Combination of a single-chain variable fragment JZC00 with 2-deoxyglucose inhibited tumor growth in murine models / 中国药科大学学报

@#This study aimed to investigate the antitumor efficacy of a single-chain variable fragment JZC00 combined with 2-deoxyglucose(2-DG)on murine non-small lung cancer cell and breast cancer cell models. JZC00 was expressed by E. coli and identified using SDS-PAGE and Western blot. The combination inhibited the proliferation of LLC and 4T1 cells. The concentration of glucose and lactic acid in the medium were determined by glucose and lactate kit, respectively, then calculated the tumor cell glucose uptake inhibition rate and lactate release inhibition rate. In vivo, the tumor volume and tumor weight were analyzed after 15-day treatment. The results showed that the molecular weight of JZC00 expressed was correct, and it could inhibit the proliferation of tumor cells in vitro. JZC00 and 2-DG could inhibit the glycolysis of tumor cells, respectively, and JZC00 combined with 2-DG could inhibit glycolysis synergistically. When hypoxic microenvironment was induced in vitro, the inhibition of glycolysis by JZC00 treatment decreased. However, it was reversed with the addition of 2-DG. The in vivo models the combination showed a significantly improved tumor suppressive effect compared with JZC00 treated group, suggesting that 2-DG could improve the anti-tumor effect of anti-angiogenic antibodies and its combination has the potentialial value in the treatment of solid tumors.

Screening and identification of human anti-C3d single chain antibodies / 国际药学研究杂志

Objective: To screen human single chain antibodies against human C3d from phage-displayed single-chain variable fragment(scFv)library, and analyze their binding activities. Methods: The phage display library was exposed to 3-round selections in immunotubes coated with recombinant C3d at a decreasing concentration range and progressively stringent washing conditions. The positive clones were identified by ELISA, followed with sequencing to determine the specific genes which were then cloned intoex-pression vectors. The single chain antibodies were expressed in the FreeStyleTM 293-F system and harvested by affinity purification. The binding activities with recombinant C3d were determined by using Bio-Layer Interferometry technology. Results: These experiments resulted in three novel single chain antibodies(that is, A1, A3 and B6)against C3d with high affinity ranging from 22.7 to 171 pmol/ L. Conclusion: The high affinity human single chain antibodies against human C3d were obtained.

Preparation of fusion protein of PD-L1 single-chain antibody and verification of its antitumor activity / 中国免疫学杂志

Objective: Using yeast surface presentation technology, secreted anti-PD-L1 single-chain antibody fragment ( sc Fv), then purify the sc Fv that specifically binds PD-L1 antigen. The sc Fv antibody gene sequence was synthesized based on the single chain antibody gene sequence. We express this sc Fv-mFc protein by using p Fuse eukaryotic expression vector to study its affinity and in vitro and in vivo inhibition of lung adenocarcinoma cells ( A549). Methods: Recombinant plasmid p Fuse-scFv was constructed by gene engineering. The recombinant plasmid p Fuse-scFv was transfected into 293 F ( human embryonic kidney cells) and cultured in serum-free Pro293 a-CDM for 72 hours, then the fusion protein was collected, and use the Rapid Protein Liquid Phase Separation and Purification System to purify the sc Fv-mFc fusion protein. Then the fusion protein and the tumor cells were detected by immunohistochemistry; the affinity of fusion protein and tumor cells was analyzed by flow cytometry; ADCC was used to determine the proliferation of tumor cells in vitro. The nude mice inoculated with lung adenocarcinoma cells, and use the fusion protein to verify its anti-tumor effect in vivo. Results: sc Fv-mFc fusion protein was secreted into serum-free culture medium by recombinant plasmid transfection into the 293 F cells; immunohistochemistry and flow cytometry showed that the fusion protein was highly expressed with the surface of PD-L1 protein;ADCC showed that the fusion protein inhibited the proliferation of tumor cells in vitro; the results of tumor-bearing mice showed that the fusion protein inhibited the growth of the tumor. At the dose of 5 mg/kg, The tumor volume growth rate decreased from 14. 90％ to3. 72％, the two independent samples t test P＜0. 05, the difference was statistically significant. Conclusion: The fusion protein containing single chain antibody was successfully prepared, which had good binding ability to A549 cells and inhibited the proliferation of tumor cells in vitro and in vivo, and provided the laboratory basis for the development of targeted anti-tumor drugs.

