Phage display technology and its application in antivirals discovery / 药学学报

The COVID-19 outbreak has drawn attention to viral infectious diseases once again, and the development of antiviral drugs for both known and potentially emerging viruses is of great significance. In recent years, peptides and protein drugs are becoming a hot spot in the field of antiviral drug research and development. Phage display technology, as a powerful tool for screening peptides and protein drugs, has been increasingly concerned in the academic and industrial fields. The present review introduced the basic principle of phage display technology, summarized phage display libraries often used in antiviral drug discovery and their applications, discussed the challenges and future direction of antiviral drug research and development based on phage display technology.

Research progress of cyclic peptides derived from phage display technology / 药学学报

Cyclic peptide drugs have gradually become an emerging research direction due to their some favorable properties such as high-efficiency binding affinity, high selectivity, lower toxicity, and stable metabolism. In recent years, the number of cyclic peptide drugs under clinical research has continued to increase. Unlike the previous cyclic peptide drugs, which were mostly derived from natural products and their derivatives, these cyclic peptide drugs are designed by genetically encoded display technologies which are based on rational design and in vitro evolution (such as BT1718, PTG-300, POL6326, etc). Among them, phage display technology has some advantages such as mature research system, low cost, and simpler operation that make it well recognized and praised by the majority of researchers in this field. Here, we reviewed the recent progress of applying phage display technology to explore diverse cyclic peptide libraries, which, we believe, will contribute more valuable candidate cyclic peptide drugs in clinical research.

Chicken antibodies against venom proteins of Trimeresurus stejnegeri in Taiwan

The venom of bamboo vipers (Trimeresurus stejnegeri - TS), commonly found in Taiwan, contains deadly hemotoxins that cause severe envenomation. Equine-derived antivenom is a specific treatment against snakebites, but its production costs are high and there are some inevitable side effects. The aim of the present work is to help in the development of an affordable and more endurable therapeutic strategy for snakebites. Methods: T. stejnegeri venom proteins were inactivated by glutaraldehyde in order to immunize hens for polyclonal immunoglobulin (IgY) antibodies production. After IgY binding assays, two antibody libraries were constructed expressing single-chain variable fragment (scFv) antibodies joined by the short or long linker for use in phage display antibody technology. Four rounds of biopanning were carried out. The selected scFv antibodies were then further tested for their binding activities and neutralization assays to TS proteins. Results: Purified IgY from egg yolk showed the specific binding ability to TS proteins. The dimensions of these two libraries contain 2.4 × 107 and 6.8 × 107 antibody clones, respectively. An increase in the titers of eluted phage indicated anti-TS clones remarkably enriched after 2nd panning. The analysis based on the nucleotide sequences of selected scFv clones indicated that seven groups of short linkers and four groups of long linkers were identified. The recombinant scFvs showed significant reactivity to TS venom proteins and a cross-reaction to Trimeresurus mucrosquamatus venom proteins. In in vivo studies, the data demonstrated that anti-TS IgY provided 100% protective effects while combined scFvs augmented partial survival time of mice injected with a lethal amount of TS proteins. Conclusion: Chickens were excellent hosts for the production of neutralization antibodies at low cost. Phage display technology is available for generation of monoclonal antibodies against snake venom proteins. These antibodies could be applied in the development of diagnostic kits or as an alternative for snakebite envenomation treatment in the near future.(AU)

Screening and Identification of the Peptides Specifically Binding to Human Non-small Cell Lung Cancer NCI-H1299 Cells / 中国肺癌杂志

BACKGROUND@#Non-small cell lung cancer (NSCLC) is the most common histological type of lung cancer, and one of the malignant tumor with the highest mortality. As the main part of the optical molecular imaging probe, peptide can realize the early screening and diagnosis of tumor and improve the survival rate of patients. The aim of this study was to screen the small-molecule peptide that highly binds to NSCLC NCI-H1299 cells using in vivo phage display technology and to identify their binding specificity by in vitro experiment.@*METHODS@#To prepare a tumor-bearing nude mouse model of NCI-H1299 cells, after 3 rounds of in vivo screening with Ph.D.-C7CTM Peptide Library, phage clones were randomly picked, using immunohistochemistry and enzyme-linked immunosorbent assay (ELISA) to identify the affinity of phage clones to NCI-H1299 cells. The positive monoclonal phages DNA was extracted and sequenced to obtain the amino acid sequence of the peptides. The peptides with the highest repetition rate was chemically synthesized and labeled with fluorescein (FITC) to prepare optical molecular probe. We preliminary identified the specificity of the probe binding to lung cancer cells by in vitro experiment.@*RESULTS@#After three rounds of in vivo screening, the phages enrichment rate was 341.3 times compared with the first round. Immunohistochemical staining showed that with the increase of screening times, the phages binding to tumor tissues continued to increase, and the binding amount was significantly higher than normal tissues; ELISA results showed that 20 clones among the 30 randomly selected phage clones were positive. After sequencing, the peptide with the highest repetition rate was synthesized and named NSP1; Methyl thiazolyl tetrazolium assay (MTT) and would healing assay showed that NSP1 will not affect cell proliferation and migration. Flow cytometry and immunofluorescence showed specific binding of NSP1 to NCI-H1299 cells.@*CONCLUSIONS@#We successfully obtained the peptide NSP1 that specifically binds to lung cancer NCI-H1299 cells by in vivo phage display, which provide a theoretical basis for NSCLC early diagnosis and targeted therapy.

