ObjectiveA mammalian expression vector encoding TAG72specific single chain variable region(scFv) fused to the transmembrane and intracellular domains of the signal transducing chain of CD28 was constructed, to generate for targeting of genetically modified T cells to gastrointestinal cancer, and to investigate the cytotoxicity against TAG72 positive target cells.MethodsThe transmembrane and intracellular domains of CD28 cDNA was amplified from human T lymphocytes using RTPCR to clone into a mammalin expression vecter, and CD28 fragments were ligated downstream of the antiTAG72 scFv cDNA and sequence verified.ResultsA 729base pair of antiTAG72 scFv was in accordance with sequence concerned; a 240base pair of cDNA of the transmembrane and intracellular domains of CD28 was confirmed as sequence concerning of Genebank.ConclusionWe constructed a mammalian expression vector encoding fusing gene to activate tumorassociated antigenspecific T lymphocyte, for generation of modified T lymphocytes to gastrointestinal tumors.
ObjectiveTo investigate the method for generating anchor chemric T lymphocytes that can target tumor associated glycoprotein-72 (TAG72) antigen and analyze their repressive effects on proliferation of TAG72 positive hepatocarcinoma cells. MethodsFirstly, peripheral blood mononuclear cells (PBMCs) from healthy volunteers were isolated. And then, CD8+ T cells were isolated from PBMCs via magnetic activated cell sorting (MACS). These lymphocytes were transfected with recombinant vector, anti-TAG72-scFv-CD28-pcDNA3, through Lipofectamine2000 to gernerate anchor chimeric TAG72-specific CD8+ T cells. SMMC7721 (TAG72 positive) hepatocarcinoma cells were co-cultured with chimeric T lymphocytes and their cell cycles were analyzed by flow cytometry (FCM). ResultsAnchor chmeric T lymphcytes targetting TAG72 recognized TAG72 positive SMM7721 cells and repressive effects on their proliferation were observed by flow cytometry. ConclusionAnchor chmeric T lymphcytes targetting TAG72 on tumor surface can specifically recognize TAG72 positive hepatocarcinoma cells and may exert repressive effect on their proliferation.
Objective To construct a green fluorescent protein expression plasmid pEGFP-C3-anti-TAG72 scFv-CD28, containing anti-TAG72 single chain variable fragment (scFv) fused into the transmembrane and intracellular domain of the signal-transducing chain of CD28 gene, and to transfect it into peripheral blood mononuclear cells． Methods Recombinant transmembrane and intracellular domain of CD28 cDNA and anti-TAG72 scFv cDNA fragment was subcloned into pEGFP-C3 vector. Recombinant clones were selected by Kanamyein， and then identified by PCR， enzyme digestion analysis and DNA sequencing. The recombinant plasmid was transfected into peripheral blood mononuclear cells by means of lipofection. The recombinant protein expression was confirmed by immunocytochemistry, laser scanning confocal microscope, PCR and Western blot analysis. Results The fused gene fragment of anti-TAG72 scFv-CD28 was successfully inserted into pEGFP-C3 plasmid, and it was confirmed by enzyme digestion and DNA sequencing. The fused anti-TAG72 scFv-CD28 gene and its protein was identified in peripheral blood mononuclear cells． Conclusion The eukaryotic expression plasmid pEGFP-C3-anti-TAG72 scFv-CD28 was successfully constructed and transiently expressed in peripheral blood mononuclear cells， which would lay a foundation for further studies on the role of it to activate tumor-associated antigen-specific T lymphocyte, for generating of modified T lymphocytes targeting gastrointestinal tumors.
