Pharmacokinetics of PEGylated recombinant human endostatin (M2ES) in rats.

AIM: M2ES is PEGylated recombinant human endostatin. In this study we investigated the pharmacokinetics, tissue distribution, and excretion of M2ES in rats. METHODS: (125)I-radiolabeled M2ES was administered to rats by intravenous bolus injection at 3 mg/kg. The pharmacokinetics, tissue distribution and excretion of M2ES were investigated using the trichloroacetic acid (TCA) precipitation method. RESULTS: The serum M2ES concentration-time curve after a single intravenous dose of 3 mg/kg in rats was fitted with a non-compartment model. The pharmacokinetic parameters were evaluated as follows: Cmax=28.3 µg·equ/mL, t1/2=71.5 h, AUC(0-∞)=174.6 µg·equ·h/mL, Cl=17.2 mL·h(-1)·kg(-1), MRT=57.6 h, and Vss=989.8 mL/kg for the total radioactivity; Cmax=30.3 µg·equ/mL, t1/2=60.1 h, AUC(0-∞)=146.2 µg·equ·h/mL, Cl=20.6 mL·h(-1)·kg(-1), MRT=47.4 h, and Vss=974.6 mL/kg for the TCA precipitate radioactivity. M2ES was rapidly and widely distributed in various tissues and showed substantial deposition in kidney, adrenal gland, lung, spleen, bladder and liver. The radioactivity recovered in the urine and feces by 432 h post-dose was 71.3% and 8.3%, respectively. Only 0.98% of radioactivity was excreted in the bile by 24 h post-dose. CONCLUSION: PEG modification substantially prolongs the circulation time of recombinant human endostatin and effectively improves its pharmacokinetic behavior. M2ES is extensively distributed in most tissues of rats, including kidney, adrenal gland, lung, spleen, bladder and liver. Urinary excretion was the major elimination route for M2ES.

[Characterization and comparison of interferon reference standards using UPLC-MS].

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.

[Characterization of the primary structure of TNK-tissue plasminogen activator using LC-MS].

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.

[Measurement of the amino acid sequence for the fusion protein FP3 with LC-MS/MS].

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.

[Quality control of recombinant oncolytic adenovirus/p53].

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.

[Structure verification of a recombinant chimeric anti-CD20 IgG1 monoclonal antibody].

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.

[Quality control methods and requirements for recombinant human lymphocyte function associated antigen 3 IgG1 fusion protein (rhLFA3-IgG1)].

To establish methods and requirements for quality control of rhLFA3-IgG1, biological potency of rhLFA3-IgG1 was determined by CD2 molecule competitive binding assay on Jurkat cell surface. Purity of rhLFA3-IgG1 was analyzed by SEC-HPLC and IEC-HPLC. Peptide mapping was preformed by tryptic digestion and RP-HPLC after sample reduced and carboxymethylation by DTT and indoacetic acid, respectively. CHO host cell protein and Protein A residual were detected by ELISA separately. The quality control methods and requirements, such as biological potency, the physical-chemical characteristic of rhLFA3-IgG1 had been established. The methods and requirements for quality control of rhLFA3-IgG1 showed advantages of assuring the products safety and efficacy, which can be used for routine quality control of rhLFA3-IgG1.

[Peptide mapping analysis of recombinant human interleukin-11 with HPLC-ESI-Q-TOF/MS spectrometry].

AIM: To analyze the peptide mapping of recombinant human interleukin-11 (rhIL-11) by HPLC-ESI-Q-TOF/MS spectrometry. METHODS: The trypsin digested rhIL-11 at 37 degrees C over night, and the peptide mapping was performed by HPLC. The relative molecular weight of the peptides fragments was measured by ESI-Q-TOF/MS, and amino acid sequence was analyzed by MS/MS. RESULTS: The peptide fragments of rhIL-11 in the peptide mapping were assigned by analyzing the retain time, relative molecular weight and amino acid sequence. And 97% of the expected peptides were detected in this way. CONCLUSION: The study proves that HPLC-ESI-Q-TOF/MS is a good method to analyze peptide mapping of protein with the advantage of sensitivity, high speed and accuracy.

