Duc Le H, Hong Huynh A, Atkins Helen S, Flick-Smith Helen C, Durrani Zarmina, Rijpkema Sjoerd, Titball Richard W, Cutting Simon M
Royal Holloway University of London, Egham, Surrey TW20 0EX, UK.
Vaccine. 2007 Jan 4;25(2):346-55. doi: 10.1016/j.vaccine.2006.07.037. Epub 2006 Aug 4.
Protective immunity to anthrax can be achieved by antibodies raised against the secreted protective antigen (PA) and this forms the basis of the current acellular vaccines for human use. Bacillus subtilis spores have previously been used for delivery of heterologous antigens by the oral and nasal routes and their intrinsic heat-stability make them attractive vaccine vehicles. In this study we have expressed PA, or segments of PA, in B. subtilis using two strategies. First, display on the spore coat, and second, in the germinated spore (or vegetative cell). Using parenteral delivery we show that recombinant spores can be used to confer protective immunity in a murine model using an in vitro toxin neutralization assay and a challenge experiment with the latter showing protection to 100 median lethal dose of B. anthracis spores. PA must be secreted from the live bacterium or alternatively displayed on the spore surface to confer protective immunity. Intracellular expression of PA failed to confer protective immunity. The highest levels of protective immunity were achieved when PA was displayed on the spore surface as well as in the germinating spore.
通过针对分泌型保护性抗原（PA）产生的抗体可实现对炭疽的保护性免疫，这构成了当前用于人类的无细胞疫苗的基础。枯草芽孢杆菌孢子此前已被用于通过口服和鼻内途径递送异源抗原，其固有的热稳定性使其成为有吸引力的疫苗载体。在本研究中，我们使用两种策略在枯草芽孢杆菌中表达PA或PA片段。第一，展示在芽孢衣上；第二，展示在萌发的孢子（或营养细胞）中。通过肠胃外给药，我们表明重组孢子可用于在小鼠模型中赋予保护性免疫，使用体外毒素中和试验以及挑战实验，后者显示对100个炭疽芽孢杆菌孢子的半数致死剂量具有保护作用。PA必须从活细菌中分泌出来，或者展示在孢子表面才能赋予保护性免疫。PA的细胞内表达未能赋予保护性免疫。当PA展示在孢子表面以及萌发的孢子中时，可实现最高水平的保护性免疫。
