African swine fever virus(ASFV)is a lethal pathogen that causes severe threats to the global swine industry and it has already had catastrophic socio-economic effects.To date,no licensed prophylactic vaccine exists.Li...African swine fever virus(ASFV)is a lethal pathogen that causes severe threats to the global swine industry and it has already had catastrophic socio-economic effects.To date,no licensed prophylactic vaccine exists.Limited knowledge exists about the major immunogens of ASFV and the epitope mapping of the key antigens.As such,there is a considerable requirement to understand the functional monoclonal antibodies(mAbs)and the epitope mapping may be of utmost importance in our understanding of immune responses and designing improved vaccines,therapeutics,and diagnostics.In this study,we generated an ASFV antibody phage-display library from ASFV convalescent swine PBMCs,further screened a specific ASFV major capsid protein(p72)single-chain antibody and fused with an IgG Fc fragment(scFv-83-Fc),which is a specific recognition antibody against ASFV Pig/HLJ/2018 strain.Using the scFv-83-Fc mAb,we selected a conserved epitope peptide(221MTGYKH226)of p72 retrieved from a phage-displayed random peptide library.Moreover,flow cytometry and cell uptake experiments demonstrated that the epitope peptide can significantly promote BMDCs maturation in vitro and could be effectively uptaken by DCs,which indicated its potential application in vaccine and diagnostic reagent development.Overall,this study provided a valuable platform for identifying targets for ASFV vaccine development,as well as to facilitate the optimization design of subunit vaccine and diagnostic reagents.展开更多
Development and application of phage display technology and research progress of virus affinity peptide were summarized in the paper,and a preliminary outlook for future development was put forward. The paper laid a f...Development and application of phage display technology and research progress of virus affinity peptide were summarized in the paper,and a preliminary outlook for future development was put forward. The paper laid a foundation for development of polypeptide drugs and polypeptide vaccine.展开更多
Phage display technology is a unique gene recombination expression technology, and it is also a simple and effective screening tool. Through panning, a protein or peptide with high affinity and selectivity to the targ...Phage display technology is a unique gene recombination expression technology, and it is also a simple and effective screening tool. Through panning, a protein or peptide with high affinity and selectivity to the target is obtained. Antibody phage display has become the first and most widely used <i><span style="font-family:Verdana;">in vitro</span></i><span style="font-family:Verdana;"> screening technology. Phage display derivatives play an important role in the diagnosis and treatment of diseases. This article reviews the phage display system of phage display technology, the size and classification of antibody libraries and their applications, and discusses the application prospects and challenges of phage display technology.</span><span style="font-family:Verdana;"> </span><span style="font-family:Verdana;">This thesis lays the foundation for the theoretical and experimental research of bacteriophages.</span>展开更多
Objective:To isolate and characterize Staphylococcus aureus(S.aureus)β-hemolysinneutralizing dAbs from phage display library of Indian desert camel.Methods:Phage display library of 5×10 dAb clones of LPS-immuniz...Objective:To isolate and characterize Staphylococcus aureus(S.aureus)β-hemolysinneutralizing dAbs from phage display library of Indian desert camel.Methods:Phage display library of 5×10 dAb clones of LPS-immunized Indian desert camel constructed in our laboratory was used for selection of S.aureus exotoxin-specific clones by panning technique.Enrichment of Ag-specific clones in successive rounds of panning was assessed by phage-ELISA and phage titration.Different dAb clones binding to S.aureus exotoxin Ags were expressed with C-terminal 6×His tag in E.coli and purified by Ni-chelate chromatography.The expression was verified by SDS-PAGE and western blotting.The purified clones were tested for inhibition of ’hot-cold’ hemolytic activity in vitro.Resistance to thermal inactivation of the dAb clones was studied by observing the effect of heat treatment from 50℃to 99℃for 30 min on the ’hot-cold’ hemolytic activity in vitro.Results:Several dAb clones binding to S.aureus exotoxins were isolated and enriched by three rounds of panning.The soluble dAb clones were approximately～16 kDa in size and reacted with 6×His tag specific murine monoclonal antibody in western blot.One of the Ni-chelate affinity purified dAb.6×His clones,inhibited S.aureusβ-hemolysin activity in vitro and resisted thermal inactivation upto 991.Conclusions:An S.aureusβ-hemolysinneutralizing dAb clone of possible therapeutic potential has been isolated.展开更多
Hepatitis B virus(HBV) has killed countless lives in human history. The invention of HBV vaccines in the 20 th century has reduced significantly the rate of the viral infection. However, currently there is no effectiv...Hepatitis B virus(HBV) has killed countless lives in human history. The invention of HBV vaccines in the 20 th century has reduced significantly the rate of the viral infection. However, currently there is no effective treatment for chronic HBV carriers. Newly emerging vaccine escape mutants and drug resistant strains have complicated the viral eradication program. The entire world is now facing a new threat of HBV and human immunodeficiency virus co-infection. Could phage display provide solutions to these life-threatening problems? This article reviews critically and comprehensively the innovative and potential applications of phage display in the development of vaccines, therapeutic agents, diagnostic reagents, as well as gene and drug delivery systems to combat HBV. The application of phage display in epitope mapping of HBV antigens is also discussed in detail. Although this review mainly focuses on HBV, the innovative applications of phage display could also be extended to other infectious diseases.展开更多
