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  • Articles  (82)
  • monoclonal antibody  (47)
  • CHO cells  (27)
  • Lepidoptera
  • temperature
  • Springer  (82)
  • Process Engineering, Biotechnology, Nutrition Technology  (82)
  • 1
    Electronic Resource
    Electronic Resource
    Production of monoclonal antibodies and ELISA for thebaine and codeine (1995)
    Springer
    Cytotechnology 19 (1995), S. 55-61 
    Details
    ISSN: 1573-0778
    Keywords: codeine ; ELISA ; monoclonal antibody ; opium alkaloid ; qualitative analysis ; thebaine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The ratio of hapten and bovine serum albumin in antigen conjugate was exactly determined by matrix-assisted laser desorption/ionization mass spectrometry. Monoclonal antibodies against thebaine and codeine were produced by hybridoma fused with the sprenocytes immunized with thebaine- and codeine-bovine serum albumin conjugate and HAT-sensitive mouse myeloma cell line, P3-X63-Ag8-653. No cross-reaction of anti-thebaine antibody against morphine was observed. Very small cross-reaction appeared in codeine (0.004%). The cross-reaction of anti-codeine antibody against morphine and thebaine was 2.97 and 5.98%, respectively. The full measuring range of the assay extends from 60 pg mL to 1 ng mL for thebaine and 1 ng mL to 100 ng mL for codeine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00749755
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  • 2
    Electronic Resource
    Electronic Resource
    CHO cell growth and recombinant interferon-γ production: Effects of BSA, Pluronic and lipids (1995)
    Springer
    Cytotechnology 19 (1995), S. 27-36 
    Details
    ISSN: 1573-0778
    Keywords: BSA ; CHO cells ; interferon-γ ; linoleic acid ; lipids ; Pluronic F68
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The role of bovine serum albumin in mammalian cell cultures and the possibility of its substitution by other components in a serum-free medium has been investigated. In this study, BSA was shown to be important for growth and product formation in CHO cells expressing recombinant human interferon-γ. There were indications that its stimulating growth effect was dependent on the source of BSA used and probably was related to the purification procedure used for the production of the desired albumin fraction. Cell growth did not occur in the absence of BSA but at low concentration (1 mg ml−1) it was stimulated by the addition of a combination of a commercial lipid mixture plus Pluronic F68. However, under the latter conditions IFN-γ production was adversely effected. The importance of individual lipid components was investigated using a statistical approach based on a Plackett-Burman design. Linoleic acid was identified as a positive variable for cell growth while cholesterol was identified as a negative variable for both cell growth and IFN-γ production. When a combination of linoleic acid plus Pluronic F68 was included in the formulation of low BSA medium, cell growth was similar to that at high BSA concentration (5 mg ml−1) but the IFN-γ concentration was significantly reduced (ca. 45%).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00749752
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  • 3
    Electronic Resource
    Electronic Resource
    High density culture of mouse-human hybridoma cells using a perfusion culture apparatus with multi-settling zones to separate cells from the culture medium (1989)
    Springer
    Cytotechnology 2 (1989), S. 5-8 
    Details
    ISSN: 1573-0778
    Keywords: hybridoma ; monoclonal antibody ; perfusion culture ; mammalian cell culture ; serum-free culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Mouse-human hybridoma X87X cells were cultivated using a novel perfusion culture apparatus provided with three-settling zones to separate the cells from the culture medium by gravitational settling. The maximum viable cell density in a serum-free culture medium attained 3.0×107 cells/ml, when the specific perfusion rate was set to 2.3 vol day-1, and monoclonal antibody was continuously produced. These results were almost the same as those in the perfusion culture vessel with one settling zone and revealed that the process with a plurality of settling zones is a promising one for scale-up of a gravitation type of perfusion culture vessel.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00365409
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  • 4
    Electronic Resource
    Electronic Resource
    SSGF-I, a potent growth-promoting substance for mammalian cells from swine serum (1989)
    Springer
    Cytotechnology 2 (1989), S. 9-17 
    Details
    ISSN: 1573-0778
    Keywords: heterohybridoma ; LDL ; monoclonal antibody ; serum-free medium ; PEG ; swine serum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A small amount of swine serum markedly stimulated cell growth for high productivity subclones derived from a mouse human-human heterohybridoma, N12-16.63, secreting an anti-tetanus toxoid human monoclonal antibody in a polyethylene glycol (PEG)-containing serum-free medium, PEG-86-1. A growth promoting substance, SSGF-I, was isolated from the serum by ammonium sulfate fractionation, Cibacron blue F3A-G affinity chromatography, DEAE-agarose ion exchange chromatography, and gel filtrations on Trisacryl GF 2000 and Sephacryl S-300. SSGF-I was characterized as a low density lipoprotein (LDL) of swine serum by its physico-chemical properties. It promoted cell growth synergistically with PEG and its optimum concentration was 1 to 100μg/ml. Human LDL was less active, and human or swine high density lipoprotein (HDL) and very low density lipoprotein (VLDL) were inactive. Based on these results, we propose an improved serum-free medium, PEG-86-3, which contains all the ingredients of PEG-86-1 and 10μg/ml SSGF-I. This medium is useful for not only high productivity heterohybridomas but also for a variety of lymphoid cell lines.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00365410
