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  • Articles  (55)
  • monoclonal antibody  (47)
  • Animals
  • Chemical Engineering
  • temperature
  • Springer  (55)
  • Process Engineering, Biotechnology, Nutrition Technology  (54)
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  • 1
    ISSN: 1573-0778
    Keywords: ELISA ; ginsenoside Rg1 ; mass spectrometry ; monoclonal antibody ; qualitative analysis
    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 an antigenconjugate was determined by matrix-assisted laserdesorption/ionization time-of-flight mass spectrometry. Ahybridoma secreting monoclonal antibody against ginsenosideRg1 was produced by fusing sprenocytes immunized with aginsenoside Rg1-bovine serum albumin conjugate withHAT-sensitive mouse myeloma cell line, P3-X63-Ag8-653. A very smallcross-reaction appeared with ginsenoside Re. The full measuringrange of the assay extends from 0.3 μg ml-1 to 10 μg ml-1 ofginsenoside Rg1.
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  • 2
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    World journal of microbiology and biotechnology 16 (2000), S. 297-301 
    ISSN: 1573-0972
    Keywords: Anaerobic bacteria ; growth ; protease ; psychrotrophs ; temperature ; volatile fatty acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Five anaerobic proteolytic bacteria were isolated from water bodies of Leh, India, where the ambient temperature varies from −25 to 25 °C. Isolates showed growth at all temperatures ranging from 5 to 37 °C except SPL-4 and SPL-5 which showed no growth at 5 °C. The cultures could grow and produce proteases on various protein substrates and the yield varied with the substrates. Two of the cultures showed the presence of spores. Acetate was the dominant VFA during hydrolysis of protein substrates.
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  • 3
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    World journal of microbiology and biotechnology 16 (2000), S. 571-572 
    ISSN: 1573-0972
    Keywords: Anaerobes ; hydrogen sulphide ; rubber stoppers ; sulphate reduction ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Common black rubber stoppers, made from natural rubber and styrene–butadiene, may cause a loss of hydrogen sulphide from aqueous media and impede the growth of sulphate-reducing bacteria under thermophilic conditions.
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  • 4
    ISSN: 1573-0972
    Keywords: Carbondioxide ; fungi ; oxygen ; Rhizopus ; solid-substrate fermentation SSF ; tempe modelling ; temperature ; water activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Rhizopus microsporus var. microsporus and var. oligosporus are used in the manufacture of various Asian fermented foods (tempe, black oncom, sufu). In view of solid-substrate fermentation (SSF) control, mycelial growth of strains of both varieties was tested for sensitivity to fluctuations of temperature, water activity and interstitial gas composition. This was achieved by measuring radial growth as well as biomass dry weight of pre-germinated microcolonies on defined media. The optimum conditions were temperature 40 °C, a w 0.995 and a gas composition of air for the growth of both strains on a model medium. Whereas radial growth rates of var. microsporus and var. oligosporus were similar, biomass growth rates of var. oligosporus were higher than those of var. microsporus under optimum conditions. The temperature-dependent growth of Rhizopus spp. at a w 〉 0.98 could be described by the Ratkowsky Equation. Carbon dioxide (5–10% v/v) inhibited the growth of Rhizopus spp. at non-limiting levels of oxygen. The two strains were able to grow at low (0.5% v/v) oxygen levels, but the mycelial density was rather low. No interrelation of water activity and gas composition was observed, but at high water activity the fungi were more sensitive to changes of temperature. The implications for process control are discussed.
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  • 5
    ISSN: 1573-0778
    Keywords: chicken ; immunoglobulin gene ; monoclonal antibody ; phage display ; prion protein ; recombinant antibody
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The chicken is a useful animal for the development of the specificantibodies against the mammalian conserved proteins. We generated twotypes of recombinant chicken monoclonal antibodies (mAbs), using a phagedisplay technique from a chicken hybridoma HUC2-13 which secreted themAb to the N-terminal of the mammalian prion protein (PrP). Althoughthe mAb HUC2-13 is a useful antibody for the prion research, thehybridoma produces a low level of antibody production. In order to producea large amount of the mAb, we have constructed a single chain fragmentvariable region (scFV) mAb by using the variable heavy(VH) and light (VL)genes which were amplified by using the two primer pairs and theflexible linker. The two phage display mAbs (HUC2p3 and HUC2p5)expressed on a M13 filamentous phage and their soluble type mAbs(HUC2s3 and HUC2s5) were reacted with the PrP peptide antigen in theELISA. In the Western blot analysis, the mAbs HUC2p3 and HUC2s3 wereas reactive to PrPc from mouse brains as the mAb HUC2-13 was. The nucleotide sequences of VH and VL genes from HUC2-13 and the two cloneswere identical except for only one residue. These results indicate that themethods presented here provide an effective tool for the improvement ofthe low levels of antibody production in the chicken hybridoma system.
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  • 6
    ISSN: 1573-0778
    Keywords: fed batch ; hybridoma ; macromolecular composition ; monoclonal antibody ; substrate limitation ; target specific growth rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Batch and fed-batch cultures of a murine hybridomacell line (AFP-27) were performed in a stirred tankreactor to estimate the effect of feed rate on growthrate, macromolecular metabolism and antibodyproduction. Macromolecular composition was foundto change dynamically during batch culture ofhybridoma cells possibly due to active production ofDNA, RNA and protein during the exponential phase.Antibody synthesis is expected to compete with theproduction of cellular proteins from the amino acidpool. Therefore, it is necessary to examine therelationship between cell growth in terms of cellularmacromolecules and antibody production. In this study,we searched for an optimum feeding strategy bychanging the target specific growth rate in fed-batchculture to give higher antibody productivity whileexamining the macromolecular composition. Concentratedglucose (60 mM) and glutamine (20 mM) in DR medium(1:1 mixture of DMEM and RPMI) with additional aminoacids were fed continuously to the culture and thefeed rate was updated after every sampling to ensureexponential feeding (or approximately constantspecific growth rate). Specific antibody productionrate was found to be significantly increased in thefed-batch cultures at the near-zero specific growthrate in which the productions of cellular DNA, RNA,protein and polysaccharide were strictly limited byslow feeding of glucose, glutamine and other nutrients. Possible implications of these results are discussed.