AIM: To construct a random peptide phage display library and search for peptides that specifically bind to the PreS region of hepatitis B virus (HBV).METHODS: A phage display vector, pFuse8, based on the gene 8 produc...AIM: To construct a random peptide phage display library and search for peptides that specifically bind to the PreS region of hepatitis B virus (HBV).METHODS: A phage display vector, pFuse8, based on the gene 8 product (pⅧ) of M13 phage was made and used to construct a random peptide library. E. coli derived thioredoxin-PreS was purified with Thio-bond beads, and exploited as the bait protein for library screening. Five rounds of bio-panning were performed. The PreS-binding specificities of enriched phages were characterized with phage ELISA assay.RESULTS: A phage display vector was successfully constructed as demonstrated to present a pⅧ fused HBV PreS1 epitope on the phage surface with a high efficiency.A cysteine confined random peptide library was constructed containing independent clones exceeding 5±108 clone forming unit (CFU). A pool of phages showing a PreS-binding specificity was obtained after the screening against thioPres with an enrichment of approximately 400 times. Five phages with high PreS-binding specificities were selected and characterized. Sequences of the peptides displayed on these phages were determined.CONCLUSION: A phage library has been constructed,with random peptides displaying as pⅧ-fusion proteins.Specific PreS-binding peptides have been obtained, which may be useful for developing antivirals against HBV infection.展开更多
AIM: To identify the scFv antibody fragments specific for hepatocellular carcinoma by biopanning from a large human naive scFv phage display library.METHODS: A large human naive scFv phage library was used to search f...AIM: To identify the scFv antibody fragments specific for hepatocellular carcinoma by biopanning from a large human naive scFv phage display library.METHODS: A large human naive scFv phage library was used to search for the specific targets by biopanning with the hepatocellular carcinoma cell line HepG2 for the positiveselecting and the normal liver cell line L02 for the counterselecting. After three rounds of biopanning, individual scFv phages binding selectively to HepG2 cells were picked out. PCR was carried out for identification of the clones containing scFv gene sequence. The specific scFv phages were selected by ELISA and flow cytometry. DNA sequences of positive clones were analyzed by using Applied Biosystem Automated DNA sequencers 3 730. The expression proteins of the specific scFv antibody fragments in E. coli HB2151were purified by the affinity chromatography and detected by SDS-PAGE, Western blot and ELISA. The biological effect of the soluble antibody fragments on the HepG2 cells was investigated by observing the cell proliferation.RESULTS: Two different positive clones were obtained and the functional variable sequences were identified.Their DNA sequences of the scFv antibody fragments were submitted to GenBank (accession nos: AY686498 and AY686499). The soluble scFv antibody fragments were successfully expressed in E. coli HB2151. The relative molecular mass of the expression products was about 36 ku,according to its predicted Mr value. The two soluble scFv antibody fragments also had specific binding activity and obvious growth inhibition properties to HepG2 cells.CONCLUSION: The phage library biopanning permits identification of specific antibody fragments for hepatocellular carcinoma and affords experiment evidence for its immunotherapy study.展开更多
AIM:To develop an affinity peptide that binds to gastric cancer used for the detection of early gastric cancer.METHODS:A peptide screen was performed by biopanning the PhD-12 phage display library,clearing non-specifi...AIM:To develop an affinity peptide that binds to gastric cancer used for the detection of early gastric cancer.METHODS:A peptide screen was performed by biopanning the PhD-12 phage display library,clearing non-specific binders against tumor-adjacent normal appearing gastric mucosa and obtaining selective binding against freshly harvested gastric cancer tissues.Tumortargeted binding of selected peptides was confirmed by bound phage counts,enzyme-linked immunosorbent assay,competitive inhibition,fluorescence microscopy and semi-quantitative analysis on immunohistochemistry using different types of cancer tissues.RESULTS:Approximately 92.8% of the non-specific phage clones were subtracted from the original phage library after two rounds of biopanning against normal-appearing gastric mucosa.After the third round of positive screening,the peptide sequence AADNAKTKSFPV(AAD) appeared in 25%(12/48) of the analyzed phages.For the control peptide,these values were 6.8 ± 2.3,5.1 ± 1.7,3.5 ± 2.1,4.6 ± 1.9 and 1.1 ± 0.5,respectively.The values for AAD peptide were statistically signif icant(P < 0.01) for gastric cancer as compared with other histological classif ications and control peptide.CONCLUSION:A novel peptide is discovered to have a specific binding activity to gastric cancer,and can be used to distinguish neoplastic from normal gastric mucosa,demonstrating the potential for early cancer detection on endoscopy.展开更多
