New progress in diagnosis and treatment of drug-resistant cytomegalovirus infection in transplant recipients / 中华器官移植杂志

This article summarizes the new progress in the diagnosis and treatment strategies on drug-resistant cytomegalovirus(CMV)infections in organ transplant recipients, including the prevention and treatment medications for CMV infection, the diagnosis and treatment strategies, and the immunological treatment regimen for drug-resistant CMV infection.The article is aimed to provide references for the prevention and treatment of drug-resistant CMV infection in organ transplant recipients.

Construction and expression of chimeric antigen receptors targeting epidermal growth factor receptor (EGFR) and programmed cell death ligand-1(PD-L1) / 中华微生物学和免疫学杂志

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.