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  • 5
    Electronic Resource
    Electronic Resource
    A serum-free medium for hybridoma cell culture (1993)
    Springer
    Cytotechnology 11 (1993), S. 169-174 
    Details
    ISSN: 1573-0778
    Keywords: cell culture ; hybridoma ; monoclonal antibody ; serum-free medium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The effects of several different substances, including insulin, transferrin, ethanolamine, selenite and butyrate on the growth of murine hybridoma 2F7 cells, which secrete monoclonal antibody against small cell lung cancer, were investigated, and a serum-free medium SFMI was formulated. The effects of taurine, spermidine, progesterone and adenine on the cell growth were tested further on the basis of the medium SFMI, and a modified serum-free medium SFM II was established. On the basis of medium SFM II, the substitution tests of ferric citrate for transferrin were carried out, and it was found that transferrin could be replaced. The experiments suggested that the formulated serum-free medium was suitable for 2F7 cell growth and monoclonal antibody secretion, and thus facilitated subsequent purification of monoclonal antibody.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00749866
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  • 6
    Electronic Resource
    Electronic Resource
    Proteolytic cleavage of recombinant two-chain factor VIII during cell culture production is mediated by protease(s) from lysed cells. The use of pulse labelling directly in production medium (1997)
    Springer
    Cytotechnology 24 (1997), S. 227-234 
    Details
    ISSN: 1573-0778
    Keywords: CHO cells ; multicatalytic proteinase complex ; proteases ; protease inhibitors ; proteasome ; pulse labelling ; recombinant coagulation factor VIII ; SDS-PAGE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract During the production by mammalian cells of recombinant factor VIII from which the B domain was deleted (rFVIII), proteolytic cleavages in the C-terminal part of the heavy chain were observed (Kjalke et al., 1995). By radioactive pulse labelling it was investigated whether the cleavages took place inside the cells during protein synthesis or after release in the medium. The rFVIII-producing CHO (Chinese hamster ovary) cells were cultured in the presence of 35S-methionine and then the cell lysate and the conditioned media were immunoprecipitated and analyzed by electrophoresis. By pulse labelling and chasing for various time periods, it was shown that the cleavages only took place after secretion of the protein from the cells. Adding cell lysate to uncleaved rFVIII caused cleavage of the heavy chain, as seen by loss of binding to a monoclonal antibody specific for intact rFVIII, indicating that the cleavage was performed by proteinase(s) released from the lysed cells. By incubating intact rFVIII with the multicatalytic proteinase (proteasome) present in cytoplasm and nucleus of eukaryotic cells, loss of binding to the monoclonal antibody was observed. This indicates that the multicatalytic proteinase, released from lysed rFVIII producing cells, could be responsible for the cleavage of rFVIII. Among several protease inhibitors tested, only bacitracin was found to diminish the extent of cleavage. Phosphatidylserine also protected rFVIII against cleavage, probably by binding to rFVIII.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007988713571
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  • 7
    Electronic Resource
    Electronic Resource
    Na-butyrate increases the production and α2,6-sialylation of recombinant interferon-γ expressed by α2,6- sialyltransferase engineered CHO cells (1999)
    Springer
    Cytotechnology 29 (1999), S. 55-64 
    Details
    ISSN: 1573-0778
    Keywords: α2,6-sialyltransferase ; CHO cells ; interferon-γ ; sialylation ; sodium butyrate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A non-human like glycosylation pattern in human recombinant glycoproteins expressed by animal cells may compromise their use as therapeutic drugs. In order to correct the CHO glycosylation machinery, a CHO cell line producing recombinant human interferon- γ (IFN) was transformed to replace the endogenous pseudogene with a functional copy of the enzyme α2,6-sialyltransferase (α2,6-ST). Both the parental and the modified CHO cell line were propagated in serum-free batch culture with or without 1 mM sodium butyrate. Although Na-butyrate inhibited cell growth, IFN concentration was increased twofold. The IFN sialylation status was determined using linkage specific sialidases and HPLC. Under non- induced conditions, IFN expressed by α2,6-engineered cells contained 68% of the total sialic acids in the α2,6- conformation and the overall molar ratio of sialic acids to IFN was 2.3. Sodium butyrate addition increased twofold the molar ratio of total sialic acids to IFN and 82% of total sialic acids on IFN were in the α2,6-conformation. In contrast, no effect of the sodium butyrate was noticed on the sialylation of the IFN secreted by the α2,6-ST deficient parental cell line. This study deals for the first time with the effect of Na-butyrate on CHO cells engineered to produce human like sialylation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008080432681
