Nanoformulation of Synergistic TLR Ligands to Enhance Amebiasis Vaccine Efficacy

描述（由申请人提供）：传统的含有纳米颗粒成分的疫苗佐剂，如水包油乳液或铝盐，不能促进有效的th1型细胞免疫反应，这对于缺乏有效疫苗的复杂疾病，如疟疾、结核病和阿米巴病至关重要。后者是一种被忽视的肠道疾病，由原生动物寄生虫溶组织内阿米巴（一种生物防御B类病原体）引起，造成重大疾病负担，全世界每年约有5000万例感染，发展中国家的负担最重。本文描述了含合成toll样受体（TLR）配体的纳米脂质体的发展和理化特性，并评价了其增强阿米巴病疫苗免疫原性和保护功效的能力。减毒活疫苗的效力可能部分归因于它们能够触发多种病原体识别受体，如tlr。然而，对于现代重组或灭活疫苗，fda批准的疫苗（即Cervarix(R)）中使用的唯一基于TLR配体的佐剂由单个TLR配体组成。然而，适当的TLR配体组合纳米配方可能促进免疫反应的协同激活，包括th1型细胞免疫。在本文中，我们将采用高压均质法制备含有合成TLR4配体（GLA）和合成TLR7/8配体（3M052）的稳定纳米脂质体。纳米脂质体的直径为~65和100nm，具有不同的表面特征（聚乙二醇化长度和浓度）。纳米脂质体在体外表现出可接受的物理化学稳定性以及与重组阿米巴病抗原（LecA）的相容性，接下来将在皮下给药后的小鼠模型中评估其增强对LecA的th1型免疫反应的能力。此外，将调整免疫方案，包括补充鼻内给药，以评估引发的能力

DESCRIPTION (provided by applicant): Conventional vaccine adjuvants with nanoparticle components such as oil-in-water emulsions or aluminum salts do not promote effective Th1-type cellular immune responses, which are critical for complex diseases lacking effective vaccines such as malaria, tuberculosis, and amebiasis. The latter is a neglected enteric disease caused by the protozoan parasite Entamoeba histolytica (a biodefense category B pathogen) and accounts for significant disease burden with some 50 million annual infections worldwide, with the greatest burden in the developing world. This proposal describes the development and physicochemical characterization of nanoliposomes containing a combination of synthetic Toll-like receptor (TLR) ligands, and the evaluation of their ability to enhance amebiasis vaccine immunogenicity and protective efficacy. The efficacy of live attenuated vaccines may in part be attributed to their capacity to trigger multiple pathogen recognition receptors such as TLRs. Nevertheless, for modern recombinant or inactivated vaccines, the only TLR ligand-based adjuvant used in an FDA-approved vaccine (i.e. Cervarix(R)) consists of a single TLR ligand. However, appropriate nanoformulation of TLR ligand combinations may promote synergistic activation of immune responses, including Th1-type cellular immunity. In the proposed work, we will employ high pressure homogenization to manufacture stable nanoliposomes containing a synthetic TLR4 ligand (GLA) and a synthetic TLR7/8 ligand (3M052). The nanoliposomes will be manufactured at ~65 and 100 nm diameters as well as with different surface characteristics (PEGylation length and concentration). Nanoliposomes demonstrating acceptable in vitro physicochemical stability as well as compatibility with a recombinant amebiasis antigen (LecA) will next be evaluated for their ability to enhance Th1-type immune responses to LecA in a mouse model after subcutaneous administration. Furthermore, the immunization regimen will be adapted to include complementary intranasal administration in order to assess the ability to elicit mucosal IgA responses (which are also correlated with protection against amebiasis) while maintaining strong Th1-type cellular responses. Finally, the nanoliposome adjuvants and immunization regimens demonstrating optimal immunogenicity profiles will be evaluated in an amebiasis mouse challenge model for their protective efficacy. The broad implications of the project include demonstrating that protective Th1-type immunity can be achieved through appropriate nanoformulation of a combination of TLR ligands in a biocompatible and stable liposomal vehicle. This approach could be applied to accelerate vaccine development for many other biodefense pathogens. Successful vaccines developed for amebiasis or other indications requiring Th1-type immune responses such as malaria or tuberculosis would result in significant public health benefits.