De Smet Rebecca, Verschuere Stephanie, Allais Liesbeth, Leclercq Georges, Dierendonck Marijke, De Geest Bruno G, Van Driessche Isabel, Demoor Tine, Cuvelier Claude A
Department of Pathology, Ghent University , 5 Blok A, De Pintelaan 185, 9000 Ghent, Belgium.
Biomacromolecules. 2014 Jun 9;15(6):2301-9. doi: 10.1021/bm5005367. Epub 2014 May 14.
During the past decade, extensive research has undeniably improved the formulation and delivery of oral vaccines. Nevertheless, several factors, such as the harsh gastrointestinal environment together with tolerance induction to exogenous antigens, have thus far impeded the optimal effectiveness and clinical application of oral delivery systems. The current study encompasses an initial evaluation of the stability, biocompatibility, and cellular uptake of two promising candidate systems for oral antigen delivery, that is, calcium carbonate- (CP) and mannitol-templated (MP) porous microspheres. Both spray-dried formulations were efficiently internalized by human intestinal epithelial cells (Caco-2 and HT-29) and degraded into phagolysosomal intracellular compartments. In addition, cellular particle uptake and processing significantly up-regulated the expression of (HLA) class-II and costimulatory molecules on intestinal epithelial cells. Even though the high surface-area-to-volume ratio of the microspheres was expected to favor protease access, antigen release was remarkably limited in simulated intestinal fluid and was even absent under gastric conditions. Finally, neither CP nor MP exerted cytotoxicity upon prolonged in vitro incubation with high antigen concentration. Altogether, these data support the potential of CP and MP for oral antigen delivery and motivate the further development of these promising carrier systems in in vivo studies.
在过去十年中，广泛的研究无疑改善了口服疫苗的配方和递送。然而，诸如恶劣的胃肠道环境以及对外源抗原的耐受性诱导等几个因素，迄今为止阻碍了口服递送系统的最佳有效性和临床应用。当前的研究包括对两种有前景的口服抗原递送候选系统，即碳酸钙（CP）和甘露醇模板化（MP）多孔微球的稳定性、生物相容性和细胞摄取的初步评估。两种喷雾干燥制剂均被人肠上皮细胞（Caco-2和HT-29）有效内化，并降解到吞噬溶酶体细胞内区室中。此外，细胞对颗粒的摄取和处理显著上调了肠上皮细胞上II类主要组织相容性复合体（HLA）和共刺激分子的表达。尽管微球的高表面积与体积比预计有利于蛋白酶的作用，但在模拟肠液中抗原释放非常有限，在胃部条件下甚至没有抗原释放。最后，在高抗原浓度下长时间体外孵育时，CP和MP均未表现出细胞毒性。总之，这些数据支持了CP和MP用于口服抗原递送的潜力，并推动了这些有前景的载体系统在体内研究中的进一步发展。