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  • 7
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    World journal of microbiology and biotechnology 16 (2000), S. 607-612 
    ISSN: 1573-0972
    Keywords: Aflatoxin ; apple ; fruit oils ; fungi ; patulin ; sodium hypochlorite ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Aspergillus flavus, A. niger, Penicillium expansum and Rhizopus stolonifer were the most frequently isolated fungi from healthy apple fruits. Alternaria alternata was the most common organism of rotten apple fruits, followed by A. niger, A. flavus, P. expansum and R. stolonifer. The prevalent type of decay, brown rot lesion, is caused by R. stolonifer followed by A. flavus, A. niger, A. alternata and P. expansum. Sodium hypochlorite had good curative properties against fruit rots. The main natural mycotoxins produced in rotten apple were patulin and aflatoxins. The optimum temperature for patulin production by P. expansum was 15 °C after 15 days. Complete inhibition of patulin formation was attained using 0.2% lemon oil and 〉 90% inhibition using 0.05% lemon and 0.2% orange oils. Also significant inhibition (〉 90%) of aflatoxin production was observed with 0.2% lemon oil.
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  • 8
    ISSN: 1573-0778
    Keywords: immunoaffinity column ; MALDI-MS ; monoclonal antibody ; solasodine glycosides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Immunoaffinity column using anti-solamargine monoclonal antibody for separation of solasodine glycosides was established. This method was specific for solasodine glycosides which was detected by thin layer chromatography and the western blotting. Total solasodine glycosides have been separated directly from the crude extract of Solanum khasianum fruit by the newly established immunoaffinity column.
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  • 9
    ISSN: 1573-0778
    Keywords: monoclonal antibody ; porous microcarrier ; prourokinase ; recombinant CHO cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Using porous microcarrier Cytopore and a low-serum medium supplement BIGBEF-3, we have successfully cultivated recombinant CHO cell line CL-11G producing prourokinase and hybridomas producing anti-prourokinase monoclonal antibody in Celligen 1.5 or 5 L bioreactor. The cell density obtained ranged from 1 to 2 × 107 cells mL-1. The yields of prourokinase and monoclonal antibody increased with increasing cell density. As the cells could spontaneously release from and reattach to porous microcarriers, it was very easy to scale-up the cultivation. Thus the bead to bead cell transfer method has been used to scale up the cultivation of CL-11G cells to a 20 L reactor-scale for the pilot production of prourokinase, and also to scale-up the culture of hybridomas for the production of monoclonal antibody for the purification of prourokinase.
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  • 10
    ISSN: 1573-0778
    Keywords: ginsenoside-Rb1 ; ELISA ; monoclonal antibody ; qualitative analysis ; mass spectrometry
    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 an antigen conjugate was determined by matrix-assisted laser desorption/ionization mass spectrometry. A hybridoma secreting monoclonal antibody against ginsenoside Rb1 was produced by fusing splenocytes immunized with a ginsenoside Rb1- bovine serum albumin conjugate with HAT-sensitive mouse myeloma cell line, P3-X63-Ag8-653. A very small cross-reaction appeared with ginsenoside Rc and ginsenoside Rd. The full measuring range of the assay extends from 20 ngml-1 to 400 ngml-1 of ginsenoside Rb1.
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  • 11
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    World journal of microbiology and biotechnology 15 (1999), S. 335-338 
    ISSN: 1573-0972
    Keywords: Anaerobic digestion ; biogas ; pathogens ; survival ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The survival of certain pathogenic bacteria was studied in anaerobic batch digesters at room temperature (18–25 °C) as well as at 35 °C under laboratory conditions. The survival of Escherichia coli and Salmonella typhi at room temperature was upto 20 days whereas at 35 °C it was only upto 10 days. Shigella dysenteriae was found to be the most sensitive organism which could survive upto 10 days at room temperature and upto 5 days at 35 °C. The longest survival was observed in case of Streptococcus faecalis which could survive upto 35 days at room temperature and 15 days at 35 °C. The survival time of Salmonella typhi increased when the solid contents of the digester were elevated from 9% to 15%.
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  • 12
    ISSN: 1573-0778
    Keywords: crocetin glycosides ; crocin ; Crocus sativus ; ELISA ; MALDI-TOF-MS ; monoclonal antibody
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Three crocin-carrier protein conjugates were synthesized and their hapten numbers were determined by matrix-assisted laser desorption/ionization time of flight mass spectrometry. Three monoclonal antibodies against crocin were produced by hybridomas fused with the splenocytes immunized with crocin hemisuccinate-bovine serum albumin conjugate and HAT-sensitive mouse myeloma cell line, P3-X63-Ag8-653. They were identified as IgG2a and IgG2b possessing λ light chain, respectively. Their wide reactivities against crocetin glycosides were discussed.
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  • 13
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    Cytotechnology 31 (1999), S. 9-27 
    ISSN: 1573-0778
    Keywords: cannabino ; ELISA ; forskolin ; idmonoclonal antibody ; monoclonal antibody ; western blotting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The ratio of hapten to bovine serum albumin (BSA) in an antigen conjugate was determined by matrix-assisted laser desorption/ionization (MALDI) tof mass spectrometry. A hybridoma secreting monoclonal antibody (MAb) was produced by fusing splenocytes immunized with an antigen-BSA conjugate with HAT-sensitive mouse myeloma cells. The cross-reaction of anti-forskolin antibodies with 7-deacetyl forskolin was 5.6%. A very small cross-reaction appeared with other derivatives. The full measuring range of the assay extends from 5 ng to 5 μg/ml of forskolin. Immunoaffinity column chromatography using anti-forskolin MAbs appears to be far superior to previously published separation methods. The capacity of the immunoaffinity column as determined by ELISA is 9 μg/ml. Forskolin has been isolated directly from the crude extracts of tuberous roots and the callus culture of Coleus forskohlii. A MAb against tetrahydrocannabinolic acid (THCA) was produced. The cross-reaction of anti-THCA antibody against other cannabinoids was very wide. Many cannabinoids and a spiro-compound were reactive, but did not react with other phenolics. It became evident that this ELISA was able to be applied to the biotransformation experiments of cannabinoids in plant tissue culture system. Anti-ginsenoside Rb1 MAbs were produced. New western blotting method of determination for ginsenosides was established. Ginsenosides separated by silica gel TLC were transferred to a polyvinylidene difluoride (PVDF) membrane. The membrane was treated with NaIO4 solution followed by BSA, resulting in a ginsenoside-BSA conjugate. Immunostaining of ginsenosides was more sensitive compared to other staining. Immunostaining of ginsenosides in the fresh ginseng root was succeeded using anti-ginsenoside Rb1 (GRb1) MAb after blotting to PVDF membrane.
