BACKGROUND: Phage display technology has become a vital tool in studies aimed at identifying molecules binding to a specific target. It enables the rapid generation and selection of high affinity, fully human antibody...BACKGROUND: Phage display technology has become a vital tool in studies aimed at identifying molecules binding to a specific target. It enables the rapid generation and selection of high affinity, fully human antibody product candidates to essentially any disease target appropriate for antibody therapy. In this study, we prepared the recombinant single-chain fragment variable ( ScFv) antibody to hepatitis B virus surface antigen (HBsAg) by the phage display technology for obtaining a virus-targeting mediator. METHODS: mRNA was isolated from B-lymphocytes from a healthy volunteer and converted into cDNA. The fragment variables of heavy and light chain were amplified separately and assembled into ScFv DNA with a specially constructed DNA linker by polymerase chain reaction. The ScFv DNA was ligated into the phagmid vector pCANT-AB5E and the ligated sample was transformed into competent E. coli TG1. The transformed cells were infected with M13K07 helper phage to form a human recombinant phage antibody library. The volume and recombinant rate of the library were evaluated by bacterial colony count and restriction analysis. After two rounds of panning with HBsAg. the phage clones displaying ScFv of the antibody were selected by enzyme-linked immunosorbant assay ( ELISA) from the enriched phage clones. The antigen binding affinity of the positive clone was detected by competition ELISA. HB2151 E. coli was transfected with the positive phage clone demonstrated by competition ELISA for production of a soluble form of the anti-HBsAg ScFv. ELISA assay was used to detect the antigen binding affinity of the soluble anti-HBsAg ScFv. Finally, the relative molecular mass of soluble anti-HBsAg ScFv was measured by SDS-PAGE. RESULTS: The variable heavy ( VH ) and variable light (VL) and ScFv DNAs were about 340bp, 320bp and 750bp, respectively. The volume of the library was up to 2 × 106 and 8 of 10 random clones were recombinants. Two phage clones could strongly compete with the original HBsAb for binding to HBsAg. Within 2 strong positive phage clones, the soluble anti-HBsAg ScFv from one clone was found to have the binding activity with HBsAg. SDS-PAGE showed that the relative molecular weight of soluble anti-HBsAg ScFv was 32 kDa. CONCLUSION: The anti-HBsAg ScFv successfully produced by phage antibody technology may be useful for broadening the scope of application of the antibody.展开更多
In order to enhance the glutathione peroxidase（GPX） catalytic activity of the selenium-containing single-chain variable fragments（Se-scFv）, a novel human scFv was designed on the basis of the structure of human an...In order to enhance the glutathione peroxidase（GPX） catalytic activity of the selenium-containing single-chain variable fragments（Se-scFv）, a novel human scFv was designed on the basis of the structure of human antibody and optimized via bioinformatics methods such as homologous sequence analysis, three-dimensional（3D） model building, binding-site analysis and docking. The DNA sequence of the new human scFv was synthesized and cloned into the expression vector pET22b（＋）, then the scFv protein was expressed in soluble form in Escherichia coli BL21（DE3） and purified by Ni2＋-immobilized metal affinity chromatography（IMAC）. The serine residue of scFv in the active site was converted into selenocysteine（Sec） with the chemical modification method, thus, the human Se-scFv with GPX activity was obtained. The GPX activity of the Se-scFv protein was characterized. Compared with other Se-scFv, the new human Se-scFv showed similar efficiency for catalyzing the reduction of hydrogen peroxide by glutathione. It exhibited pH and temperature dependent catalytic activity and a typical ping-pong kinetic mechanism.展开更多