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  • 8
    Electronic Resource
    Electronic Resource
    Quantitative analysis of transcription and translation in gene amplified Chinese hamster ovary cells on the basis of a kinetic model (1999)
    Springer
    Cytotechnology 29 (1999), S. 93-102 
    Details
    ISSN: 1573-0778
    Keywords: CHO cells ; gene expression ; kinetic model ; protein secretion ; transcription ; translation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The elevation of expression levels for secreted glycoproteins by gene amplification in mammalian cells shows a saturation behavior at high levels of gene amplification. At high expression levels a drop in the secretion efficiency for the recombinant protein occurs (Schröder and Friedl, 1997), coinciding with the appearance of misfolded protein in the cell. In this communication we investigated whether additional limitations exist at the levels of transcription and translation. Four Chinese hamster ovary (CHO) cell lines expressing different amounts of human antithrombin III (ATIII) were used as a model system. A tenfold increase in the ATIII cDNA copy number from the lowest to the highest producing cell line coincided with a 38-fold increase in ATIII mRNA levels, and an 80-fold increase in the amount of intracellular ATIII levels. The data was analyzed using a simple kinetic model. The following conclusions were derived: I. The transcriptional activity for the recombinant protein is not saturated. II. Translation itself is not saturated either, but may be downregulated as secretion efficiency drops. III. Two explanations for the previously reported drop in secretion efficiency for the recombinant protein with increasing expression level are possible: A. Protein degradation is an alternative fate for translated ATIII and the fraction of ATIII degraded after translation increases as expression level is increased. B. Translation is downregulated as the secretory apparatus becomes exhausted to maintain cell viability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008077603328
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  • 9
    Electronic Resource
    Electronic Resource
    Cell growth and protein formation on various microcarriers (1999)
    Springer
    Cytotechnology 29 (1999), S. 151-158 
    Details
    ISSN: 1573-0778
    Keywords: CHO cells ; comparison ; microcarriers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A large number of microcarriers are commercially available. The capability of cells to successfully proliferate on microcarriers varies with cell lines and media. Choosing the right microcarrier for a particular cell line is more than a choice of a microcarrier. It is part of an integrated process design. A detailed picture of cell growth and product formation will not only be essential in identifying the kind of microcarrier, but also in determining other parts of the process, such as operation mode and media. Our initial screening on thirteen microcarriers showed that cultures on some microcarriers reached a low cell density but high cell-specific productivity, and high density microcarrier cultures have a low specific productivity. The result is a similar product output per unit volume and time for these two types of cultures. An ideal culture system shall have increased volumetric productivity at elevated cell density. This requires the process goal to be incorporated as early as cell line construction and screening. A high output process can then be realized through high density culture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008053421462
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  • 10
    Electronic Resource
    Electronic Resource
    Productivity enhancement of recombinant protein in CHO cells via specific promoter activation by oncogenes (1999)
    Springer
    Cytotechnology 31 (1999), S. 103-109 
    Details
    ISSN: 1573-0778
    Keywords: CHO cells ; human interleukin 6 ; oncogene ; promoter activation ; recombinant protein production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract To construct a recombinant protein highly producing cell lines, we have previously developed the Oncogene Activated Production (OAP) system by using BHK-21 cells. Here we verified the availability of the OAP system in CHO cells. We firstly generated ‘primed’ ras amplified CHO cells, ras clone I, by introducing human c-Ha-ras oncogene into CHO cells. This ras clone I enables quick and easy establishment of recombinant protein hyper producing cell lines by introduction reporter gene of interest. Then we generated I13 by introducing human interleukin 6 (hIL-6) gene as a reporter gene, which showed enhanced productivity rate as compared to A7 established by conventional method. Furthermore, we found that hIL-6 production level of I13 was slightly improved by raising the CO2 concentration from 5 to 8% possibly because of the enhanced growth rate. We further introduced the E1A oncogene, which has been shown to have a synergistic effect on the recombinant protein production of the ras-amplified BHK-21 cells, then evaluated the productivity. When culture in 5% CO2 condition, only the slight effect can be seen. However when cultured in 8% CO2 condition, not only cell number, but also productivity increased significantly, resulted in great augmentation of hIL-6 production, maximum production being 88.6 μg/ml/3 days. This study demonstrates that recombinant protein production level reached commercially desirable level by utilizing our OAP system in CHO cells and optimizing the culture condition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008048928053
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