Pulmonary immune response after a single-dose immunization of inhalable SARS-CoV-2 vaccine

The ongoing COVID-19 pandemic has fostered major advances in vaccination technologies, yet it is notable that all of the COVID-19 vaccines approved to date are based on intramuscular injections, and require multiple doses to achieve a protective immune response. Here, we developed a single-dose inhalable SARS-CoV-2 vaccine that induces potent systemic and mucosal immune responses. Our vaccine encapsulates proteinaceous cholera toxin B subunit (CTB)-assembled nanoparticles evenly displaying the SARS-CoV-2 RBD antigen (R-CNP) within microcapsules of optimal aerodiameter (aerodynamic particle size) for efficient delivery to alveoli-the tiny, immune-cell-laden air sacs positioned at the end of the bronchioles in lungs, and the known site of SARS-CoV-2 infection.

持续的新冠疫情推动了疫苗技术的重大进展，但值得关注的是，迄今为止获批的所有新冠疫苗均采用肌内注射（intramuscular injection）方式，且需接种多剂次才能诱导保护性免疫应答。本研究开发了一款单剂次可吸入型新冠病毒（SARS-CoV-2）疫苗，该疫苗可诱导强效的系统性与黏膜免疫应答。我们的疫苗将均匀展示新冠病毒受体结合域（Receptor Binding Domain, RBD）抗原的、由蛋白源性霍乱毒素B亚基（cholera toxin B subunit, CTB）组装而成的纳米颗粒（R-CNP），封装于具有优化空气动力学粒径（aerodynamic particle size）的微胶囊内，以高效递送至肺泡——即肺部细支气管末端、布满免疫细胞的微小气囊，同时也是新冠病毒已知的感染位点。