Objective To study the prokaryotic expression of the anti-tumor associated glycoprotein-72 (TAG-72) singlechain fragment variable (scFv) antibody and its specific affinity to hepatocellular carcinoma cell lines and tissues. Methods The cDNA of anti-TAG-72 scFv antibody was inserted into pCANTAB5E to obtain phage vector anti-TAG-72 -scFv-pCANTAB5E. Isopropyl-β-D-thiogalactoside (IPTG) was used to induce the expression of anti-TAG-72 scFv antibody. SDS-PAGE and Western blot were used to identify the anti-TAG-72 scFv antibody. Human hepatocellular carcinoma cells were cultured, and TAG-72 was determined with the obtained scFv by immunohistochemistry in the cells and paraffin-embedded hepatocellular carcinoma tissues. Results SDS-PAGE and Western blot showed that the anti-TAG-72-scFv antibody was successfully expressed. Anti-TAG-72 scFv could bind to hepatocellular carcinoma cell lines SMMC7721, HepG2, and HHCC, but not to BEL7402, suggesting that SMMC7721, HepG2, and HHCC cells expressed TAG-72. For the 40 cases of hepatocellular carcinoma tissues, the positive rate of TAG-72 in stage Ⅰ and Ⅱ-Ⅲ was 23.08% (3/13) and 62.96%(17/27), respectively. While no TAG-72 expression was found in the 10 normal cases. TAG-72 expression was significantly different between hepatocellular carcinomas and normal tissues (Plt;0.05). Conclusions The prokaryotic expression of anti-TAG-72 scFv antibody is successfully achieved, and can be used to identify TAG-72 antigen. TAG-72 is highly expressed in hepatocellular carcinoma, but not in normal liver tissue, which may be suggested as cancer marker of hepatocellular carcinoma.
【Abstract】 Objective To investigate the expression of tumor associated glycoprotein-72 （TAG-72） in human breast cancer cells. Methods Two breast cancer cell lines MCF-7 and Bcap-37 were cultured and prepared. TAG-72 expressions in MCF-7 and Bcap-37 were detected immunochemically with anti-TAG-72 single chain variable fragment (scFv). Results TAG-72 was positively expressed in MCF-7 cells but negatively expressed in Bcap-37 cells. Conclusion Tumor associated antigen TAG-72 is expressed in certain human breast cancer cells, which indicate TAG-72 may be used as a tumor maker and anti-TAG-72 scFv may play a role in the diagnosis and treatment of breast cancer.
Objective To study effect of carcinoembryonic antigen (CEA) positive targeted lymphocytes on gastric cancer cells in vitro and in vivo. Methods The peripheral blood mononuclear cells (PBMCs) were isolated from the peripheral blood of healthy volunteers. The recombinant vector anti-CEA-scFv-CD3ζ-pcDNA3.0 was transfected into the PBMCs by lipofectamine 2000, by this means, the CEA special lymphocytes were obtained. Meanwhile, the PBMCs transfected with empty plasmid pcDNA3.0 were used as control (empty vector lymphocytes). The different lymphocytes and gastric cancer cells (CEA positive KATOⅢ gastric cancer cells and CEA negative BGC-823 gastric cancer cells) were co-cultured, then the ability to identify the gastric cancer cells and it’s effect on apoptosis of gastric cancer cells were observed at 24 h or 36 h later respectively. The CEA special lymphocytes and empty vector lymphocytes were injected by the tail vein of nude mice bearing gastric cancer cells, then it’s effect on the tumor was observed. Results ① The CEA special lymphocytes could strongly identify the KATOⅢ gastric cancer cells (identification rate was 72.3%), which could weakly identify the BGC-823 gastric cancer cells (identification rate was 7.8%). ② The apoptosis rate of the co-culture of CEA special lymphocytes and KATOⅢ gastric cancer cells was significantly higher than that of the co-culture of empty vector lymphocytes and KATOⅢ gastric cancer cells (P=0.032), which had no significant difference between the co-culture of CEA special lymphocytes and BGC-823 gastric cancer cells and the co-culture of empty vector lymphocytes and BGC-823 gastric cancer cells (P=0.118). ③ The tumor volume of the co-culture of CEA special lymphocytes and KATOⅢ gastric cancer cells was significantly smaller than that of the co-culture of empty vector lymphocytes and KATOⅢ gastric cancer cells (F=5.010, P<0.01) or the co-culture of CEA special lymphocytes and BGC-823 gastric cancer cells (F=4.982, P<0.01), which had no significant difference between the co-culture of CEA special lymphocytes and BGC-823 gastric cancer cells and the co-culture of empty vector lymphocytes and BGC-823 gastric cancer cells (F=1.210, P>0.05). Conclusion CEA special lymphocytes can promote cell apoptosis and inhabit tumor reproduction of CEA positive gastric cancer cells in vitro and in vivo.