Phage display is very strong technique in drug discovery and development. Phage display has many applications in improving the immunological studies. Development of monoclonal antibody, peptides, peptidomimetics and e...Phage display is very strong technique in drug discovery and development. Phage display has many applications in improving the immunological studies. Development of monoclonal antibody, peptides, peptidomimetics and epitope mapping are main application of phage display. Selection of monoclonal antibody or peptides that are displayed on the surface of the phages can be occurred through biopanning process. In biopanning process phage library is incubated with antigen and particular phages can be identified and isolated. Increasing the stringency in the biopanning rounds can be help to select phages with high affinity and specificity. Here, we describe an overview of phage display application with focusing on monoclonal antibody production and epitope mapping.展开更多
The blood brain barrier represents a formidable obstacle for the transport of most systematically administered neurodiagnostics and neurotherapeutics to the brain. Phage display is a high throughput screening strategy...The blood brain barrier represents a formidable obstacle for the transport of most systematically administered neurodiagnostics and neurotherapeutics to the brain. Phage display is a high throughput screening strategy that can be used for the construction of nanomaterial peptide libraries. These libraries can be screened for finding brain targeting peptide ligands. Surface functionalization of a variety of nanocarriers with these brain homing peptides is a sophisticated way to develop nanobiotechnology-based drug delivery platforms that are able to cross the blood brain barrier. These efficient drug delivery systems raise our hopes for the diagnosis and treatment of various brain disorders in the future.展开更多
Objective: To screen and identify the mimotopes of lipopolysaccharide (LPS) epitope. Methods: A random phage display dodecapeptide library was screened with monoclonal antibody 2B4 specifically against LPS conservativ...Objective: To screen and identify the mimotopes of lipopolysaccharide (LPS) epitope. Methods: A random phage display dodecapeptide library was screened with monoclonal antibody 2B4 specifically against LPS conservative epitope. The positive clones were identified by phage EUSA and competitive inhibition assay with either S. typhimurium T861 LPS or E. coli Olll:B4 LPS. Results: After 3 rounds of biopanning, the clones bound with monoclonal antibody 2B4 were well enriched with the positive rate of 80%. The bindings between 12 positive phage clones and screening antibody were inhibited by both kinds of LPS. The positive peptide sequences were deduced from the corresponding DNA sequences. There were some identical sequences among them: PPQWFFSQPQL (5/12, 41. 7%), LPQYFW NTATTA (3/12, 25%), FPQNHWNVPWAT(2/12, 16. 6% ),HSQSFWNAPLAM and AHPWTHGYFPPL (l/12, 8. 3% ). Conclusion: The peptides screened with 2B4 antibody are mimotopes of LPS conservative epitope.展开更多
The human CD81(hCD81),the most recently proposed receptor of hepatitis C virus(HCV),can especifically bind to HCV envelope glycoprotein 2(E2).In this study,hCD81-expressing murine NIH/3T3 cells were used to select hCD...The human CD81(hCD81),the most recently proposed receptor of hepatitis C virus(HCV),can especifically bind to HCV envelope glycoprotein 2(E2).In this study,hCD81-expressing murine NIH/3T3 cells were used to select hCD81-binding peptides from a phage displayed nonapeptide library(PVIII9aaCys).Eighteen of the 75clones selected from the library showed specific binding to the hCD81-expressing NIH/3T3 cells by enzyme linked immunosorbent assay(ELISA)and competitive inhibition test.Twelve out of the 18 clones shared the amino acid motif SPQYWTGPA.Sequence comparison of the motif showed no amino acid homology with the native HCV E2.The motif-containing phages could competitively inhibit the ability of HCV E2 binding to native hCD81-expressing MOLT-4 cells,and induce HCV E2 specific immune response in vivo.These results suggest that the selected motif SPQYWTGPA should be a mimotope of HCV E2 to bind to hCD81 molecules.Our findings cast new light on developing HCV receptor antagonists.展开更多
In order to construct a single chain fragment variable (ScFv) phage display library against ovarian tumor, by using RT-PCR, the human heavy chain variable region genes (VH) and light chain variable region genes (VL) w...In order to construct a single chain fragment variable (ScFv) phage display library against ovarian tumor, by using RT-PCR, the human heavy chain variable region genes (VH) and light chain variable region genes (VL) were amplified from lymphocytes of ovarian tumor patients and subsequently assembled into ScFv genes by SOE. The resulting ScFv genes were electrotransformed into E. coli TG1 and amplified with the co-infection of helper phage M13KO7 to obtain phage display library. The capacity and titer of the resulting library were detected. The phage antibody library with a capacity of approximately 3×109cfu/μg was obtained. After amplification with helper phage, the titer of antibody library reached 5×1012cfu/mL. Human ScFv library against ovarian tumor was constructed successfully, which laid a foundation for the screening of ovarian tumor specific ScFv for the radioimmunoimaging diagnosis of ovarian tumor.展开更多
