毁灭性的机会致病真菌，在世界范围内造成大量死亡。目前治疗退伍军人感染C。新生菌或相关的真菌病原体是长期的、经常有毒的并且经常无效。需要在延长的时间内产生和维持这种1型或“经典活化”免疫应答，以实现完全清除C。新形式和防止所有太常见的持续感染和/或复发的发展。越来越多的抗炎TNF中和单克隆抗体治疗的副作用之一是对真菌感染（包括C。neoformans）。我们的初步数据强烈表明，TNF是1型树突状细胞（DC 1）编程和随后发展稳定的保护性Th 1/Th 17反应所需的中心分子。目前的研究旨在确定TNF如何有助于骨髓DC的编程，以在清除C所需的延长时间内维持保护性Th 1/Th 17应答。新人类假设：我们的中心假设是，有效清除C。新生儿需要TNF介导的髓样DC的DC 1编程，以在清除C所需的整个延长时间段内维持保护性Th 1/Th 17应答。新人类我们进一步假设，DC和/或其髓系前体中的TNF信号转导有助于执行支持DC 1表型稳定性并阻止DC 2表型发展的表观遗传修饰。下面的目标是为了严格检验这一假设。目的1：确定在对隐球菌感染的保护性反应期间是否需要TNF来稳定DC 1编程。目的2：确定TNF α是否介导了C.新型人感染了肺部目的3：确定TNF诱导的DC 1编程是否是产生对C.新人类研究计划和方法：我们的建议是利用高度翻译的CBA/J小鼠感染模型与中等毒力的C。24067株的肿瘤坏死因子和一系列的体外研究，这些研究将确定在感染时使用一剂单克隆抗体的瞬时TNF-α分泌的影响。这些研究将使我们能够确定TNF是否以及在多大程度上引起DC 1程序的稳定性。我们将确定在DC发育的哪个阶段（骨髓前体，DC分化或成熟）TNF使DC稳定。我们将确定DC 1表型稳定性是否可归因于负责表观遗传染色质修饰的酶的变化以及由此产生的对执行DC 1程序至关重要的基因启动子区域的组蛋白甲基化特征的变化。DC及其髓样前体对肺中执行稳定的保护性免疫应答的贡献随后将在一系列过继转移实验中进行测试。这些研究的完成将证明TNF-α稳定对C的保护性免疫反应的新作用。新人类这项翻译研究将提供表观遗传染色质修饰与TNF体内生物学效应之间的联系，并提供对抗TNF抗体治疗患者真菌感染风险增加的潜在机制的见解，我们实验室的小鼠模型非常有效地模仿。

DESCRIPTION (provided by applicant): Cryptococcus neoformans is a common and devastating opportunistic fungal pathogen that causes substantial mortality worldwide. Current therapies for veterans infected with C. neoformans or related fungal pathogens are lengthy, frequently toxic, and often ineffective. Generation and maintenance of this type 1 or "classically-activated" immune response over extended time is required to achieve complete clearance of C. neoformans and to prevent the all too common development of persistent infection and/or relapses. One of the side effects of the increasingly prescribed anti-inflammatory TNF�eutralizing monoclonal antibody therapy is susceptibility to fungal infections (including C. neoformans). Our preliminary data strongly suggest that TNF�s a central molecule required for programing of type 1 dendritic cell (DC1) and the subsequent development of a stable, protective Th1/Th17 response. The present studies are designed to determine how TNF�ontributes to programming of myeloid DC to sustain a protective Th1/Th17 response throughout the extended time period required for clearance of C. neoformans. Hypothesis: Our central hypothesis is that effective clearance of C. neoformans requires the TNF�ediated DC1 programming of myeloid DC to sustain a protective Th1/Th17 response throughout the extended time period required for clearance of C. neoformans. We further hypothesize that TNF�ignaling in DC and/or their myeloid precursors contributes to execution of epigenetic modifications that support stability of the DC1 phenotype and prevents the development of a DC2 phenotype. The following aims have been constructed to rigorously test this hypothesis. Aim 1: To determine whether TNF�s required for stable DC1-programing during the protective response to cryptococcal infection. Aim 2: To determine if TNF�ediates epigenetic programing of the DC1 phenotype in myeloid precursors and/or DC in C. neoformans infected lungs. Aim 3: To determine whether TNF�nduced DC1 programming is necessary and sufficient for generating protective immune responses to C. neoformans. Research Plan and Methods: Our proposal utilizes highly translational model of infection of CBA/J mice with the moderately virulent C. neoformans strain 24067 and series of in vitro studies that will define the effects of transient TNF�epletion using one dose of monoclonal antibodies at the time of infection. These studies will allow us to define whether, and to what degree, TNF�nduces stability of the DC1 program. We will define at which stage of DC development (bone marrow precursor, DC differentiation or maturation) TNF�tabilizes DC. We will determine whether the DC1 phenotype stability can be attributed to changes in enzymes responsible for epigenetic chromatin modification and resultant changes in histone methylation signatures at gene promoter regions crucial for execution of DC1 program. The contribution of DC and their myeloid precursors to the execution of stable protective immune responses in the lungs will be then tested in a series of adoptive transfer experiments. Completion of these studies will demonstrate a novel role of TNF�n stabilization of a protective immune response to C. neoformans. This translational study will provide a link between epigenetic chromatin modification and biological effects of TNF�n vivo and provide an insight into a potential mechanism of increased risk of fungal infections in patients treated with anti-TNF�ntibodies, which our lab's mouse model very effectively mimics.