Objective To establish and validate a method for the determination of the interesting protein expression level of recombinant adeno-associated virus(rAAV)infected cells,so as to monitor the product quality in different stages of rAAV9production process.Methods After incubation of serial diluted rAAV samples with infection enhancer Envirus-AAV,the human malignant glioblastoma cells(U87-MG)pretreated with hydroxyurea(HU)were infected.Using rAAV9 reference as the standard,the expression level of glutaryl-CoA dehydrogenase(GCDH)was detected by ELISA,and the specificity,accuracy,precision,linear range,limit of quantitation(LOQ)and durability of the method were verified.Eight batches of rAAV9 samples were detected by the established method.Results The A_(450)-A_(630) value of the sample buffer was 0.3,which was slightly lower than the lowest dilution point(1 ng/mL)of the four-parameter standard curve for protein quantification.The average recoveries of samples with 150%,100% and 50% theoretical relative titer levels were in the range of 100.0%-107.3%.The RSDs of the target protein expression level of the samples with three theoretical relative titer levels detected by the same experimenter three times and different experimenters were all less than 25%.There was a good linear relationship between rAAV9 samples and the target protein expression levels in the range of 50%-150% theoretical relative titer levels,and the linear regression equation was y = 1.077 x-0.022,R~2= 0.984.The LOQ of the method was 0.59,namely 6.0×10~(12) vg/mL.After U87-MG cells were incubated with HU for different time(18,21,24 h),and the culture supernatant was stored under different conditions(room temperature for 0.5 h,below-60 ℃ for 12 h,below-60 ℃ for 24 h).The RSDs of target protein expression levels were all less than 25%.The target protein expression levels of 1-8 batches of rAAV9 samples were 111%,121%,72%,65%,86%,75%,102% and 91%,respectively.Conclusion The established method for the determination of the target protein expression level after rAAV infection has good specificity,accuracy,precision and durability,and can be used for the quality control of products in different stages of rAAV9 production.

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 Methods:Totally 66 batches of recombinant human interferonα2b injection produced by 9 manufacturers were withdrawn, and the osmolality was determined according to the appendix of Chinese Pharmacopoeia Ⅲ(2010 edition).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.

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.

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.

Objective: To evaluate the quality status of recombinant human interferon α2a injections and find out some quality problems. Methods:The statutory testing methods combining with the exploratory studies were used to examine the samples, and the quality status of recombinant human interferon α2a injections was evaluated by statistical analysis of the results. Results: All 28 bat-ches of the injections were qualified using the statutory testing methods. The exploratory studies showed that if the specific activity was determined, the qualified rate was only 87. 0%. All 7 batches of drug substances were qualified using the statutory testing methods. The exploratory studies showed that if the related protein was determined, the qualified rate was 57. 1%. Conclusion:At present the quality of recombinant human interferonα2a injections is generally good. The current standards are feasible;however, improvement is still needed. Specific activity determination should be supplemented the standards for drug products and related protein determination should be supplemented the standards of drug substances.

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.

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.