肺递送炭疽疫苗干粉气溶胶用以预防吸入性炭疽的研究

Pulmonary vaccination is a most promising immunization route against inhalational anthrax, since pulmonary is the primary entry site of inhaled anthrax spores, and pulmonary vaccination can induce the broadest and most intense local and systemic immunity according to previous researches in other respiratory diseases. However, to our knowledge, researches about pulmonary delivering anthrax vaccines have not been reported yet worldwide. Protective antigen(PA)-based anthrax vaccines were reported to be less effective and need additional antigens to enhance the protection efficacy. As the host pulmonary entry form of inhalational anthrax, anthrax spores are of strong immunogenicity. Therefore, it is expected that recombinant protective antigen (rPA) and formaldehyde-inactivated spores(FIS) co-vaccinate through pulmonary delivery route may induce a rapid and broad immune response, and make a better protective effect. In addition, inhaled dry powder vaccine may also strengthen the immune response. Meanwhile, dry powder formulation have excellent stability characteristics, and can be transported in the absence of a continuous cold chain. This research try to evaluate the protective efficacy of pulmonary delivered rPA+FIS dry powder vaccine to mice against inhalational anthrax, through comparing the immunogenicity and protective effect with other immunization routes and vaccine formulations. This research is the first attempt in the world to discover the possibility and advantage of pulmonary delivery route to prevent inhalational anthrax, it may start a new focus on developing the inhaled anthrax vaccines.

肺是炭疽芽孢入侵的原位器官，在预防其它呼吸道疾病的研究中肺吸入免疫能诱导最广泛且最强的局部与全身免疫，因此肺吸入是预防吸入性炭疽最有前景的免疫途径，但目前国内外鲜有肺吸入炭疽疫苗的报导。有研究表明炭疽保护性抗原PA单独免疫的保护效果不佳，需与其它抗原联合免疫。炭疽芽孢具有较强的免疫原性，且吸入性炭疽是以芽孢形式入侵宿主肺部，因此炭疽保护性抗原（rPA）与灭活芽孢（FIS）经肺吸入途径联合免疫预期能快速诱导较全面的免疫反应，获得更好的免疫保护效果。此外，肺吸入疫苗干粉制剂的应用也可以增强免疫应答，同时具有良好的稳定性，解决了现有疫苗冷链运输的局限性。本研究在优化炭疽疫苗成分（rPA+FIS）、剂型（干粉）以及疫苗佐剂的基础上，通过与其它免疫途径在免疫原性、对炭疽芽孢气溶胶攻毒的保护效果这两发面进行比较研究，探索肺吸入途径免疫吸入性炭疽的可行性及优越性，为炭疽吸入型疫苗的开发奠定基础。

肺是炭疽芽孢入侵的原位器官，在预防其它呼吸道疾病的研究中肺吸入免疫能诱导最广泛且最强的局部与全身免疫，因此肺吸入是预防吸入性炭疽最有前景的免疫途径，但目前国内外鲜有肺吸入炭疽疫苗的报导。此外，肺吸入疫苗干粉制剂的应用也可以增强免疫应答，同时具有良好的稳定性，解决了现有疫苗冷链运输的局限性。本研究在优化炭疽疫苗佐剂、剂型的基础上，通过与其它免疫途径在免疫原性方面进行比较研究，探索肺吸入途径免疫吸入性炭疽的可行性及优越性，为炭疽吸入型疫苗的开发奠定基础。. 本次研究获得以下成果：（1）成功搭建了喷雾冷冻干燥技术平台，并利用该平台成功制备出符合良好可吸入颗粒物特性的炭疽rPA抗原、FIS芽孢干粉吸入制剂，该技术平台可广泛应用于热敏感物质的细微固体颗粒制备，具有一定市场前景；（2）成功建立了小鼠气溶胶肺递送技术，通过该技术可完成液体气溶胶样品的发生，并将其均匀递送至小鼠肺部，为小鼠的吸入毒理及吸入免疫实验提供了可靠、高效的技术平台；（3）证实了肺递送免疫途径全身免疫与局部免疫兼具，诱导的免疫反应强度优于或等于其他免疫途径，是预防吸入性炭疽的优选免疫途径；（4）首次发现黏膜免疫佐剂C48/80与TMC60联用能显著增强黏膜免疫应答，为今后的黏膜免疫研究提供了优秀的佐剂配方参考；（5）通过本次研究，可以得出针对吸入性炭疽的预防，其优化的免疫方案为炭疽疫苗添加TMC60、C48/80佐剂，肺递送气溶胶免疫接种。