摘要/Abstract
肿瘤的免疫疗法是利用人体自身的免疫系统去治疗肿瘤的一种方法，程序性死亡受体1（PD-1）是肿瘤免疫疗法中的一种免疫检查点，利用PD-1或PD-L1的单克隆抗体，可以阻断PD-1/PD-L1信号通路，恢复T细胞的免疫杀伤功能，实现肿瘤的免疫治疗.为了研究PD-1抗体药物与人体PD-1抗原的结合有效性，以PD-1蛋白质分子为实验对象，用纳米孔传感器件开展了PD-1、PD-1抗体及其结合物的辨识.分别对纯PD-1蛋白质分子和其抗体分子进行了纳米孔过孔实验研究，发现PD-1及其抗体的相对堵塞电流幅值比分别为0.00404和0.01297，实现了抗原抗体分子的区分.并对Si3N4纳米孔内壁进行了PD-1抗体修饰，再将PD-1蛋白质分子通过经抗体修饰后的纳米孔，以期实现结合物的检测，实验结果显示部分抗原抗体实现了特异性结合，剩下部分呈游离状，所以纳米孔技术可实现抗原抗体结合物的区分.未来，纳米孔有望成为无标志检测药物有效性的一种新手段.
关键词: 纳米孔, 程序性死亡受体1(PD-1), 抗体, 抗原, 无标志
Immunotherapy for cancer is a method to treat cancer by using the body's own immune system. Programmed death receptor 1 (PD-1) is one of the checkpoints in the immunotherapy. The signal pathway PD-1 (programmed death receptor 1)/PD-L1 (ligand of PD-1) is closely related to the immune escape of the cancer cells. The inhibitor drugs for PD-1 checkpoint, essentially the monoclonal antibodies of PD-1 or PD-L1 which is essentially the immune checkpoints inhibitors could block the PD-1/PD-L1 pathway and reactivate T-cells to kill cancer cells, and as a result, the immunotherapy for cancer is realized. In order to study the binding process of PD-1 drugs and PD-1 antigen in vivo, in this work, solid-state nanopore as a single molecule method is used to detect the binding of PD-1 antibody and antigen. The PD-1 antibody as well as antigen is driven though the same nanopore under the same experimental condition by the external electric field. Since the antibody's block is about 0.01297 while the antigen's block is 0.00404, the PD-1 antibody is distinguished with the PD-1 antigen according to the theoretical formula. Driving the PD-1 antigen though the nanopore modified by PD-1 antibody (a series of experiments are conducted for characterization) under the same temperature and buffer concentration, the antibody-antigen complexes are detected and distinguished with PD-1 protein and its antibody through the relative current drop analysis and the current drop achieved before. The results suggest that the antibody and antigen have a specific binding (the smaller peak represents the free PD-1 antibody and antigen) and the binding process can be detected by nano-sensors. So the nanopore is able to distinguish the antibody, the antigen and the complexes without any labling. And in the future, the nanopore technology may be a rapid and label-free way for patients and doctors to evaluate the drugs' efficiency.
Key words: nanopore, programmed death receptor 1 (PD-1), antibody, antigen, label-free
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