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  • 14
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    World journal of microbiology and biotechnology 14 (1998), S. 847-850 
    ISSN: 1573-0972
    Keywords: Kinema ; soybean ; Bacillus subtilis KK2:B10 ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Kinema was prepared by fermenting whole cooked soybeans with pure culture of Bacillus subtilis KK2:B10 (MTCC 2756) strain at 35°C, 40°C and 45°C for 24h. Temperature, mesophilic plate counts, relative viscosity, water-soluble nitrogen, formal nitrogen contents and reducing sugars of fermenting soybeans were investigated during fermentation. At higher temperatures the growth rate of B. subtilis KK2:B10 was faster. A remarkable increase in the relative viscosity of kinema was observed at 40°C during fermentation. Water-soluble nitrogen and formol nitrogen to total nitrogen contents increased throughout the 24h of fermentation. Reducing sugars increased during the log phase and then decreased sharply. Kinema matured below 10°C for 1 day after the desired fermentation showed a significant increase in relative viscosity. The quality of kinema was maintained with pure culture fermentation by B. subtilis KK2:B10 at 40°C for 20h and matured at 5°C for 1 day.
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  • 15
    ISSN: 1573-0778
    Keywords: CA19-9; F(ab')2 fragment ; F(ab')2μ fragment ; flow cytometry ; IgM ; monoclonal antibody ; sialyl Lewis A.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract F(ab')2 fragments, herein designated as F(ab')2μ fragments, were prepared from a mouse IgM monoclonal antibody specific to sialyl Lewis A antigen. The fragments were applied to flow cytometry to analyze the antigen on human cancer cells. The binding of the fragments to the antigen-positive cells was stronger than that of the original IgM. The non-specific binding of the IgM antibody to the antigen-negative cells was much decreased by using the F(ab')2μ fragments. These results indicate that the F(ab')2μ fragments are more suitable than the original IgM monoclonal antibody in flow cytometric analysis.
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  • 16
    ISSN: 1573-0778
    Keywords: monoclonal antibody ; immobilization ; collagen gel ; BHK ; productivity ; recombinant ; high density culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Animal cell perfusion high density culture is often adopted for the production of biologicals in industry. In high density culture sometimes the productivity of biologicals has been found to be enhanced. Especially in immobilized animal cell culture, significant increase in the productivity has been reported. We have found that the specific monoclonal antibody (MAb) productivity of an immobilized hybridoma cell is enhanced more than double. Several examples of enhancing productivities have been also shown by collagen immobilized cells. Immobilized cells involve some different points from non-immobilized cells in high density culture: In immobilized culture, some cells are contacted together, resulting in locally much higher cell concentration more than 108 cells/ml. Information originating from a cell can be easily transduced to the others in immobilized culture because the distance between cells is much nearer. Here we have performed collagen gel immobilized culture of recombinant BHK cells which produce a human IgG monoclonal antibody in a protein-free medium for more than three months. In this high density culture a stabilized monoclonal antibody production was found with around 8 times higher specific monoclonal antibody productivity compared with that in a batch serum containing culture. No higher MAb productivity was observed using a conditioned medium which was obtained from the high density culture, indicating that no components secreted from the immobilized cells work for enhancing monoclonal antibody production. The MAb productivity by the non-immobilized cells obtained by dissolving collagen using a collagenase gradually decreased and returned to the original level in the batch culture using a fresh medium. This suggests that the direct contact of the cells or a very close distance between the cells has something to do with the enhancement of the MAb productivity, and the higher productivity is kept for a while in each cell after they are drawn apart.
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  • 17
    ISSN: 1573-0778
    Keywords: antigenicity ; β-lactoglobulin ; monoclonal antibody ; recombinant protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract We purified recombinant bovine β-lactoglobulin (rβ-LG) from the culture supernatant of transformed yeast and investigated whether rβ-LG maintained the functional ability and antigenicity of native β-LG. Immunostaining following gel electrophoresis and reversed-phase high-performance liquid chromatography confirmed that rβ-LG was purified homogeneously. rβ-LG showed almost the same retinol-binding ability as native β-LG purified from bovine milk. However, affinities of two anti-β-LG monoclonal antibodies (mAbs) to rβ-LG were different from those to native β-LG, although three other mAbs bound these two proteins equally. Since our panel of five mAbs has been previously shown to be able to detect structural changes occurring in β-LG, this variance in antigenicity can be attributed to conformational differences between rβ-LG and native β-LG. Then, we studied which step in the production and purification procedure was responsible for altering the antigenicity of rβ-LG. Bovine milk native β-LG was added to several steps in this procedure and purified in the same manner as rβ-LG. The results suggested that incubation in the yeast culture had adverse effects on maintaining the antigenicity of this recombinant protein. We conclude from these results that even if no difference between the native and recombinant proteins can be detected by functional analysis, some subtle conformational change which can be distinguished by mAbs may be incorporated into the recombinant protein during its production and ultimately cause a different immune reaction in vivo. Abbreviations β-LG, β-lactoglobulin; rβ-LG, recombinant β-LG; PBS, phosphate-buffered saline; PBS-Tween, PBS containing 0.05% Tween 20; ELISA, enzyme-linked immunosorbent assay.
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  • 18
    ISSN: 1573-0778
    Keywords: antibody consistency ; hollow fibre bioreactor ; hybridoma ; monoclonal antibody
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract This paper analyses the performance of MAbMaxTM/TricentricTM, a new generation hollow fibre bioreactor, for hybridoma growth and antibody productivity, the down stream processing of monoclonal antibody harvests throughout the run and the further control of antibody quality consistency. Handling and process parameters were optimised using a mouse hybridoma, IgG1K secretor, and then confirmed with several other hybridomas. Cells were kept at optimal viability during an unusually long period of time and a continuously high production of antibodies was detected over several months. Foetal bovine serum concentration was reduced to 1\% and the effects of weaning of cells from serum were monitored in terms of cell metabolism and antibody productivity. Antibody harvests collected at regular intervals throughout the run (2 to 12 weeks) were purified using affinity chromatography on a recombinant protein A/G matrix and then analysed in terms of antigen binding properties, isoelectric forms and oligosaccharide structures, in order 1) to control antibody quality consistency as a function of time and serum concentration and 2) to compare antibody characteristics as a function of culture conditions, in vitro bioreactor cultivation versus in vivo mouse ascite cultivation.
