新型pDC疫苗联合多种作用方式抗多发性骨髓瘤免疫效应研究

Cellular immunotherapy such as that initiated by myeloid dendritic cell (mDC) vaccine is capable of eradicating cancer stem cells and restoring the homeostasis imbalance, and therefore has emerged as a promising approach to cure multiple myeloma (MM). However, the satisfactory therapeutic benefits of mDCs observed in vitro and in vivo (animal) studies could barely be recapitulated in clinical settings. Thus, it is imperative to improve the therapeutic potential of mDCs, or alternative approaches must be explored. It was recently found that plasmacytoid dendritic cells (pDCs), which are mainly involved in the initial immune response, possess a similar biological function to mDCs in the secondary immune response under certain circumstances. Our previous studies have showed that the pDCs activated by bacteria possess such a functional plasticity. In this project, we aim to explore the therapeutic potential of pDCs for MM. Highly purified pDCs will be obtained through a combination of immunomagnetic beads and antibody based flow cytometric sorting. The isolated pDCs will be stimulated with pseudomonas aeruginosa and conjugated with MM specific antigen peptide DKK1. The biological activity of the generated pDC vaccine will be examined by testing its effect on cellular phenotype, cytokine secretion, T cell proliferation, and generation of DKK1-specific CTLs. Further studies will be conducted using the APS extract (Astragalus polysaccharide, a Chinese herbal medicine with demonstrated immune boosting activity), NK cells and GM-CSF as adjuvants to enhance the antigen presenting ability of the pDC vaccine.

mDC（髓样树突细胞）疫苗等细胞免疫治疗因能消灭肿瘤干细胞或纠正免疫失衡，有望治愈多发性骨髓瘤（MM）。虽然mDC体外及动物实验结果良好，但临床疗效欠佳，且异质性大，急需改进或寻找新型免疫疗法。新近发现主导初始免疫的pDC（浆样树突细胞）在某种情形下具有和mDC类似的继发免疫效应（功能可塑性），我们前期发现经细菌活化的pDC具有该可塑功能。为探讨pDC能否作为治疗肿瘤的新型疫苗，本研究借助免疫磁珠联合流式细胞双分选技术获得高纯度pDC，经细菌活化并负载MM特异性抗原肽DKK1，通过细胞表型分析及细胞因子检测、T细胞增殖实验及四聚体技术检测DKK1特异性CTL，构建具有抗原递呈功能的pDC疫苗，并观察黄芪多糖等佐剂能否进一步增强疫苗的功能；以及探讨pDC疫苗抗MM免疫效应。

从项目立项2014年1月1日开始至2014年12月31日课题组严格按照原定项目计划实施，以兰州大学第二医院血液病研究所、生物技术医学转化中心作为科研平台，借助免疫磁珠联合流式细胞双分选技术获得高纯度pDC，经细菌活化并负载MM特异性抗原肽DKK1，通过细胞表型分析及细胞因子检测、T细胞增殖实验及四聚体技术检测DKK1特异性CTL，构建具有抗原递呈功能的pDC疫苗，并观察黄芪多糖等佐剂能否进一步增强疫苗的功能；以及探讨pDC疫 苗抗MM免疫效应，并将研究成果在国内核心期刊杂志发表。