Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), 66123 Saarbrücken, Germany; Department of Pharmacy, Saarland University, 66123 Saarbrücken, Germany; Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Ain Shams University, 11566 Cairo, Egypt.
Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), 66123 Saarbrücken, Germany.
Int J Pharm. 2022 Jun 10;621:121794. doi: 10.1016/j.ijpharm.2022.121794. Epub 2022 May 4.
Pneumococcal infections represent a global health threat, which requires novel vaccine developments. Extracellular vesicles are secreted from most cells, including prokaryotes, and harbor virulence factors and antigens. Hence, bacterial membrane vesicles (MVs) may induce a protective immune response. For the first time, we formulate spray-dried gram-positive pneumococcal MVs-loaded vaccine microparticles using lactose/leucine as inert carriers to enhance their stability and delivery for pulmonary immunization. The optimized vaccine microparticles showed a mean particle size of 1-2 µm, corrugated surface, and nanocrystalline nature. Their aerodynamic diameter of 2.34 µm, average percentage emitted dose of 88.8%, and fine powder fraction 79.7%, demonstrated optimal flow properties for deep alveolar delivery using a next-generation impactor. Furthermore, confocal microscopy confirmed the successful encapsulation of pneumococcal MVs within the prepared microparticles. Human macrophage-like THP-1 cells displayed excellent viability, negligible cytotoxicity, and a rapid uptake around 60% of fluorescently labeled MVs after incubation with vaccine microparticles. Moreover, vaccine microparticles increased the release of pro-inflammatory cytokines tumor necrosis factor and interleukin-6 from primary human peripheral blood mononuclear cells. Vaccine microparticles exhibited excellent properties as promising vaccine candidates for pulmonary immunization and are optimal for further animal testing, scale-up and clinical translation.
肺炎球菌感染是全球健康威胁，需要开发新型疫苗。细胞外囊泡是由大多数细胞（包括原核生物）分泌的，其中含有毒力因子和抗原。因此，细菌膜囊泡（MVs）可能会引起保护性免疫反应。我们首次使用乳糖/亮氨酸作为惰性载体，制备喷雾干燥的革兰氏阳性肺炎球菌 MVs 负载的疫苗微球，以提高其稳定性和用于肺部免疫接种的递呈效率。优化的疫苗微球粒径为 1-2μm，表面呈波纹状，具有纳米结晶性质。它们的空气动力学直径为 2.34μm，平均发射剂量百分比为 88.8%，细粉分数为 79.7%，使用下一代撞击器显示出了用于深肺泡递呈的最佳流动特性。此外，共聚焦显微镜证实了肺炎球菌 MVs 成功包封在制备的微球中。人巨噬细胞样 THP-1 细胞表现出良好的活力，细胞毒性可忽略不计，在与疫苗微球孵育后，约有 60%的荧光标记 MVs 被迅速摄取。此外，疫苗微球增加了原代人外周血单核细胞中促炎细胞因子肿瘤坏死因子和白细胞介素-6 的释放。疫苗微球具有良好的性质，有望成为肺部免疫接种的候选疫苗，非常适合进一步的动物试验、放大和临床转化。
