Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, 1300 S. Coulter St., Amarillo, Texas, 79106, USA.
Pharm Res. 2010 May;27(5):905-19. doi: 10.1007/s11095-010-0094-x. Epub 2010 Mar 16.
To test the hypothesis that particle size influences the magnitude of immune response produced by hepatitis B surface antigen (HBsAg) encapsulated in poly (lactic-co-glycolic acid) (PLGA) microspheres.
Microspheres were prepared by a double-emulsion-solvent-evaporation method, and the particles were characterized for size, morphology, porosity and antigen content. Immunogenicity of encapsulated antigen and safety were studied in rats. Uptake of fluorescent-labeled particles by rat alveolar macrophages was studied by confocal microscopy.
With increasing internal aqueous phase (IAP) volume of the microsphere, an increase in particle size and a decrease in particle density were observed. Particles with varying geometric diameters showed aerodynamic diameters between 1 and 6 mu. Addition of poly vinyl alcohol to the IAP resulted in particles with a porous surface. The integrity of HBsAg was maintained upon encapsulation in microspheres. Continuous release of the antigen was observed for formulations incubated in phosphate-buffered saline for 28 days. Immunogenicity increased as a function of particle size upon pulmonary administration. HBsAg encapsulated in approximately 5 mum particles elicited a significantly higher immune response compared to that encapsulated in approximately 12 mum particles. Similar to in vivo immune response data, fluorescent-labeled microspheres of smaller size were taken up more efficiently by rat alveolar macrophages compared to those of larger size. No significant increase in either tumor necrosis factor alpha level in bronchoalveolar lavage fluid or wet lung weight, indicators of inflammation, was observed in rats that received optimized formulations via the pulmonary route.
HBsAg delivered in PLGA microspheres elicited an increase in immunogenicity, and the magnitude of immune response was more pronounced with smaller particles. Inhalable particles of HBsAg could be a viable approach to needle-free vaccination.
检验这样一个假设，即乙肝表面抗原（HBsAg）被包裹在聚（乳酸-共-乙醇酸）（PLGA）微球中，其颗粒大小会影响免疫反应的强度。
通过双乳液-溶剂蒸发法制备微球，并对其粒径、形态、孔隙率和抗原含量进行了表征。在大鼠中研究了包裹抗原的免疫原性和安全性。通过共焦显微镜研究了荧光标记的颗粒被大鼠肺泡巨噬细胞的摄取情况。
随着微球内部水相（IAP）体积的增加，观察到颗粒粒径增大，颗粒密度降低。具有不同几何直径的颗粒显示出 1 至 6 微米之间的空气动力学直径。在 IAP 中添加聚乙烯醇可使颗粒表面多孔。HBsAg 在包裹于微球中时保持完整性。在磷酸盐缓冲液中孵育 28 天后，观察到抗原的持续释放。通过肺部给药，抗原的免疫原性随着颗粒大小的增加而增加。与包裹在约 12 微米颗粒中的抗原相比，包裹在约 5 微米颗粒中的 HBsAg 引发了更高的免疫反应。与体内免疫反应数据相似，与较大粒径的荧光标记微球相比，较小粒径的微球更有效地被大鼠肺泡巨噬细胞摄取。通过肺部途径给予优化配方的大鼠，支气管肺泡灌洗液中肿瘤坏死因子-α水平或湿肺重量均无明显升高，这是炎症的指标。
PLGA 微球中递送的 HBsAg 引发了免疫原性的增加，并且较小的颗粒引起的免疫反应强度更大。可吸入的 HBsAg 颗粒可能是一种可行的无针接种方法。
