Functional Activity Of Humanized PD-L1 Monoclonal Antibody And Its Toxic Effects On Human Lung Adenocarcinoma Cell Line HCC827

Purpose To explore the functional activity of self-developed human humanized PD-L1monoclonal antibody and its toxicity to human lung adenocarcinoma cell line HCC827.Methods Sodium dodecyl sulfate polypropylene gel electrophoresis（SDS-PAGE）was used to identify the purity of Atezolizumab and self-developed PD-L1 monoclonal antibody（mAb）;The binding and competitive blocking activity of the self-developed PD-L1 mAb were determined by enzyme linked immunosorbent assay（ELISA）with Atezolizumab as a positive control;Cell blocking activity of two antibody was measured by cell interruption test;Flow cytometry（FACS）was used to detect the expression of PD-L1 on the surface of human lung adenocarcinoma cell lines A549 and HCC827;Human lung adenocarcinoma HCC827 cells were used as target cells,and human peripheral blood mononuclear cells were used as effector cells,Antibody dependent cell-mediated cytotoxicity（ADCC）effects were detected in atezolizumab and self-developed PD-L1 mAb,respectively.Results High purity Atezolizumab and self-developed PD-L1 mAb were identified by SDS-PAGE;ELISA showed that both self-developed PD-L1 mAb and Atezolizumab could bind to human PD-L1 and block the binding of PD-L1 to PD-1;The results of cell interruption test showed that the self-developed PD-L1 mAb and Atezolizumab could block the binding of PD-L1 and PD-1 on the surface of two cells,EC₅₀ were 0.2085ug/ml and 0.1548 ug/ml,respectively,There was no significant differences in certain concentration;FACS results showed that high expression of PD-L1 in human lung adenocarcinoma HCC827 cells and low expression of PD-L1 in A549 cells;Cytotoxicity experiments showed that when the ratio between effector cells and target cells was constant,the self-developed PD-L1 mAb and Atezolizumab had a certain toxic effects on human lung adenocarcinoma HCC827 cells.Conclusions The self-developed PD-L1 monoclonal antibody has certain functional activity,it can block the T cell receptor signal which is weakened by binding of PD-L1and PD-1 on the cell surface,and can also exert a certain antitumor effect through the ADCC effect.