Synthesis and activity of an octapeptide inhibitor designed for SARS coronavirus main proteinase.

The outbreak of SARS, a life-threatening disease, has spread over many countries around the world. So far there is no effective drug for the treatment of SARS. Stimulated by the binding mechanism of SARS-CoV Mpro with the octapeptide AVLQSGFR reported recently as well as the "Chou's distorted key" theory, we synthesized the octapeptide AVLQSGFR for conducting various biochemical experiments to investigate the antiviral potential of the octapeptide against SARS coronavirus (BJ-01). The results demonstrate that, compared with other compounds reported so far, AVLQSGFR is the most active in inhibiting replication of the SARS coronavirus, and that no detectable toxicity is observed on Vero cells under the condition of experimental concentration.

Expression of human nerve growth factor beta gene in central nervous system mediated by recombinant adeno-associated viruses type-2 vector.

BACKGROUND: Neurone atrophy and loss are major causes of chronic neurodegenerative disorders such as Alzheimer's disease. Despite many pharmacotherapies for neurodegeneration, there are no accepted treatments. We investigated the feasibility of human nerve growth factor beta (hNGFbeta) gene expression mediated by recombinant adeno-associated viruses type-2 (rAAV-2) vector in the central nervous system (CNS) after blood brain barrier (BBB) disruption. METHODS: rAAV-2 containing hNGFbeta gene was constructed. The ability of hNGFbeta gene mediated by rAAV-2 vector (rAAV-2/hNGFbeta) to transfect cells in vitro was confirmed by both ELISA and bioassay of hNGFbeta in the culture supernatant of BHK-21 cells infected by rAAV-2/hNGFbeta. rAAV-2/hNGFbeta and rAAV-2/green fluorescence protein (GFP) were administrated separately to rat brains through internal carotid intubation after BBB disruption with hypertonic mannitol. Brain hNGFbeta concentration was measured by ELISA and GFP in brain sections was examined by laser scan confocal microscope. RESULTS: After 48 hours, hNGFbeta content in supernatant was up to (188.0 +/- 28.6) pg/ml when BHK-21 cells were infected by rAAV-2/hNGFbeta at multiplicity of infection (MOI) 1.0 x 10(6) vector genome. Neurone fibre outgrowths were obvious in dorsal root ganglion neurone assays by adding serum free culture medium harvested from BHK-21 cells exposed to rAAV-2/hNGFbeta. Whole brain hNGFbeta content in rAAV-2/hNGFbeta transferred group was up to (636.2 +/- 140.6) pg/ml. hNGFbeta content of BBB disruption in rAAV-2/hNGFbeta infused group increased significantly compared to the control group (P <0.05). GFP expression was clearly observed in brain sections of rAAV-2/GFP transferred group. CONCLUSION: rAAV-2/hNGFbeta successfully expresses in the CNS after BBB disruption induced by hypertonic mannitol.

[Study on methods for quality control of recombinant human neu epitope peptide 12].

AIM: To establish methods and requirements for the quality control of recombinant human neu epitope peptide 12. METHODS: Biological activity of recombinant human neu epitope peptide 12 was evaluated in FVB/N transgenic mice (TgN MMTV neu 202 Mul, Jackson Lab., USA) administered with samples. The percentage of antibody-positive mice detected by ELISA was used in the biological activity evaluation. The peptide map was performed by peptic digestion. The antigen content was determined by SEC-HPLC. RESULTS AND CONCLUSION: The quality control methods, such as biological activity, peptide map, antigen content, and the requirements for the quality control of recombinant human neu epitope peptide 12 were established. The established methods and requirements were already used for the quality control of recombinant human neu epitope peptide 12 products.

[Study on methods and requirements for quality control of recombinant human tumor necrosis factor receptor Fc fusion protein].

