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Background: Gain-of-function of fibroblast growth factor receptor 3 (FGFR3) is involved in the pathogenesis of many tumors. More and more studies have focused on the potential usage of therapeutic single-chain Fv (ScFv) antibodies against FGFR3. RNA interference (RNAi) has been considered as a promising therapeutic method against cancer. A tool which can deliver small interference RNAs (siRNAs) into FGFR3 positive cancer cells is very promising for anti-tumor therapy. Results: In this study, a novel fusion protein R3P, which consists of FGFR3-ScFv and protamine, was generated in Escherichia coli by inclusion body expression strategy and Ni-NTA chromatography. Its yield reached 10 mg per liter of bacterial culture and its purity was shown to be higher than 95%. 1 µg of R3P could efficiently bind to about 2.5 pmol siRNAs and deliver siRNAs into FGFR3 positive RT112 and K562 cells. Annexin V staining results showed that R3P can deliver the amplified breast cancer 1 (AIB1) siRNAs to induce RT112 cell apoptosis. Conclusion: These results indicated that R3P was a promising carrier tool to deliver siRNAs into FGFR3 positive cancer cells and to exert anti-tumor effect.
Subject(s)
Urinary Bladder Neoplasms/metabolism , Recombinant Fusion Proteins/metabolism , Single-Chain Antibodies/metabolism , Recombinant Fusion Proteins/genetics , Protamines/metabolism , Inclusion Bodies , Cloning, Molecular , Apoptosis , RNA, Small Interfering , Escherichia coli/metabolism , Receptor, Fibroblast Growth Factor, Type 3 , Single-Chain Antibodies/isolation & purification , Single-Chain Antibodies/genetics , Flow CytometryABSTRACT
Background Overexpression or mutated activation of Fibroblast growth factor receptor 3 (FGFR3) is involved in the pathogenesis of many tumors. More and more studies focus on the potential usage of therapeutic antibodies against FGFR3. Results In this study, a novel single-chain Fv (ScFv) against FGFR3 was prepared and characterized. To achieve the soluble expression, ScFv was fused with Sumo (Small ubiquitin-related modifier) by polymerase chain reaction (PCR), and cloned into pET-20b. The recombinant bacteria were induced by 0.5 mM Isopropyl-ß-d-thiogalactopyranoside (IPTG) for 16 h at 20°C, and the supernatant liquid of Sumo-ScFv was harvested and purified by Ni-NTA chromatography. After being cleaved by the Sumo protease, the recombinant ScFv was released from the fusion protein, and further purified by Ni-NTA chromatography. The purity of ScFv was shown to be higher than 95% and their yield reached 4 mg per liter of bacterial culture. In vitro data showed that ScFv can significantly attenuate FGF9-induced phosphorylation of FGFR3. Conclusion We provide a novel method to produce soluble expression and bioactive functions of ScFv in Escherichia coli.
Subject(s)
Receptor, Fibroblast Growth Factor, Type 3/metabolism , Single-Chain Antibodies/isolation & purification , Single-Chain Antibodies/metabolism , Solubility , Mass Spectrometry , Recombinant Proteins , Blotting, Western , Escherichia coliABSTRACT
Objective To obtain the specific human scFv basic fibroblast growth factor(bFGF)using phage antibody library technology. Methods The library was panned with human recombinant bFGF for 4 rounds. The antigen binding activities of random clones were tested by ELISA in order to select specific antibodies, which were then examined by DNA sequence analysis. Results The positive clone selected from the 104 random clones was able to bind bFGF specifically, while not able to bind other growth factors,such as aFGF, VEGF(vascular endothelial growth factor). By competition ELISA assay we found one clone 44 could inhibit bFGF binding to FGFR1. Conclusion Seven specific human phage antibody against bFGF was obtained by phage display technique, one clone could inhibit bFGF binding to its high affinity receptor FGFR1.
