Le Pecq Jean-Bernard
Anosys Inc. 1014 Hamilton Court, Menlo Park, CA 94025, USA.
Blood Cells Mol Dis. 2005 Sep-Oct;35(2):129-35. doi: 10.1016/j.bcmd.2005.06.003.
Exosomes released from dendritic cells, now referred as dexosomes, have recently been extensively characterized. Preclinical studies in mice have shown that, when properly loaded with tumor antigens, dexosomes can elicit a strong antitumor activity. Before dexosomes could be used in humans as a therapeutic vaccine, extensive development work had to be performed to meet the present regulatory requirements. First a manufacturing process amenable to cGMP for isolating and purifying dexosomes was established. Methods for loading the Major Histocompatibility Complex (MHC) molecules class II and I in a quantitative and reproducible way were developed. The most challenging task was the establishment of a quality control method for accessing the biological activity of individual lots. Such a method must remain relatively simple and reflect the mechanism of action of dexosomes. This was accomplished by measuring the transfer of a MHC class II superantigen complex to an antigen presenting cell that was MHC class II negative. More than 100 separate dexosome lots were prepared from blood cells of healthy volunteers to evaluate the variability of the manufacturing process. The analysis of the data showed that the main source of variability was related to the heterogeneity of the human population and not to the manufacturing process. These studies allowed to perform two phase I clinical trials. A total of 24 cancer patients received Dex therapy. Dexosome production from cells of cancer patient was found equivalent to that of normal volunteer. No adverse events related to this therapy were reported. Evidence of dexosome bioactivity was observed.
从树突状细胞释放的外泌体，现在被称为树突状细胞外泌体，最近已得到广泛的表征。在小鼠身上进行的临床前研究表明，当正确装载肿瘤抗原时，树突状细胞外泌体可以引发强大的抗肿瘤活性。在树突状细胞外泌体能够作为治疗性疫苗用于人类之前，必须进行大量的研发工作以满足当前的监管要求。首先，建立了一种适用于cGMP的用于分离和纯化树突状细胞外泌体的生产工艺。开发了以定量且可重复的方式装载主要组织相容性复合体（MHC）II类和I类分子的方法。最具挑战性的任务是建立一种用于评估各批次生物活性的质量控制方法。这样的方法必须保持相对简单，并反映树突状细胞外泌体的作用机制。这是通过测量MHC II类超抗原复合物向MHC II类阴性的抗原呈递细胞的转移来实现的。从健康志愿者的血细胞中制备了100多个单独的树突状细胞外泌体批次，以评估生产过程的可变性。数据分析表明，可变性的主要来源与人群的异质性有关，而不是与生产过程有关。这些研究使得能够进行两项I期临床试验。共有24名癌症患者接受了树突状细胞外泌体治疗。发现从癌症患者细胞中产生的树突状细胞外泌体与正常志愿者的相当。未报告与该治疗相关的不良事件。观察到了树突状细胞外泌体生物活性的证据。
