DKK1肽链疫苗的抗骨髓瘤作用及其机制研究

Dickkopf-1 (DKK1) is shown to play important roles in regulating multiple myeloma(MM)and MM pathogenesis. Moreover, DKK1 is broadly expressed in myeloma but not expressed in most of the normal tissues, these evidence together make DKK1 an ideal target for immunotherapy on MM. Our previous study clearly show that mouse DKK1-DNA vaccine protects mice from myeloma and is also therapeutic against established myeloma, furthermore our preliminary results demonstrate that human DKK1 long peptide harboring a number of T cell epitopes is able to induce specific expansion of both CD8+T and CD4+T cells. In the current study we intend to investigate potential effects of DKK1 vaccine on stimulating expansion of specific T cells including both CD8+T and CD4+T cells, and its therapeutic effects on myeloma in animal models; to explore putative effects of Lenalidomide and/or B7H1 blocking antibody on enhancing the specific immune response induced by the DKK1 vaccine and on inhibiting expansion of regulatory T cells as well as Th2 type cells. It is undoubtedly that the success of such study on DKK1 vaccine will create solid knowledge for developing further clinical trials of DKK1 vaccine on MM.

Dickkopf-1 (DKK1)在多发性骨髓瘤（MM）发生和MM细胞生长方面起重要作用。DKK1在MM广泛表达，而大多数正常组织不表达，这些特性表明DKK1应是理想免疫治疗MM的靶分子。我们前期研究发现鼠源性DKK1 DNA疫苗可诱导体内抗骨髓瘤作用(Qian, Blood 2012)。合成肽疫苗工艺较简单，且安全性好。本研究是在我们前期研究的基础上探索含有多个MHC-I和MHC-II限制性T细胞表位的DKK1长肽(DKK1-3-76长肽)疫苗诱导特异性CD8+T和CD4+T细胞应答的作用，及其体内抗骨髓瘤细胞的作用；分别研究来那度胺和B7H1阻断性抗体对DKK1长肽疫苗诱导的特异性免疫反应和抗骨髓瘤细胞作用的协同效应，以及它们体外和体内抑制调节性T细胞和Th2 CD4+T细胞扩增的作用。本研究旨在为DKK1长肽疫苗用于治疗MM的临床研究提供重要的实验依据和理论基础。

Dickkopf-1（DKK1）在多发性骨髓瘤（MM）发生和MM细胞生长方面起重要作用。DKK1在MM广泛表达，而大多数正常组织不表达，这些特征表面DKK1应是理想免疫治疗MM的靶分子。本研究探索了含有多个MHC-I和MHC-II限制性T细胞表位的DKK1长肽疫苗诱导特异性CD8+T和CD4+T细胞应答的作用，及其体内抗骨髓瘤细胞的作用。为了开发针对所有骨髓瘤患者以及其他具有骨损伤的癌症的DKK1-DC疫苗，我们鉴定了包含74个氨基酸和可能与所有主要MHC I类和II类表位潜在结合的长肽DKK13-76分子。使用HLA-A2转基因小鼠模型，我们发现DKK13-76特异性CTL和DKK1特异性CD4+T细胞是通过DKK13-76肽链在体内交叉呈递诱导的。此外，DKK13-76肽链增强了HLA-A2转基因小鼠和多发性骨髓瘤（MM）患者的外周血单核细胞（PBMC）中特异性CTL的诱导。此外，我们发现DKK13-76肽链可以诱导HLA-A2转基因小鼠的体液免疫，并且DKK1抗体抑制破骨细胞的形成。本研究旨在为DKK1长肽疫苗用于治疗MM的临床研究提供重要的实验依据和理论基础。