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  • 19
    ISSN: 1573-0778
    Keywords: fluidized-bed reactor ; monoclonal antibody ; on-line monitoring ; sample system ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The monoclonal-antibody production of an immobilized hybridoma cell line cultivated in a fluidized-bed reactor was monitored on-line for nearly 900 h. The monoclonal antibody concentration was determined by an immuno affinity-chromatography method (ABICAP). Antibodies directed against the product, e.g. IgG, were immobilized on a micro-porous gel and packed in small columns. After all IgG present in the sample was bound to the immobilized antibodies, unbound proteins were removed by rinsing the column. Elution of the bound antibodies followed and the antibodies were determined by fluorescence. The analytical procedure was automated with a robotic device to enable on-line measurements. The correlation between the on-line determined data and antibody concentrations measured by HPLC was linear. A sampling system was constructed, which was based on a pneumatically actuated in-line membrane valve integrated into the circulation loop of the reactor. Separation of the cells from the sample stream was achieved by a depth filter made of glass-fibre, situated outside the reactor. Rapid obstruction of the filter by cells or cell debris and contamination of the sample system was avoided by intermittent rinsing of the sample system with a chemical solution. The intermittent rinsing of the filter, which had a surface of 4.8 cm2, resulted in an operational capacity of up to 40 samples (1.0 l total sample volume). Both the sampling system and the analytical device functioned without failure during this long-term culture. The culture temperature was varied between 34 and 40 °C. Raising the temperature from 34 up to 37 °C resulted in a simultaneous increase of growth and specific antibody production rate. Specific metabolic rates of glucose, lactate, glutamine and ammonium stayed constant in this temperature range. A further enhancement of temperature up to 40 °C had a negative effect on the growth rate, whereas the specific monoclonal antibody production rate showed a small increase. The other specific metabolic rates also increased in the temperature range between 38 to 40 °C.
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  • 20
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    Cytotechnology 24 (1997), S. 213-218 
    ISSN: 1573-0778
    Keywords: gene deletion ; hybrid antibody ; hybridoma ; immunoglobulin light chain ; monoclonal antibody
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Monoclonal antibodies (mAbs) of the IgG class produced by mouse hybridomas raised with NS-1 myelomas have been shown to contain two types of immunoglobulin light (κ) chains derived from the myelomas and antigen-stimulated spleen lymphocytes, and the hybridomas produce three mAb species with light chain heterogeneity (Abe and Inouye, 1993). In the present study, 9 hybridoma lines secreting homogeneous mAbs have been isolated from 63 lines cloned from an established hybridoma line producing three mAbs. They secrete homogeneous mAbs containing light chains derived from either myeloma or spleen cells. They contain either κ gene derived from the respective cells, and the other gene was deleted during the cultivation. The deletion frequency of the κ gene of myelomas is 3 times higher than that of spleen cells, although 80–85% of hybridomas reach the stable state containing both κ genes.
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  • 21
    ISSN: 1573-0778
    Keywords: hybridoma ; monoclonal antibody ; stirred tank perfusion culture ; potassium acetate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract To increase the yield of monoclonal antibody in a hybridoma culture, it is important to optimize the combination of several factors including cell density, antibody productivity per cell, and the duration of the culture. Potassium acetate enhances the production of antibodies by cells but sometimes depresses cell density. The production of anti-(human B-type red blood cell surface antigen) antibody by Cp9B hybridoma was studied. In batch cultures, potassium acetate inhibited Cp9B cells growth and decreased the maximal cell density but the productivity of antibody per cell was increased. The balance of the two effects resulted in a slight decline of antibody production. In a stirred tank bioreactor, the inhibitory effect of potassium acetate on cell density was overcome by applying the perfusion technique with the attachment of a cell-recycling apparatus to the bioreactor. In such a reactor, potassium acetate at 1 g l-1 did not cause a decrease in the cell density, and the antibody concentration in the culture supernatant was increased from 28 μg ml-1 to 38 μg ml-1. Potassium acetate also suppressed the consumption of glucose and the accumulation of lactate in batch cultures, but the glucose and lactate levels were kept stable by applying the perfusion technique in the stirred tank bioreactor.
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  • 22
    ISSN: 1573-0778
    Keywords: adaptation ; hybridoma ; monoclonal antibody ; protein free medium ; suspension culture ; weaning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A simple protein free medium was formulated and tested in suspension culture using three hybridoma cell lines. The medium, referred to as CDSS (Chemically Defined Serum Substitutes), consisted of the basal medium DMEM:Ham F12, 1:1, with HEPES (D12H), plus pluronic F68, trace elements, ferric citrate, ascorbic acid, and ethanolamine. No protein or lipid components were added. All three cell lines were weaned off serum using CDSS and a commercially available protein free medium PFHM-II. Data shown here indicated that normally cells took 1–7 weeks to wean off serum and an additional 2–7 weeks to adapt to suspension culture. After adaptation the cells were able to grow well in suspension culture using both protein free media and in the main performed better than serum containing controls. The stability of the three hybridoma cells for antibody production following freeze/thaw procedures and long term subculturing was also tested. All three lines were frozen using our protein free CDSS medium (containing 0.75% bovine serum albumin and 10% dimethyl sulfoxide) in liquid nitrogen for up to one year. Cells thawed from these stocks recovered well and were able to maintain good growth and antibody production characteristics. One line was shown to grow using our protein free CDSS medium in suspension culture for 12 weeks without loss of antibody productivity.
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  • 23
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    Cytotechnology 19 (1995), S. 55-61 
    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.
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  • 24
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    Cytotechnology 18 (1995), S. 35-50 
    ISSN: 1573-0778
    Keywords: ammonium removal ; cross-flow filtration ; monoclonal antibody ; membrane fouling ; perfusion culture ; zeolite ; hybridoma cells ; defined medium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Production of monoclonal antibody against hepatitis B surface antigen was carried out by perfusion culture coupled with a selective removal system for ammonium ion. The removal system is composed of three sub-systems namely, cell separation by cross-flow ceramic filter, dialysis by hollow fiber module and ion-exchange by zeolite A-3 packed bed column. The ammonium ion concentration in the culture broth was effectively maintained below the inhibitory level, and the viable cell density reached 2.5×107 cells ml−1 which was three times that of conventional perfusion cultures. The monoclonal antibody accumulated to a concentration as high as 26.3×105 mIU−1. This is already almost half of the amount producedin vivo. The numerical investigation of the ammonium ion removal system showed the possibility to improve much more the performance of this perfusion cultivation system.
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  • 25
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    Cytotechnology 18 (1995), S. 93-106 
    ISSN: 1573-0778
    Keywords: Cytokines ; monoclonal antibody ; immunotherapy ; coagulation ; complement neutrophils ; hypotension ; vascular leak syndrome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Recombinant cytokines and monoclonal antibodies (mAbs) are increasingly used in the treatment of a number of human diseases. Monitoring of the clinical efficacy of these agents requires specific clinical and laboratory measurements. A number of these novel therapies share common side effects, ranging from fever, headache and general malaise to hypotension, the development of edema leading to the vascular leak syndrome, the occurrence of thromboembolic processes and, in severe cases, organ dysfunction. As an example of the pathogenesis of these side effects, recent data are presented which were obtained in patients receiving immunotherapy with high doses of the cytokine interleukin-2 as an anti-cancer treatment.