BACKGROUND：Studies have shown that monoclonal or polyclonal antibody injections of amyloid β peptide are effective in removing amyloid β peptide overload in the brain. OBJECTIVE： Based on successful screening of a...BACKGROUND：Studies have shown that monoclonal or polyclonal antibody injections of amyloid β peptide are effective in removing amyloid β peptide overload in the brain. OBJECTIVE： Based on successful screening of a human single-chain fragment variable antibody specific to amyloidβpeptide, this paper aimed to express recombinant human single-chain variable antibody against amyloid β peptide. DESIGN, TIME AND SETTING： A single sample experiment was performed at the Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Hospital （Beijing, China） from January to July 2006. MATERIALS： Human single-chain fragment variable antibody gene against amyloid β peptide was screened from a human phage-display antibody library. METHODS： Human single-chain fragment variable antibody gene was mutated to eliminate a BamHI restriction site and cloned into a T easy plasmid for pT-scFvAβ construction, which was identified by PCR amplification and endonuclease digestion. Plasmid pT-scFvAβ was cut by EcoRI and NotI endonucleases, and the antibody gene was cloned into pPIC9K plasmid to construct pPIC9K-scFvAβ expression vector, which was confirmed by gene sequencing. Linearized pPIC9K-scFvAβ was used to transform a Pichia pastoris GS115 cell line, and the recombinant was induced by 0.5% methanol to express human single-chain fragment variable antibody specific to amyloid β peptide. MAIN OUTCOME MEASURES： Protein electrophoresis was used to identify PCR products, gene sequencing was used to verify the pPIC9K-scFvA sequence, and SDS-PAGE was used to detect recombinant expression of human single-chain fragment variable antibody specific to amyloid β peptide in Pichia pastoris. RESULTS： Gene sequencing confirmed pPIC9K-scFvAβ orientation. Recombinants were obtained by linearized pPIC9K-scFvAβ transformation. After induction with 0.5% methanol, the recombinant yeast cells secreted proteins of 33-ku size. CONCLUSION： The expression vector pPIC9K-scFvAβ was successfully constructed. Human single-chain fragment variable antibody specific to amyloid β peptide was recombinantly expressed in Pichia pastoris.展开更多
Single-chain variable domain fragment （scFv） 637 is an antigen-specific scFv of myasthenia gravis. In this study, scFv and human serum albumin genes were conjugated and the fusion pro-tein was expressed in Pichia pa...Single-chain variable domain fragment （scFv） 637 is an antigen-specific scFv of myasthenia gravis. In this study, scFv and human serum albumin genes were conjugated and the fusion pro-tein was expressed in Pichia pastoris. The afifnity of scFv-human serum albumin fusion protein to bind to acetylcholine receptor at the neuromuscular junction of human intercostal muscles was detected by immunolfuorescence staining. The ability of the fusion protein to block myas-thenia gravis patient sera binding to acetylcholine receptors and its stability in healthy serum were measured by competitive ELISA. The results showed that the inhibition rate was 2.0-77.4%, and the stability of fusion protein in static healthy sera was about 3 days. This approach suggests the scFv-human serum albumin is a potential candidate for speciifc immunosuppressive therapy of myasthenia gravis.展开更多
Zinc transporter 8 （ZnT8） is a major autoantigen and a predictive marker in type 1 diabetes （T1D）. To investigate ZnT8-specific antibodies, a phage display library from TID was constructed and single-chain antibod...Zinc transporter 8 （ZnT8） is a major autoantigen and a predictive marker in type 1 diabetes （T1D）. To investigate ZnT8-specific antibodies, a phage display library from TID was constructed and single-chain antibodies against ZnT8 were screened and identified. Human T1D single-chain variable fragment （scFv） phage display library consists of approximately 1 ~ l0s clones. After four rounds of bio-panning, seven unique clones were positive by phage ELISA. Among them, C27 and C22, which demonstrated the highest affinity to ZnT8, were expressed in Escherichia coli Topl0F＇ and then purified by affin- ity chromatography. C27 and C22 specifically bound ZnT8 N/C fusion protein and ZnT8 C terminal dimer with one Arg325Trp mutation. The specificity to human islet cells of these scFvs were further confirmed by immunohistochemistry. In conclusion, we have successfully constructed a T1D phage display antibody library and identified two ZnT8-specific scFv clones, C27 and C22. These ZnT8-specific scFvs are potential agents in immunodiagnostic and immunotherapy of T1D.展开更多
