Development of a Safe and Potent Vaccine Against Melioidosis using the LVS dcapB Vector Platform

使用 LVS dcapB 载体平台开发安全有效的类鼻疽疫苗

• 批准号: 10308602
• 负责人: MARCUS AARON HORWITZ
• 金额: $ 15.51万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-06-01 至 2021-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10308602
• 关键词: Aerosols; Animals; Antibiotic Resistance; Antibiotics; Antigens; Area; Attenuated; Attenuated Vaccines; Bacillus anthracis; Bacteria; Bioterrorism; Burkholderia pseudomallei; CD69 antigen; CD8B1 gene; Cells; Cellular Immunity; Centers for Disease Control and Prevention (U.S.); Cessation of life; Chimeric Proteins; Chromosomes; Chronic Disease; Clinical; Combined Vaccines; Cytosol; DNA cassette; Development; Diagnosis; Disease; Disease Outbreaks; Dose; Endemic Diseases; Environment; Formulation; Francisella tularensis; Fresh Water; Future; Goals; Gram-Negative Bacteria; Growth; Health Policy; Human; Immune; Immune response; Immunity; Immunocompetent; Immunologics; In Vitro; Inbred BALB C Mice; Individual; Infection; Ingestion; Inhalation; Invaded; Kinetics; Laboratories; Life Style; Listeria monocytogenes; Marker Vaccines; Mediating; Melioidosis; Military Personnel; Mucous Membrane; Mus; Phagocytes; Plasmids; Pneumonia; Property; Prophylactic treatment; Proteins; Public Health; Recombinant Vaccines; Recombinants; Regimen; Resistance; Risk; Route; Safety; Skin; Soil; Symptoms; T-Lymphocyte; Testing; Vaccines; Vacuole; Virulence; Virulent; Water; aerosolized; base; biodefense; bioweapon; booster vaccine; cell mediated immune response; cost; improved; novel; overexpression; pathogen; protective efficacy; protein expression; respiratory; subcutaneous; vaccine efficacy; vaccine evaluation; vaccine safety; vector; vector vaccine

PROJECT SUMMARY/ABSTRACT Burkholderia pseudomallei (Bp), an environmental bacterium capable of infecting humans and animal hosts, is the causative agent of melioidosis, a highly fatal disease endemic in many tropical areas. In addition to its significant public health burden in endemic regions, causing ~89,000 deaths annually, Bp is categorized as a Tier 1 Select Agent of bioterrorism, in large part because inhalation of low doses of Bp can cause rapidly fatal pneumonia. As naturally acquired melioidosis is often difficult to diagnose and requires very lengthy treatment, and as post-exposure prophylaxis is not a practical public health policy for countering an outbreak of pneumonic melioidosis from a bioterrorist attack, a safe and effective pre-exposure vaccine would be highly beneficial in both circumstances. Currently, there are no licensed vaccines against Bp. Hence, a vaccine against Bp would be of great benefit to people living in endemic regions, travelers, and military personnel stationed in these areas, and it would also reduce the risk from an intentional release in a bioterrorist attack. The goal of this application is to develop a safe and highly potent vaccine against Bp, suitable for both biodefense and public health purposes, based on a readily expandable single vector platform vaccine. Specifically, we shall use a novel, safe, yet potent live attenuated vector, LVS ΔcapB. The LVS ΔcapB vector, developed in this laboratory, is a further attenuated version (>10,000 fold less virulent in mice) of a multi- deletional Francisella tularensis vaccine (F. tularensis subsp. holarctica Live Vaccine Strain; LVS) already extensively tested in humans; hence, LVS ΔcapB is anticipated to be exceedingly safe. Moreover, recombinant vaccines comprising this vector have been shown to induce potent humoral and cell-mediated (including both CD4+ and CD8+) immune responses, all likely important to long-lasting potent immunoprotection against Bp. In preliminary studies, homologous boosting with rLVS ΔcapB vaccines expressing immunoprotective Bp anti- gens has already demonstrated impressive protective efficacy against respiratory challenge with virulent Bp in sensitive BALB/c mice; protection was superior to the unlicensed attenuated Bp82 vaccine, which is unlikely to be approved because of concerns about reversion to virulence and the possibility of causing chronic disease. To accomplish our goal of developing a safe and highly potent vaccine against Bp, we shall a) construct optimized rLVS ΔcapB vaccines expressing multiple immunoprotective Bp antigens as fusion proteins; b) evaluate the vaccines systematically in vitro for protein expression, growth kinetics, and stability; c) evaluate the vaccines administered by different routes for safety, dissemination, clearance, and stability in both immune competent and immune deficient mice; d) evaluate protective efficacy against challenge with highly virulent Bp by the respiratory (IN) route, the route of greatest concern in a bioterrorist attack, and by the subcutaneous route, the route principally responsible for natural infection; and e) explore correlates of protective immunity using vaccines of escalating efficacy.

