To enhance recombinant protein production by CHO cells, We compared the impact of overexpression of metabolic enzymes, namely pyruvate carboxylase 2 (PYC2), malate dehydrogenase Ⅱ (MDH2), alanine aminotransferase Ⅰ (ALT1), ornithine transcarbamylase (OTC), carbamoyl phosphate synthetase Ⅰ (CPSⅠ), and metabolism related proteins, namely taurine transporter (TAUT) and Vitreoscilla hemoglobin (VHb), on transient expression of anti-hLAG3 by ExpiCHO-S. Overexpression of these 7 proteins could differentially enhance antibody production. OTC, CPSI, MDH2, and PYC2 overexpression could improve antibody titer by 29.2%, 27.6%, 24.1%, and 20.3%, respectively. Specifically, OTC and MDH2 could obviously improve early-stage antibody production rate and the culture period was shortened by 4 days compared with that of the control. In addition, OTC and MDH2 had little impact on the affinity of anti-hLAG3. In most cases, overexpression of these proteins had little impact on the cell growth of ExpiCHO-S. MDH2 and ALT1 overexpression in H293T cells could also improve antibody production. Overall, overexpression of enzymes involved in cellular metabolism is an effective tool to improve antibody production in transient expression system.
Animals ; CHO Cells ; Cricetinae ; Cricetulus ; Enzymes/metabolism* ; Recombinant Proteins/genetics*

OBJECTIVETo overexpress hepatitis B virus S gene in CHO cells cultured in serum-free media.

METHODPlasmid was constructed by cloning of HBV S gene and then it was transfected into CHO cells. After cell screen, the positive clones were identified and isolated into a serum-free media followed by the serological and morphological characterization of the expression product.

RESULTCHO cell strains which can express HBsAg efficiently and stably were obtained. Spherical and filamentous HBsAg could be detected under electronic microscope. The titer of the expression product was up to 1:5000.

CONCLUSIONSerum-free media cultured CHO cell strain for overexpression of HBsAg was successfully constructed and the expression product was high antigenic.

Animals ; CHO Cells ; Cricetinae ; Cricetulus ; Gene Expression ; Hepatitis B Surface Antigens ; genetics ; immunology ; Transfection

OBJECTIVEOur previous studies have shown that an anti-sense plasmid to mouse fibrinogen like protein 2 (mfgl2) significantly reduced mfgl2 expression in vivo, markedly ameliorated inflammatory infiltration, fibrin deposition and hepatocyte necrosis, prolonged the survival time period and elevated the survival rate in Balb/cJ mice with murine hepatitis virus type 3 (MHV-3) induced fulminant hepatitis. This study was designed to explore the opportunity of RNA interference technique in the inhibitory application of hfgl2 expression, which has been reported to be involved in a variety of disease developments including fulminant viral hepatitis, acute rejection of allo/xeno transplantation and fetal loss syndrome.

METHODSA plasmid named p-hfgl2shRNA complimentary to the sequence responsible for hfgl2 was constructed; meanwhile irrelevant shRNA plasmid with a random combination of the p-hfgl2shRNA sequence was used as a control. A plasmid named pEGFP-hfgl2 expressing hfgl2-EGFP fusion protein was also constructed for the screening of the effect of p-hfgl2shRNA on the hfgl2 expression. By cotransfection of the constructed p-hfgl2shRNA and pEGFP-hfgl2 or pcDNA3.1-hfgl2 expression plasmids into CHO cells, the inhibition of hfgl2 expression by hfgl2shRNA was analyzed by direct observation through fluorescent microscopy, FACS, real time PCR and immunohistochemistry staining.

RESULTSThe experiments showed a significant inhibitory effect of p-hfgl2shRNA on hfgl2 expression at 48 h post-cotransfection by observation of green fluorescent cells, FACS, real time PCR and immunohistochemistry staining, with the inhibitory efficiency reaching as high as 85.5%.

CONCLUSIONThe study demonstrated that p-hfgl2shRNA successfully interfered with hfgl2 expression in vitro. This provides a foundation to further explore its application in vivo.

Animals ; CHO Cells ; Cricetinae ; Cricetulus ; Fibrinogen ; genetics ; Plasmids ; RNA Interference ; RNA, Small Interfering ; genetics

In recent years, Chinese hamster ovary (CHO) production vessel volume has reached more than 1 000 L in Chinese biopharms, and 10 000 L in foreign big biopharms, such as Lonza and Genetech. In general, there are some steps seed bioreactor for seed expansion, which decreases the efficiency of production process. In this work, a perfusion-based process was developed to drastically increase the split ratio during the scale-up of CHO cell cultures. Fed-batch cultures were inoculated with cells propagated in either batch or perfusion cultures that grown in disposable Cellbags using the WAVE Bioreactor system. The higher cell concentration of 2 x 10(7) cells/mL with 95% viability allowed to increase the split ratio to about 1:50-1:100 for inoculum propagated in perfusion culture. The method described here could reduce the number of required expansion steps and eliminate two or three bioreactors. Disposable perfusion bioreactor with only a few liters working volume have the potential to directly inoculate volumes of up to 1 000 liters. This would allow to shorten process time in these bioreactors, which often are the bottleneck in plant throughput.
Animals ; Bioreactors ; CHO Cells ; cytology ; Cell Culture Techniques ; instrumentation ; methods ; Cricetinae ; Cricetulus

No abstract available.
Ammonium Compounds* ; Ammonium Sulfate* ; Animals ; Bromodeoxyuridine* ; CHO Cells* ; Chromosome Aberrations* ; Cricetinae ; Humans ; Siblings* ; Sister Chromatid Exchange*