Expression and functional detection of recombinant immunotoxins anti-B7-H4-scFv/PE38KDEL / 中国免疫学杂志

Objective:To construct anti-B7-H4-scFv-PE38KDEL,a recombinant toxin based on anti-B7-H4 single chain antibody (scFv),to detect anti-tumor effect of toxin protein.Methods:The anti-B7-H4-scFv gene was ligated with the toxin PE38KDEL gene by overlapping extension PCR(SOE-PCR).The recombinant gene was cloned into prokaryotic expression vector pET28a(+),and the protein was renatured and purified by chromatography (Ni-NTA),and was identified by Western blot.Indirect ELISA and flow analysis technology were used for specific identification.The inhibitory effects of toxins on tumor cells were detected by MTT assay and subcutaneous xenograft model in vitro and in vivo.HE staining and immunohistochemical analysis were performed on tumor tissues.Results:The recombinant expression vector pET28a-anti-B7-H4-scFv-PE38KDEL was obtained by restriction endonuclease di-gestion.The purified toxin protein was inoculated on the tumor cells.The tumor growth was inhibited in the tumor model.Conclusion:The recombinant toxin expression system based on anti-B7-H4 single chain antibody was successfully constructed.The recombinant toxin protein had good biological activity and anti-tumor activity.

Agonistic anti-CD40 single-chain antibody enhances anti-tumor effect of mouse NK cells / 中华微生物学和免疫学杂志

Objective To obtain a mouse CD40-specific single-chain antibody (scFv) with high purity and to investigate its in vivo and in vitro agonistic activity on natural killer(NK) cells against tumor. Methods Agonistic anti-mouse CD40 scFv with high purity was obtained by genetic engineering. Mouse dendritic cells (DCs) were treated with different strategies including anti-CD40 monoclonal antibody (McAb),anti-CD40 scFv and negative control. Expression of IL-12 in the supernatants of DC cultures was measured by ELISA. Then DCs and NK cells were co-cultured to obtain activated NK cells,which were co-cultured with T6-17 cells. WST-8 was used to test the cytotoxic effects of NK cells on T6-17 cells. A mouse tumor model was established by injecting BALB/c nude mice with T6-17 cells. Anti-CD40 scFv was injected into tumor to evaluate its inhibitory effect on tumor growth. Levels of IL-12 and IFN-γ in the tumor microen-vironment were detected by ELISA. Changes in the percentages of tumor-infiltrating NK cells and the expres-sion of NKG2D protein(natural-killer group 2,member D) were detected by flow cytometry and immunohis-tochemistry,respectively. Results The recombinant plasmid CD40 scFv-pET28a was confirmed to be con-structed correctly. Results of SDS-page and His-tag Western blot revealed that anti-CD40 scFv could be ex-pressed successfully with a relative molecular mass of 27×103. The level of IL-12 in the supernatant of DC culture of anti-CD40 scFv group was (555.86 ±40.48) pg/ml, which was significantly higher than that of negative control group (P<0.05). The killing ability of NK cells in anti-CD40 scFv group was (72.23 ± 3.99)%,which was significantly higher than that in negative control group (P<0.05). Anti-CD40 scFv significantly inhibited the tumor growth in BALB/c nude mice as compared with negative control group(P<0.05). The levels of IL-12 and IFN-γ in tumor microenvironment of anti-CD40 scFv group were(188.801± 32.718) pg/ml and(121.428±30.994) pg/ml,respectively,which were significantly higher than those in normal saline(NS) group(P<0.05). The positive rate of NKG2D protein and the percentage of CD3-DX5+cells in anti-CD40 scFv group were respectively(8.18±2.01)% and(19.15±2.24)%,which were signifi-cantly higher than those in NS group (P<0.05). Conclusion Agonistic anti-mouse CD40 scFv could en-hance the anti-tumor ability of NK cells by activating DCs.