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  • 26
    ISSN: 1573-0778
    Keywords: steroidal alkaloid ; Solanum khasianum ; solamargine ; ELISA ; monoclonal antibody ; qualitative analysis ; mass spectrometry
    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 an antigen conjugate was determined by matrix-assisted laser desorption/ionization mass spectrometry. A hybridoma secreting monoclonal antibodies against solamargine was produced by fusing splenocytes immunized with a solamargine-bovine serum albumin conjugate with HAT-sensitive mouse myeloma cell line, P3-X63-Ag8-653. Extensive cross-reaction of anti-solamargine antibodies against solasonine appeared. Aglycone of solamargine, solasodine cross-reacted with anti-solamargine antibodies resulting in a 43.8% cross-reaction. Insignificant cross-reaction appeared with tomatine (2.06%). The full measuring range of the assay extends from 57.5 pmol ml−1 to 11.5 nmol ml−1 of solamargine.
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  • 27
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    Natural hazards 9 (1994), S. 5-16 
    ISSN: 1573-0840
    Keywords: Fourier transform ; maximum entropy spectral analysis ; precipitation ; temperature ; climatic change
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract In the present work, a precipitation and temperature series from Barcelona (Spain) are analysed in order to detect the possible existence of climatic changes or cycles. The analysis is carried out both from the temporal and spectral standpoints. The techniques used range from the classical periodogram and Blackman-Tukey method through to the Maximum Entropy method. The results do not show the existence of climatic cycles, though they do show a clear tendency toward increased precipitation and decreased temperature, since the last years of series.
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  • 28
    ISSN: 1573-0778
    Keywords: Cell cycle ; flow cytometry ; heavy chain ; hybridoma ; light chain ; monoclonal antibody ; population balance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Rates of accumulation of immunoglobulin proteins have been determined using flow cytometry and population balance equations for exponentially growing murine hybridoma cells in the individual G1, S and G2+M cell cycle phases. A producer cell line that secretes monoclonal antibodies, and a nonproducer clone that synthesizes only κ-light chains were analyzed. The pattern for the kinetics of total intracellular antibody accumulation during the cell cycle is very similar to the previously described pattern for total protein accumulation (Kromenaker & Srienc 1991). The relative mean rate of heavy chain accumulation during the S phase was approximately half the relative mean rate of light chain accumulation during this cell cycle phase. This indicates an unbalanced synthesis of heavy and light chains that becomes most pronounced during this cell cycle phase. The nonproducer cells have on average an intracellular light chain content that is 42% lower than that of the producer cells. The nonproducer cells in the G1 phase with low light chain content did not have a significantly higher rate of light chain accumulation relative to other G1 phase nonproducer cells. This is in sharp contrast to what was observed for the G1 phase producer cells. In addition, although the relative mean rate of accumulation of light chain was negative for G2+M phase nonproducer cells, the magnitude of this relative mean rate was less than half that observed for the producer cells in this cell cycle phase. This suggests that the mechanisms that regulate the transport of fully assembled antibody molecules through the secretion pathway differ from those which regulate the secretion of free light chains. The results reported here indicate that there is a distinct pattern for the cell cycle dynamics of antibody synthesis and secretion in hybridomas. These results are consistent with a model for the dynamics of secretion which suggests that the rate of accumulation of secreted proteins will be greatest for newborn cells due to an interruption of the secretion pathway during mitosis.
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  • 29
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    Cytotechnology 14 (1994), S. 219-232 
    ISSN: 1573-0778
    Keywords: animal cells ; cellular metabolism ; cultivation ; hybridomas ; modelling ; monoclonal antibody ; process control ; optimisation ; simulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The objective of this paper is to explore the range of methods and strategies available for the process control and optimization of monoclonal antibody production by hybridoma cell culture. Emphasis will be placed on the choice of the level of complexity incorporated into the process control and optimisation procedure. It will be shown that the behaviour of hybridomas in culture is influenced by sophisticated cellular metabolic activities and various interactive environmental factors and that the understanding and modelling of the way hybridomas grow in the bioreactor should enable optimisation of bioreactor operating conditions to achieve maximum monoclonal antibody formation. However, due to the lack of on-line instrumentation of important biological variables and the incomplete knowledge of hybridoma cultivation process, there exist many limitations and challenges to the advent of applications of process control and optimisation in this field. To solve the problem, introduction of industrially practical biological measurements and development of new control concepts are inevitable. At the end of this paper, we shall discuss possible schemes for the control of the physsiological state of cells in order that balanced cell growth and maximum monoclonal antibody synthesis may be achieved.
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  • 30
    ISSN: 1573-0778
    Keywords: Hybridoma cell culture ; monoclonal antibody ; exponentially fed-batch ; culture kinetics ; metabolism ; chemostat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Exponentially fed-batch cultures (EFBC) of a murine hybridoma in T-flasks were explored as a simple alternative experimental tool to chemostats for the study of metabolism, growth and monoclonal antibody (MAb) production kinetics. EFBC were operated in the variable volume mode using an exponentially increasing and predetermined stepwise feeding profile of fresh complete medium. The dynamic and steady-state behaviors of the EFBC coincided with those reported for chemostats at dilution rates below the maximum growth rate. In particular, steady-state for growth rate and concentration of viable cells, glucose, and lactate was attained at different dilution rates between 0.005 and 0.05 h−1. For such a range, the glucose and lactate metabolic quotients and the steady-state glucose concentration increased, whereas total MAb, volumetric, and specific MAb production rates decreased 65-, 6-, and 3-fold, respectively, with increasing dilution rates. The lactate from glucose yield remained relatively constant for dilution rates up to 0.03 h−1, where it started to decrease. In contrast, viability remained above 80% at high dilution rates but rapidly decreased at dilution rates below 0.02 h−1. No true washout occurred during operation above the maximum growth, as concluded from the constant viable cell number. However, growth rate decreased to as low as 0.01 h−1, suggesting the requirement of a minimum cell density, and concomitant autocrine growth factors, for growth. Chemostat operation drawbacks were avoided by EFBC in T-flasks. Namely, simple and stable operation was obtained at dilution rates ranging from very low to above the maximum growth rate. Furthermore, simultaneous operation of multiple experiments in reduced size was possible, minimizing start-up time, media and equipment costs.
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  • 31
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    Cytotechnology 15 (1994), S. 111-116 
    ISSN: 1573-0778
    Keywords: Adherent animal cells ; glucose ; lactate ; productivity ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Adherent recombinant BHK cells were cultivated at temperatures between 30 and 37°C. Batch and repeated-batch-cultivations in a 2-litre bioreactor showed a significant influence on metabolism and cell growth. The low-temperature-cultivations showed a lower growth rate and a lower glucose consumption rate and, therefore, less lactate production. On the other hand, the maximum cell density and productivity seemed not to be affected by the temperature reduction.