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Objective To design and express a novel peptide based on ricin toxin antibody in E. coli, and to evaluate its biological activity. Methods Based on the crystal structure of ricin toxin A chain (RTA) and the RTA-rRNA interact in the complex model, the steric conformation of RTA was theoretical modeled and its functional domain was preliminarily determined. The humanized single-domain RTA antibody was designed rationally by computer-guidod molecular design method. Its coding sequence was ob- tained by overlapping extension PCR, and cloned into the pET-32a vector. The fusion protein was then ex-pressed in E. coli BL21 (DE3), identified by Western blot, and purified with Ni-NTA agarose. The binding and neutralizing activity of this novel peptide for riein was evaluated by competitive ELlSA assay and MTT assay. Results A recombinant human single-domain antibody expressing a polypeptide against RTA in the CDR3 loop was designed. The fusion protein was successfully expressed in E. coll. The purified protein can bind to ricin, and neutralize its activity in SP2/0 viability assay. Conclusion The success of the novel pep-tide based on riein toxin antibody provides a novel method to develop new generation of ricin antagonists.
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Objective To obtain the gene of murine Single chain Fv fragment (ScFv) against human cervical cancer and to express it in E. coli. Methods The variable region gene fragments of the heavy and light chains, which were amplified respectively using recombinant DNA techniques from CsA125 hybridoma cells, were spliced together through a flexible linker to ScFv against human cervical cancer. The ScFv genes were then cloned into expression vector pCANTAB 5E and expressed in E. coli HB2151 and TG1 respectively. The soluble ScFv were characterized by SDS PAGE and Western blot. The antigen-binding activities of the soluble and phage displayed ScFv were assayed by ELISA and cell immunohistochemical analysis. Results The expressed ScFv antibodies were soluble and phage displayed. The soluble ScFv secreted and expressed in E. coli HB2151 induced by IPTG were confirmed with SDS-PAGE, Western blot and ELISA. The specific binding capacity of the soluble and phage displayed ScFv to the surface associated antigen of human cervical cancer cell line was further confirmed with immunohistochemical studies. Conclusion The soluble and phage displayed ScFv expressed in E. coli against human cervical cancer showed high, specific affinity for the cervical cancer cell line surface associated antigen.
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Objective To construct high-capacity ribosome display single-chain Fv library for selection of high affinity ScFv antibody.Methods We isolate human lymphocyte from peripheralblood(2 normal,3 gastric cancer,3 colonic cancer,1 pancreatic cancer,each 5 mL and 2 newborn,each 2 mL)and extract RNA for cloning whole human heavy chain and light chain gene by RT-PCR.VH and VL were rearranged randomly by SOEing(splicing by overlap extension,SOEing).Finally,the elements for in vitro screening such as T7 promoter and ribosome binding site were introduced while the SOEing products were amplified.Moreover,ribosome display template were verified by blue/white screening and further sequencing.Results We successfully constructed ribosome display ScFv library with a volume of 1.1?1013.Conclusion The construction of high-capacity ScFv library shed light on multiple therapeutic ScFv screening.
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Objective To prepare a specific anti-lactoferrin single chain variable fragment(ScFv).Methods Anti-lactoferrin clones were screened from a 'naive' phage antibody library against the immobilized lactoferrin antigen,then the clones were transformed to the E.coli HB2151 to give soluble expression of antibody fragments.The culture supernatant containing ScFv was purified by immobilized metal affinity chromatography,and then determined with SDS-PAGE and ELISA.Results The results demonstrated that ScFvs were specific;they did not react with transferrin,lysozyme and bovine serum albumin in ELISA.The SDS-PAGE showed that the ScFvs had high purity through affinity chromatography and the molecular weight of them was about 32 kD.Conclusions The successful generation of the ScFvs against lactoferrin provides a basis for further study and clinical applications for dry eye and other ocular diseases.