Establishing a genebank for phage single-chain antibody using silicotic rats / 中国职业医学

OBJECTIVE: To establish a genebank for phage single-chain antibody for further screening the specificity of single chain fragment variable( Sc Fv) in lung tissue of silicosis rats by phage display technology. METHODS: Twenty-four specific pathogen free male SD rats were used to construct silicosis model by one-time bronchial perfusion with 1. 0 m L of silicon dioxide suspension( mass concentration,100 g / L). We took periphery blood from 6 rats 3,6,9 and 12 weeks respectively after establishing the model. The peripheral lymphocytes were mixed,and total RNA was extracted using Trizol,and c DNA was synthesized by reverse transcription. The degenerated primers were used to amplify the variable region of heavy chain( VH) gene and variable region of light chain( VL) gene by polymerase chain reaction( PCR).Then VH and VL genes were assembled to form Sc Fv by T4 DNA linker. The cloning recombinant of Sc Fv and plasmid of PCANTAB-5e were transformed into competence E. coli TG1 by calcium chloride. The Sc Fv genebank of silicosis model was constructed by M13K07 helper phage superinfection. There were 10 bacterial colonies for plasmid restriction dualenzyme digestion randomly selected for confirmation. RESULTS: Agarose gel electrophoresis showed that there were two bands of obvious 28 S and 18 S in total RNA of periphery blood lymphocytes of silicosis rats. The total RNA was intact. The size of VH gene fragment was about 400 bp,the size of VL gene fragment was about 350 bp and recombinant Sc Fv gene fragment length was about 750 bp. The helper phage was amplified and placed with double-deck agar plate and observed limpid plaque with the size of a rice grain. The phage titer was 1. 35 × 10~(16) pfu / L. The recombinant plasmids were transformed into E. coli TG1 and total bacterial count was 8. 0 × 10~9 cfu / L in resistant plate. The positive cloned plasmid PCR gel electrophoresis and double enzyme results showed a positive inserting rate of 90. 0%. The capacity of phage single-chain antibody genebank of experimental silicosis was 7. 2 × 10~9 cfu / L. CONCLUSION: The silicosis rat model with phage Sc Fv gnebank could be successfully established,and its capacity and diversity provide support for the follow-up screening.

Desarrollo de una vacuna mejorada de la subunidad del virus de la diarrea viral bovina basada en la glicoproteína E2 fusionada con un anticuerpo de cadena única que se dirige a las células presentadoras de antígenos / Development of an enhanced bovine viral diarrhea virus subunit vaccine based on E2 glycoprotein fused to a single chain antibody which targets to antigen-presenting cells

Bovine viral diarrhea virus (BVDV) is an important cause of economic losses worldwide. E2 is an immunodominant protein and a promising candidate to develop subunit vaccines. To improve its immunogenicity, a truncated E2 (tE2) was fused to a single chain antibody named APCH, which targets to antigen-presenting cells. APCH-tE2 and tE2 proteins were expressed in the baculovirus system and their immunogenicity was firstly compared in guinea pigs. APCH-tE2 vaccine was the best one to evoke a humoral response, and for this reason, it was selected for a cattle vaccination experiment. All the bovines immunized with 1.5Ag of APCH-tE2 developed high levels of neutralizing antibodies against BVDV up to a year post-immunization, demonstrating its significant potential as a subunit vaccine. This novel vaccine is undergoing scale-up and was transferred to the private sector. Nowadays, it is being evaluated for registration as the first Argentinean subunit vaccine for cattle

El virus de la diarrea viral bovina (BVDV) es causante de importantes pérdidas económicas a nivel mundial. La proteína E2 es la inmunodominante del virus y es la candidata para desarrollar vacunas de subunidad. Para mejorar su inmunogenicidad, una versión truncada de la E2 (tE2) se fusionó a un anticuerpo de cadena simple (APCH), que se dirige a las células presentadoras de antígeno. Se expresaron las proteínas APCH-tE2 y tE2 en el sistema de baculovirus y su inmunogenicidad fue evaluada y comparada en cobayos; la proteína APCH-tE2 fue la que indujo la mejor respuesta humoral. Por dicha razón se la evaluó en bovinos utilizando 1,5µg de antígeno. Los animales presentaron altos títulos de anticuerpos neutralizantes contra BVDV hasta un año posinmunización. Esta nueva vacuna está en proceso de escalado y se transfirió al sector privado. Actualmente se está evaluando para su registro como la primera vacuna argentina de subunidad para bovinos

Prokaryotic expression and purification of anti-AEG-1 single-chain variable antibody / 国际检验医学杂志