Avian influenza virus(AIV) nonstructural 1(NS1) gene was amplified by real-time polymerse chain reac tion(RT-PCR) and inserted into pET28a, then transformed into E. coli BL21(DE3) competent cell. With the induction of...Avian influenza virus(AIV) nonstructural 1(NS1) gene was amplified by real-time polymerse chain reac tion(RT-PCR) and inserted into pET28a, then transformed into E. coli BL21(DE3) competent cell. With the induction of isopropyl-β-D-thiogalactoside(IPTG) and the purification of Ni-NTA column, we finally obtained purified NS1 protein. T7-phage display system was used to screen the proteins that interacted with NS1 from lung cell cDNA li brary. The selected positive clones were identified by DNA sequencing and analyzed by BLAST program in Gene Bank. Two proteins were obtained as NS1 binding proteins, Homo sapiens nucleolar and coiled-body phosphoprotein 1(NOLC1) and Homo sapiens similar to colon cancer-associated antigen. By co-immunoprecipitation and other me thods, Homo sapiens NOLC1 was found to interact with the NS1 protein, the results would provide the basis for fur ther studying biological function of NS1 protein.展开更多
The purpose of this study was to screen peptides that can specifically bind to human hepatocellular carcinoma(hHCC) cells using phage display of random peptide library in order to de-velope a peptide-based carrier for...The purpose of this study was to screen peptides that can specifically bind to human hepatocellular carcinoma(hHCC) cells using phage display of random peptide library in order to de-velope a peptide-based carrier for the diagnosis or therapy of hHCC.A peptide 12-mer phage display library was employed and 4 rounds of subtractive panning were performed using the hHCC cell line HepG2 as the target.After panning,the phages that specifically bound to and internalized in hHCC cells were selected.The selected phages demonstrated highly specific affinity to HepG2 cells analyzed by ELISA and immunofluorescence analysis.57.3% of the selected phage clones displayed repeated sequence FLLEPHLMDTSM,and 4 amino acid residues,FLEP were extremely conservative.Based on the sequencing results,a 16-mer peptide(WH-16) was synthesized.The competitive ELISA showed that the binding of the phage clones displayed sequence FLLEPHLMDTSM to HepG2 cells was efficiently inhibited by WH-16.Our findings indicate that cellular binding of phage is mediated via its displayed peptide and the synthesized 16-mer peptide may have the potential to be a delivery carrier in target diagnosis or therapy for hHCC.展开更多
Clostridium perfringens phospholipase C(plc),also calledα-toxin,is encoded by the plc gene Clostridium perfringers.The production ofα-toxin can lead to the occurrence of gas gangrene.Vaccination is considered as one...Clostridium perfringens phospholipase C(plc),also calledα-toxin,is encoded by the plc gene Clostridium perfringers.The production ofα-toxin can lead to the occurrence of gas gangrene.Vaccination is considered as one of the best solutions against Clostridium infections.In this study,an anti-Cpα-toxin monoclonal antibody(mAbs)A10E5 was successfully prepared,which had better biological reactivity.Then,the phage random 12-peptide library was used to screen mAb A10E5 protein.After four rounds of screening,three peptides with high affinity to the anti-α-toxin mAbs were screened.Two 12-peptide peptide Q and peptide E with higher inhibition rate were obtained by indirect ELISA.Two polypeptides of 500μg·mL^(-1)synthesized in vitro were mixed with30μg·mL^(-1)α-toxin at a concentration to treat Hela cells.Cell viability was determined by MTT assay.The results showed that both of the peptides significantly increased the survival rate of Hela cells compared with theα-toxin group,and the effect of peptide Q was more obvious.The chickens were immunized with phages expressing two different affinity polypeptides and then challenged.The results of chicken weight change,intestinal lesion score,bacterial count,and antibody titer in peripheral blood showed that the two phages expressing the polypeptides had a certain protective effect on the chickens compared with the PBS group,and peptide Q had better protection effect.In conclusion,the high affinity peptide with mAb A10E5 was screened in this study,and the protective effect of the plc polypeptide vaccine was verified by in vivo and in vitro experiments,which was of great significance for the comprehensive prevention and treatment of the disease.展开更多
Phage display technique provides a powerful approach for the discovery of new tumor-specific peptides.However,the peptides isolated through this technique usually did not possess high tumor-specific property.A pre-cle...Phage display technique provides a powerful approach for the discovery of new tumor-specific peptides.However,the peptides isolated through this technique usually did not possess high tumor-specific property.A pre-clearing step was introduced to increase the efficiency of biopanning by removal of particles that could interact with ubiquitously expressed cellular receptors in the non-target organs.The randomized Ph.D-CX7C phage library (Phage III) was first pre-cleared in normal mice to reduce vasculatureor organ-targeting phages to get the pre-cleared phage library,and then the tumor-targeting bacteriophage particles (Phage I) were screened from pre-clearing phage library in S180 tumor-bearing mice.The biodistribution results of 99mTc-labeled phages in mice bearing S180 tumor show that the uptake of 99mTc-labeled Phage I in tumor is high but low in normal organs,and the tumor-to-liver and tumor-to-spleen ratios of 99mTc-labeled Phage I are higher than those of 99mTc-labeled Phage II (tumor-specific phages screened from the original CX7C library) and Phage III (unscreened phages from the original CX7C library).It indicates that the yield of tumor-targeting bacteriophage particles could be improved and the non-specific binding in organs becomes weak.Consequently,the pre-clearing phage display method could improve the yield of positive hits by reducing the non-target organ accumulation of bacteriophage particles.展开更多
基金supported by the National Natural Science Foundation of China(31941001 and 32002292)the Major Science and Technology Project of Henan Province,China(221100110600)the Natural Science Foundation of Henan Province(202300410199).