项目概要/摘要 鼻疽伯克霍尔德氏菌 (Bp)，一种能够感染人类和动物的环境细菌 宿主，是类鼻疽的病原体，类鼻疽是许多热带地区流行的高度致命的疾病。此外 鉴于其在流行地区造成的巨大公共卫生负担，每年造成约 89,000 人死亡，Bp 被归类为 作为生物恐怖主义的一级选择代理，很大程度上是因为吸入低剂量的 Bp 会迅速导致 致命性肺炎。由于自然获得性类鼻疽通常很难诊断并且需要很长时间 治疗，并且暴露后预防并不是对抗疫情爆发的实用公共卫生政策 生物恐怖袭击引起的肺炎类鼻疽，安全有效的暴露前疫苗将非常有效 在这两种情况下都是有益的。目前，尚无针对 Bp 的许可疫苗。因此，疫苗 对抗 Bp 对流行地区的人们、旅行者和军事人员有很大好处 驻扎在这些地区，这也将降低生物恐怖袭击中故意释放的风险。 本申请的目标是开发一种安全且高效的 Bp 疫苗，适用于 基于易于扩展的单一载体平台疫苗，实现生物防御和公共卫生目的。 具体来说，我们将使用一种新型、安全且有效的活减毒载体，LVS ΔcapB。 LVS ΔcapB 向量， 该实验室开发的，是一种多重减毒版本（对小鼠的毒性降低了 10,000 倍以上） 已删除土拉弗朗西斯菌疫苗（F. tularensis subsp. holarctica 活疫苗株；LVS） 在人体中进行了广泛的测试；因此，LVS ΔcapB 预计非常安全。此外，重组 包含该载体的疫苗已被证明可诱导有效的体液和细胞介导（包括两者） CD4+ 和 CD8+) 免疫反应，对于针对 Bp 的持久有效免疫保护可能都很重要。 在初步研究中，使用表达免疫保护性 Bp 抗-的 rLVS ΔcapB 疫苗进行同源加强 Gens 已在以下领域表现出令人印象深刻的针对有毒 Bp 呼吸道感染的保护功效： 敏感的BALB/c小鼠；保护效果优于未经许可的 Bp82 减毒疫苗，后者不太可能 由于担心毒力回复和引起慢性疾病的可能性而被批准。 为了实现我们开发安全且高效的 Bp 疫苗的目标，我们应 a) 构建 优化的 rLVS ΔcapB 疫苗将多种免疫保护性 Bp 抗原表达为融合蛋白； b) 在体外系统地评估疫苗的蛋白质表达、生长动力学和稳定性； c) 评估 通过不同途径接种疫苗，以确保免疫和免疫系统的安全性、传播、清除和稳定性 有能力且免疫缺陷的小鼠； d) 评估针对高毒力 Bp 攻击的保护功效 通过呼吸（IN）途径，这是生物恐怖袭击中最受关注的途径，以及通过皮下途径 途径，主要负责自然感染的途径； e) 探索保护性免疫的相关性 使用效力不断增强的疫苗。