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Objective:To investigate the feasibility of targeted imaging and therapy of prostate cancer using nanocomposite probes composed of fluorescent magnetic nanoparticles(FMCNPs) and single chain Fv(ScFv) antibody specific for gama-seminoprotein.Methods:The nanocomposite probes(FMCNPs-ScFv) were prepared by conjugating fluorescent magnetic nanoparticles with singlegama-chain Fv antibody specific gama-seminoprotein,and were characterized by high resolution transmission electron microscopy,fluorescent spectrum and magnetic spectrum.Nanocomposite probes were incubated with prostate cancer LNCaP cells,and the targeting results of nanocomposite probes were observed by fluorescent microscopy.The cytotoxicity effect of the nanocomposite probes was measured by MTT.Nude mice models of prostate cancer were established and identified by immunohistochemistry method.The nanocomposite probes were injected into nude mice via tail vein.The distribution of nanocomposite probes in the nude mice was observed by Micro-animal imaging system,targeted imaging of the prostate cancer was observed by MR instrument.The nude mice with prostate cancer were irradiated with 100 W magnetic field for 30 min,and the changes of tumor sizes were observed.Results:The FMCNPs-ScFv nanocomposite probes were successfully prepared.Nanocomposite probes entered into the cytoplasm of cancer cells and exhibited low cytotoxicity effect.Nude mice model with prostate cancer were successfully fabricated;the nanocomposite probes distributed quickly in the main organs of mice,and gradually concentrated on the tumor tissues within 24 h.MR images showed that the tumor images were gradually enhanced from 6 h to 24 h after injection of the nanocomposite probe.Four days after magnetic irradiation,the tumors in the nude mice grew slower compared with the control nude mice(P
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To construct human antibody repertory with phage display technology. Total RNA was extracted from peripheral blood lymphocytes (PBL) of clinical glioma patients and subjected to reverse transcription PCR. Variable region genes(V ? and V H genes) were amplified from the cDNA using nested polymerase chain reaction. V ? gene library was first constructed and attached to the Linker which could specially connect V ? gene and V H gene, then V H gene was cloned into V ? gene library to build ScFv repertoire. Positive colonies were selected randomly and sequenced. The results implied that amplified human V ? gene and V H gene could be derived from PBL of clinical glioma patients. ScFv phage antibody gene repertoire in about 2?10 6 capacity was successfully constructed. The sequencing indicated that the cloned genes encoded variable regions of heavy chains of human antibody and were highly homologous with human kappa heavy chain group III of Kabat's database. Then human antibody repertoire was successfully constructed with phage display technology. The present study can be used as a foundation for succeeding screening of specific antibody against human glioma.
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PURPOSE: CD1a antigen is observed in diseases such as Langerhans cell histiocytosis, T cell acute lymphoblastic leukemia, acute myelogenous leukemia and CD1a presenting cells would be associated with transplantation disorders. In this study, anti-CD1a single-chain Fv (scFv) was made and its DNA sequence was obtained to use as useful implement and informations for the diagnosis, therapy, and study of the diseases mentioned above. METHODS: The cDNA of anti-CD1a scFv was constructed with multiple steps of PCR from NA1/34.HLK and it was inserted into pCANTAB 5 E phagemid. The anti-CD1a scFvs were expressed on transformed DH5alpha Eschericia coli and secreted into cultured media. Thymocytes were used as CD1a antigen presenting cells. ScFvs were tested with flow cytometry. DNA sequence was obtained with PCR generated DNA sequencing method. RESULTS: There were 7 clones that secreted scFvs binding thymocytes. When using thymocytes after being incubated with anti-CD1a antibody, there was only one clone (D-24) scFv of which binding reaction was significantly inhibited. DNA sequence of scFv of D-24 was obtained. CONCLUSION: The obtained scFv of D-24 should be anti-CD1a scFv because of its binding thymocytes and being inhibited by anti-CD1a antibody. It needs further purification and confirmative test such as immunoprecipitation. The obtained DNA sequence would be informative to construct various and humanized antibodies for CD1a antigen.
