To construct the recombinant expression functionally in Chinese hamster ovary cells in order vector for CD80-IgG fusion gene and to express it to be used as an effective method to eliminate the immune escape of leukem...To construct the recombinant expression functionally in Chinese hamster ovary cells in order vector for CD80-IgG fusion gene and to express it to be used as an effective method to eliminate the immune escape of leukemic cells, the cDNA encoding the signal and extracellular domains of murine CD80 was generated by PCR amplification from plasmid pcDNMB7 containing the full length cDNA of murine CD80 and those of murine IgG1, in which the Fc fragment was obtained through RT-PCR amplification from murine spleen cells. These two cDNAs were then cloned in tandem into eukaryotic expression vector pcDNA3.0 and the resultant recombinant plasmid pcDNA/CD80-IgG was then transfected to Chinese hamster ovary cells with liposome transfection reagent. The cell clones constitutively expressing CD80-IgG fusion protein were obtained by G418 screening. Western blotting and dot ELISA assay were used to detect the expression of the fusion protein in the supernatants of these cells. Meanwhile, the fusion protein expressed was then purified with affinity chromatography, and its biological activity was demonstrated by flow cytometry, MTr colorimetry and ELISA assay. The experimental resuits showed that these two inserts were successfully cloned into plasmid pcDNA3.0, and the highly purified fusion protein was obtained. This fusion protein was proved to be able to upregulate the density of CD80 on leukemic cells, deliberately promote the proliferative reactions of mouse allogenic lymphocytes and increase the killing activity against WEHI-3 cells from 49.7 % up to 84.6 %. In addition, this fusion protein could also enhance the IL-2 secretion from allogenic lymphocytes activated by tumorspecific antigens. It is concluded that the recombinant vector constructed can be functionally expressed in the mammalian cells, thus providing a solid foundation for the further investigation on the mechanism to eliminate the immune escape of leukemic cells in vivo.展开更多
文摘To construct the recombinant expression functionally in Chinese hamster ovary cells in order vector for CD80-IgG fusion gene and to express it to be used as an effective method to eliminate the immune escape of leukemic cells, the cDNA encoding the signal and extracellular domains of murine CD80 was generated by PCR amplification from plasmid pcDNMB7 containing the full length cDNA of murine CD80 and those of murine IgG1, in which the Fc fragment was obtained through RT-PCR amplification from murine spleen cells. These two cDNAs were then cloned in tandem into eukaryotic expression vector pcDNA3.0 and the resultant recombinant plasmid pcDNA/CD80-IgG was then transfected to Chinese hamster ovary cells with liposome transfection reagent. The cell clones constitutively expressing CD80-IgG fusion protein were obtained by G418 screening. Western blotting and dot ELISA assay were used to detect the expression of the fusion protein in the supernatants of these cells. Meanwhile, the fusion protein expressed was then purified with affinity chromatography, and its biological activity was demonstrated by flow cytometry, MTr colorimetry and ELISA assay. The experimental resuits showed that these two inserts were successfully cloned into plasmid pcDNA3.0, and the highly purified fusion protein was obtained. This fusion protein was proved to be able to upregulate the density of CD80 on leukemic cells, deliberately promote the proliferative reactions of mouse allogenic lymphocytes and increase the killing activity against WEHI-3 cells from 49.7 % up to 84.6 %. In addition, this fusion protein could also enhance the IL-2 secretion from allogenic lymphocytes activated by tumorspecific antigens. It is concluded that the recombinant vector constructed can be functionally expressed in the mammalian cells, thus providing a solid foundation for the further investigation on the mechanism to eliminate the immune escape of leukemic cells in vivo.
