Normal/Pathologic Mechanisms Of Inflammation & Immunity

该计划的研究重点是宿主动员和调节细胞炎症反应以防御外来抗原和感染性病原体的基本机制。在多学科的方法中，整合素粘附，趋化性，信号传导，介体合成和凋亡的机制在体外进行了探索，并扩展到实验动物模型（基因敲除和转基因小鼠）进行体内分析。此外，在细胞、分子和生物化学水平上探讨了人类慢性炎症性疾病对创伤、肿瘤、感染性病原体或未知病因的反应。了解控制正常免疫细胞募集、激活和/或缺失以及向发病机制转变的机制，是我们长期开发调节慢性致病性炎症性疾病策略的基础。在实验动物模型中，除了DNA微阵列和蛋白质组学分析之外，我们还通过表型、功能和形态学参数表征了免疫病理学，以确定治疗干预的靶点。对涉及CD 4 + CD 25+调节性T细胞、TGF-β和SLPI的免疫功能调节的新认识提高了控制免疫耐受、哮喘、自身免疫和肿瘤免疫的新方法的前景。 分泌性白细胞蛋白酶抑制剂-一种天然免疫调节分子： 宿主对细胞内病原体的有效防御依赖于先天性和适应性免疫应答的激活，以遏制或消除感染性微生物。同样重要的是终止旺盛反应以恢复免疫系统内稳态的调节机制。SLPI是一种有效的丝氨酸蛋白酶抑制剂，具有抗微生物和抗炎功能，存在于与口腔、鼻腔、呼吸道和生殖道粘膜表面相关的液体中。此外，SLPI由小鼠巨噬细胞产生，但也通过抑制NF κ B依赖性信号传导途径抑制巨噬细胞活化。SLPI的组合？的杀微生物活性和对细菌介导的免疫应答的抑制活性暗示该分子参与先天宿主防御，SLPI -/-小鼠提供了探索SLPI在炎症应答和宿主防御中的体内作用的模型。为了确定SLPI是否在宿主防御中起作用，在皮肤利什曼病模型中用细胞内寄生虫硕大利什曼原虫感染SLPI -/-和+/+小鼠。与C57 B1/6 SLPI +/+同窝出生的小鼠相比，其在L.主要接种，SLPI -/-小鼠最初对L.严重，但发展为恶化的慢性感染，病变大小和寄生虫数量增加（与SLPI +/+小鼠相比增加3至5个对数），导致寄生虫的全身传播。尽管SLPI +/+小鼠中病变的自发愈合涉及Th 1-显性细胞因子应答，但SLPI -/-小鼠中升高的抑制性Th 2细胞因子IL-4、IL-10和TGF-β可能导致宿主应答失败，尽管IFN-γ水平持续升高。这些研究强调了SLPI在利什曼病慢性感染阶段的保护作用及其作为治疗炎症和感染性疾病的治疗剂的潜力。重要的是，将外源SLPI（含有SLPI的腺病毒构建体）施用至L.主要感染的SLPI -/-小鼠减少了病变大小和寄生虫数量，从而提供了SLPI在调节宿主对利什曼原虫感染的反应中的关键作用的明确证据。 TGF-β和调节性T细胞在控制感染性、免疫性和肿瘤性疾病中的作用： 除了可诱导/适应性Tr 1和Th 3细胞之外，天然存在的调节性T细胞（鉴定为CD 4 + CD 25 + Treg）在控制对自身和非自身抗原的免疫应答中是基本的。Treg占CD 4 + T细胞的5-10%，因为它们具有对外周自身耐受和控制感染性和非感染性免疫应答至关重要的有效免疫调节功能，因此引起了人们的浓厚兴趣。Treg以CD 4、CD 25、GITR、CTLA-4、TGF-β和TGF-β受体II型的膜表达为特征，所有这些都有助于其独特的功能库，Treg特异性表达Foxp 3，Foxp 3是转录因子的叉头翅螺旋家族的成员。我们以前已经表明，这些细胞在体外产生和过继转移到实验动物与免疫介导的粘膜病理减轻疾病的症状。同样明显的是，虽然Treg的增加在自身免疫和抗原驱动的病理中是有益的，其中数量不足是贡献的，但是这些细胞的过度表达也可能是有害的，特别是在感染性和肿瘤性疾病中。在这方面，我们已经确定了TGF-β在浸润肿瘤组织的细胞中的高水平表达，以及与这些肿瘤相关的Foxp 3+细胞的丰度。这些Treg可能导致免疫监视无法检测和/或消除此类肿瘤，并可能成为促进免疫介导的肿瘤治疗的潜在靶点。

Research in this program is focused on the basic mechanisms by which the host mobilizes and modulates cellular inflammatory reactions in defense against foreign antigens and infectious pathogens. In a multi-disciplinary approach, mechanisms of integrin adhesion, chemotaxis, signaling, mediator synthesis and apoptosis are explored in vitro and extended into experimental animal models (knockout and transgenic mice) for in vivo analysis. In addition, human conditions of chronic inflammatory disease in response to trauma, tumors, infectious pathogens, or of unknown etiology are explored at the cellular, molecular and biochemical levels. Understanding the mechanisms, which control normal immune cell recruitment, activation and/or deletion and the switch to pathogenesis, underlies our longterm development of strategies for modulating chronic pathogenic inflammatory diseases. In experimental animal models, we have characterized immunopathology through phenotypic, functional and morphologic parameters, in addition to DNA microarrays and proteomic analyses, to identify targets for therapeutic intervention. New insights into the regulation of immune function involving CD4+CD25+ regulatory T cells, TGF-beta, and SLPI raise the prospect of novel approaches to controlling immunological tolerance, asthma, autoimmunity, and tumor immunity. Secretory Leukocyte Protease Inhibitor - an Innate Immunomodulatory Molecule: Effective host defense against intracellular pathogens relies upon activation of both innate and adaptive immune responses to contain or eliminate the infectious microbe. Equally important are regulatory mechanisms to terminate exuberant responses to restore homeostasis in the immune system. SLPI is a potent serine protease inhibitor with both anti-microbial and anti-inflammatory functions and