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  • 32
    ISSN: 1573-0778
    Keywords: Anti-D ; effector function ; glycosylation ; immunoglobulin G ; monoclonal antibody
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Cell lines BTSN4 and BTSN5 were produced by the Epstein-Barr Virus (EBV) transformation of B-lymphocytes from the same human donor. Both secrete an anti-D monoclonal of the IgG1 subclass but these antibodies display vastly different effector activities. Specifically, anti-D from BTSN4 has a far greater activity in both monocyte-and lymphocyte-mediated ADCC reactions and causes a higher percentage of rosettes to be formed with monocyte-like U937 cells. This variation in functional activity is shown to coincide with changes in the structure of the sugar chains attached to the asparagine-297 site on the immunoglobulin heavy chain.
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  • 33
    ISSN: 1573-0778
    Keywords: Hybridomate ; monoclonal antibody ; perfusion ; microfiltration ; membrane ; fouling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract In this study two microporous hollow fibre membranes were evaluated for their use as cell retention device in continuous perfusion systems. A chemically modified permanent hydrophillic PTFE membrane and a hydrophilized PP membrane were tested. To investigate the filtration characteristics under process conditions each membrane was tested during a long term perfusion cultivation of a hybridoma cell line. In both cultivations the conditions influencing membrane filtration (e.g. transmembrane flux) were kept constant. Filtration behaviour was investigated by monitoring transmembrane pressure and protein permeability. Transmembrane pressure was measured on-line with an autoclavable piezo-resistive pressure sensor. Protein permeability was determined by quantitative evaluation of unreduced, Coomassie stained SDS-PAGE. The membrane fouling process influences the filtration characteristics of both membranes in a different way. After fermentation the PP membrane was blocked by a thick gel layer located in the big outer pores of the asymmetric membrane structure. The hydraulic resistance was higher but the protein permeability was slightly better than of the PTFE membrane. For this reason the PP membrane should be preferred. On the other hand, transmembrane pressure decreases slower when the PTFE membrane is used, which favours this membrane for long term cultivations, especially when low molecular weight proteins (〈30 KD) are produced.
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  • 34
    ISSN: 1573-0778
    Keywords: Adenylate cyclase activator ; Coleus forskohlii ; enzyme immunoassay ; forskolin ; monoclonal antibody ; mass spectrometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The ratio of hapten to bovine serum albumin in an antigen conjugate was exactly determined by matrix-assisted laser desorption/ionization mass spectrometry. A hybridoma secreting monoclonal antibodies against forskolin was produced by fusing splenocytes immunized with a forskolin-bovine serum albumin conjugate with HAT-sensitive mouse myeloma cells. The cross-reaction of anti-forskolin antibodies with 7-deacetyl forskolin was 5.57%. A very small cross-reaction appeared with 1-deoxy, 9-deoxy and 1,9-dideoxy forskolin derivatives. The full measuring range of the assay extends from 6 ng to 200 ng of forskolin. The competitive ELISA assay used for this analysis was found to be more sensitive than TLC (10 μg), GLC (30 ng) and HPLC (1 μg) methods.
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  • 35
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    Cytotechnology 16 (1994), S. 147-150 
    ISSN: 1573-0778
    Keywords: Hybridoma ; peptone ; monoclonal antibody ; cell culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Hybridoma WuT3 secreting a monoclonal antibody against T lymphocytes was grown in RPMI 1640 medium supplemented with 1% human serum. The effect of the concentration of peptone, as an additive, was investigated on cell growth, monoclonal antibody formation, and cell metabolism over 0–10 g l−1 range. It was found that 1–5 g l−1 peptone can significantly promote the growth of cells and increase the formation of monoclonal antibody, especially at 3–5 g l−1, when both the accumulating level and secretion rate of monoclonal antibody are higher than that at other peptone concentrations. Based on glucose, lactate and ammonia analysis data, the efficiency of glycolysis was assessed and the utilization of amino acids was more efficient at 3–5 g l−1 peptone. The cell growth and monoclonal antibody formation were inhibited at higher peptone concentrations, e.g. 10 g l−1.
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  • 36
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    Cytotechnology 11 (1993), S. 169-174 
    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.
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  • 37
    ISSN: 1573-0778
    Keywords: hybridoma cells ; medium design ; monoclonal antibody ; transferrin substitution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract KB-26.5, a murine hybridoma cell line producing an IgG3 monoclonal antibody used in blood type determination, primarily adapted to grow at 5% foetal calf serum (FCS) concentration has been adapted to grow at 0.5% FCS, maintaining its ability to produce antibodies at the same level. In the final step of adaptation, the addition of insulin, transferrin, ethanolamine and selenium to the media formulation was studied, using factorial assay techniques to check the effect of the different compounds and to optimize their required level for satisfactory growth and antibody secretion. KB-26.5 cells required only 20 μg/ml of transferrin to adapt to 0.5% FCS medium. Furthermore, transferrin could be substituted by FeCl3, at a relatively low level of 2 μg/ml. Maximum cell density decreased by 31.5% in spinner flask test, but the antibody titer was maintained, thus the specific productivity increased. However, inoculum size had to be increased three-fold with 0.5% FCS medium in order to assure cell growth.
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  • 38
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    Cytotechnology 12 (1993), S. 91-107 
    ISSN: 1573-0778
    Keywords: C219 ; diagnosis of multidrug resistance ; monoclonal antibody ; multidrug resistance ; MRK16 ; P-glycoprotein ; therapy of multidrug resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Multidrug resistance (MDR) is a major problem in cancer chemotherapy. As P-glycoprotein is the key molecule in MDR, many investigators have constructed anti-P-glycoprotein monoclonal antibodies (MAbs). Those antibodies, including MRK16 and C219, were used for elucidation of the mechanism of MDR and for overcoming of MDR. This article describes the characterization of the antibodies against the P-glycoprotein and other proteins of multidrug-resistant tumor cells, and discusses the therapeutic implication of the antibodies.
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  • 39
    ISSN: 1573-0778
    Keywords: collagen microspheres ; DOT influence ; fluidized bed bioreactor ; monoclonal antibody ; perfusion culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract In the study presented here a laboratory scale (150 ml) fluidized bed bioreactor was used as a tool for making kinetic measurements on the production of monoclonal antibodies (MAb) with a hybridoma cell line. We determined the influence of dissolved oxygen tension (DOT) on the metabolic activity of a hybridoma population immobilized in macroporous collagen microspheres. The data obtained showed a reduction of the metabolic activity of the immobilized population at reduced DOT, the total number of immobilized cells, however, remained constant. At decreasing DOT an increasing lactate yield from glucose at reduced glutamine consumption was noticed, indicating a shift in the pattern of substrate usage. A mathematical description of maintenance metabolism was formulated and the parameters of growth and maintenance requirements were calculated. A growth associated MAb production was determined under the conditions applied leading to space time yields of 225 mg MAb per liter of total reactor volume and day.