Grass carp （Ctenopharyngodon idella） is an important species of freshwater aquaculture fish in China. However, grass carp reovirus （GCRV） can cause fatal hemorrhagic disease in yearling populations. Until now, a s...Grass carp （Ctenopharyngodon idella） is an important species of freshwater aquaculture fish in China. However, grass carp reovirus （GCRV） can cause fatal hemorrhagic disease in yearling populations. Until now, a strategy to define the antigenic ca- pacity of the virus＇s structural proteins for preparing an effective vaccine has not been available. In this study, some sin- gle-chain variable fragment antibodies （scFv）, which could specifically recognize grass carp IgM, were selected from a con- structed mouse naive antibody phage display cDNA library. The identified scFv C1B3 clone was shown to possess relatively higher specific binding activity to grass carp IgM. Furthermore, ELISA analysis indicated that the IgM level in serum from vi- rus-infected grass carp was more than two times higher than that of the control group at 5-7 days post infection. Moreover, Western blot analysis demonstrated that the outer capsid protein VP7 has a specific immuno-binding-reaction with the serum IgM from virus-infected grass carp. Our results suggest that VP7 can induce a stronger immune response in grass carp than the other GCRV structural proteins, which implies that VP7 protein could be used as a preferred immunogen for vaccine design.展开更多
Total RNA was isolated from the hybridoma cell line （LC- 1 ）, which secretes anti-lung adenocarcinoma monoclonal antibody, and was transferred into cDNA. Based on the FRl （framework region l） and FR4 conserved reg...Total RNA was isolated from the hybridoma cell line （LC- 1 ）, which secretes anti-lung adenocarcinoma monoclonal antibody, and was transferred into cDNA. Based on the FRl （framework region l） and FR4 conserved regions of LC-1 gene, the variable regions of heavy chain （Vh） and light chain （Vl） were amplified, and the Vh and modified Vl were connected to single chain Fv （ScFv） by SOE-PCR （splice overlap extension PCR）. The modified ScFv was fused with green fluorescent protein （GFP） and introduced into E. coli JM109. The fusion protein induced by lPTG （Isopropylthiogalactoside） was about 57000 on a 10% SDS-PAGE gel （10% Sds Polyacrylamide Gel Electrophoresis）, and primarily manifested as inclusion bodies. The renatured protein purified by Ni-NTA Superflow resins showed ability to bind to antigen on SPC-A-l lung adenocarcinoma. In addition, the induced host cells fluoresced bright green under 395 nm wavelength, which indicated that the expected protein with dual activity was expressed in the prokaryotic system. The ScFv with GFP tag used in this research can be applied as a new reagent to detect immunological dye, and provide a feasible way to detect adenocarcinoma in a clinical setting.展开更多
The single chain variable fragments of antibodies(scFvs) against cTnI were screened from the phage display antibody library by using cTnI as the target antigen. After four rounds of panning, four clones(H2, G5, A9, B9...The single chain variable fragments of antibodies(scFvs) against cTnI were screened from the phage display antibody library by using cTnI as the target antigen. After four rounds of panning, four clones(H2, G5, A9, B9) from the phage display antibody library were verified to show higher binding affinity for cTnI by ELISA and to contain the variable region genes of the light and heavy chains of scFvs by sequencing. The variable region genes of scFvs H2 and G5 were successfully amplified by polymerase chain reactions(PCR) and cloned into expression vector pPELB and expressed as a soluble protein in E.coli Rosetta, whose expression yield was about 2% of total proteins. The expressed proteins were purified by nickel(Ni) affinity chromatography and a single band is shown in the position of 28 kDa on SDS-PAGE. The western blot analysis result verifies that the expressed scFv proteins are capable of binding with monoclonal antibodies against hexa-histidine, indicating that they are hexa-histidin-tagged aim proteins. The immunoassay demonstrates that the expressed scFv proteins are able to specifically react with cTnI molecules. The association constant(K_A) values range from 1.2×10 4 to 1.7 ×10 5 L/mol that are correspondent to the affinities of polyclonal antibodies against cTnI from rabbits. These antibodies can be valuable reagents for the immunoassay of cTnI.展开更多
比较表达于大肠杆菌中的人源性抗细胞毒性T淋巴细胞抗原4单链抗体(A n ti-CTLA 4 scFv)的三种体外复性方法的复性效率。稀释、透析和亲和柱上三种复性方式复性A n ti-CTLA 4 scFv,采用B rad ford法分析蛋白复性得率,采用间接细胞EL ISA...比较表达于大肠杆菌中的人源性抗细胞毒性T淋巴细胞抗原4单链抗体(A n ti-CTLA 4 scFv)的三种体外复性方法的复性效率。稀释、透析和亲和柱上三种复性方式复性A n ti-CTLA 4 scFv,采用B rad ford法分析蛋白复性得率,采用间接细胞EL ISA法检测所得蛋白的活性。透析复性蛋白得率最高,稀释复性蛋白得率其次,亲和柱上复性蛋白得率最低;透析复性所得蛋白结合活性是稀释复性的1.95倍,是亲和柱上复性所得蛋白活性的4.13倍(无谷胱甘肽氧化还原对G SH/G SSH)及3.63倍(有G SH/G SSH)。结论:采用含0.15 m o l/L N aC、l1 mm o l/L G SSH和3 mm o l/L G SH的50 mm o l/L T ris-HC l(pH 8.0)缓冲液作为A n ti-CTLA 4 scFv的复性液,4℃下透析复性48 h,可获得较高复性得率和结合活性。展开更多
基金This study was supported by grants from the National Natural Science Foundation of China (No. 30572213)and Student Innovation Program of Shanxi Medical University (No.200404).
