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: 8044810
• 负责人: Egil Lien
• 金额: $ 42.15万
• 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 2014-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8044810
• 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. PUBLIC HEALTH RELEVANCE: This proposal will identify mechanisms by which live vaccines against some bacterial infections work. We will use novel avirulent, immunostimulatory strains of the plague bacillus Yersinia pestis as a model system. Our results may help in the design of future vaccines against plague and other infectious diseases.

描述（由申请人提供）：实时疫苗有悠久的历史，可为随后的传染性挑战提供有效的保护。但是，在许多情况下，导致保护的机制尚未得到很好的定义。我们的目标是使用新型的Yersinia Pestis菌株作为模型系统来定义革兰氏阴性细菌疫苗菌株免疫保护的机制。革兰氏阴性细菌耶尔森氏菌是鼠疫的病因。目前尚无可用的许可瘟疫疫苗，并且探索性疫苗具有可改变肺炎疾病的能力，这是生物疾病攻击后预期的形式。我们已经开发了一种新方法，用于基于固有细菌Toll样受体（TLR）-4介导的辅助活性的增强，以保护有效的疫苗菌株，以防止瘟疫和潜在的其他微生物。与其他各种革兰氏阴性细菌相似，Y. pestis产生的脂多糖（LPS）在37：c时具有低刺激能力。 TLR4是LPS通过其脂质A的细胞受体A。我们生成了一种表达LPXL的新Y. Pestis菌株，一个大肠杆菌脂质A生物合成酶，并发现它在37：c时产生有效的LPS。由于通过TLR4诱导抗菌先天免疫机制，该菌株通过外周种接种在小鼠中是无毒的，这也是与强佐剂作用相关的途径。我们的结果表明，使用Y. pestis lpxl菌株对小鼠的疫苗接种可诱导针对毒细菌的小鼠皮下和鼻内挑战的全面保护，模仿泡泡糖和肺炎瘟疫。我们的主要假设是，许多含有效力的LP的活细菌疫苗菌株是有效的疫苗，而增加的TLR4信号传导将提供增强的适应性免疫反应。我们建议通过与没有增加TLR4刺激的菌株进行比较，在体外和体内测试中测试菌株，从而确定使用生物和生成有效LPS的鼠疫的疫苗功效的机制。将使用现有的和新颖的减毒菌株。依靠原发性树突状细胞和T细胞以及遗传缺陷的小鼠，我们将研究TLR信号传导途径，导致体内树突状细胞激活，体外，体外，抗原表现和T细胞子集激活。我们将分析针对皮下和鼻内感染的疫苗作用。这些研究的完成将提供有关疫苗菌株对革兰氏阴性感染的机制的信息。将TLR-刺激辅助活性直接掺入免疫散发病原体可能构成一种新型方法，用于衰减和生成疫苗。公共卫生相关性：该提案将确定针对某些细菌感染起作用的实用疫苗的机制。我们将使用新型的无毒鼠疫耶尔森氏芽孢杆菌作为模型系统。我们的结果可能有助于设计未来针对瘟疫和其他传染病的疫苗。