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Recombinant human interferon α2b(rhIFNα2b)is widely used as an antiviral therapy agent for the treatment of hepatitis B and hepatitis C.The current identification test for rhIFNα2b is complex.In this study,an anti-rhIFNα2b nanobody was discovered and used for the development of a rapid lateral flow strip for the identification of rhIFNα2b.RhIFNα2b was used to immunize an alpaca,which established a phage nanobody library.After five steps of enrichment,the nanobody I22,which specifically bound rhIFNα2b,was isolated and inserted into the prokaryotic expression vector pET28a.After subsequent purification,the physicochemical properties of the nanobody were determined.A semiquantitative detection and rapid identification assay of rhIFNα2b was developed using this novel nanobody.To develop a rapid test,the nanobody I22 was coupled with a colloidal gold to produce lateral-flow test strips.The developed rhIFNα2b detection assay had a limit of detection of 1 μg/mL.The isolation of I22 and successful construction of a lateral-flow immunochromatographic test strip demonstrated the feasibility of performing ligand-binding assays on a lateral-flow test strip using recombinant protein products.The principle of this novel assay is generally applicable for the rapid testing of other com-mercial products,with a great potential for routine use in detecting counterfeit recombinant protein products.
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Accurate determination of biological activity is essential in quality control of recombinant human brain natriuretic peptide (rhBNP). In previous study, we successfully developed a genetically modified cell line 293GCAC3-based ELISA assay for rhBNP. But ELISA procedure is still tedious, so this study was aimed to develop a rapid and simple bioassay for rhBNP using GloSensor technology, which provides a platform of flexible luciferase-based biosensors for real-time detection of signaling events in live cells, including cGMP production. A reporter cell line 293GCAGlo-G1 was constructed by transfecting pGloSensor?40 F plasmid into 293GCAC3. The reporter assay based on 293GCAGlo-G1 showed high precision with intra-assay CV being 8.3% and inter-assay CV being 14.1%; high accuracy with 80%, 100% and 120% recovery rate being 99.2%, 102.4% and 99.0% respectively; and great linearity with R2of linear fitting equation being 0.99. Besides, no significant difference was found in test results of reporter assay and 293GCAC3-based ELISA assay (paired t test, p＝0.630). All these results suggested that the reporter assay was a viable assay for biological determination of rhBNP.
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Objective To evaluate the quality status of recombinant human interferon α1b injection and find out some quality problems.Methods Totally 31 batches of recombinant human interferon α1b for injection and 11 batches of recombinant human interferon α1b injection from two enterprises were examined according to Chinese Pharmacopoeia Volume Ⅲ (2010),and the quality status of recombinant human interferon α1b injection was evaluated by statistical analysis of the results.Results All 42 batches of samples were qualified.The production process of each enterprise was steady.Conclusion At present the quality of recombinant human interferon αlb injection is generally good.The current standards are feasible,but the specified standard of osmolality needs to be improved.
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Objective:To examine the osmolality of domestic recombinant human interferon α2b injection to provide evidence for the improvement of the national quality standard. Methods:Totally 66 batches of recombinant human interferonα2b injection produced by 9 manufacturers were withdrawn, and the osmolality was determined according to the appendix of Chinese Pharmacopoeia Ⅲ(2010 edition). The results were analyzed with statistical methods. Results:The pass rate of osmolality was 98. 5%. The osmolality of more than 90% of the batches was between 85% and 115% of the intermediate value set by the manufacturers. Conclusion:Comprehensive understanding of the quality control of osmolality of domestic recombinant human interferon α2b injection is obtained, which provides data support for the improvement of quality standard of osmolality.
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The study aims to characterize and compare interferon reference standards from 5 manufacturers. By testing molecular mass and trypsin-digested peptide mass mapping, the amino acid sequence was verified and post-translational modifications such as disulfide bond were identified. Results show that the molecular mass and amino acid sequence were consistent with theory; the disulfide bonds of 4 lots of interferon were Cys1-Cys98/Cys29-Cys138, 1 lot was Cys29-Cys139/Cys86-Cys99; N-terminal "+Met", acetyl N-terminal and Met oxidation were identified in part of the sample. UPLC-MS can be used to characterize and compare interferon reference standards from different manufacturers.
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The primary structure of TNK-tissue plasminogen activator (TNK-tPA) was characterized using liquid chromatography-mass spectrometry (LC-MS). Firstly, the molecular mass of deglycosylated protein was measured. Then peptide mass mapping and MS/MS of the reduced, alkylated and trypsin-digested sample were tested and analyzed so as to verify its amino acid sequence and identify post-translational modifications. Results show that the amino acid sequence was consistent with designed structure; about 5% of M207 was oxidized; T61 was fucosylated with -80% occupancy; N103, N448 and N184 (-15% occupancy) were glycosylated with complex-type oligosaccharides. LC-MS coupled with proper sample pretreatment is approved to be a rapid and powerful approach to characterize the primary structure of TNK-tPA.