The aim of this study is to investigate the effect of the chimeric intron in different directions on the expression of the nerve growth factor (NGF) in recombinant Chinese hamster ovary (CHO) cells. The chimeric intron that contained the splice sequence of the first intron of the human β-globin and the human immunoglobulin heavy chain variable region intron was used. NGF gene was cloned into the expression vectors containing the chimeric intron in the forward or reverse direction, followed by transfecting into CHO cells, and screened under G418 to produce the stable transfected CHO cells. Fluorescence quantitative PCR, ELISA, and Western blotting were performed to detect the recombinant NGF gene expression in CHO cells. The results showed that the chimeric introns could significantly enhance the expression of NGF in recombinant CHO cells. Moreover, the enhancing effect on NGF expression level by the intron in the forward direction showed stronger than that of the reverse direction both at mRNA and protein level. In conclusion, the chimeric intron could increase NGF expression in stably transfected CHO cells and the effect is associated with the direction of the intron insertion.
Animals ; Animals, Genetically Modified ; CHO Cells ; Cricetinae ; Cricetulus ; Gene Expression ; Humans ; Introns ; Transfection

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.
Animals ; Batch Cell Culture Techniques ; trends ; Bioreactors ; standards ; CHO Cells ; Cricetulus ; Mammals ; Perfusion

In order to achieve large-scale production of HSV-IgM (HSV1, HSV2) human-mouse chimeric antibody in vitro, the gene sequence of the corresponding hybridoma cell was harvested by RNA ligase-mediated rapid amplification of cDNA ends (RLM-RACE) technique to clone the chimeric antibody into eukaryotic expression vectors, and express the target proteins in CHO-S cells. At the same time, the screening process of stable cell lines was optimized, and the pressure conditions of pool construction stage and monoclonal screening stage were explored. Finally, the target protein was purified by protein L affinity purification method and the biological activity was detected. The recombinant IgM antibodies, HSV1 and HSV2, weighted at 899 kDa and 909 kDa respectively, were prepared. The optimal screening pressure was 20P200M (the first phase of pressure) and 50P1000M (the second phase of pressure). The final titer for the monoclonal expression of HSV1-IgM and HSV2-IgM was 1 620 mg/L and 623 mg/L, respectively. This study may facilitate the development of quality control products of HSV1 and HSV2 IgM series recombinant antibodies as well as efficient expression of IgM subtype antibodies in vitro.
Cricetinae ; Humans ; Animals ; Mice ; Immunoglobulin M/genetics* ; Antibodies, Viral ; CHO Cells ; Cricetulus ; Hybridomas ; Recombinant Fusion Proteins

Anti-reflective nanocoatings that mimic the eyes of fruit flies are biodegradable materials with great market potential for a variety of optical devices that require anti-reflective properties. Microbial expression of retinin provides a new idea for the preparation of nanocoatings under mild conditions compared to physicochemical methods. However, the current expression level of retinin, the key to anti-reflective coating, is low and difficult to meet mass production. In this study, we analyzed and screened the best expression hosts for Drosophila-derived retinin protein, and optimized its expression. Chinese hamster ovary (CHO) cells were identified as the efficient expression host of retinin, and purified retinin protein was obtained. At the same time, the preparation method of lanolin nanoemulsion was explored, and the best anti-reflective ability of the nano-coating was determined when the ratio of specific concentration of retinin protein and wax emulsion was 16:4, the pH of the nano-coating formation system was 7.0, and the temperature was 30 ℃. The enhanced antireflective ability and reduced production cost of artificial antireflective nanocoatings by determining the composition of nanocoatings and optimizing the concentration, pH and temperature of system components may facilitate future application of artificial green degradable antireflective coatings.
Animals ; Cricetinae ; CHO Cells ; Emulsions ; Cricetulus ; Drosophila ; Eye Proteins ; Drosophila Proteins

The aim of this study was to produce recombinant porcine interferon gamma (rPoIFN-γ) by Chinese hamster ovarian (CHO) cells expression system and to analyze its antiviral activity. Firstly, we constructed the recombinant eukaryotic expression plasmid pcDNA3.1-PoIFN-γ and transfected into suspension cultured CHO cells for secretory expression of rPoIFN-γ. The rPoIFN-γ was purified by affinity chromatography and identified with SDS-PAGE and Western blotting. Subsequently, the cytotoxicity of rPoIFN-γ was analyzed by CCK-8 test, and the antiviral activity of rPoIFN-γ was evaluated using standard procedures in VSV/PK-15 (virus/cell) test system. Finally the anti-Seneca virus A (SVA) of rPoIFN-γ activity and the induction of interferon-stimulated genes (ISGs) and cytokines were also analyzed. The results showed that rPoIFN-γ could successfully expressed in the supernatant of CHO cells. CCK-8 assays indicated that rPoIFN-γ did not show cytotoxicity on IBRS-2 cells. The biological activity of rPoIFN-γ was 5.59×10⁷ U/mg in VSV/PK-15 system. Moreover, rPoIFN-γ could induced the expression of ISGs and cytokines, and significantly inhibited the replication of SVA. In conclusion, the high activity of rPoIFN-γ was successfully prepared by CHO cells expression system, which showed strong antiviral activity on SVA. This study may facilitate the investigation of rPoIFN-γ function and the development of novel genetically engineered antiviral drugs.
Swine ; Animals ; Cricetinae ; Interferon-gamma/pharmacology* ; Cricetulus ; CHO Cells ; Sincalide ; Recombinant Proteins/pharmacology* ; Antiviral Agents/pharmacology*