The role of LPS-TLR4 signaling in live vaccine-induced protective responses

LPS-TLR4 信号在活疫苗诱导的保护性反应中的作用

• 批准号: 8441620
• 负责人: Egil Lien
• 金额: $ 39.54万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-04-01 至 2015-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8441620
• 关键词: Adjuvant; Animals; Anti-Bacterial Agents; Antibody Formation; Antigen Presentation; Attenuated; Attenuated Vaccines; Bacillus (bacterium); Bacteria; Bacterial Infections; Bacterial Vaccines; Biological Models; Bubonic Plague; CD14 Antigen; Cells; Communicable Diseases; Dendritic Cells; Dendritic cell activation; Dependence; Development; Disease; Escherichia coli; Exposure to; Future; Generations; Goals; Gram-Negative Bacteria; Health; IRF3 gene; Immune; Immune response; In Vitro; Infection; Interferons; Licensing; Life; Lipid A; Lipopolysaccharides; Mediating; Methods; Mus; Natural Immunity; Pathway interactions; Peripheral; Plague; Plague Vaccine; Pneumonic Plague; Receptor Signaling; Recording of previous events; Role; Signal Pathway; Signal Transduction; Survival Analysis; T-Cell Activation; T-Lymphocyte; T-Lymphocyte Subsets; TLR4 gene; Testing; Toll-like receptors; Vaccinated; Vaccination; Vaccines; Virulent; Wild Type Mouse; Work; Yersinia pestis; adaptive immunity; attenuation; base; cytokine; design; enzyme biosynthesis; in vivo; killings; microorganism; novel; pathogen; response; subcutaneous; toll-like receptor 4; vaccine efficacy

DESCRIPTION (provided by applicant): Live vaccines have a long history for providing efficient protection against subsequent infectious challenge. However, the mechanisms leading to protection are in many cases not well defined. Our goal is to define mechanisms for immune protection by Gram-negative bacterial vaccine strains, using novel Yersinia pestis strains as model systems. The gram-negative bacterium Yersinia pestis is the causative agent of plague. Currently there is no available licensed plague vaccine, and exploratory vaccines have variable ability to protect against pneumonic disease, the form expected after a bioterror attack. We have developed a new method for the generation of efficient vaccine strains for protection against plague and potentially other microorganisms, based upon enhancement of inherent bacterial Toll-like receptor (TLR)-4 mediated adjuvant activity. Similar to various other gram-negative bacteria, Y. pestis produces a lipopolysaccharide (LPS) with low stimulatory ability at 37:C. TLR4 is the cellular receptor for LPS via its lipid A. We generated a new Y. pestis strain expressing LpxL, an E. coli lipid A biosynthesis enzyme, and found this to produce a potent LPS at 37:C. This strain is avirulent in mice by peripheral inoculation, due to induction of antibacterial innate immune mechanisms via TLR4, a pathway also associated with strong adjuvant effects. Our results indicate that vaccination of mice with the Y. pestis LpxL strain induces full protection against both subcutaneous and intranasal challenge of mice with virulent bacteria, mimicking bubonic and pneumonic plague. Our main hypotheses are that many live bacterial vaccine strains containing LPS with increased potency are efficient vaccines, and that the increased TLR4 signaling will provide enhanced adaptive immune responses. We propose to determine mechanisms influencing the vaccine efficacy using live and killed Y. pestis producing a potent LPS, by comparing to strains without increased TLR4 stimulation, testing both in vitro and in vivo responses. Both existing and novel attenuated strains will be used. Relying on primary dendritic and T cells and genetically deficient mice, we will study TLR signaling pathways leading to dendritic cell activation in vivo and in vitro, antigen presentation and T cell subset activation. We will analyze vaccine effects against both subcutaneous and intranasal infection. The completion of these studies will provide information on the mechanism by which vaccine strains towards Gram-negative infections may act. Incorporation of TLR- stimulating adjuvant activity directly into immune-evading pathogens may constitute a novel method for attenuation and generation of vaccines.

描述（由申请人提供）：活疫苗在提供针对后续感染挑战的有效保护方面有着悠久的历史。然而，在许多情况下，导致保护的机制并没有明确定义。我们的目标是使用新型鼠疫耶尔森菌菌株作为模型系统，定义革兰氏阴性细菌疫苗菌株的免疫保护机制。革兰氏阴性菌鼠疫耶尔森氏菌是鼠疫的病原体。目前还没有获得许可的鼠疫疫苗，而探索性疫苗预防肺炎疾病的能力各不相同，这是生物恐怖袭击后预期的形式。我们开发了一种新方法，基于固有细菌 Toll 样受体 (TLR)-4 介导的佐剂活性的增强，产生有效的疫苗株，以预防鼠疫和潜在的其他微生物。与其他各种革兰氏阴性细菌类似，鼠疫耶尔森氏菌在 37:C 时产生低刺激能力的脂多糖 (LPS)。 TLR4 是 LPS 通过其脂质 A 的细胞受体。我们培育了一种新的鼠疫耶尔森菌株，表达 LpxL（一种大肠杆菌脂质 A 生物合成酶），并发现它可以在 37:C 下产生有效的 LPS。由于通过 TLR4 诱导抗菌先天免疫机制，该菌株通过外周接种对小鼠无毒力，该途径也与强佐剂作用相关。我们的结果表明，用鼠疫耶尔森氏菌 LpxL 菌株接种小鼠可诱导针对小鼠皮下和鼻内有毒细菌攻击的全面保护，类似于腺鼠疫和肺鼠疫。我们的主要假设是，许多含有增强效力的 LPS 的活细菌疫苗株是有效的疫苗，并且增强的 TLR4 信号传导将提供增强的适应性免疫反应。我们建议通过与未增加 TLR4 刺激的菌株进行比较，测试体外和体内反应，使用活的和灭活的鼠疫杆菌产生有效的 LPS，确定影响疫苗功效的机制。现有的和新型的减毒菌株都将被使用。依靠原代树突状细胞和T细胞以及遗传缺陷小鼠，我们将研究导致体内和体外树突状细胞激活、抗原呈递和T细胞亚群激活的TLR信号通路。我们将分析疫苗对皮下和鼻内感染的效果。这些研究的完成将提供有关针对革兰氏阴性感染的疫苗株的作用机制的信息。将 TLR 刺激佐剂活性直接掺入免疫逃避病原体中可能构成一种减毒和生产疫苗的新方法。