文摘African swine fever virus(ASFV)is a lethal pathogen that causes severe threats to the global swine industry and it has already had catastrophic socio-economic effects.To date,no licensed prophylactic vaccine exists.Limited knowledge exists about the major immunogens of ASFV and the epitope mapping of the key antigens.As such,there is a considerable requirement to understand the functional monoclonal antibodies(mAbs)and the epitope mapping may be of utmost importance in our understanding of immune responses and designing improved vaccines,therapeutics,and diagnostics.In this study,we generated an ASFV antibody phage-display library from ASFV convalescent swine PBMCs,further screened a specific ASFV major capsid protein(p72)single-chain antibody and fused with an IgG Fc fragment(scFv-83-Fc),which is a specific recognition antibody against ASFV Pig/HLJ/2018 strain.Using the scFv-83-Fc mAb,we selected a conserved epitope peptide(221MTGYKH226)of p72 retrieved from a phage-displayed random peptide library.Moreover,flow cytometry and cell uptake experiments demonstrated that the epitope peptide can significantly promote BMDCs maturation in vitro and could be effectively uptaken by DCs,which indicated its potential application in vaccine and diagnostic reagent development.Overall,this study provided a valuable platform for identifying targets for ASFV vaccine development,as well as to facilitate the optimization design of subunit vaccine and diagnostic reagents.
基金Supported by Scientific and Technological Project of Henan Province(162102110136)Science and Technology Foundation for Outstanding Young Scientists of Henan Academy of Agricultural Sciences(2016YQ28)
文摘Development and application of phage display technology and research progress of virus affinity peptide were summarized in the paper,and a preliminary outlook for future development was put forward. The paper laid a foundation for development of polypeptide drugs and polypeptide vaccine.
文摘Phage display technology is a unique gene recombination expression technology, and it is also a simple and effective screening tool. Through panning, a protein or peptide with high affinity and selectivity to the target is obtained. Antibody phage display has become the first and most widely used <i><span style="font-family:Verdana;">in vitro</span></i><span style="font-family:Verdana;"> screening technology. Phage display derivatives play an important role in the diagnosis and treatment of diseases. This article reviews the phage display system of phage display technology, the size and classification of antibody libraries and their applications, and discusses the application prospects and challenges of phage display technology.</span><span style="font-family:Verdana;"> </span><span style="font-family:Verdana;">This thesis lays the foundation for the theoretical and experimental research of bacteriophages.</span>
基金Financial support by Department of Biotechnology,Government of India,New Delhi for construction of phage display library and its applications, and Indian Council of Agricultural Research,New Delhi for infrastructure assistance
文摘Objective:To isolate and characterize Staphylococcus aureus(S.aureus)β-hemolysinneutralizing dAbs from phage display library of Indian desert camel.Methods:Phage display library of 5×10 dAb clones of LPS-immunized Indian desert camel constructed in our laboratory was used for selection of S.aureus exotoxin-specific clones by panning technique.Enrichment of Ag-specific clones in successive rounds of panning was assessed by phage-ELISA and phage titration.Different dAb clones binding to S.aureus exotoxin Ags were expressed with C-terminal 6×His tag in E.coli and purified by Ni-chelate chromatography.The expression was verified by SDS-PAGE and western blotting.The purified clones were tested for inhibition of ’hot-cold’ hemolytic activity in vitro.Resistance to thermal inactivation of the dAb clones was studied by observing the effect of heat treatment from 50℃to 99℃for 30 min on the ’hot-cold’ hemolytic activity in vitro.Results:Several dAb clones binding to S.aureus exotoxins were isolated and enriched by three rounds of panning.The soluble dAb clones were approximately～16 kDa in size and reacted with 6×His tag specific murine monoclonal antibody in western blot.One of the Ni-chelate affinity purified dAb.6×His clones,inhibited S.aureusβ-hemolysin activity in vitro and resisted thermal inactivation upto 991.Conclusions:An S.aureusβ-hemolysinneutralizing dAb clone of possible therapeutic potential has been isolated.
文摘Hepatitis B virus(HBV) has killed countless lives in human history. The invention of HBV vaccines in the 20 th century has reduced significantly the rate of the viral infection. However, currently there is no effective treatment for chronic HBV carriers. Newly emerging vaccine escape mutants and drug resistant strains have complicated the viral eradication program. The entire world is now facing a new threat of HBV and human immunodeficiency virus co-infection. Could phage display provide solutions to these life-threatening problems? This article reviews critically and comprehensively the innovative and potential applications of phage display in the development of vaccines, therapeutic agents, diagnostic reagents, as well as gene and drug delivery systems to combat HBV. The application of phage display in epitope mapping of HBV antigens is also discussed in detail. Although this review mainly focuses on HBV, the innovative applications of phage display could also be extended to other infectious diseases.