Objective To construct anti-astrocyte elevated gene-1(AEG-1)single-chain variable antibody (V23)prokaryotic ex-pression vector,and to conduct the protein purification and immunological activity detection.Methods The Primer5 software was applied to design the primers aiming at the gene sequence of the antibody anti-AEG-1 single-chain variable region for constructing the prokaryotic expression plasmid of PRsetC/V23.After the enzyme digestion by the restriction enzyme Pst1 and correct DNA se-quencing,the prokaryotic expression plasmid was led to E.coli BL21 ,the prokaryotic expression engineering strain containing the V23 gene was constructed.After the induction with IPTG,the interest protein was purified by the magnetic beads with the HIS tag,and the content of interest protein was determined by the SDS-PAGE electrophoresis.Western blot and ELISA were adopted to detect the immune activity of the nti-AEG-1 single-chain variable region antibody.Results For the constructed prokaryotic expres-sion plasmid PRsetC/V23,the single enzyme digestion and sequencing analysis displayed that the constructed V23 gene was com-pletely consistent to the designing sequences.After IPTG induction,SDS-PAGE electrophoresis showed an apparent protein band at 31×103 ,the Western blot detection showed a specific AEG-1 response band at 80 ×103 ,the ELISA test showed the positive re-sults.Conclusion The PRsetC/V23 prokaryotic expression plasmid and the V23 prokaryotic expression engineering strain are suc-cessfully constructed,this engineering strain can express anti-AEG-1 single-chain variable region antibody protein,and the protein has good immune activity.

Construction, Screening and Antibody Structure Homology Modeling of Phage Single Chain Variable Fragment Library Against Ofloxacin / 分析化学

To construct a library of mouse single chain variable fragment (scFv) antibody against ofloxacin using phage display and recombinant antibody technique, specific anti-ofloxacin scFv was screened and 3D structure was homology modeling. Total RNA was extracted from hybridoma cell of ofloxacin mAb, and was used to amplify VH and VL gene by RT-PCR using random primer. Then they were linked by a DNA linker encoding (G1y4 Ser) 3 as VH-linker-VL sequence forming scFv by SOE(splicing by overlap extension) PCR. These fragments were inserted into phage T7 after double digestion and transformed with host bacteria BLT5403. 3 ×105 pfu / ml single chain antibody phage libraries were successfully constructed. Four positive phage scFv clones were screened by direct competitive ELISA after four times of enriched procedure in the order of adsorption-elution-amplificatio, 3D structure of specific scFv was homology modeling finally. This research lays a foundation for further massive expression of anti-ofloxacin scFv.

Inhibitory effect of humanized anti-VEGFR-2 ScFv-As2O3-stealth nanoparticles conjugate on growth of human hepatocellular carcinoma: in vitro and in vivo studies

OBJECTIVE@#To investigate the inhibitory effect of humanized anti-VEGFR-2 ScFv-As2O3-stealth nanoparticles conjugate on growth of human hepatocellular carcinoma both in vitro and in vivo, which may be a potential agents with sensitivity and targeting ability for human hepatocellular cancer.@*METHODS@#Humanized anti-VEGFR-2 ScFv-As2O3-stealth nanoparticles conjugate was previously constructed using ribosome display technology and antibody conjugate technology. In this combined in vitro and in vivo study, the inhibitory effects of anti-VEGFR-2 ScFv-As2O3-stealth nanoparticles conjugate on tumor growth, invasion, and metastasis was observed with human liver carcinoma cell line Bel7402 and normal cell L02 by MTT assay, Tanswell assay, Hochest33258 staining, and DNA ladder analysis. The anticancer activity and distribution of anti-VEGFR-2 ScFv-As2O3-stealth nanoparticles was then verified in a mouse model of Bel7402 xenografts.@*RESULTS@#Anti-VEGFR-2 ScFv-As2O3-stealth nanoparticles significantly inhibited the proliferation of Bel7402 in the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay while had almost no effects on L02 cells. And the apoptosis inducing effects were proved by Hochest33258 staining and DNA ladder analysis. Transwell assay found that the drug also inhibited the metastasis ability of tumor cells. Furthermore, anti-VEGFR-2 ScFv-As2O3-stealth nanoparticles significantly delayed the growth of Bel7402 xenografts after administration (92.9%), followed by As2O3-stealth nanoparticles, anti-VEGFR-2 ScFv, and As2O3 (61.4%, 58.8%, 20.5%, P<0.05). The concentration of As2O3 in anti-VEGFR-2 ScFv-As2O3-stealth nanoparticles group was more selectively.@*CONCLUSIONS@#Anti-VEGFR-2 ScFv-As2O3-stealth nanoparticles is a potent and selective anti-hepatocellular carcinoma agent which could inhibit the growth of liver cancer as a targeting agent both in vitro and in vivo and also significantly inhibit angiogenesis.