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The amino acid sequence of the fusion protein FP3 was measured by two types of LC-MS/MS and its primary structure was confirmed. After reduction and alkylation, the protein was digested with trypsin and glycosyl groups in glycopeptide were removed by PNGase F. The mixed peptides were separated by LC, then Q-TOF and Ion trap tandem mass spectrometry were used to measure b, y fragment ions of each peptide to analyze the amino acid sequence of fusion protein FP3. Seventy-six percent of full amino acid sequence of the fusion protein FP3 was measured by LC-ESI-Q-TOF with the remaining 24% completed by LC-ESI-Trap. As LC-MS and tandem mass spectrometry are rapid, sensitive, accurate to measure the protein amino acid sequence, they are important approach to structure analysis and identification of recombinant protein.
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To establish a detection method of oncolytic adenovirus/p53 and standard of quality control, human telomerase reverse transcriptase (hTERT) promoter, CMV fusion promoter containing hypoxia reaction element (HRE) and p53 gene were identified by vector DNA restriction enzyme digestion and PCR analysis. The result conformed that all modified regions were in consistent with theoretical ones. Particle number was 2.0 x 10(11) mL(-1) determined by UV (A260). Infectious titer was 5.0 x 10(10) IU mL(-1) analyzed by TCID50. In vitro p53 gene expression in human lung cancer cell H1299 was determined by ELISA, and A450 ratio of nucleoprotein in virus infection group to control group was 5.2. Antitumor potency was evaluated by cytotoxicity assay using human lung cancer cell A549, and the MOI(IC50) of this gene therapy preparation was 1.0. The tumor cells targeted replication ability of recombinant virus was determined by TCID50 titer ratio of filial generation virus between human lung cancer cell A549 and human diploid epidermal fibrolast BJ cells after infected by virus with same MOI. TCID50 titer ratio of tumor cell infection group to normal cell infection control group was 398. The IE-HPLC purity of virus was 99.5%. There was less than 1 copy of wild type adenovirus within 1 x 10(7) VP recombinant virus. Other quality control items were complied with corresponding requirements in the guidance for human somatic cell therapy and gene therapy and Chinese pharmacopeia volume III. The detection method of oncolytic adenovirus/p53 was successfully established for quality control standard. The study also provided reference for quality control of other oncolytic viral vector products.
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Structure of a recombinant chimeric anti-CD20 IgG1 monoclonal antibody was verified by the application of high-performance liquid chromatography-mass spectrometry (HPLC-MS)and N-terminal sequencer. Molecular masses, N-terminal sequences and peptide maps of the antibody treated with different reagents and enzymes were measured. Results indicate that the amino acid sequences of light and heavy chains and 10 disulfide bonds were consistent with theoretical structure. By comparison of molecular masses and peptide maps for the fully glycosylated and deglycosylated samples, the N-linked glycosylation site was identified. The method is simple, rapid, precise, and could be referred to the quality control and structure determination of other IgG1 products.
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Objective: To establish a sensitive and effective method for bioassay of stem cell factor (SCF) in vitro used for evaluation of biological potency of this products. Methods: Leukemia cell line UT-7 was used in the bioassay of rhSCF. The optimal test condition was determined, by comparing different results of MTT staining from different cell concentration and cell culture time. The potency of SCF was calibrated by the National Reference. Results: According to dose-response curve of SCF on UT-7 cell proliferation, the optimal reaction time and dose range were determined. Conclusion: The established method of using UT-7 dependent cell line to test the SCF bioactivity can be used in routine quality control of the biological potency of recombinant SCF.
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Objective: To establish National Standard of rhTNF-? complying with the requirements of research and quality control. Methods: National Standard of rhTNF-? were assayed against international standard (NIBSC) of rhTNF-? by cytotoxicity bioassay (L929 ) in vitro. The collaborative study has been carried out among four laboratories. Results: Based on the statistical analysis the results show that mean pf 95 % confidence interval is 3 289 ~ 4 266 IU per ampoule; the 95 % reference range is 1 735 ~ 8 087 IU per ampoule. Based on this study, the potency of rhTNF-? standard is defined as 3500 IU per ampoule. Stability tests indicate that the bioactivity has not been changed significandy under the storage of four different temperautres for 27 monthes. Conclusion: The preparation of rhTNF-? met the requirement of quality and could be used as a National Standard.
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Through the improvement on determination of rhTNF-? bioassay, we established the formal procedure . Methods; We choose L929 cell for rhTNF-? bioassay determination. To identify the influence of rhTNF-? on the growth of HL-60 cells, various concentration and effecting time were studied. Results: The results showed that the inhibition of rhTNF-? on HL-60 cells based on dose and time. Northern Dot Blot and DNA electrophoresis showed c-myc gene was surpressed, and DNA was damaged by rhTNF-?. Conclusion: Autometic calculation is responsible for bioassay of rhTNF-?. rhTNF-? could inhibit the proliferation of HL-60 cells and its mechanism is different from doxirubicin.