CAR-T细胞疗法在治疗淋巴系统肿瘤中取得显著效果，但是存在可用靶点不多、靶点逃逸和CAR-T细胞耗竭等导致疾病复发等问题。由于CAR-T细胞核心部分单链抗体可变区基因片段（scFv）多是由噬菌体展示技术筛出，得到的主要是高亲和力抗体，在整合到T细胞并表达时，可能存在激活过弱、容易耗竭、持续性较差等问题，因此我们拟在噬菌体展示技术的基础上，引入细胞功能实验和高通量测序技术，实现直接的功能最优筛选，以CAR-T细胞的增殖能力、靶细胞刺激后T细胞活化和杀伤通路的激活水平等作为筛选指标，筛选出功能更好的scFv，避免了传统筛选方法可能造成的亲和力偏低但功能更好的scFv的漏筛。基于此筛选系统，以CD70为靶点，筛选其全人源scFv构建CAR-T细胞，并在细胞水平和动物水平测试其各项功能，为CD70阳性淋巴系统肿瘤的新的靶点治疗方案提供依据。

Chimeric antigen receptor (CAR) T cell immunotherapy has achieved great success in lymphocytic malignancies but still suffers from targets limitation, antigen escape, T-cell exhaustion and/or depletion. Since single chain variable fragment (scFv) as one of the vital parts of CAR T-cell is commonly screened by phage display, higher affinity candidates are screened out but which are probably not the functional best after they have been integrated in T cells, behaving as weak or no activation, easy exhaustion or depletion. Hence, we intend to screen functionally best scFvs directly by combining phage display and T-cell functional assays, and utilizing high throughput sequencing technologies to accurately quantify enriched scFvs and obtain scFvs sequences. Functional assay screening is mainly based on proliferative potentiality and cytotoxicity associated pathways activation, which favors of scFvs that boost T cell functions regardless of stronger or weaker affinity. On the new integrated screening platform, fully human anti-CD70 scFvs will be screened for preparation of CD70 targeting CAR T-cells and followed with performing ex vivo and in vivo assays to provide the information of effectiveness and safety about CAR T-cell therapy targeting CD70 on CD70 positive lymphocytic malignancies.