Subject(s)
Antibodies, Monoclonal, Humanized , Antigen-Presenting Cells , Bacteriophages , Base Sequence , Clone Cells , Diagnosis , DNA, Complementary , Flow Cytometry , Histiocytosis, Langerhans-Cell , Immunoprecipitation , Leukemia, Myeloid, Acute , Mass Screening , Polymerase Chain Reaction , Precursor Cell Lymphoblastic Leukemia-Lymphoma , Sequence Analysis, DNA , Single-Chain Antibodies , ThymocytesABSTRACT
To develop simple, rapid, and efficacious diagnostic methods for malaria is one of the remaining key tasks for malaria control. Previously, we have created a phage-displayed antibody library against Plasmodium falciparum. Six clones of antibody with good reactivity to HRP-II in ELISA were isolated from the library after 3 rounds of enrichment. Soluble ScFvs were produced and the characteristics were determined. The results of Western blot showed that they could bind to HRP-II specifically and had a relative molecular mass(Mr) about 31 000. The work provided a solid fund for diagnostic kit development for malaria.
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A three-dimensional (3D) graphic model of a single-chain Fv (scFv) which was derived from an anti-human placental acidic isoferritin (PAF) monoclonal antibody (Mab) was constructed by a homologous protein-predicting computer algorithm on Silicon graphic computer station.The structure, surface static electricity and hydrophobicity of scFv were investigated. Computer graphic modelling indicated that all regions of scFv including the linker, variable regions of the heavy (VH) and light (VL) chains were suitable. The VH region and the VL region were involved in composing the "hydrophobic pocket". The linker was drifted away VH and VL regions. The complementarity determining regions (CDRs) of VH and VL regions surrounded the "hydrophobic pocket". This study provides a theory basis for improving antibody affinity, investigating antibody structure and analyzing the functions of VH and VL regions in antibody activity.
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A three-dimensional (3D) graphic model of a single-chain Fv (scFv) which was derived from an anti-human placental acidic isoferritin (PAF) monoclonal antibody (Mab) was constructed by a homologous protein-predicting computer algorithm on Silicon graphic computer station.The structure, surface static electricity and hydrophobicity of scFv were investigated. Computer graphic modelling indicated that all regions of scFv including the linker, variable regions of the heavy (VH) and light (VL) chains were suitable. The VH region and the VL region were involved in composing the "hydrophobic pocket". The linker was drifted away VH and VL regions. The complementarity determining regions (CDRs) of VH and VL regions surrounded the "hydrophobic pocket". This study provides a theory basis for improving antibody affinity, investigating antibody structure and analyzing the functions of VH and VL regions in antibody activity.
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Objective:To express the recombinant single chain Fv(scFv) in E.coli and reduce immunogenicity and molecular weight of a monoclonal antibody specific for human platelet.Methods:The variable regions of the heavy and light chains of platelet specific antibody SZ 2 were amplified by reverse transcription and polymerase chain reaction.VH and VL gene segments were cloned into pUC Tm and joined together with a (gly 4ser) 3 linker.The resulting scFv was expressed in PET expression system.The expressed recombinant protein was characterized by its size on SDS PAGE,by Western blot,by flow cytometry and its functions.Results:The VH and VL genes were homologous with the published gene sequences of mouse antibody variable region.The recombinant scFv was expressed mostly in the form of inclusion bodies,and the yield was up to 25% of the total cell proteins.Functional studies showed that SZ 2 scFv could bind to platelet and could suppress platelet aggregation induced by ristocatin and thrombin.Conclusion:A recombinant SZ 2 scFv specific against platelet was developed and characterized.
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Objective:To create a large human phage antibody library from which easy to get diabody and select human antibody clones.Methods:VL and VH genes were amplified by RT-PCR from RNA which came from normal adult peripheral blood and new-born cord blood lymphocytes. VL and VH genes were reamplified to add a region of overlap in the ScFv linker to form ScFv genes in which VH genes were flanked by two non-homologous loxp sites. The ScFv genes were cloned into PDF to obtain a primary library. This primary library was used to infect bacteria Bs1365(expressing cre recombinase) with high multiplicity of infection(MOI) 200∶1. This procedure resulted in a very large phage antibody library through VL and VH recombined by the cre recombinase. Following recombination, phagemide were derived from these bacteria and used to infect bacteria not expressing cre(XL1-Blue) at MOI
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Objective:To develop non-immunized human phage display library.Methods:The total RNA of lymphocyte cells from peripheral blood of healthy voluntee was isolated and cDNA was synthesized,and the genes of heavy variable chain (VH) and light variable chain (V? and V?) were amplified by direct PCR and half-nested PCR.By overlapping extension PCR,the genes of VH and VL (V? and V?) were linked.The linked genes of single chain Fv fragment (scFv) were ligated with the vector pCANTAB-5E and then cloned into TG1 for the scFv library construction.Results:By direct PCR and half-nested PCR,42 VH fragments,16 V? and 18 V? fragments were obtained.The size of linked scFv library genes was 750 bp and the volume of constructed scFv library was 1.35?108.The results of BstN Ⅰ analysis of scFv genes from the phage library showed that fingerprint map of the selected scFvs was different.Conclusion:The developed phage library is diversity and can be used for selecting humanized scFv.