AIM: To establish methods and requirements for quality control of recombinant human tumor necrosis factor receptor Fc fusion protein (rhTNFR-Fc). METHODS: Biological potency of rhTNFR-Fc was determined by neutralizing the bioactivity of TNF-alpha. rhTNFR-Fc samples were reduced by beta-mercaptoethanol and the peptide map was performed by tryptic digestion. Residual protein A and the host cell protein content were detected by ELISA. Anti-TNFR and anti-Fc antibodies were used in ELISA for detection of the rhTNFR-Fc content. RESULTS: The quality control methods, such as bioassay, peptide map, residual protein A detection, were established and used for quality control of rhTNFR-Fc. The unit of rhTNFR-Fc (AU) was defined according to the international unit of TNF-alpha. The specific activity was up to 8 x 10(4) AU.mg-1. The requirements for quality control of rhTNFR-Fc were established. CONCLUSION: The methods and requirement were used for quality control of rhTNFR-Fc products.

[Quality control of recombinant adeno-associated virus type 2/human blood coagulation factor IX].

AIM: To establish quality control requirements and methods for recombinant adeno-associated virus(rAAV) type 2/human blood coagulation factor IX (rAAV-2/hFIX). METHODS: Identification of rAAV genome fragments, potential contaminants including wild type AAV(wtAAV) and helper virus, were detected by PCR. Purity of rAAV-2/hFIX was analyzed by cation-exchange HPLC and SDS-PAGE. Virus partical numbers were performed by dot blot assay. hFIX expression was demonstrated by ELISA and potency of hFIX was verified by APTT. RESULTS: Identity of rAAV-2/hFIX was proved. Residues of wtAAV and helper virus were conformed to requirements. Purity of rAAV-2/hFIX were more than 98%. Partical numbers of rAAV-2/hFIX were more than 1.0 x 10(15) VG.L-1. hFIX expression was more than 20.0 micrograms.L-1. hFIX potency was verified by APTT following rAAV-2/hFIX injected to FIX gene knockout mice, potency results conformed to requirements. CONCLUSION: The methods and requirements had been established for quality control of rAAV-2/hFIX.

[Quality control for recombinant adenovirus-IL2].

AIM: To investigate the quality and optimized test methods and establish the quality specification of recombinant adenovirus-IL2. METHODS: The titer of Adv-IL2 was measured by cytopathic effect (CPE). Hela cells were infected with Adv-IL2 in vitro, the expressed IL-2 and its bioactivity in Hela cell were determined by enzyme-linked immunosorbent assay (ELISA) and 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) respectively. The purity of Adv-IL2 was analysed by UV and IE-HPLC method. The molecular weight and enzyme digestive map of Adv-IL2 genome were analysed by electrophoresis. The characteristic gene E2B, IL-2 expression casseter and foreign factors (RCV, HIV, HBV, HCV) were detected with polymerase chain reaction (PCR). Other tests were carried out according to the Chinese Requirements for Biological Products. RESULTS: Adv-IL2 was generated efficiently with a titer of 3 x 10(10) pfu.mL-1. The expressed IL-2 and its bioactivity were 25 ng.mL-1 and 700 u.mL-1 respectively. A260 nm/A280 nm was 1.23. The purity determined by IE-HPLC was higher than 98%. The molecular weight, enzyme digestive map of Adv-IL2 genome, the characteristic gene E2B and IL-2 expression casseter conformed to expected values. CONCLUSION: The specification for Adv-IL2 is established and can be used for the quality control of the product.

[Quality control methods for recombinant human endostatin].

AIM: To establish the quality control methods for recombinant human endostatin. METHODS: Biological activity was determined by endothelial cell migration assays. Peptide mapping was tested by trypsin digestion and RP-HPLC. Purity was determined by non-reduced SDS-PAGE and RP-HPLC. Other tests including molecular weight, isoelectrical point, etc. were done according to the National Requirements for Biological Products (2000). RESULTS: The method of bioassay was established and used for determining activity of endostatin. Specific activity of the three batchs of drug substance was 1.45 x 10(6), 1.57 x 10(6) and 2.73 x 10(6) u.mg-1 proteins. Peptide mappings of the three batches of drug substance were completely identified. Both purity results of the products tested by SDS-PAGE and RP-HPLC were more than 99%. CONCLUSION: The established methods can effectively control the quality of recombinant human endostatin.