Construction and expression of chimeric antigen receptors targeting epidermal growth factor receptor (EGFR) and programmed cell death ligand-1(PD-L1)
10.3760/cma.j.cn112309-20191105-00365
- VernacularTitle:EGFR和PD-L1双靶向嵌合抗原受体构建及表达
- Author:
Shuping LI
1
;
Xiaojue WANG
;
Bin YANG
;
Helin WANG
;
Zhuohong YAN
;
Ling YI
;
Panjian WEI
;
Xin JIN
;
Jianqing HAO
;
Hongtao ZHANG
Author Information
1. 北京市结核病胸部肿瘤研究所中心实验室 101149
- From:
Chinese Journal of Microbiology and Immunology
2020;40(3):198-205
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To construct an expression system of lentivirus vector encoding epidermal growth factor receptor-specific chimeric antigen receptor (EGFR-CAR) and programmed cell death ligand-1 (PD-L1) antibody.Methods:Human PD-L1-Fc protein was used to immunize BALB/c mice. Cell-fusion and subcloning were performed to screen stable hybridoma strains with high secretion of PD-L1-specific antibodies, which were identified by both ELISA and Western blot. The activity of the antibodies in blocking the binding of programmed cell death-1 (PD-1) to PD-L1 was determined by fluorescence-activated cell sorting (FACS). Antibody affinity was analyzed by Fortebio Octet96. A single-chain variable fragment (scFv) was further constructed after antibody full-length sequencing and humanization using CDR grafting method. Meanwhile, the genes encoding the light and heavy chain variable regions (VL and VH) were cloned from a hybridoma secreting antibody against human EGFR by 5′ RACE technology to construct scFv gene. The expression of scFv was confirmed using pcDNA3.1 vector. EGFR-CAR containing CD137 intracellular function domain and PD-L1-scFv was ligated using 2A gene. The synthetic single molecule was cloned into pLVX-EF1a-IRES-ZsGreen1 lentivirus expression vector, and then transfected into 293T cells using Lenti-X Packaging Single Shots (VSV-G) to prepare infectious virus. Expression of CAR on cell surface and the soluble form of PD-L1-scFv in the supernatant of transfected 293V cells were detected by FACS and ELISA.Results:A PD-L1 antibody named 11E3 with high ligand-receptor blocking performance was obtained. The humanized antibody showed a stable affinity (2.67×10 -10 mol/L) after directly grafting the mouse CDRs (CDR1, CDR2 and CDR3) to human frameworks. EGFR-scFv was effectively expressed in a form of Fc-fusion. Secretory CAR (CTZ0431-1) and membrane CAR (CTZ0431-2) expression plasmids were constructed using lentivirus vector containing EGFR-CAR and PD-L1-scFv. The infection efficiency in 293V cells was around 10%. EGFR-scFv on the cell membranes and PD-L1-scfv in the culture supernatants were detected after 293V cells were infected with CTZ0431-1. EGFR-scFv and PD-L1-scfv were expressed on the cell membranes of 293V cells infected with CTZ0431-2. The expression rate of CAR in LV-CART46407-1-transfected activated T cells was 39.3%. Conclusions:The lentivirus vectors co-expressing EGFR-CAR with moderate binding affinity and PD-L1-scFv with high binding affinity were successful constructed, which provided an essential tool for investing EGFR- and PD-L1 double targeted CAR-T cell therapy against solid tumor.