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Objective To study the expression, purification and bioactivity of a recombinant fusion protein consisting of anti-HBs single chain Fv and interleukin-2. Methods The engineering bacterium M15[pQE-ScFv-IL-2] which can express the fusion protein consisting of anti-HBsAg single chain Fv and interleukin-2, was induced by IPTG, then a 43kD recombinant protein was identified by SDS-PAGE and Western-blot analysis. Results The ratio of target protein to total protein of host reached 18%. Further analysis confirmed that the recombinant protein formed inclusion body in the cytoplasm of bacteria. 95% purity could be achieved after two-step purification of ScFv-IL-2, including Ni metal chelating chromatography (the first) and ion-exchange chromatogram (the second). The bioactivity assay of the purified product showed that the antibody-cytokine fusion protein could bind to HBsAg specifically and stimulate the proliferation of CTLL-2. Conclusion These results suggest that the fusion protein retains the bioactivity of its parental molecules, and may be a potential gene-engineering targeting drug for the treatment of chronic hepatitis B and other relevant diseases.
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Objective To detect hepatitis C virus core antigen in 7721 cells transfected with HCV cDNA by immunohistochemistry method with human single chain Fv antibody(scFv). Methods The recombinant phages were panned by core antigen which was coated in a microtiter plate. After three rounds of biopanning, 48 clones were identified specific to core antigen. The affinity and specificity of scFv were evaluated by ELISA and immunohistochemistry. Results ScFv-core DNA digestion and sequence data showed that the scFv gene was composed of 774bp. Conclusion Human single chain Fv antibody against HCV core antigen has a specific combining capacity with hepatitis C virus core antigen.
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To construct expressive vector for human ScFv against core protein of hepatitis C virus (HCV core ScFv),and to express soluble HCV core ScFv in E.coli JM109. Using phage display technique, the recombinant phages were panned by recombinant core antigen which was coated in a microtiter plate, and after five rounds of biopanning, 86 clones were identified specific to core antigen. 750 bp fragment could be released from the plasmid of positive phage clones, and the sequence analysis indicated that we have obrained the ScFv DNA fragment. Then DNA fragment was inserted into the expressive vector pCANTAB5E, and E. coli host JM109 was transformed and induced by IPTG. The specificity of ScFv in the culture medium was evaluated by enzyme linked immunosorbent assay (ELISA).The molecular weight of expressed HCV core ScFv protein is 28 000 dalton as determined with the aid of SDS polyacrymide gel electrophoresis (PAGE). The expressed HCV core ScFv protein will be useful in the immunohistochemical study of liver tissue from patients with hepatitis C and gene therapy against HCV infection.
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Objective To prepare the immunotoxin protein (183B 2ScFvPE38) which might be useful in immuno guided therapy for ovarian carcinoma and study the activity of the protein. Methods The methods of ELISA and cytotoxicity were used to study the immunotoxin after induced with IPTG and the activity of the immunotoxin. Results The expressed fusion proteins were detected mostly as inclusion bodies at high level, and soluble immunotoxins were also observed. The results showed liable activity of antibody part and toxic part. Conclusion The recombinant fusion protein 183B 2ScFvPE38 keeps the activity of both components and might be of great use in the future to deal with ovarian carcinoma. [