Development and optimization of perfusion process for mammalian cell culture / 生物工程学报

In recent years, the demand of biologics has increased rapidly. Cell culture process with perfusion mode has become more and more popular due to its high productivity, good quality and high efficiency. In this paper, the unique operation and the details of process optimization for perfusion culture mode are discussed by comparing with traditional batch culture process. Meanwhile, the progress and strategies in the development and optimization of perfusion culture process in recent years are summarized to provide reference for the future development of mammalian cell perfusion culture technology.

Anti-tumor effect and its mechanism of co-administration of fusion proteins hVEGF121/βhCG and mGM-CSF/βhCG / 中国药科大学学报

This study aimed at investigating the inhibitory effects and the anti-tumor mechanisms of co-adminis-tration of fusion proteins mGM-CSF/βhCG ( GC ) and hVEGF121/βhCG ( VC ) on RM-1 prostatic cancer and B16 F10 melanoma in the C57 BL/6 J mouse model. Two recombinant stains containing pET-28 a-mGM-CSF-X10-βhCGCTP37 and pET-28 a-VEGF-M2-X10-βhCG-CTP37 were induced by lactose to express fusion proteins. The fusion proteins were separated and purified to prepare the anti-tumor protein vaccines ( VC protein vaccine and GC protein vaccine) , which were then mixed to prepare a combined protein vaccine named VGC protein vac-cine. The prostatic cancer and melanoma tumor-bearing mice C57 BL/6 J were immunized with described vac-cines, then the growth of each tumor was measured;splenocyte proliferation of immunized mice was detected;and the cytotoxic effects of the vaccine on tumor cells were tested. After that, the in vivo concentrations of IFN-γ and anti-hVEGF antibodies were investigated by ELISA. The difference between each experimental group and normal saline group ( NS) was statistically significant in both tumor-bearing mouse models ( P <0. 05) respectively. Besides, VGC group exhibited significantly better anti-tumor effect compared with the GC and VC groups with the anti-tumor rate ( 41. 7 ± 0. 83)% and ( 46. 4 ± 1. 27)% for prostatic cancer and melanoma tumor, respectively. The co-administration of the two proteins, VC and GC, could inhibit the growth of RM-1 prostatic tumor and B16F10 melanoma effectively via anti-tumor immunity and anti-tumor angiogenesis.

Costimulate moleculars amplified the DRibble mediated T cells response / 中国药科大学学报

@#Autophagosomes derived from tumor cells have been proved to induce potent T cell response both in mouse and human. In human in vitro study, dendritic cells(DC)loaded with cytomegalovirus(CMV)pp65 antigen-containing DRibble were capable to efficiently re-stimulate pp65-specific T-cell recall responses from freshly isolated or frozen humanperipheral blood mononuclear cell(PBMC). This study developed more robust assays using in vitro expanded antigen-specific T cells that contained a much higher percentage of antigen-specific T cells. DC cross-presentation efficiency of OX40 and CD80 modified pp65-DRibble was detected by intracellular IFN-γ staining. Compared with Ctrl/pp65 DRibble, the percentage of IFN-γ+ in total CD8+ T cells andCD4+ T cells was improvedwith OX40/pp65 DRibbleand CD80/pp65 DRibble stimulation. In addition, vaccine induced IL-12indendritic cells, whichpolarizes Th cells toward the IFN-γ high Th1 phenotype, evaluated by ELISA inco-culture supernatantwas dramatically higher in OX40/pp65 DRibble and CD80/pp65 DRibblegroups than in Ctrl/pp65 DRibble group. These results have implications for the immuneactivity of OX40 and CD80 modified DRibble and choice for prospective clinical use ofDRibble-based cancer immunotherapy.

Effects of Mycobacterium tuberculosis HSP65 on Treg/Th17 immune balance in ApoE-knockout mice / 中国药科大学学报

@#To investigate the effects of Mycobacterium tuberculosis heat shock protein 65(HSP65)on Treg/Th17 immune balance in ApoE-knockout(ApoE-/-)mice, ApoE-/- mice with a high-cholesterol diet were immunized with M. tuberculosis HSP65. Sera were obtained for measurement of anti-HSP65 antibodies by ELISA; the effect of administration of different antigens was investigated, respectively, using flow cytometry analysis on the number of CD4+CD25+Foxp3+Tregs and CD4+IL-17+ Th17; the production of cytokines(IL-10, TGF-β1, IL-17 and IL-21)by these cells were determined by ELISA; total plasma cholesterol(TC), triglyceride(TG), high-density lipoprotein cholesterol(HDL-C)and low-density lipoprotein cholesterol(LDL-C)levels were detected by biochemical autoanalyzer. Atherosclerotic lesions were measured by lipid deposition stained with oil red O. The results demonstrated that the levels of anti-HSP65 IgG antibodies were increased significantly in Mycobacterium tuberculosis HSP65-treated ApoE-/- mice, revealed obvious decrease in Treg number, Treg related cytokines(IL-10, TGF-β1)levels and significant increase in Th17 number, Th17 related cytokines(IL-17 and IL-21)levels, the levels of TC, TG, HDL-C and LDL-C did not change between groups, while the atherosclerotic lesions significantly increased. Results indicate that M. tuberculosis HSP65 could interrupt the Th17/Treg immune balance in ApoE-/- mice, suggesting a potential role in the formation and progression of atherosclerosis.

