Developing a Multivalent Subunit Particle Vaccine Against Tuberculosis

项目摘要 可能需要一种有效的疫苗来减轻结核病（TB）的全球负担。开发一 一直很困难，部分原因是结核分枝杆菌（Mtb）能够长时间驻留 在宿主抗原（Ag）呈递细胞（APC）中，它表达大量Ag，其中许多具有 成为疫苗研发的目标。重组Ag已经成为许多疫苗的焦点， 然而，临床试验的结果并不理想。本R61/R33提案响应计划 公告RFA-AI-21 - 007："结核病疫苗发现的创新"将利用下一个- 诱导重组Ag的无缝颗粒形成的疫苗佐剂系统，以评估 多价Mtb疫苗。一种新的免疫模式将被推进，基于结合（通过简单的 混合）充分表征的可溶性蛋白Mtb Ags与诱导自发免疫的疫苗佐剂， 纳米脂质体-Ag颗粒化。含有少量钴卟啉-磷脂的脂质体 CoPoP（CoPoP）通过将his-标签自发插入到双层中而与his-标签的Ag结合。这种方法给出了 在生物介质中稳定的快速颗粒化。重组Ag简单地与CoPoP混合 脂质体在接种疫苗时（无需进一步纯化）完全转化以展示在表面上 约100 nm的颗粒。CoPoP最近完成了I期，并进入了II期临床试验， COVID-19疫苗（NCT 04783311）的组分。CoPoP还使用短时间诱导有效的细胞反应 小鼠中纳克肽剂量的MHC-I限制性肽免疫原;低多个数量级 与常规疫苗佐剂的Ag剂量相比，初步数据显示， 用已建立的Mtb Ags Ag85A、CFP10、ESAT-6、HSP-X和Mpt 64修饰的多价颗粒 诱导小鼠保护性细胞免疫反应。潜在的假设是多价粒子- 基于结核分枝杆菌抗原的疫苗将诱导比卡介苗更有效的有效保护性免疫应答。 Guérin（BCG）在结核病感染的多个小动物模型中的应用。该提案的R61阶段将使用鼠标 结核病感染模型：（1）开发良好表征的多价Mtb Ag颗粒;（2）评估颗粒如何 影响功能性免疫原性的参数;和（3）比较鼻内和肌内给药的功效。 颗粒给药。根据A）提出了雄心勃勃的定量R61-R33过渡里程碑 产生具有储存稳定性的良好表征的颗粒，其中B）多价Ag提供上级 保护相对于最好的单一Ag颗粒，C）优于小鼠中的常规BCG免疫。 该项目的R33阶段将涉及（4）在豚鼠模型中评估疫苗，以及（5）开发 以及评估冻干的热稳定形式的疫苗的效力和毒性。

PROJECT SUMMARY An effective vaccine is likely required to reduce the global burden of tuberculosis (TB). Development of one has been difficult, in part due to the ability for Mycobacterium tuberculosis (Mtb) to reside for long periods within host antigen (Ag) presenting cells (APCs), where it expresses a multitude of Ags, many of which have been targeted for vaccine development. Recombinant Ags have been the focus of numerous vaccines, however outcomes to clinical testing have been less than ideal. This R61/R33 proposal in response to program announcement RFA-AI-21-007: “Innovation for Tuberculosis Vaccine Discovery” will leverage a next- generation, vaccine adjuvant system that induces seamless particle-formation of recombinant Ags to assess a multivalent Mtb vaccine. A new immunization paradigm will be advanced, based on combining (via simple mixing) well-characterized soluble protein Mtb Ags with a vaccine adjuvant that induces spontaneous nanoliposome-Ag particleization. Liposomes that contain small amounts of cobalt porphyrin-phospholipid (CoPoP) bind to his-tagged Ags via spontaneous insertion of the his-tag into the bilayer. This approach gives rise to rapid particleization that is stable in biological media. Recombinant Ags are simply admixed with CoPoP liposomes at the time of vaccination (without further purification) to be fully converted for display on the surface of ~100 nm particles. CoPoP recently completed phase I and entered phase II clinical testing as a key component of a COVID-19 vaccine (NCT04783311). CoPoP also induces potent cellular responses using short MHC-I restricted peptide immunogens at nanogram peptide dosing in mice; multiple orders of magnitude lower dosing compared to Ag doses with conventional vaccine adjuvants. Preliminary data demonstrates that multivalent particles decorated with the established Mtb Ags Ag85A, CFP10, ESAT-6, HSP-X, and Mpt64 induce protective cellular immune responses in mice. The underlying hypothesis is that multivalent, particle- based Mtb Ags will induce a potently protective immune responses more effective than Bacillus Calmette– Guérin (BCG) in multiple small animal models of TB infection. The R61 phase of the proposal will use mouse models of TB infection to: (1) Develop well-characterized, multivalent Mtb Ag particles; (2) Assess how particle parameters impact functional immunogenicity; and (3) Compare the efficacy of intranasal and intramuscular particle administration. Ambitious and quantitative R61-R33 transitional milestones are proposed based on A) generating well-characterized particles with storage stability with B) multivalent Ags providing superior protection relative to the best single Ag particles with C) superiority to conventional BCG immunization in mice. The R33 phase of the project will involve (4) assessing the vaccine in the guinea pig model, and (5) developing and assessing the efficacy and toxicity of a lyophilized thermostable version of the vaccine.