基金Supported by Basic Research Program from Ministry of Science and Technology of China, No. G1999054105special funds for Sino-France Center for Life Science and Genome Research from Chinese Academy of Sciences and Pasteur Institute in France
文摘AIM: To construct a random peptide phage display library and search for peptides that specifically bind to the PreS region of hepatitis B virus (HBV).METHODS: A phage display vector, pFuse8, based on the gene 8 product (pⅧ) of M13 phage was made and used to construct a random peptide library. E. coli derived thioredoxin-PreS was purified with Thio-bond beads, and exploited as the bait protein for library screening. Five rounds of bio-panning were performed. The PreS-binding specificities of enriched phages were characterized with phage ELISA assay.RESULTS: A phage display vector was successfully constructed as demonstrated to present a pⅧ fused HBV PreS1 epitope on the phage surface with a high efficiency.A cysteine confined random peptide library was constructed containing independent clones exceeding 5±108 clone forming unit (CFU). A pool of phages showing a PreS-binding specificity was obtained after the screening against thioPres with an enrichment of approximately 400 times. Five phages with high PreS-binding specificities were selected and characterized. Sequences of the peptides displayed on these phages were determined.CONCLUSION: A phage library has been constructed,with random peptides displaying as pⅧ-fusion proteins.Specific PreS-binding peptides have been obtained, which may be useful for developing antivirals against HBV infection.
基金This work was supported by grants from the National Natural Science Foundation of China(No.30400111)the Natural Science Foundation of Jiangsu Province(No.BK2004041).
文摘与 B 房间淋巴瘤在病人的管理把单音的同种细胞的抗体用作指向的治疗的赞同为这组病人导致了新治疗选择。由传统的 hybridoma 技术的单音的同种细胞的抗体的生产是昂贵的，并且结果鼠科的抗体经常有触发人的反老鼠抗体(HAMA ) 反应的劣势。因此，噬菌体产生的重组体 Fab 抗体显示技术能是在管理 B 房间淋巴瘤的一种合适的选择。在这研究，我们从与人的 B 淋巴瘤房间使免疫的 BALB/c 老鼠的怒气房间提取了全部的 RNA，并且使用了 RT-PCR 为 kappa 光链和重链的 Fd 碎片放大 cDNAscoding。在适当限制文摘以后，这些 cDNA 碎片连续地被插入到噬菌体构造一个使免疫的 Fab 噬菌体显示图书馆的中间的向量 pComb3H-SS。构造图书馆的差异是近似 1.94x10 (7 ) 。跟随五轮简历 panning，可溶的 Fab 抗体从 ELISA 识别的积极克隆被生产。从八积极克隆， FabC06， FabC21， FabC43 andFabC59 为顺序分析被选择。在氨基酸顺序的水平，可变的重域(V (H)) 和可变的轻域(V (L)) 被发现分享 88-92% 和 89-94% 相同，序列分别地由相应鼠科的细菌行基因编码了。而且，有 B 房间淋巴瘤的膜蛋白质的反应被 immunohistochemistryand 表明西方的弄污。这些使免疫的 Fab 抗体可以为 B 房间淋巴瘤的进一步的学习提供一个珍贵工具并且能也贡献疾病治疗的改进。
基金Supported by the Major State Basic Research Development Program of China, 973 Program, No. 2002CB513100
文摘AIM: To identify the scFv antibody fragments specific for hepatocellular carcinoma by biopanning from a large human naive scFv phage display library.METHODS: A large human naive scFv phage library was used to search for the specific targets by biopanning with the hepatocellular carcinoma cell line HepG2 for the positiveselecting and the normal liver cell line L02 for the counterselecting. After three rounds of biopanning, individual scFv phages binding selectively to HepG2 cells were picked out. PCR was carried out for identification of the clones containing scFv gene sequence. The specific scFv phages were selected by ELISA and flow cytometry. DNA sequences of positive clones were analyzed by using Applied Biosystem Automated DNA sequencers 3 730. The expression proteins of the specific scFv antibody fragments in E. coli HB2151were purified by the affinity chromatography and detected by SDS-PAGE, Western blot and ELISA. The biological effect of the soluble antibody fragments on the HepG2 cells was investigated by observing the cell proliferation.RESULTS: Two different positive clones were obtained and the functional variable sequences were identified.Their DNA sequences of the scFv antibody fragments were submitted to GenBank (accession nos: AY686498 and AY686499). The soluble scFv antibody fragments were successfully expressed in E. coli HB2151. The relative molecular mass of the expression products was about 36 ku,according to its predicted Mr value. The two soluble scFv antibody fragments also had specific binding activity and obvious growth inhibition properties to HepG2 cells.CONCLUSION: The phage library biopanning permits identification of specific antibody fragments for hepatocellular carcinoma and affords experiment evidence for its immunotherapy study.
