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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.
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Objective To establish a human lung cancer cell line that can stably express firefly luciferase (Fluc) and red fluorescent protein (RFP) gene so as to lay the foundation for the further establishment of a live-imaging lung cancer xenograft model in nude mice and therapeutic research.Methods The lentiviral vector pHBLV-FlucRFP containing luciferase and red fluorescent protein was constructed and then transfected into 293T cells for virus packaging.The complete virus was used to infect human lung cancer cell lines A549,H1975 and human B-cell lymphoma cell line K562.The stable cell lines were obtained by puromycin selection.Fluorescence microscopy and quantitative PCR were used to confirm the RFP and Fluc expression.Results The lentiviral vector pHBLV-FlucRFP was successfully constructed.Cancer cell line A549,H1975 and K562 stably expressing Fluc and RFP was obtained.The real-time quantitative PCR results showed that the relative expression of Fluc gene in the three stable infected cells was much higher than that in the corresponding wild-type cells,and the differences were statistically significant(all P＜0.05).Conclusion The human lung cancer cell line A549,H1975 and human B-cell lymphoma cell line K562 with dual expression of RFP and Fluc were obtained,which provided a new model of fluorescent cells for in vivo imaging of immunodeficient mouse models such as nude mice.
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Objective To explore the value of IFN-γ produced or secreted by CD+4 T Lymphocytes from pleural effusion mononuclear cells for the diagnosis of tuberculous pleurisy(plTB).Methods The PEMCs of 40 patients with tuberculous pleural effusion and 30 patients with malignancy pleural effusion were selected as the tuberculosis and disease control groups, then co-cultured with the early secretory antigenic target 6 (ESAT-6) and culture filtered protein 10 (CFP-10) fusion protein (E/C).The numbers of spot forming cells(SFC) secreting IFN-γ were enumerated by ELISpot and the ratios of cells producing IFN-γ were detected by flow cytometry and intracellular cytokine staining.Moreover, the two indicators were compared between tuberculosis and disease control groups to evaluate the 2 methods detecting IFN-γ in the diagnosis of plTB.Results After E/C stimulation, the numbers of SFC were 205(125-450)SFC/5×104 PEMC in tuberculosis group and 5(2-18)SFC/5×104 PEMC in disease control group by ELISpot.The difference between two groups was statistically significant (U= 20.00, P<0.01).The proportion of IFN-γ-secreting CD+4 T lymphocytes was 3.27% (1.81%-7.34%) in tuberculosis group and 0.12% (0.06%-0.46%) in control group detected by FCM. The difference between the two groups was statistically significant (U=45.00, P<0.01).The indicators of ELISpot in detection of IFN-γ which was secreted by PEMC after co-cultured with E/C were as follows: sensitivity 92.5% (37/40), specificity 80.0% (24/30), positive predictive value 0.86, negative predictive value 0.89, positive likelihood ratio 4.63, negative likelihood ratio 0.09 and accuracy 87.1%;and for FCM, they were 87.5% (35/40), 90.0% (27/30), 0.92, 0.84, 8.75 and 0.14, respectively and accuracy 88.6%.Conclusion After E/C stimulation, the assay for IFN-γ-secreting CD+4 T lymphocytes by FCM and ELISpot is highly sensitive and specific for diagnosis of plTB as an auxiliary method.
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<p><b>BACKGROUND AND OBJECTIVE</b>The p53 as a transcription factor in cell stress was activated to regulate cell cycle and programmed cell death to inhibit tumor growth. Usually, p53 is kept in non-activated state through various mechanisms, including the action of p53 C-terminal negative regulatory sequences. The purpose of the study is to prepare the two types p53 recombinant adenoviruses that carry full-length p53 as well as deletion of negative regulatory sequences at p53 C-terminus and to detect exogenous GFP expression in human lung cancer cell infected-virus by FCM scatter plot.</p><p><b>METHODS</b>Using pAdEasy-Track vector system the p53 recombinant plasmids was constructed and the homologous recombinants in E. coli was produced. The three kinds of recombinant adenovirus in L293 cells was generated, sequencing proved. Exogenous GFP expression in human lung cancer 801D cells infected-virus was detected by FCM scatter plot.</p><p><b>RESULTS</b>p53 recombinant adenoviruses named Ad-p53(wtp), Ad-p53(del) and Ad-(empty carrier) were produced. Results of sequences indicate that the Ad-p53(del) was deletion of 111 bases before stop codon TGA and of 3 untranslated region at p53, the Ad-p53(wtp) no loss of any p53 base, the Ad-(empty carrier) no p53 sequence. FCM scatter plot indicate the percentage of 801D cells expressed GFP with three kinds of viral infection was almost same and was increased with the virus density. 801D contains ratio of cells with different fluorescence intensity.</p><p><b>CONCLUSION</b>The preparation of recombinant adenovirus, Ad-p53(del), pA-p53(wtp) and Ad-(empty carrier). The cells expressed-GFP can be quantitatively detected by FCM scatter plot. It was provide that the reliability of the virus system and accurate method for selecting viruses density to infecting cells.</p>
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Animals , Humans , Mice , Adenoviridae , Genetics , Flow Cytometry , Methods , Genes, p53 , Green Fluorescent Proteins , Genetics , Recombination, GeneticABSTRACT
Objective To determine whether regulatory T cells(Tr)are increased in patients with tuberculosis and whether they are associated with its immunopathology.Meantime,to investigate the possibility of tuberculosis(TB)as a model for studying Tr functions.Methods The lymphocyte subsets were isolated from peripheral blood mononuclear cells by sorting with flow cytometry.Total cellular RNA was extracted and RT-PCR was performed to detect the Foxp3 mRNA in purified CD3+CIM+T cells,CD3+CD8+T cells and non-CD3+CD4+CD8+T cells.Using FACS analysis.we further investigated the distribution of Foxp3+ population in CD4+ CD25+T cells.Finally,we compared the percentage of CD4+CD25highFoxp3+T cells present in 51 active patients with tuberculosis and 40 uninfected healthy control subjects by FACS.The detection of Tr infiltration of Foxp3+ cells were performed with immunohistochemistry(IHC)method on tuberculosis pathological sections.Results Foxp3 was specific expressed in CD3+CD4+T cells,either in tuberculosis patients or healthy control subjects.Foxp3+ T cells took about 85%fraction of CD4+ CD25highpopulation.We used CD4+CD25high Foxp3+as a detective markers for Tr in the FACS analysis.The results showed that patients with active TB had a 4.4 fold higher percentage within the CD4+T cells in peripheral blood compared to healthy control group(modian,1.01%vs 0.23%,P<0.01).Much higher frequency of Tr were found along with T cells infiltration at the tuberculosis pathological tissues.A few individuals that we can followed indicated the expanded Tr was declined after curative treatment with operation.Conclusion Tr cells are increased in tuberculosis patients and closely correlate with its immunopathology.Tuberculosis should be a valuable model for Tr functional study.