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  • 40
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    Cytotechnology 13 (1993), S. 51-53 
    ISSN: 1573-0778
    Keywords: cell recycle ; filtration ; hybridoma ; monoclonal antibody
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract At the end of a hybridoma batch culture, the cells are usually discarded after separation from the culture broth. If, however, they are aseptically recycled into the reactor, the production process can be resumed simply by the addition of fresh medium. This cycle can then be repeated several times consecutively. In a test case, with a mouse hybridoma, we found antibody yields for each cycle in the same range as for a standard batch. In a 15 1 stirred tank reactor we could, within 6 days, produce 2.8 g of monoclonal antibody (MAb). This type of reactor operation allowed a doubling in the reactor volumetric productivity (mg/l/day).
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  • 41
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    Cytotechnology 6 (1991), S. 65-78 
    ISSN: 1573-0778
    Keywords: hybridoma ; monoclonal antibody ; serum free culture ; low protein medium ; weaning protocol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A general weaning procedure is described which allowed a range of hybridomas to be weaned readily off serum without loss of antibody production. Initial work was carried out with one cell line only (SPO1 cells) and one serum substitute containing a final protein concentration of 40 mg l-1. The SPO1 cells were first adapted to a range of readily available basal media and then weaned off serum by a range of protocols. From this work an optimal weaning protocol and basal medium for weaning were determined. These were then used to wean the SPO1 cells and two other cell lines off serum with a second, protein free, serum substitute with varying concentrations of defined proteins added. All three cell lines investigated were readily weaned off serum by this protocol at protein concentrations as low as 1 mg l-1. No loss of antibody production was observed with any of the cell lines. The weaning procedure outlined is both simple and rapid and has been successfully adopted in our laboratory by relatively inexperienced cell culture technicians.
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  • 42
    ISSN: 1573-0778
    Keywords: Chuzan virus ; monoclonal antibody ; neutralizing antibody ; forward sandwich assay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract We established sixteen mouse monoclonal antibodies reactive to Chuzan virus K-47 strain using P3-X63-Ag8-U1 cells as fusion partner cells. Among them, CG53/2/4 recognized a 100K structural protein of the virus. The 100K antigen lost it's antigenicity for CG53/2/4 after mild periodate oxidation treatment, suggesting that the 100K viral antigen is a glycoprotein. In addition, CG53/2/4 neutralized the viral infectivity. This indicates that the 100K glycoprotein is essential for the infection of the virus. The other monoclonal antibodies reacted with a 41K antigen of the virus. Especially CG1/1 showed the highest reactivity to the virus. Forward step sandwich assay using CG1/1 and biotinylated CG53/2/4 could detect the virus at 10TCID50/ml. Therefore, these monoclonal antibodies can evantually predict the virus infection to the animals before their sideration.
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  • 43
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    Cytotechnology 6 (1991), S. 33-38 
    ISSN: 1573-0778
    Keywords: hybridoma ; monoclonal antibody ; myeloma ; serum-free and tissue plasminogen activator
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract We established a serum-free medium of low protein content(125μg/ml) TYI 100, consisting of three hormones and five growth factors for the growth of lymphoid and hybridoma cell lines. In TYI 100 medium, mouse and human hybridomas grew equally well as in RPMI 1640 supplemented with 10% fetal bovine serum (10% FBS) without adaptation to the serum-free medium. TYI 100 medium allowed several passages of mouse hybridoma lines and the total cell number was more than in 10% FBS. TYI 100 medium also supported growth of myelomas and anchorage dependent cell lines, Bowes and CHO, well. TYI 100 medium is composed of inexpensive supplements and is therefor applicable to large scale culture.
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  • 44
    ISSN: 1573-0778
    Keywords: cell improvement ; FGF ; hepatitis B virus ; human-human hybridoma ; monoclonal antibody ; proliferative activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Highly purified recombiaant basic fibroblast growth factor (rbFGF) and acidic FGF (aFGF) stimulated the proliferation of human-human (h-h) hybridomas to the extent of over four-fold from a low cell density such as 1×103 cells per ml in a serum-free medium in 24-well plates. The stimulatory effect of rbFGF was also observed in various lymphoid cell lines. Expecting that FGF could be an autocrine growth factor, we introduced bFGF gene into a h-h hybridoma using an expression plasmid induced by dexamethasone. The transformed cells thus obtained, HPO-75.11bbFGF-7, were able to grow well from a low inoculum density in a serum-free medium and antibody production was also increased when bFGF gene expression was induced. The transformed cells could grow at clonal density in a serum-free medium in 96-well plates, though the original cells could not. We also obtained a more practical transfectant, HPO-75.29-H74, using a high-shear stress adapted clone as the recipient and an expression plasmid having bFGF gene under the control of metallothioneine-I promoter. The HOP-75.29-H74 cells were capable of growing and producing human monoclonal antibody against hepatitis B virus surface antigen from an inoculum density of 1×103 cells per ml in an agitation vessel without addition of an inducer.
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  • 45
    ISSN: 1573-0778
    Keywords: growth-associated production ; hepatitis B virus ; human-human hybridoma ; immobilized culture ; monoclonal antibody ; perfusion culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Human-human hybridomas which secrete a human monoclonal antibody (h-MoAb) against hepatitis B virus surface antigen showed growth associated production kinetics. The rate of h-MoAb production rapidly decreased after cell growth was arrested in a perfusion culture, even if the perfusion rate was increased. A continuous suspended-perfusion culture, in which both culture broth and culture supernatant are continuously harvested and the same volume of fresh medium is continuously fed into the reactor, was developed to maintain continuous growing conditions during cultivation. In this culture system, the production of h-MoAb continued for more than 50 days with an average productivity of 5.0 mg/l of working volume/day. A semicontinuous immobilized-perfusion culture in which parts of the cells are repeatedly removed from the immobilized reactor was another useful technique for the long term cultivation of these h-h hybridomas. As an average h-MoAb production rate, 62 mg/l of immobilized-bed volume/day was achieved for 65 days of cultivation using a ceramic matrix reactor, and 327 mg/l/day was achieved over 47 days of cultivation using a hollow fiber reactor equipped with Cultureflo MTM Thus, the antibody productivity per reactor volume per day by the semicontinuous immobilized-perfusion culture was much higher than that of the continuous perfusion culture in an agitation reactor.