基金Supported by The National Natural Science Foundation of China,No.81172359
文摘AIM:To develop an affinity peptide that binds to gastric cancer used for the detection of early gastric cancer.METHODS:A peptide screen was performed by biopanning the PhD-12 phage display library,clearing non-specific binders against tumor-adjacent normal appearing gastric mucosa and obtaining selective binding against freshly harvested gastric cancer tissues.Tumortargeted binding of selected peptides was confirmed by bound phage counts,enzyme-linked immunosorbent assay,competitive inhibition,fluorescence microscopy and semi-quantitative analysis on immunohistochemistry using different types of cancer tissues.RESULTS:Approximately 92.8% of the non-specific phage clones were subtracted from the original phage library after two rounds of biopanning against normal-appearing gastric mucosa.After the third round of positive screening,the peptide sequence AADNAKTKSFPV(AAD) appeared in 25%(12/48) of the analyzed phages.For the control peptide,these values were 6.8 ± 2.3,5.1 ± 1.7,3.5 ± 2.1,4.6 ± 1.9 and 1.1 ± 0.5,respectively.The values for AAD peptide were statistically signif icant(P < 0.01) for gastric cancer as compared with other histological classif ications and control peptide.CONCLUSION:A novel peptide is discovered to have a specific binding activity to gastric cancer,and can be used to distinguish neoplastic from normal gastric mucosa,demonstrating the potential for early cancer detection on endoscopy.
文摘Phage display is very strong technique in drug discovery and development. Phage display has many applications in improving the immunological studies. Development of monoclonal antibody, peptides, peptidomimetics and epitope mapping are main application of phage display. Selection of monoclonal antibody or peptides that are displayed on the surface of the phages can be occurred through biopanning process. In biopanning process phage library is incubated with antigen and particular phages can be identified and isolated. Increasing the stringency in the biopanning rounds can be help to select phages with high affinity and specificity. Here, we describe an overview of phage display application with focusing on monoclonal antibody production and epitope mapping.
文摘The blood brain barrier represents a formidable obstacle for the transport of most systematically administered neurodiagnostics and neurotherapeutics to the brain. Phage display is a high throughput screening strategy that can be used for the construction of nanomaterial peptide libraries. These libraries can be screened for finding brain targeting peptide ligands. Surface functionalization of a variety of nanocarriers with these brain homing peptides is a sophisticated way to develop nanobiotechnology-based drug delivery platforms that are able to cross the blood brain barrier. These efficient drug delivery systems raise our hopes for the diagnosis and treatment of various brain disorders in the future.
基金Supported by Natural Science Foundation of Guangdong Province, No. 970334
文摘Objective: To screen and identify the mimotopes of lipopolysaccharide (LPS) epitope. Methods: A random phage display dodecapeptide library was screened with monoclonal antibody 2B4 specifically against LPS conservative epitope. The positive clones were identified by phage EUSA and competitive inhibition assay with either S. typhimurium T861 LPS or E. coli Olll:B4 LPS. Results: After 3 rounds of biopanning, the clones bound with monoclonal antibody 2B4 were well enriched with the positive rate of 80%. The bindings between 12 positive phage clones and screening antibody were inhibited by both kinds of LPS. The positive peptide sequences were deduced from the corresponding DNA sequences. There were some identical sequences among them: PPQWFFSQPQL (5/12, 41. 7%), LPQYFW NTATTA (3/12, 25%), FPQNHWNVPWAT(2/12, 16. 6% ),HSQSFWNAPLAM and AHPWTHGYFPPL (l/12, 8. 3% ). Conclusion: The peptides screened with 2B4 antibody are mimotopes of LPS conservative epitope.
基金supported by research grants from the National Natural Science Foundation of China(No.30271l87)the Shanghai Science and Technology Development Foundation(No.02DJ14015)
文摘The human CD81(hCD81),the most recently proposed receptor of hepatitis C virus(HCV),can especifically bind to HCV envelope glycoprotein 2(E2).In this study,hCD81-expressing murine NIH/3T3 cells were used to select hCD81-binding peptides from a phage displayed nonapeptide library(PVIII9aaCys).Eighteen of the 75clones selected from the library showed specific binding to the hCD81-expressing NIH/3T3 cells by enzyme linked immunosorbent assay(ELISA)and competitive inhibition test.Twelve out of the 18 clones shared the amino acid motif SPQYWTGPA.Sequence comparison of the motif showed no amino acid homology with the native HCV E2.The motif-containing phages could competitively inhibit the ability of HCV E2 binding to native hCD81-expressing MOLT-4 cells,and induce HCV E2 specific immune response in vivo.These results suggest that the selected motif SPQYWTGPA should be a mimotope of HCV E2 to bind to hCD81 molecules.Our findings cast new light on developing HCV receptor antagonists.
基金This project was supported by a grant from the National Natural Sciences Foundation of China (No. 30200295).
文摘In order to construct a single chain fragment variable (ScFv) phage display library against ovarian tumor, by using RT-PCR, the human heavy chain variable region genes (VH) and light chain variable region genes (VL) were amplified from lymphocytes of ovarian tumor patients and subsequently assembled into ScFv genes by SOE. The resulting ScFv genes were electrotransformed into E. coli TG1 and amplified with the co-infection of helper phage M13KO7 to obtain phage display library. The capacity and titer of the resulting library were detected. The phage antibody library with a capacity of approximately 3×109cfu/μg was obtained. After amplification with helper phage, the titer of antibody library reached 5×1012cfu/mL. Human ScFv library against ovarian tumor was constructed successfully, which laid a foundation for the screening of ovarian tumor specific ScFv for the radioimmunoimaging diagnosis of ovarian tumor.