文摘BACKGROUND: Phage display technology has become a vital tool in studies aimed at identifying molecules binding to a specific target. It enables the rapid generation and selection of high affinity, fully human antibody product candidates to essentially any disease target appropriate for antibody therapy. In this study, we prepared the recombinant single-chain fragment variable ( ScFv) antibody to hepatitis B virus surface antigen (HBsAg) by the phage display technology for obtaining a virus-targeting mediator. METHODS: mRNA was isolated from B-lymphocytes from a healthy volunteer and converted into cDNA. The fragment variables of heavy and light chain were amplified separately and assembled into ScFv DNA with a specially constructed DNA linker by polymerase chain reaction. The ScFv DNA was ligated into the phagmid vector pCANT-AB5E and the ligated sample was transformed into competent E. coli TG1. The transformed cells were infected with M13K07 helper phage to form a human recombinant phage antibody library. The volume and recombinant rate of the library were evaluated by bacterial colony count and restriction analysis. After two rounds of panning with HBsAg. the phage clones displaying ScFv of the antibody were selected by enzyme-linked immunosorbant assay ( ELISA) from the enriched phage clones. The antigen binding affinity of the positive clone was detected by competition ELISA. HB2151 E. coli was transfected with the positive phage clone demonstrated by competition ELISA for production of a soluble form of the anti-HBsAg ScFv. ELISA assay was used to detect the antigen binding affinity of the soluble anti-HBsAg ScFv. Finally, the relative molecular mass of soluble anti-HBsAg ScFv was measured by SDS-PAGE. RESULTS: The variable heavy ( VH ) and variable light (VL) and ScFv DNAs were about 340bp, 320bp and 750bp, respectively. The volume of the library was up to 2 × 106 and 8 of 10 random clones were recombinants. Two phage clones could strongly compete with the original HBsAb for binding to HBsAg. Within 2 strong positive phage clones, the soluble anti-HBsAg ScFv from one clone was found to have the binding activity with HBsAg. SDS-PAGE showed that the relative molecular weight of soluble anti-HBsAg ScFv was 32 kDa. CONCLUSION: The anti-HBsAg ScFv successfully produced by phage antibody technology may be useful for broadening the scope of application of the antibody.
基金Supported by the National Natural Science Foundation of China(No.30970608)the Applicative Technological Project of Bureau of Science and Technology of Changchun City, China(No.2009045)+1 种基金the Development and Planning Major Program of Jilin Provincial Science and Technology Department, China(No.20100948)the Innovation Method Fund of China (No.2008IM040800)
文摘In order to enhance the glutathione peroxidase（GPX） catalytic activity of the selenium-containing single-chain variable fragments（Se-scFv）, a novel human scFv was designed on the basis of the structure of human antibody and optimized via bioinformatics methods such as homologous sequence analysis, three-dimensional（3D） model building, binding-site analysis and docking. The DNA sequence of the new human scFv was synthesized and cloned into the expression vector pET22b（＋）, then the scFv protein was expressed in soluble form in Escherichia coli BL21（DE3） and purified by Ni2＋-immobilized metal affinity chromatography（IMAC）. The serine residue of scFv in the active site was converted into selenocysteine（Sec） with the chemical modification method, thus, the human Se-scFv with GPX activity was obtained. The GPX activity of the Se-scFv protein was characterized. Compared with other Se-scFv, the new human Se-scFv showed similar efficiency for catalyzing the reduction of hydrogen peroxide by glutathione. It exhibited pH and temperature dependent catalytic activity and a typical ping-pong kinetic mechanism.