is found in fluids associated with mucosal surfaces of the oral, nasal, respiratory, and reproductive tracts. Furthermore, SLPI is produced by mouse macrophages but also inhibits macrophage activation by suppressing NFkB-dependent signaling pathways. The combination of SLPI?s microbicidal activity and suppressive activity on bacterial-mediated immune responses implicate this molecule in innate host defense and the SLPI -/- mouse provides a model to explore the in vivo role for SLPI in inflammatory responses and host defense. To determine whether SLPI plays a role in host defense, SLPI -/- and +/+ mice were infected with the intracellular parasite Leishmania major in a model of cutaneous leishmaniasis. In contrast to C57Bl/6 SLPI +/+ littermates which develop self-healing skin lesions at the site of L. major inoculation, SLPI -/- mice are initially resistant to cutaneous infection by L. major but develop an exacerbated chronic infection with increased lesion size and parasite numbers (3 to 5 log increase as compared to SLPI +/+ mice) that results in systemic spread of parasites. Whereas spontaneous healing of lesions in SLPI +/+ mice involves a Th1-dominant cytokine response, elevated suppressive Th2 cytokines IL-4, IL-10 and TGF-beta in SLPI -/- mice likely contribute to the failed host response, despite persistently elevated levels of IFN-g. These studies highlight a protective role for SLPI in the chronic infective phase of leishmaniasis and its potential as a therapeutic agent for the treatment of inflammatory and infectious disease. Importantly, administration of exogenous SLPI (adenoviral construct containing SLPI) to L. major-infected SLPI -/- mice reduces lesion size and parasite numbers, thus providing definitive evidence of the crucial role of SLPI in the regulation of the host response to leishmania infection. TGF-beta and regulatory T cells in the control of infectious, immune and neoplastic diseases: Naturally occurring regulatory T cells, identified as CD4+CD25+ Treg, in addition to inducible/adaptive Tr1 and Th3 cells, are fundamental in the control of immune responsiveness to self and nonself antigens. Intense interest has focused on Treg, which represent 5-10% of CD4+ T cells, because they possess potent immunoregulatory functions essential to peripheral self-tolerance and to reining in infectious and noninfectious immune responses. Characterized by membrane expression of CD4, CD25, GITR, CTLA-4, TGF-beta and TGF-beta receptor type II, all of which contribute to their unique functional repertoire, Treg specifically express Foxp3, a member of the forkhead-winged helix family of transcription factors. We have previously shown that generation of these cells in vitro and adoptive transfer into experimental animals with immune-mediated mucosal pathology alleviates the symptoms of disease. It is also evident that whereas an increase in Treg is beneficial in autoimmune and antigen-driven pathologies where insufficient numbers are contributory, an over-representation of these cells can also be detrimental, especially evident in infectious and neoplastic diseases. In this regard, we have identified a high level of expression of TGF-beta in cells infiltrating tumor tissues, in addition to an abundance of Foxp3+ cells in association with these tumors. These Treg may contribute to the failure of immune surveillance to detect and/or eliminate such tumors and be a potential target in promoting immune-mediated tumor therapy.