Development of Lipid-based Nanoparticle Vaccines Against Mycobacterium tuberculosis

项目摘要 结核分枝杆菌（Mtb）仍然是人类发病的主要原因之一。唯一的 现有的结核病（TB）疫苗BCG对预防成人肺结核无效。这 因此，有必要开发替代疫苗或加强策略，以提供更好的抗结核病保护。 已经使用Mtb蛋白抗原开发了几种亚单位疫苗候选物， 应答然而，关于Mtb脂质抗原在针对Mtb的疫苗中的潜在用途知之甚少。以来 结核分枝杆菌细胞壁富含脂质，分枝菌酸（MA）是最丰富的脂质种类，利用细胞内的 对MA的免疫应答可能是一种有前途的疫苗策略。CD 1分子呈现一系列Mtb脂质 to cognate同源T cells细胞.它们分为第1组（CD 1a、CD 1b和CD 1c）和第2组（CD 1d）。四 CD 1亚型，CD 1b代表最大的Mtb衍生脂质队列，包括MA。MA特异性CD 1b- 已在Mtb感染个体的血液以及疾病部位中检测到限制性T细胞。在 此外，我们最近发现MA特异性CD 1b限制性T细胞在Mtb过程中起保护作用。 在人源化转基因小鼠模型中的感染。这些数据表明，MA将是一个理想的模型 抗原，以测试基于脂质的结核病亚单位疫苗的可行性。 在这个提议中，我们将研究使用纳米颗粒封装的MA作为亚基的可能性 疫苗，以检查其在用Mtb攻击的人CD 1转基因小鼠中的保护能力。按照建议 根据我们的初步数据，使用纳米颗粒有助于通过鼻内给药途径将MA容易地递送至肺部。 路线由于已知纳米颗粒的大小影响抗原呈递细胞（APC）靶向，因此，在特定情况下， 目的1，我们建议比较当胶束（~30 nm） 直径）或聚合物囊泡（直径约120 nm）用于将MA与双重佐剂一起包封， CpG ODN和MPLA。为了在免疫后引起最强的MA特异性T细胞应答， 我们将进一步测试β-GalCer和GM-CSF的共递送是否会增强这些MA的免疫原性 纳米粒子来自具体目标1的MA-纳米颗粒和佐剂的最佳组合将用于 特异性目的2在多克隆中免疫人CD 1转基因小鼠以诱导MA特异性T细胞应答 设置.最后，用MA-佐剂纳米颗粒疫苗接种抵抗Mtb感染的保护能力将增强。 被评价。总的来说，这项研究不仅提供了一个“概念证明”，即第1组CD 1限制性脂质 抗原可以被包括在抗Mtb感染的亚单位疫苗中， 纳米颗粒用于将脂质抗原有效递送至感染的原发部位。

PROJECT SUMMARY Mycobacterium tuberculosis (Mtb) remains one of the major causes of morbidity in humans. The only available vaccine against tuberculosis (TB), BCG, is ineffective in protecting against adult pulmonary TB. This warrants the development of alternative vaccines or booster strategies that confer better protection against Mtb. Several subunit vaccine candidates have been developed using Mtb protein antigens that elicit potent Th1 responses. However, little is known about the potential use of Mtb lipid antigens in vaccines against Mtb. Since the Mtb cell wall is lipid rich, with mycolic acid (MA) being the most abundant lipid species, harnessing cellular immune responses to MA could be a promising vaccine strategy. CD1 molecules present a range of Mtb lipids to cognate T cells. They are divided into group 1 (CD1a, CD1b and CD1c) and group 2 (CD1d). Of the four CD1 isoforms, CD1b presents the largest cohort of Mtb-derived lipids, including MA. MA-specific CD1b- restricted T cells have been detected in the blood as well as disease sites of Mtb-infected individuals. In addition, we have recently shown that MA-specific CD1b-restricted T cells play a protective role during Mtb infection in a humanized transgenic mouse model. These data suggest that MA would be an ideal model antigen to test the feasibility of a lipid-based subunit vaccine to TB. In this proposal, we will investigate the possibility of using nanoparticle-encapsulated MA as a subunit vaccine to examine its protective capacity in human CD1 transgenic mice challenged with Mtb. As suggested by our preliminary data, use of nanoparticles facilitates easy delivery of MA to the lungs through the intranasal route. Since it is known that the size of nanoparticles affects antigen-presenting cell (APC) targeting, in specific aim 1, we propose to compare the efficiency of antigen presentation in vivo when either micelles (~30 nm diameter) or polymersomes (~120 nm diameter) are used to encapsulate MA together with the dual adjuvants, CpG ODN and MPLA. In an attempt to elicit the most robust MA-specific T cell response upon immunization, we will further test if the co-delivery of -GalCer and GM-CSF will enhance the immunogenicity of these MA nanoparticles. The best combination of MA-nanoparticles and adjuvants from specific aim 1 will be used in specific aim 2 to immunize human CD1 transgenic mice to induce MA-specific T cell responses in a polyclonal setting. Lastly, the protective capacity of vaccination with MA-adjuvant nanoparticles against Mtb infection will be evaluated. Collectively, this study will not only provide a “proof of concept” that group 1 CD1-restricted lipid antigens can be included in subunit vaccines against Mtb infection but also explore the possibility of using nanoparticles for efficient lipid antigen delivery to the primary site of infection.