基金the National Natural Science Foundation of China, No. 30500573
文摘BACKGROUND：Studies have shown that monoclonal or polyclonal antibody injections of amyloid β peptide are effective in removing amyloid β peptide overload in the brain. OBJECTIVE： Based on successful screening of a human single-chain fragment variable antibody specific to amyloidβpeptide, this paper aimed to express recombinant human single-chain variable antibody against amyloid β peptide. DESIGN, TIME AND SETTING： A single sample experiment was performed at the Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Hospital （Beijing, China） from January to July 2006. MATERIALS： Human single-chain fragment variable antibody gene against amyloid β peptide was screened from a human phage-display antibody library. METHODS： Human single-chain fragment variable antibody gene was mutated to eliminate a BamHI restriction site and cloned into a T easy plasmid for pT-scFvAβ construction, which was identified by PCR amplification and endonuclease digestion. Plasmid pT-scFvAβ was cut by EcoRI and NotI endonucleases, and the antibody gene was cloned into pPIC9K plasmid to construct pPIC9K-scFvAβ expression vector, which was confirmed by gene sequencing. Linearized pPIC9K-scFvAβ was used to transform a Pichia pastoris GS115 cell line, and the recombinant was induced by 0.5% methanol to express human single-chain fragment variable antibody specific to amyloid β peptide. MAIN OUTCOME MEASURES： Protein electrophoresis was used to identify PCR products, gene sequencing was used to verify the pPIC9K-scFvA sequence, and SDS-PAGE was used to detect recombinant expression of human single-chain fragment variable antibody specific to amyloid β peptide in Pichia pastoris. RESULTS： Gene sequencing confirmed pPIC9K-scFvAβ orientation. Recombinants were obtained by linearized pPIC9K-scFvAβ transformation. After induction with 0.5% methanol, the recombinant yeast cells secreted proteins of 33-ku size. CONCLUSION： The expression vector pPIC9K-scFvAβ was successfully constructed. Human single-chain fragment variable antibody specific to amyloid β peptide was recombinantly expressed in Pichia pastoris.
基金supported by the National Natural Science Foundation of China,No.30360100,30760234,30860260,81160373,81360458
文摘Single-chain variable domain fragment （scFv） 637 is an antigen-specific scFv of myasthenia gravis. In this study, scFv and human serum albumin genes were conjugated and the fusion pro-tein was expressed in Pichia pastoris. The afifnity of scFv-human serum albumin fusion protein to bind to acetylcholine receptor at the neuromuscular junction of human intercostal muscles was detected by immunolfuorescence staining. The ability of the fusion protein to block myas-thenia gravis patient sera binding to acetylcholine receptors and its stability in healthy serum were measured by competitive ELISA. The results showed that the inhibition rate was 2.0-77.4%, and the stability of fusion protein in static healthy sera was about 3 days. This approach suggests the scFv-human serum albumin is a potential candidate for speciifc immunosuppressive therapy of myasthenia gravis.
基金supported by National Natural Science Foundation of China (81070622, 81370939)Provincial Six Talent Foundation of Jiangsu (2010-022)+1 种基金Municipal Science and Technology Foundation of Nanjing (009010684)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD, JX10231801)
文摘Zinc transporter 8 （ZnT8） is a major autoantigen and a predictive marker in type 1 diabetes （T1D）. To investigate ZnT8-specific antibodies, a phage display library from TID was constructed and single-chain antibodies against ZnT8 were screened and identified. Human T1D single-chain variable fragment （scFv） phage display library consists of approximately 1 ~ l0s clones. After four rounds of bio-panning, seven unique clones were positive by phage ELISA. Among them, C27 and C22, which demonstrated the highest affinity to ZnT8, were expressed in Escherichia coli Topl0F＇ and then purified by affin- ity chromatography. C27 and C22 specifically bound ZnT8 N/C fusion protein and ZnT8 C terminal dimer with one Arg325Trp mutation. The specificity to human islet cells of these scFvs were further confirmed by immunohistochemistry. In conclusion, we have successfully constructed a T1D phage display antibody library and identified two ZnT8-specific scFv clones, C27 and C22. These ZnT8-specific scFvs are potential agents in immunodiagnostic and immunotherapy of T1D.
