Wang Lixin, Barclay Thomas, Song Yunmei, Joyce Paul, Sakala Isaac G, Petrovsky Nikolai, Garg Sanjay
School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, Australia.
Future Industries Institute, University of South Australia, Adelaide, Australia.
Vaccine. 2017 Aug 3;35(34):4382-4388. doi: 10.1016/j.vaccine.2017.06.045. Epub 2017 Jul 1.
Insoluble, nanostructured delta inulin particles enhance the immunogenicity of co-administered protein antigens and consequently are used as a vaccine adjuvant (Advax™). To better understand their immunomodulatory properties, the in vitro hydrolysis and in vivo distribution of delta inulin particles were investigated. Delta inulin particle hydrolysis under bio-relevant acidic conditions resulted in no observable change to the bulk morphology using SEM, and HPLC results showed that only 6.1% of the inulin was hydrolysed over 21days. However, 65% of the terminal glucose groups were released, showing that acid hydrolysis relatively rapidly releases surface bound chemistries. This was used to explain in vivo biodistribution results in which delta inulin particles surface-labelled with fluorescein-5-thiosemicabizide were administered to mice using intramuscular (I.M.) or subcutaneous (S.C.) routes. Comparison analysis of the fluorescence of soluble inulin in the supernatants of homogenised tissues maintained at room temperature or heated to 100°C to solubilise particulate inulin was used to distinguish between fluorescent probe on soluble inulin and probe bound to inulin within particles. Following both I.M. and S.C. injection delta inulin exhibited a depot behaviour with local injection site residence for several weeks. Over this time, as injection site inulin reduced, there was measurable transport of intact delta inulin particles by macrophages to secondary lymphoid organs and the liver. Ultimately, the injected delta inulin became solubilised resulting in its detection in the plasma and in the urine. Thus injected delta inulin particles are initially taken up by macrophages at the site of injection, trafficked to secondary lymphoid tissue and the liver, and hydrolysed resulting in their becoming soluble and diffusing into the blood stream, from whence they are glomerularly filtered and excreted into the urine. These results provide important insights into the biodistribution of I.M. or S.C. injected delta inulin particles when used as vaccine adjuvants and their method of excretion.
不溶性纳米结构的δ-菊粉颗粒可增强共同给药的蛋白质抗原的免疫原性，因此被用作疫苗佐剂（Advax™）。为了更好地了解其免疫调节特性，对δ-菊粉颗粒的体外水解和体内分布进行了研究。在生物相关酸性条件下，δ-菊粉颗粒的水解通过扫描电子显微镜（SEM）观察，其整体形态没有明显变化，高效液相色谱（HPLC）结果显示，在21天内只有6.1%的菊粉被水解。然而，65%的末端葡萄糖基团被释放，表明酸水解相对迅速地释放了表面结合的化学物质。这被用于解释体内生物分布结果，即通过肌肉注射（I.M.）或皮下注射（S.C.）途径将用荧光素-5-硫代半卡巴腙表面标记的δ-菊粉颗粒注射到小鼠体内。通过比较分析在室温下保持或加热到100°C以溶解颗粒状菊粉的匀浆组织上清液中可溶性菊粉的荧光，来区分可溶性菊粉上的荧光探针和与颗粒内菊粉结合的探针。在肌肉注射和皮下注射后，δ-菊粉都表现出一种储存行为，在局部注射部位停留数周。在此期间，随着注射部位菊粉的减少，巨噬细胞可将完整的δ-菊粉颗粒运输到次级淋巴器官和肝脏，且可检测到这种运输。最终，注射的δ-菊粉溶解，导致其在血浆和尿液中被检测到。因此，注射的δ-菊粉颗粒最初在注射部位被巨噬细胞摄取，运输到次级淋巴组织和肝脏，并被水解，从而变得可溶并扩散到血流中，从那里它们被肾小球滤过并排泄到尿液中。这些结果为将肌肉注射或皮下注射的δ-菊粉颗粒用作疫苗佐剂时的生物分布及其排泄方法提供了重要见解。
