肿瘤全细胞疫苗进入临床试验后效果并不理想，需要寻找新的制备方法。Toll样受体(TLRs)是特异与非特异免疫反应的桥梁，CpG ODN(DNA)是TLR9 的配体和常用的免疫佐剂。免疫吞噬细胞通过一种以DNA为主要成分的胞外诱捕网(ETs)结构，将病原体或细胞包裹从而将包裹物清除并诱导免疫反应。研究还发现封闭肿瘤细胞CD47分子可以促使免疫细胞通过阻断SIRPα通路吞噬肿瘤细胞并诱导免疫反应。因此，本项目利用自主技术将CpG ODN粘附于肿瘤细胞表面(ETs化，同时封闭CD47)。在体外研究这种ETs化肿瘤细胞的理化特征和功能活性后将其用作全细胞疫苗，在肿瘤模型小鼠中了解其治疗肿瘤的效果和副作用，同时了解这种ETs化肿瘤细胞疫苗是否通过TLR9和CD47/SIRPα通路诱导特异的抗肿瘤免疫反应和肿瘤免疫原性死亡，是否改变免疫微环境等分子机理，为ETs化肿瘤细胞疫苗的转化应用提供理论依据。

Various whole-tumor cell vaccines have been developed and some of them have been tested in III clinical trials, but their clinic effectiveness is unsatisfactory for tumor patients. Therefore, more innovative strategies must be found to develop new whole-tumor cell vaccines. Toll-like receptors (TLRs) expressed on the phagocyte surfaces are the bridge between innate and adaptive immune responses. CpG ODN (DNA) is one of the ligands for TLR9 and an effective adjuvants used in many types of traditional and newly developed vaccines at present. Extracellular traps (ETs) are produced by several immune cells including neutrophils, eosinophils, mast cells, monocytes and macrophages. The release of ETs results in extrusion of a fibrous network of nuclear DNA, histones and a concentration of granular proteins. ETs have been implicated in a growing number of human diseases with beneficial roles in bacterial and fungal infections and deleterious roles in autoimmunity. In addition, previous studies have identified CD47, a cell-surface molecule, as a “marker of self” that prevents cells of the innate immune system from attacking tumors. CD47 acts by sending inhibitory signals through SIRPα, a receptor expressed on the surface of macrophages and other myeloid cells. In this sense, the CD47/SIRPα interaction serves as a myeloid-specific immune checkpoint, and blocking the interaction lowers the threshold for macrophage phagocytosis of cancer. Thus, in this study, we will use our proprietary technology to adhere the CpG ODN on the tumor cell surface (we called these tumor cells as ETs tumor cells), through which CpG ODN can act with TLR9 on DCs (including other APCs) and covered the CD47 on the tumor cells, leading to promote immune system to induce phagocytosis of tumor cells and presentation of the tumor cell antigens. After in vitro investigate the physico-chemical characteristics and functional activities of the ETs tumor cells, we will further use the ETs tumor cells as a whole-tumor cell vaccine to investigate their anti-tumor effects and potential side-effects in mouse tumor models. Moreover, we will study its immune mechanisms, including whether TLR9 and CD47/SIRPα pathways were involved in. Lastly, the immune mechanisms especially those that involved to antigenic cell death and micro-environment will also be investigated. Thus, our current study will potentially offer a new approach to develop an effective whole-tumor cell vaccine.