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  • 46
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    Cytotechnology 4 (1990), S. 13-28 
    ISSN: 1573-0778
    Keywords: monoclonal antibody ; hybridoma ; electron microscopy ; endoplasmic reticulum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Electron microscopy of mouse hybridoma cell lines shows that the major difference between non, low and high producer cell lines is the amount of endoplasmic reticulum. Vesicular-tubular or cavernous structures of endoplasmic reticulum, which can survive long after cell death, are particularly abundant in producer cell lines. Immunogold labelling with anti-mouse IgG reveals that antibodies are predominantly located in these structures. The cell membrane undergoes structural changes during the late stages of batch culture with the disappearance of microvilli and the appearance of blebs and deep indentations. Necrosis disrupts the cytoplasmic structures and the nucleus is last to degrade.
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  • 47
    ISSN: 1573-0778
    Keywords: animal cell culture ; hybridoma ; monoclonal antibody ; packed bed reactor ; continuous culture ; perfusion ; protein-free medium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The present work demonstrates the utility of packed bed reactors for the production of monoclonal antibody. We present data from a continuous process run for the production of over 100 grams of antibody, using serum-free medium. An additional pilot run also demonstrates the potential for continued antibody production under protein-free conditions, using a standard basal medium.
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  • 48
    ISSN: 1573-0778
    Keywords: hybridoma ; perfusion culture ; monoclonal antibody ; serum-free culture ; centrifuge
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The influence of centrifugal force on the growth of cells was examined by exposing the cells of the mouse-human hybridoma X87 line to centrifugal force (100–500 G) for ten minutes twice a day and comparing the static culture with that of unexposed cells. In this experiment, both cell proliferation and specific antibody productivity were independent of the centrifugal effect, and gave the same results as in the case of no exposure to centrifugal force. High density cultivation of the mouse-human hybridoma X87 line was obtained by a perfusion system where the cells were separated from the culture medium by continuous centrifugation. In the serum-free culture, the maximum viable cell density exceeded 107 cells/ml, and monoclonal antibody was stably produced for 37 days. The results in this culture were equivalent to those obtained by intermittent centrifugal cell separation from the culture medium, and separation by gravitational settlement.
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  • 49
    ISSN: 1573-0778
    Keywords: hybridoma ; monoclonal antibody ; rIL-2 ; Tac gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The presence of a highly purified recombinant interleukin-2 (rIL-2) increased the production of immunoglobulin (IgM or IgG) by human-human hybridomas to 1.5–2.0 times the production by untreated cells. However, these cells did not react with anti-Tac (IL-2 receptor α) antibody. To enhance the response of the hybridoma cells to rIL-2, Tac gene was introduced by co-transfection with Tac gene expression plasmid pTB459 and G418 resistant gene expression plasmid pRSVneo. Tac cDNA transfected hybridoma (HBW-4.16.459-6-126) was induced to produce 6 times as much IgG by rIL-2 as was the control. This antibody production promoting phenomenon mediated by rIL-2 was depressed by anti-Tac antibody.
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  • 50
    ISSN: 1573-0778
    Keywords: human-human hybridoma ; monoclonal antibody ; Pseudomonas aeruginosa exotoxin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A hybridoma secreting human monoclonal antibody (MAB) against Pseudomonas aeruginosa exotoxin A (PEA) was constructed by fusing Epstein-Barr virus-transformed peripheral blood lymphocytes with human B lymphoblastoid cell line TAW-925. The human-human hybridoma stably produced human IgG2 MAB at the rate of 0.4–0.5 μg/ml per 106 cells per day for more than six months, and the MAB was capable of neutralizing the in vitro cytotoxic and in vivo lethal effects of PEA with approximately 100-and 70-fold, respectively, higher activity than serum polyclonal antibody preparations.
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  • 51
    ISSN: 1573-0778
    Keywords: circularity ; hybridoma volume ; membrane blebs ; microvilli ; monoclonal antibody
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Hybridoma volume and surface membrane structure were found to vary as a function of specific growth rate using a method of cell recycle with continuous medium perfusion to vary growth rate. Mean hybridoma volume determined at constant osmolality by both electronic particle counting and scanning electron microscopic (SEM) methods indicated that rapidly growing cells are significantly larger than very slowly growing cells. We have previously determined that during both rapid and slow growth over a range of L-glutamine provision rates (Gln PR) that specific monoclonal antibody (MoAb) secretion rate was not changed. In this study a constant MoAb secretion rate per unit of membrane area was found which may indicate that changing membrane area is not a rate-determining factor in MoAb secretion. SEM methods were of limited use for accurate determination of cell volume due to cell shrinkage and large coefficients of variations. In spite of this limitation, SEM stereology methods were useful in confirming that cells remained spherical over a wide range of specific growth rates and that hybridoma cells were not circular. Sequential SEM observations also revealed that surface membrane structure of the 9.2.27 murine hybridoma investigated was correlated with growth rate. Under conditions of very slow growth, hybridoma surface microvilli density appeared to be significantly reduced.
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  • 52
    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.
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  • 53
    Electronic Resource
    Electronic Resource
    Springer
    Cytotechnology 2 (1989), S. 9-17 
    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.
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  • 54
    ISSN: 1573-0778
    Keywords: lipoprotein ; egg yolk ; serum-free medium ; cell growth ; monoclonal antibody ; ITES
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Egg yolk lipoprotein promoted growth of a wide variety of mammalian cell lines, including plasma-cytomas and epithelial cell lines, in serum-free medium. The lipoprotein was active for cell growth when used with insulin, transferrin, ethanolamine and selenite. The most active lipoprotein fraction (YLP-pI7.5) was purified to give a single peak by chromatofocusing and gel filtration, and was homogeneous on a 0.35% agarose gel electrophoretogram. The lipoprotein was characterised as a very low density lipoprotein with a protein content of only 1.3%. This lipoprotein had an optimal concentration of 300 μg/ml (4 μg protein/ml). It was easily separable from proteinous molecules secreted into the serum-free medium by the cells, since it floated on the surface of the medium after addition of ammonium sulfate, to precipitate protein, and centrifugation. An associated structure of lipid and protein seemed to be still necessary for the lipoprotein to exhibit a growth promoting activity.
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  • 55
    ISSN: 1573-0778
    Keywords: high-density ; hybridoma ; monoclonal antibody ; perfusion culture ; serum-free ; suspension culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract We have developed a high cell density and high product concentration culture system recycling high molecular weight components. The production of monoclonal antibodies in high concentration was performed by this culture system with mouse human hybridoma H2 and V6 cells in serum-free defined media. The concentration of IgG after 48 days culture of H2 cells in ITES-eRDF reached 2 mg/ml and the purity of IgG in culture fluid was 61%. In addition, high molecular weight components in serum-free media, such as transferrin or BSA, could be reduced to 5% of the original concentration.
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