基金Supported by the National Natural Science Foundation of China(No.30671852)the Open Research Fund Program of the State Key Laboratory of Virology of China(Nos.2010009, 2007007) the Research Fund of the Key Laboratory of Department of Education of Liaoning Province, China(No.2009S043)
文摘Avian influenza virus(AIV) nonstructural 1(NS1) gene was amplified by real-time polymerse chain reac tion(RT-PCR) and inserted into pET28a, then transformed into E. coli BL21(DE3) competent cell. With the induction of isopropyl-β-D-thiogalactoside(IPTG) and the purification of Ni-NTA column, we finally obtained purified NS1 protein. T7-phage display system was used to screen the proteins that interacted with NS1 from lung cell cDNA li brary. The selected positive clones were identified by DNA sequencing and analyzed by BLAST program in Gene Bank. Two proteins were obtained as NS1 binding proteins, Homo sapiens nucleolar and coiled-body phosphoprotein 1(NOLC1) and Homo sapiens similar to colon cancer-associated antigen. By co-immunoprecipitation and other me thods, Homo sapiens NOLC1 was found to interact with the NS1 protein, the results would provide the basis for fur ther studying biological function of NS1 protein.
基金a grant from National Natural Science Foundation of China(N0.30171062)
文摘The purpose of this study was to screen peptides that can specifically bind to human hepatocellular carcinoma(hHCC) cells using phage display of random peptide library in order to de-velope a peptide-based carrier for the diagnosis or therapy of hHCC.A peptide 12-mer phage display library was employed and 4 rounds of subtractive panning were performed using the hHCC cell line HepG2 as the target.After panning,the phages that specifically bound to and internalized in hHCC cells were selected.The selected phages demonstrated highly specific affinity to HepG2 cells analyzed by ELISA and immunofluorescence analysis.57.3% of the selected phage clones displayed repeated sequence FLLEPHLMDTSM,and 4 amino acid residues,FLEP were extremely conservative.Based on the sequencing results,a 16-mer peptide(WH-16) was synthesized.The competitive ELISA showed that the binding of the phage clones displayed sequence FLLEPHLMDTSM to HepG2 cells was efficiently inhibited by WH-16.Our findings indicate that cellular binding of phage is mediated via its displayed peptide and the synthesized 16-mer peptide may have the potential to be a delivery carrier in target diagnosis or therapy for hHCC.
基金Supported by the National Natural Science Foundation of China(31370140,31372438)。
文摘Clostridium perfringens phospholipase C(plc),also calledα-toxin,is encoded by the plc gene Clostridium perfringers.The production ofα-toxin can lead to the occurrence of gas gangrene.Vaccination is considered as one of the best solutions against Clostridium infections.In this study,an anti-Cpα-toxin monoclonal antibody(mAbs)A10E5 was successfully prepared,which had better biological reactivity.Then,the phage random 12-peptide library was used to screen mAb A10E5 protein.After four rounds of screening,three peptides with high affinity to the anti-α-toxin mAbs were screened.Two 12-peptide peptide Q and peptide E with higher inhibition rate were obtained by indirect ELISA.Two polypeptides of 500μg·mL^(-1)synthesized in vitro were mixed with30μg·mL^(-1)α-toxin at a concentration to treat Hela cells.Cell viability was determined by MTT assay.The results showed that both of the peptides significantly increased the survival rate of Hela cells compared with theα-toxin group,and the effect of peptide Q was more obvious.The chickens were immunized with phages expressing two different affinity polypeptides and then challenged.The results of chicken weight change,intestinal lesion score,bacterial count,and antibody titer in peripheral blood showed that the two phages expressing the polypeptides had a certain protective effect on the chickens compared with the PBS group,and peptide Q had better protection effect.In conclusion,the high affinity peptide with mAb A10E5 was screened in this study,and the protective effect of the plc polypeptide vaccine was verified by in vivo and in vitro experiments,which was of great significance for the comprehensive prevention and treatment of the disease.
文摘Phage display technique provides a powerful approach for the discovery of new tumor-specific peptides.However,the peptides isolated through this technique usually did not possess high tumor-specific property.A pre-clearing step was introduced to increase the efficiency of biopanning by removal of particles that could interact with ubiquitously expressed cellular receptors in the non-target organs.The randomized Ph.D-CX7C phage library (Phage III) was first pre-cleared in normal mice to reduce vasculatureor organ-targeting phages to get the pre-cleared phage library,and then the tumor-targeting bacteriophage particles (Phage I) were screened from pre-clearing phage library in S180 tumor-bearing mice.The biodistribution results of 99mTc-labeled phages in mice bearing S180 tumor show that the uptake of 99mTc-labeled Phage I in tumor is high but low in normal organs,and the tumor-to-liver and tumor-to-spleen ratios of 99mTc-labeled Phage I are higher than those of 99mTc-labeled Phage II (tumor-specific phages screened from the original CX7C library) and Phage III (unscreened phages from the original CX7C library).It indicates that the yield of tumor-targeting bacteriophage particles could be improved and the non-specific binding in organs becomes weak.Consequently,the pre-clearing phage display method could improve the yield of positive hits by reducing the non-target organ accumulation of bacteriophage particles.
