Mechanisms of Monophosporyl Lipid A Immuno-Modulation in Septic Shock

单磷酰脂质 A 感染性休克免疫调节机制

基本信息

批准号：
7679255
负责人：
Christopher-David Michael Romero
金额：
$ 2.91万
依托单位：
UNIVERSITY OF TEXAS MED BR GALVESTON
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-08-03 至 2011-08-02
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7679255
关键词：
Abbreviations Acid-Base Equilibrium Acids Adjuvant Adoptive Transfer Agar Antibiotic Resistance Antibiotics Antibodies Apoptosis Attenuated Bacterial Infections Biological Assay Body Temperature Bone Marrow C3H/HeJ Mouse C57BL/6 Mouse Cell Respiration Cells Cellular biology Colony-forming units Coupled Dependence Dose Endotoxins Equipment Flow Cytometry Fluorescein Fluorescein-5-isothiocyanate Fluoresceins Genes Goals Greater sac of peritoneum Hour Human IRAK1 gene IRF3 gene Immune Immune response Immunologics Immunophenotyping Inbred C3H Mice Infection Inflammatory Inflammatory Response Interferon-beta Interferons Isothiocyanates Knockout Mice Lactated Ringer&apos s Solution Leukocytes Lipid A Lipids Lipopolysaccharides Lymphocyte Count Measures Mediating Membrane Proteins Modeling Molecular Morbidity - disease rate Mus Myelogenous Myeloid Cells NF-kappa B Necrosis Normal saline Pathway interactions Patients Peritoneal Phagocytosis Phenotype Phosphate Buffer Phosphatidylinositols Phosphotransferases Phycoerythrin Population Production Pseudomonas aeruginosa Recruitment Activity Relative (related person)Respiratory Burst Role Route Saline Sepsis Septic Shock Signal Pathway Signal Transduction Solutions Suppressor-Effector T-Lymphocytes TLR4 gene TNF gene Temperature Testing Toll-like receptors Tumor Necrosis Factor-alpha Tumor Necrosis Factors Vaccine Adjuvant White Blood Cell Count procedure X-Ray Crystallography antimicrobial base conventional therapy cytokine design diacetyldichlorofluorescein dichlorofluorescin human IRF3 protein immunoregulation improved in vivo interferon regulatory factor-3 interleukin-1 receptor-associated kinase intraperitoneal monophosphoryl lipid A mortality pathogen receptor research study response salt balance soy stem

项目摘要

DESCRIPTION (provided by applicant): While strides have been made to reduce the lethality of septic shock, it is still a highly fatal condition that is on the rise. Immunomodulation may prove to be a viable treatment option for sepsis. Immunomodulation consists of the induction of an immunologically tolerant state typified by a reduced inflammatory response to infection. Tolerance induction by LPS has been shown to be highly effective in reducing both morbidity and mortality in murine sepsis models; however LPS is too toxic to be used in humans. Monophosphoryl Lipid A (MPLA) is an endotoxin derivative used as a vaccine adjuvant. When administered independently of other immuno-stimulants or antibiotics, MPLA elicits a tolerant phenotype characterized by an attenuated pro-inflammatory response to subsequent bacterial challenges; and also improved bacterial clearance and reduced mortality in murine sepsis models. The mechanisms contributing to this altered immunologic phenotype are not well understood. Preliminary results show an expansion of a mixed myeloid cell population (including immature myeloid suppressor cells) after MPLA priming, coupled with a relative decrease in lymphocyte numbers. Two Specific Aims are proposed to further assess the impact of MPLA-mediated immuno-modulation at the systemic and cellular levels. The goals of aim 1 are to characterize the effect of MPLA priming on the host response to infection by determining: 1. how long the altered immuno-phenotype persists after MPLA priming; 2. the phenotype of leukocyte populations that are recruited by MPLA priming; and 3. the effect of MPLA priming on the pro-inflammatory and antimicrobial functions of specific leukocyte populations. Mice will be treated with MPLA prior to bacterial challenge. Specific leukocyte populations in the peritoneal cavity, and bone marrow will be characterized by flow cytometry. The functional importance of the identified leukocyte populations will be determined by antibody depletion, adoptive transfer, cytokine production, phagocytosis, oxidative metabolism, and bacterial clearance assays. MPLA may activate the TLR pathway in a MyD88-independent fashion, resulting in a predominant TRIF-based signaling cascade. Aim 2 will assess the ability to induce an immuno-modulated state in TLR4, MyD88, and Trif Knock out mice to determine the importance of these signaling pathways in vivo. This study is designed to characterize the molecular and cellular mechanisms involved in MPLA mediated tolerance induction. Greater mechanistic understanding is needed for MPL and other immunomoduolators to become clinically available treatment options. The use of such immune based therapies may help to reduce the dependence upon antibiotics, and stem the rise in antibiotic-resistant pathogens.

描述（由申请人提供）：虽然在降低感染性休克的致死率方面已经取得了长足的进步，但它仍然是一种高度致命的疾病，并且呈上升趋势。免疫调节可能被证明是脓毒症的可行治疗选择。免疫调节包括诱导免疫耐受状态，其典型特征是减少对感染的炎症反应。 LPS 诱导耐受已被证明可以非常有效地降低小鼠脓毒症模型的发病率和死亡率；然而，LPS 的毒性太大，不能用于人类。单磷酰脂质 A (MPLA) 是一种用作疫苗佐剂的内毒素衍生物。当独立于其他免疫刺激剂或抗生素施用时，MPLA 会引发耐受表型，其特征是对随后的细菌攻击的促炎反应减弱；还提高了小鼠脓毒症模型中的细菌清除率并降低了死亡率。导致这种免疫表型改变的机制尚不清楚。初步结果显示，MPLA 引发后混合骨髓细胞群（包括未成熟骨髓抑制细胞）扩张，同时淋巴细胞数量相对减少。提出了两个具体目标，以进一步评估 MPLA 介导的免疫调节在系统和细胞水平上的影响。目标 1 的目标是通过确定以下因素来表征 MPLA 引发对宿主感染反应的影响： 1. MPLA 引发后改变的免疫表型持续多长时间； 2. MPLA引发募集的白细胞群的表型； 3. MPLA引发对特定白细胞群促炎和抗菌功能的影响。在细菌攻击之前，将用 MPLA 处理小鼠。腹膜腔和骨髓中的特定白细胞群将通过流式细胞术进行表征。已确定的白细胞群的功能重要性将通过抗体耗竭、过继转移、细胞因子产生、吞噬作用、氧化代谢和细菌清除测定来确定。 MPLA 可能以不依赖 MyD88 的方式激活 TLR 通路，从而产生主要的基于 TRIF 的信号级联。目标 2 将评估在 TLR4、MyD88 和 Trif 敲除小鼠中诱导免疫调节状态的能力，以确定这些信号通路在体内的重要性。本研究旨在表征 MPLA 介导的耐受诱导中涉及的分子和细胞机制。需要对 MPL 和其他免疫调节剂的机制有更深入的了解，才能成为临床上可用的治疗选择。使用这种基于免疫的疗法可能有助于减少对抗生素的依赖，并阻止抗生素耐药病原体的增加。