pMHC/scFv fusion protein mediates killing of tumor cells by viral specific cytotoxic T cells / 中华微生物学和免疫学杂志

Objective To study whether the HBC-A2/scFv fusion protein mediates killing of tumor cells by viral specific cytotoxic T cells. Methods The fusion protein was attached to the CD71-expressing, HLA class Ⅰ negative tumor cells. And then, cytolysis by viral peptide-specific CTLs which were generated by co-culture of peripheral blood lymphocytes from HLA-A2 positive donors with inactivated T2 cells pulsed with the viral peptide were tested by lactate dehydrogenase (LDH) releasing. Results The fusion protein can attach the active viral peptide/HLA-A2 complex to K562, HepG2 and U937 cells through binding of CD71 scFv to CD71 (37.30% ±8.25%, 27.20% ±3.88%, 21.80% ±6.49% ) and mediate cytotoxicity of viral peptide-specific CTLs against those cells in vitro ( K562: 42.08% ± 1.14% vs 8.07%± 1.39%; HepG2: 49.72% ± 1.59% vs 12.46% ± 1.26%; U937: 39.72% ± 3.26% vs 7.13% ±1.48% ). Conclusion This viral peptide/HLA-A2 complex targeted by CD71 scFv is able to redirect viral peptide-specific T-cell mediated immune responses against tumor cells.

Preparation of human malignant melanoma ganglioside ScFv antibody-conjugated quantum dot nanoprobe and its specific binding with human malignant melanoma cells / 中国肿瘤生物治疗杂志

Objective: To prepare a nanoprobe, anti-human melanoma ganglioside single chain variable fragment (GD/ScFvMEL) antibody conjugated with CdTe quantum dot, and to observe its ability to specifically bind human malignant melanoma cells. Methods: The GD/ScFvMEL gene was cloned into pET32a (+), and the plasmid was then transformed into E. coli BL21 (DE3) for GD/ScFvMEL protein antibody expression. The expressed GD/ScFvMEL antibody was purified by denaturing method and further refolded by modified dialysis method. The purified GD/ScFvMEL antibody was analyzed by SDS-PAGE. The GD/ScFvMEL-QDs nanoprobe was prepared by conjugating GD/ScFvMEL antibody with CdTe quantum dot, and its specificity was observed by incubating with MGC-803 cells and melanoma A375 cells. Results: The recombinant pET32a-GD/ScFvMEL was constructed and confirmed by PCR, restriction endonuclease analysis and DNA sequencing. The proportion of expressed GD/ScFvMEL antibody in total bacteria proteins was about 40% as detected by SDS-PAGE. The purified- and refolded-GD/ScFvMEL antibody was effectively conjugated with CdTe quantum dot, and the resulting GD/ScFvMEL-QDs nanoprobe was successfully prepared. The GD/ScFvMEL-QDs nanoprobe could specifically bind melanoma A375 cells, but could not bind stomach cancer MGC-803 cells. Conclusion: We have successfully prepared an anti-human melanoma ganglioside single-chain antibody-CdTe quantum dot nanoprobe, which can specifically bind melanoma cells.

Construction, expression and identification of the anti-idiotypic single chain variable fragment against Edwardsiella tarda / 西安交通大学学报(医学版)

Objective To construct, express and identify the anti-idiotypic antibody single chain variable fragment (scFv) against Edwardsiella tarda. Methods By using RT-PCR method, the variable regions of the heavy and light chain of the anti-idiotypic monoclonal antibody (mAb) 1E11 against Edwardsiella tarda were cloned and joined with a (Gly_4ser)_3 linker, and the scFv in the orientation of V_L-linker-V_H was constructed. It was then cloned into vector plasmid pET-28a, expressed in Escherichia coli BL21(DE3), and confirmed by SDS-PAGE, Western blot and ELISA. Results The recombinant scFv could be expressed in E.coli BL21 (DE3) in a fusion protein pattern. The expression product was in the form of an inclusion body and the purified fusion protein was obtained after being purified and refolded. The SDS-PAGE and Western blot analysis showed that the molecular had the binding activity to the antigen. Conclusion The recombinant anti-idiotype scFv has been successfully constructed and expressed in E.coli BL21 (DE3), providing the basis and potential for preparation of genetically engineered vaccine against Edwardsiella tarda.

