嵌合抗原受体（CAR）修饰免疫细胞疗法已成为肿瘤治疗的重要手段。然而肿瘤表面抗原脱落造成的免疫逃逸问题限制了单一靶点CAR疗法的临床应用。本项目拟以NK细胞活化受体NKG2D为元件通过蛋白质结构建模技术理性设计一种集肿瘤免疫抑制逆转和多靶点识别杀伤于一体的新型CAR。所设计NKG2D-CAR可由肿瘤细胞脱落的可溶性NKG2D配体（sNKG2DLs）介导的二聚化进行活化，从而逆转其免疫抑制作用；同时利用NKG2D的多种配体结合特性实现多靶点靶向，最终阻断肿瘤细胞通过sNKG2DLs进行免疫逃逸。本项目将使用所构建NKG2D-CAR修饰临床应用安全且可体外扩增的NK92细胞，赋予其高效广谱的抗肿瘤作用，研究改造后NK92细胞对sNKG2DLs的响应能力（前期实验已证实），并在细胞水平和动物水平考察其抗肿瘤功能，从而为通用型现货式同种异体免疫细胞疗法的临床应用提供新思路和新材料。

Chimeric antigen receptor (CAR) modified immune cell therapy has become an important method for cancer treatment. However, the immune escape caused by tumor surface antigen shedding limits the clinical application of single-target CAR therapy. This project intends to use NK cell activation receptor NKG2D as the element to rationally design a novel CAR that integrates tumor immune suppression reversal and multi-target recognition by transmembrane protein 3D structure modeling. This NKG2D-CAR can be activated by dimerization mediated by soluble NKG2D ligands (sNKG2DLs) shedding from tumor cells, thus reversing the immunosuppressive effect of sNKG2DLs, and simultaneously utilizes multiple ligand binding properties of NKG2D to achieve multi-target targeting and ultimately blocks the immune escape of tumor cells caused by sNKG2DLs. We will use the NKG2D-CAR to modify NK92 cells, which are safe for clinical application and able to be expanded in vitro, to endow them with high-efficiency and broad-spectrum antitumor effect. The responsiveness of NKG2D-CAR-engineered NK92 cells to sNKG2DLs (Confirmed by previous experiments) and their antitumor function at the cellular and animal levels will be investigated in depth. The study will provide new ideas and materials for the clinical application of universal “off-the-shelf” allogeneic immune cell therapy.