基金supported by the National Basic Research Program of China (2009CB118701,2009CB118704)the National Natural Science Foundation of China (31072233,31172434)
文摘Grass carp （Ctenopharyngodon idella） is an important species of freshwater aquaculture fish in China. However, grass carp reovirus （GCRV） can cause fatal hemorrhagic disease in yearling populations. Until now, a strategy to define the antigenic ca- pacity of the virus＇s structural proteins for preparing an effective vaccine has not been available. In this study, some sin- gle-chain variable fragment antibodies （scFv）, which could specifically recognize grass carp IgM, were selected from a con- structed mouse naive antibody phage display cDNA library. The identified scFv C1B3 clone was shown to possess relatively higher specific binding activity to grass carp IgM. Furthermore, ELISA analysis indicated that the IgM level in serum from vi- rus-infected grass carp was more than two times higher than that of the control group at 5-7 days post infection. Moreover, Western blot analysis demonstrated that the outer capsid protein VP7 has a specific immuno-binding-reaction with the serum IgM from virus-infected grass carp. Our results suggest that VP7 can induce a stronger immune response in grass carp than the other GCRV structural proteins, which implies that VP7 protein could be used as a preferred immunogen for vaccine design.
基金Project (No. 396007) supported by the National Natural ScienceFoundation of China
文摘Total RNA was isolated from the hybridoma cell line （LC- 1 ）, which secretes anti-lung adenocarcinoma monoclonal antibody, and was transferred into cDNA. Based on the FRl （framework region l） and FR4 conserved regions of LC-1 gene, the variable regions of heavy chain （Vh） and light chain （Vl） were amplified, and the Vh and modified Vl were connected to single chain Fv （ScFv） by SOE-PCR （splice overlap extension PCR）. The modified ScFv was fused with green fluorescent protein （GFP） and introduced into E. coli JM109. The fusion protein induced by lPTG （Isopropylthiogalactoside） was about 57000 on a 10% SDS-PAGE gel （10% Sds Polyacrylamide Gel Electrophoresis）, and primarily manifested as inclusion bodies. The renatured protein purified by Ni-NTA Superflow resins showed ability to bind to antigen on SPC-A-l lung adenocarcinoma. In addition, the induced host cells fluoresced bright green under 395 nm wavelength, which indicated that the expected protein with dual activity was expressed in the prokaryotic system. The ScFv with GFP tag used in this research can be applied as a new reagent to detect immunological dye, and provide a feasible way to detect adenocarcinoma in a clinical setting.
文摘The single chain variable fragments of antibodies(scFvs) against cTnI were screened from the phage display antibody library by using cTnI as the target antigen. After four rounds of panning, four clones(H2, G5, A9, B9) from the phage display antibody library were verified to show higher binding affinity for cTnI by ELISA and to contain the variable region genes of the light and heavy chains of scFvs by sequencing. The variable region genes of scFvs H2 and G5 were successfully amplified by polymerase chain reactions(PCR) and cloned into expression vector pPELB and expressed as a soluble protein in E.coli Rosetta, whose expression yield was about 2% of total proteins. The expressed proteins were purified by nickel(Ni) affinity chromatography and a single band is shown in the position of 28 kDa on SDS-PAGE. The western blot analysis result verifies that the expressed scFv proteins are capable of binding with monoclonal antibodies against hexa-histidine, indicating that they are hexa-histidin-tagged aim proteins. The immunoassay demonstrates that the expressed scFv proteins are able to specifically react with cTnI molecules. The association constant(K_A) values range from 1.2×10 4 to 1.7 ×10 5 L/mol that are correspondent to the affinities of polyclonal antibodies against cTnI from rabbits. These antibodies can be valuable reagents for the immunoassay of cTnI.
文摘比较表达于大肠杆菌中的人源性抗细胞毒性T淋巴细胞抗原4单链抗体(A n ti-CTLA 4 scFv)的三种体外复性方法的复性效率。稀释、透析和亲和柱上三种复性方式复性A n ti-CTLA 4 scFv,采用B rad ford法分析蛋白复性得率,采用间接细胞EL ISA法检测所得蛋白的活性。透析复性蛋白得率最高,稀释复性蛋白得率其次,亲和柱上复性蛋白得率最低;透析复性所得蛋白结合活性是稀释复性的1.95倍,是亲和柱上复性所得蛋白活性的4.13倍(无谷胱甘肽氧化还原对G SH/G SSH)及3.63倍(有G SH/G SSH)。结论:采用含0.15 m o l/L N aC、l1 mm o l/L G SSH和3 mm o l/L G SH的50 mm o l/L T ris-HC l(pH 8.0)缓冲液作为A n ti-CTLA 4 scFv的复性液,4℃下透析复性48 h,可获得较高复性得率和结合活性。