Construction of human phage display antibody ScFv library and identification of antibody ScFv against lung adenocarcinoma / 基础医学与临床

Objective To construct a human phage single chain-antibody library, and to sieve out the antibody ScFv against lung cancer from the library. Methods Total RNA was abstracted from lymph node tissue of the lung cancer, and was used to amplify V_H and V_L gene by RT-PCR. V_H and V_L were joined by a DNA linker by SOE-PCR to form the single chain variable fragment ( ScFv) gene. ScFv gene was coloned into the phage vector pCANT-AB5E. Panning against lung cancer cell line A549 was performed and positive clones were chosen for soluble expression. Results A recombination phage single chain-antibody library was constructed. After 4 rounds panning, the number of eluted phages increased by 115 times. Positive reactions to A549 were detected in 7 of 10 random clones. The human ScFvs against lung cancer were produced and confirmed by SDS-PAGE and ELISA analysis. Conclusion ScFvs against lung cancer were acquired by the construction of phage single chain-antibody library. The soluble ScFvs has specificall avidity to human lung cancer cells.

Expression of Human Single-chain Antibody Against A?40 in Pichia Pastoris / 医学研究杂志

Objective To express human single-chain antibody against amyloid?peptide 40 in pichia pastoris for passive immuniza- tion to Alzheimer's disease patients.Methods Human single-chain antibody gene from a phage display library was mutated to obliterate BamHI site and cloned into pAO815 plasmid for pT-scFvA?40 construction which was identified by PCR amplification and endonuclease digestion.Vector pT-scFvA?40 was cut by EcoRI and NotI endonucleases and the antibody gene was cloned into pPICgK plasmid to con- struct pPIC9K-scFvA?40 expression vector which was confirmed by gene sequencing.Linearized pPIC9K-scFvA?40 was used to trans- form pichia pastoris GS115 and the recombinant was induced by 0.5% methanol to express human single - chain antibody against amyloid?peptide 40.Results Gene sequencing confirmed pPIC9K-scFvA?40 orientation.Recombinants were obtained by linearized pPICgK - scFvA?40 transformation.After inducing with 0.5% methanol,the recombinant secreted proteins with 33 kD size.Conclusions Expression vector pPIC9K-scFvA?40 was constructed successfully.Human single-chain antibody against amyloid?peptide 40 was recombinantly expressed in pichia pastoris.

Construction of human phage display antibody ScFv library and identification of antibody ScFv against lung adenocarcinoma / 基础医学与临床

Objective To construct a human phage single chain-antibody library,and to sieve out the antibody ScFv against lung cancer from the library.Methods Total RNA was abstracted from lymph node tissue of the lung cancer,and was used to amplify VH and VL gene by RT-PCR. VH and VL were joined by a DNA linker by SOE-PCR to form the single chain variable fragment (ScFv) gene. ScFv gene was coloned into the phage vector pCANTAB5E. Panning against lung cancer cell line A549 was performed and positive clones were chosen for soluble expression.Results A recombination phage single chain-antibody library was constructed. After 4 rounds panning,the number of eluted phages increased by 115 times. Positive reactions to A549 were detected in 7 of 10 random clones. The human ScFvs against lung cancer were produced and confirmed by SDS-PAGE and ELISA analysis.Conclusion ScFvs against lung cancer were acquired by the construction of phage single chain-antibody library. The soluble ScFvs has specificall avidity to human lung cancer cells.

