Design and development of a novel, thermostable, and inhalable dry powder COVID-19 vaccine

总结 严重急性呼吸综合征-冠状病毒2型（SARS-CoV-2）是一种高度传染性病毒 已知导致2019冠状病毒病（COVID-19）。该疾病已被宣布为 世界卫生组织的全球流行病。在美国，截至2021年1月20日， 我们有2 400多万感染者，约40万人死亡。COVID-19 在患有高血压和糖尿病等合并症的患者中似乎更致命， 表现为肺炎、腹泻、多器官功能衰竭等多种临床表现。 感染者中。此外，预计感染人数和死亡率将增加 根据IHME模型，在接下来的几个月里，有一个紧急的全球 需要开发一种耐热的、可自我接种的疫苗。表面的刺突蛋白 冠状病毒是开发疫苗的绝佳候选者，目前已用于 EUA获得疫苗，因为它在病毒进入宿主细胞中起重要作用。 脂质体是优异的药物递送系统，其可以将抗原作为颗粒呈递给药物递送系统。 并允许掺入有助于产生强免疫的佐剂 反应此外，脂质体可以被设计为具有与病毒和脂质体类似的大小。 刺突蛋白可以缀合到脂质体表面以模拟在脂质体表面上的天然呈递， 病毒免疫细胞会像病毒一样内化和处理抗原， 中和抗体滴度。目前市场上销售的疫苗大多需要冷链 （冷藏）储存和分发疫苗，以保持效力，并要求访问 由受过训练的医务人员开设免疫诊所。这些都是实现 大规模疫苗接种给医院和供应链带来了进一步的压力。在 此外，一个主要的限制是现有的制造设施的能力有限， 数十亿剂量。在这项提案中，我们的目标是开发一种热稳定和可吸入的干粉 疫苗易于扩大规模，无需冷链储存和运输， 可由个人在家通过简单吸入自行施用。为了实现这一目标，我们将 追求两个目标：1）制备可吸入和热稳定的COVID-19干粉疫苗 含有S蛋白吸附的脂质体载体和2）中和粘膜和 COVID-19干粉疫苗雾化接种后全身伊加和IgG抗体滴度 对小鼠这一项目的顺利完成将对我国的发展产生深远的影响。 干粉COVID-19疫苗，特别是在探索热稳定和可吸入疫苗， 易于制造、储存和分发，这些特性在流行病中至关重要。

Summary Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV-2) is a highly infectious virus known to cause the 2019 coronavirus disease (COVID-19). The disease has been declared as a global pandemic by the World Health Organization. In the United States, as of January 20, 2021, we have more than 24 million infected individuals with approximately 400,000 deaths. COVID-19 appears to be more deadly in patients with co-morbidities such as hypertension and diabetes and presents many clinical manifestations such as pneumonia, diarrhea, multiple organ failure, etc. among those infected. Moreover, the number of infections and fatality rate is expected to increase significantly over the next few months, according to the IHME model. There is an urgent global need to develop a thermostable and self-administrable vaccine. The spike protein on the surface of coronavirus is an excellent candidate for developing vaccines, has been used in the currently EUA obtained vaccines, as it plays an important role in the entry of the virus into the host cell. Liposomes are excellent drug delivery systems that can present the antigen as particulate in nature and allow the incorporation of an adjuvant that aids in the generation of a robust immune response. Further, the liposomes can be designed to be of similar size to that of the virus and the spike protein can be conjugated to the liposomal surface to mimic the natural presentation on the virus. The immune cells will internalize and process the antigen like the virus and generate neutralizing antibody titers. Most of the vaccines currently in the market require cold chain (refrigeration) to store and distribute the vaccine to maintain the efficacy and require a visit to the clinic for immunization by trained medical personnel. These serve as bottlenecks in achieving mass vaccination in a pandemic adding further stress to the hospitals and the supply chain. In addition, a major limitation is the limited ability of existing manufacturing facilities to manufacture billions of doses. In this proposal, we aim to develop a thermostable and inhalable dry powder vaccine that is easy to scale-up, eliminates the need for cold-chain storage and transport, and is self-administrable by individuals’ at-home by simple inhalation. To achieve this goal, we will pursue two aims: 1) Formulation of an inhalable and thermostable dry powder COVID-19 vaccine containing S protein-adsorbed liposomal carriers and 2) Evaluation of neutralizing mucosal and systemic IgA and IgG antibody titers after aerosol administration of dry powder COVID-19 vaccine in mice. Successful completion of this project will have a profound impact on the development of dry powder COVID-19 vaccine, particularly in exploring thermostable and inhalable vaccines that are easy to manufacture, store, and distribute, characteristics that are critical in pandemic.