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Live Oral Listeria Vaccine Vector

活口服李斯特菌疫苗载体

基本信息

批准号：
7849973
负责人：
PAUL Edwin ORNDORFF
金额：
$ 21.24万
依托单位：
NORTH CAROLINA STATE UNIVERSITY RALEIGH
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：
2009-06-01 至 2012-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7849973
关键词：
Aerosols Antigens Attenuated Bacteriophages Characteristics Chimeric Proteins Collaborations Colony-forming units Colorado Dose Enterocytes Epidemic Funding Gene Fusion Genes Genetic Engineering Growth Head Health Heterophile Antigens Human Immune Immune response Immunity Immunization Infection Infectious Agent Intestines Lesion Life Listeria Listeria monocytogenes Liver Malignant Neoplasms Measures Methods Modeling Mus Mycobacterium tuberculosis Mycobacterium tuberculosis antigens Nature Oral Oral Administration Parents Phage Receptors Population Production Property Proteins Research Design Residual state Resistance Route Safety Signal Transduction Spleen Study models Testing Therapeutic Tuberculosis Universities Vaccinated Vaccination Vaccines Viral Viral Tumor Antigens Virulent attenuation cell mediated immune response combat in vivo microorganism mutant oral vaccine potency testing prevent public health relevance research study resistant strain response vaccine delivery vaccine development vector vaccine

项目摘要

DESCRIPTION (provided by applicant): The purpose of this R21 application is to explore the feasibility of using bacteriophage resistance as a feature of a live, attenuated, oral Listeria monocytogenes vaccine delivery platform. We are studying a phage resistant mutant in which a Tn917 insertion interrupts a gene whose product is required for the production of the phage receptor. This lesion also results in profound attenuation but retention of the immunostimulatory characteristics for which L. monocytogenes is well known. We intend to use the funding requested to conduct proof-of-principle experiments that will determine the usefulness of a derivative of this strain in expressing a heterologous antigen. The antigen we have chosen to express is the early secretory antigenic target 6 (ESAT-6) a secreted protein produced by Mycobacterium tuberculosis whose properties as a protective immunogen are well established. Several properties of the phage resistant mutant revealed its potential value as a vaccine platform: First, the mutant made minute plaques on cultured mouse enterocytes, indicating that it was not attenuated to the point where it would be nonimmunogenic. Second, the mutant prospered in the mouse intestinal tract following oral administration, but could not be detected in the liver and spleen--features that speak to the applicability, practicality, and safety of the mutant. Third, the parent strain we have employed is highly infective for mice via the oral route, making it a good model for studies of oral (as opposed to parenteral) listerial immunization. The strain is additionally advantageous because it is serologically similar to the most prevalent human epidemic isolates. Consequently, the development of a vaccine platform using this strain will have added value in protecting susceptible populations against infection with L. monocytogenes, a potential bioterror agent. In our protection studies, mice challenged at 22 and 52 days post vaccination had a 10,000-fold stimulation in the adaptive immune response--measured as splenic colony forming units recovered from vaccinated versus sham vaccinated mice 5 days post oral challenge with the virulent parental (phage sensitive) strain. In this application, we propose experiments to construct a L. monocytogenes phage resistant expression platform, and conduct tests of its safety and efficacy. Specifically, we propose to: (1) Construct a gene fusion strain expressing the Mycobacterium tuberculosis antigen ESAT-6 and document the level and type of immunity engendered to ESAT-6 following oral vaccination in mice. (2) Assess the level of protective immunity conferred against an aerosol M. tuberculosis challenge in mice orally vaccinated with the ESAT-6-expressing strain. A demonstration of protective immunity to M. tuberculosis by the platform would provide justification for testing antigens from other infectious agents (e.g., viral), and tumor antigens--where the platform could be applied as a therapeutic adjunct to combat certain forms of cancer--to the benefit of human health in the US. PUBLIC HEALTH RELEVANCE: The purpose of this R21 application is to explore the feasibility of using bacteriophage resistance as a feature of a live, oral, Listeria monocytogenes vaccine delivery platform. We propose means to construct the expression platform, and conduct tests of its safety and efficacy in preventing tuberculosis in mice. A demonstration of protective immunity by the platform would provide justification for testing antigens from other infectious agents (e.g., viral) and exploring the platform's applicability as a therapeutic adjunct to combat certain forms of cancer-- all to the benefit of human health in the US.

描述(由申请人提供)：本R21申请的目的是探索利用噬菌体抗药性作为活的、减毒的、口服的单核细胞增生性李斯特菌疫苗递送平台的可行性。我们正在研究一种抗噬菌体突变体，在该突变体中，Tn917插入会中断一个基因，该基因的产物是生产噬菌体受体所必需的。这种病变还导致严重的衰减，但保留了众所周知的单核细胞增多性李斯特菌的免疫刺激特性。我们打算利用所要求的资金进行原则验证实验，以确定该菌株的衍生物在表达异源抗原方面的有用性。我们选择表达的抗原是早期分泌性抗原靶标6(ESAT-6)，这是一种由结核分枝杆菌产生的分泌性蛋白，其作为保护性免疫原的特性已经得到了很好的证实。噬菌体抗性突变体的几个特性揭示了它作为疫苗平台的潜在价值：首先，突变体在培养的小鼠肠上皮细胞上形成了微小的斑块，表明它没有减弱到非免疫原性的程度。其次，突变体在口服给药后在小鼠肠道中生长旺盛，但在肝脏和脾中检测不到--这些特征说明了突变体的适用性、实用性和安全性。第三，我们使用的亲本菌株通过口服途径对小鼠具有很高的感染性，使其成为研究口服(而不是非肠道)李斯特菌免疫的良好模型。该毒株具有额外的优势，因为它在血清学上与最流行的人类流行病分离株相似。因此，使用这种菌株的疫苗平台的开发将在保护易感人群免受单核细胞增多性乳杆菌感染方面具有附加值，单核细胞增多性乳杆菌是一种潜在的生物恐怖因子。在我们的保护研究中，在接种后22天和52天受到挑战的小鼠在适应性免疫反应中得到了10,000倍的刺激--衡量的是在口服强毒亲本(噬菌体敏感)菌株5天后，从接种疫苗的小鼠中恢复的脾克隆形成单位与假接种小鼠相比。在这一应用中，我们提出了构建单核细胞增多性李氏杆菌噬菌体抗性表达平台的实验，并对其安全性和有效性进行了测试。具体地说，我们建议：(1)构建表达结核分枝杆菌抗原ESAT-6的基因融合株，并证明ESAT-6在小鼠口服疫苗后产生的免疫水平和类型。(2)评估口服表达ESAT-6菌株的小鼠对结核分枝杆菌气溶胶攻击的保护性免疫水平。该平台展示了对结核分枝杆菌的保护性免疫，这将为测试来自其他传染病病原体(例如，病毒)的抗原和肿瘤抗原--该平台可以作为治疗辅助手段对抗某些形式的癌症--在美国为人类健康提供依据。公共卫生相关性：此R21应用程序的目的是探索将噬菌体抗药性用作口服单核细胞增生性李斯特菌活疫苗交付平台的可行性。我们提出了构建表达平台的方法，并对其在小鼠体内预防结核病的安全性和有效性进行了测试。该平台的保护性免疫展示将为测试其他感染性病原体(例如病毒)的抗原并探索该平台作为治疗辅助手段对抗某些形式的癌症的适用性提供理由--所有这些都有利于美国的人类健康。