The packaging and purification of recombinant adeno-associated virus loaded with anti-amyloid ? peptide single-chain antibody gene / 基础医学与临床

Objective To produce and purify recombinant adeno-associated virus(AAV) loaded with anti-amyloid ? peptide single-chain antibody gene for gene therapy of Alzheimer's disease.Methods The plasmid pSNAV2.0-Abeta-scFv was used to transform BHK-21 cell by Lipofectamine 2000 for stable package cell line establishment.The helper virus HSV1-rc/?UL2 was used to transfect package cell for anti-amyloid ? peptide single-chain antibody gene loaded recombinant adeno-associated virus production.The chloroform-PEG/NaCl-chloroform extraction and ion-exchange chromatography were employed for recombinant AAV purification.SDS-PAGE and PCR amplification were adopted for purified virus identification.The final virus physical titer was determined by digoxin-labeled DNA probes.The effect of gene therapy was tested with transgenic mice by water maze test.Results The purity of recombinant adeno-associated virus with our target gene reach up to 98% after stable cell package and serial purification.The physical titer of the final virus was 1?1012vg/mL.The latency of treated mice in water maze test were reduced significantly.Conclusion The adeno-associated virus carrying anti-amyloid? peptide single-chain antibody gene was produced by HSV1system and purified.The animal behavior test demonstrated the recombinant AAV waseffective in the gene therapy of Alzheimer's disease.

The Construction and Expression of Phage Display scFv Library from the Spleen Cells of Mice Immunized With B3HM Cells / 中国生物工程杂志

To construct a scFv library by phage display technique from the spleen cells of mice immunized with B3HM cells. Three mice were immunized with B3HM cells, and their spleen cells were harvested. The genes of VH and Vk were amplified by RT-PCR from the cDNA of the immunized spleen cells and a scFv-phage display antibody library was constructed. The capacity of library was measured,and the variety of the library was analyzed by digesting with restriction endonuclease BstNI.ScFv phage clones were randomly picked and identified phage-scFv clone by binding B3HM cells using immunofluorescein.A scFv library containing 5?106 individual clones which showed different patterns after digested with restriction endonuclease BstNI was produced. Individnal phage-scFv clone showed B3HM cells positive using immunofluorescein. A scFv library of anti-B3HM cell surface molecules has been constructed. It will be useful for finding out some novel genes of causing leukemia, and establishs the infarctate foundation of clarifying the pathogenesis of leukemiagenesis.

Expression and Identification of Single Chain Antibody of Prokaryotic Expression Vector pOPE101-8E5 / 中国生物工程杂志

In the present study, we inserted the core-streptavidin cDNA into downstream of multi-cloning site of plasmid pOPE101-8E5 by DNA gene recombination technology. And then, the variable fragments of heavy and light chain of the scFv-8E5 were replaced by the scFv-C4 variable fragments to construct the expression vector pOPE101-C4∷core-streptavidin. After transformed the vector pOPE101-C4∷core streptavidin into E.coil, the fusion protein C4∷core streptavidin-His-tag can be expressed by inducing with IPTG, and the expression level and activity of the expressed fusion protein analyzed by SDS-PAGE and Western blot. The results show that a scFv-C4∷core-streptavidin fusion protein of 45kDa was obtained, which can bind proteins of 60kDa & 45kDa from the KG1a cells lysate simultaneously. The binding function can be detected by the binding of core-streptavidin and biotin directly.

Construction,expression and identification of the anti-idiotypic single chain variable fragment against Edwardsiella tarda / 西安交通大学学报(医学版)

Objective To construct,express and identify the anti-idiotypic antibody single chain variable fragment(scFv) against Edwardsiella tarda.Methods By using RT-PCR method,the variable regions of the heavy and light chain of the anti-idiotypic monoclonal antibody(mAb) 1E11 against Edwardsiella tarda were cloned and joined with a(Gly4Ser)3 linker,and the scFv in the orientation of VL-linker-VH was constructed.It was then cloned into vector plasmid pET-28a,expressed in Escherichia coli BL21(DE3),and confirmed by SDS-PAGE,Western blot and ELISA.Results The recombinant scFv could be expressed in E.coli BL21(DE3) in a fusion protein pattern.The expression product was in the form of an inclusion body and the purified fusion protein was obtained after being purified and refolded.The SDS-PAGE and Western blot analysis showed that the molecular weight of scFv protein was 27 ku.Indirect ELISA confirmed that the scFv had the binding activity to the antigen.Conclusion The recombinant anti-idiotype scFv has been successfully constructed and expressed in E.coli BL21(DE3),providing the basis and potential for preparation of genetically engineered vaccine against Edwardsiella tarda.