Preparation of mGM-CSF/βhCG fusion protein and the effect of its sensitized DC vaccine on RM-1 prostate tumor in mice / 中国药科大学学报

@#An expression vector pET-28a-mGM-CSF-X10-βhCGCTP37 plasmid containing the βhCG and mGM-CSF gene was designed and constructed. The fusion protein was induced by lactose and purified by ammonium sulfate precipitation and DEAE-cellulose anion exchange column. Then dendritic cells(DC)in C57BL/6J mice were extracted and sensitized by the fusion protein to obtain DC vaccine. The DC vaccine was inoculated to C57BL of / 6J mice with prostate cancer RM-1. The results indicated that the anti-tumor effects of DC group and DC combined with paclitaxel(DP)group were superior to that of paclitaxel(Pac)group(P< 0. 01), and the anti-tumor effect of DP group was better than that of DC group. Thus, the constructed DC vaccine can inhibit the growth of prostate cancer, and have synergistic anti-tumor when used with paclitaxel.

Enhanced inhibition of murine prostatic carcinoma growth by immunization with or administration of viable human umbilical vein endothelial cells and CRM197

Vaccination with xenogeneic and syngeneic endothelial cells is effective for inhibiting tumor growth. Nontoxic diphtheria toxin (CRM197), as an immunogen or as a specific inhibitor of heparin-binding EGF-like growth factor, has shown promising antitumor activity. Therefore, immunization with or administration of viable human umbilical vein endothelial cells (HUVECs) combined with CRM197 could have an enhanced antitumor effect. Six-week-old C57BL/6J male mice were vaccinated with viable HUVECs, 1 x 10(6) viable HUVECs combined with 100 μg CRM197, or 100 μg CRM197 alone by ip injections once a week for 4 consecutive weeks. RM-1 cells (5 x 10(5)) were inoculated by sc injection as a preventive procedure. During the therapeutic procedure, 6-week-old male C57BL/6J mice were challenged with 1 x 10(5) RM-1 cells, then injected sc with 1 x 10(6) viable HUVECs, 1 x 10(6) viable HUVECs + 100 μg CRM197, and 100 μg CRM197 alone twice a week for 4 consecutive weeks. Tumor volume and life span were monitored. We also investigated the effects of immunization with HUVECs on the aortic arch wall and on wound healing. Vaccination with or administration of viable HUVECs+CRM197 enhanced the inhibition of RM-1 prostatic carcinoma by 24 and 29 percent, respectively, and prolonged the life span for 3 and 4 days, respectively, compared with those of only vaccination or administration with viable HUVECs of tumor-bearing C57BL/6J mice. Furthermore, HUVEC immunization caused some damage to the aortic arch wall but did not have remarkable effects on the rate of wound healing; the wounds healed in approximately 13 days. Treatment with CRM197 in combination with viable HUVECs resulted in a marked enhancement of the antitumor effect in the preventive or therapeutic treatment for prostatic carcinoma in vivo, suggesting a novel combination for anti-cancer therapy.

Cloning,expression and purification of recombinant human proinsulin C-peptide in E.coli / 中国药科大学学报

Aim:To obtain recombinant human proinsulin C-peptide,a novel expression vector pEDCC was constructed to facilitate the expression and purification of C-peptide. Methods:Gene fragments encoding a truncated asparaginase fragment mutant,native C-peptide,a hinge fragment of human IgG1,an extra acid-labile dipeptide and a basic-amino-acid-riched octopeptide were introduced in turn into plasmid pET28a. The fusion protein ansB-C-hinge-DPKRKRKKSRNGSGR-C-peptide was expressed effectively as inclusion bodies after induced by lactose and partially purified by means of washing and ethanol fractionation. After being hydrolyzed,the polypeptide PKRKRKKSRNGSGR-C-peptide was liberated from the fusion partner. The N-terminal tetradecapeptide extension of C-peptide was subsequently cleaved by trypsin and removed by DE52 column. Results:The nucleotides sequence of plasmid pEDCC was confirmed to be identical with that of designed fusion protein. Recombinant human proinsulin C-peptide was obtained with high purity after purification. Conclusion:Employing truncated asparaginase as the fusion partner and basic-amino-acid-riched octopeptide to modulate isoelectric point is an effective approach to produce recombinant human proinsulin C-peptide.