The screening and identification of internalized nanobody against EpCAM / 药学学报

Epithelial cell adhesion molecule (EpCAM) is a popular target for cancer therapy. In this research, 3 nanobodies with high specificity and endocytosis activity against EpCAM were developed, which provides a basis for the study of immunotoxin based on EpCAM. In our preliminary experiments, we have immunized a camel with EpCAM-Fc antigen and constructed a high-quality phage display library. Seventeen nanobodies with different complementarity determining region (CDR) 3 sequences have been screened after 3 rounds of biopanning by phage display technology. The animal procedures were approved by the Institutional Animal Care and Use Committee (IACUC) of Fudan University School of Pharmacy. After purification, 7 nanobodies showed high cell binding activity by fluorescent activated cell sorting (FACS) identification. Furthermore, 3 nanobodies presented high endocytosis activity based on FACS and laser confocal microscopy, which also showed high affinity to EpCAM measured by ForteBio. According to this study, we aimed to provide a novel alternative approach to the EpCAM-targeted therapy and to provide guidance for the study of nanobody based immunotoxins for other targets.

Advances in effectively screening anti-tumor peptides / 药学学报

Malignant tumor is a disease that severely threaten human health. Common chemotherapeutical drugs currently used in clinical practice have some problems in severe side effects and chemoresistance. In contrast, natural venom peptides and artificially designed targeting peptides have excellent biological activities and potential druggability due to their small molecular weights and high affinity to tumor tissues. Thus, the methods for the discovery of anti-tumor peptides have attracted much attention. In this paper, we summarized the types of anti-tumor peptides from recent literatures. Then, we systematically reviewed screening theories, methods and applications based on traditional chromatographic separation, peptidomics, phage display, phenotypic screening, and artificial intelligence. These strategies and technologies will provide a methodological reference for accelerating anti-tumor peptides research.

Identification of High-affinity Novel Targeted Peptides for the Treatment of Human Ovarian Cancer

Background: To investigate the potential of the phage display-identified tumor cellbinding peptide as a biomarker of epithelial ovarian cancer using phage display technology. Method: The Ph.D.-7 Phage Display Peptide Library was used to identify the specific conjugated phages with SKOV3 epithelial ovarian cancer cells, while Chinese hamster ovary cells formed the basis. After employing the rapid differential screening method invitro, the enzyme-linked immunosorbent assay (ELISA), DNA sequencing, immunohistochemistry, immunofluorescence, and the competitive inhibition test of synthetic peptides were used to determine the affinity and specificity of the phages with SKOV3 cells. Results: Using bio panning, we screened the phages, showing a 3590-fold increase after the third round. A total of 61 titers of the phage were randomly selected for ELISA and 10 kinds of the phages with an optical density >0.5 were used for DNA sequencing. Clones of the phage TRRNIPN were derived from DNA sequencing based on ELISA, exhibiting both the brown granular phenomenon and green fluorescence. The specific targeted peptide TRRNIPN was incorporated in tumor cells through the competitive inhibition test. Conclusion: The results of our study indicate that the phage display identified polypeptide TRRNIPN may be an effective biomarker for the early diagnosis and targeted therapy of ovarian cancer

Preparation and identification of anti-human ICAM-1 scFv / 生物工程学报

To screen the specific anti-human intercellular adhesion molecule-1 (ICAM-1) single chain fragment variable (scFv) using phage display library technology and to identify its biological activity. P1 peptide was used as antigen, and the phage antibodies against human ICAM-1 antigen were panned by four binding-eluting-amplifying cycles using Tomlinson I+J phage display library. After four rounds of selective enrichment screening, the positive clones were determined by PCR, enzyme linked immunosorbent assay (ELISA)-based antigenic cross reaction and Dot blotting. Then the binding specificity and biological activity of purified scFv were identified by Western blotting, competitive ELISA and cell adhesion inhibition assay respectively. Furthermore, four positive clones were first panned through P1 peptide coated-ELISA assay, and then J-A1 was obtained and identified by PCR, ELISA-based antigenic cross reaction and Dot blotting, which could show a specific binding between P1 peptide and human ICAM-1 protein antigen. Subsequently, the purified scFv showed a satisfactory specificity and anti-adhesive activity in competitive ELISA and the cell adhesion inhibition assay. The specific anti-human ICAM-1 scFv was prepared successfully from Tomlinson I+J phage display library, which pave the way for further application of anti-human ICAM-1 scFv for inflammation diseases therapeutics.

Generation of an alpaca derived nanobody recognizing human Her2 antigen / 军事医学

Objective To obtain alpaca single domain antibody targeting Her2.Methods An alpaca was immunized with human recombination Her2 protein mixed with Freund's adjuvant.Total RNA was extracted from the alpaca's blood and was used to synthesize first strand cDNA.Single domain antibody variable region (VHH) gene of the alpaca was amplified by PCR and cloned into pMES4 vector for library construction.After screening, E.coli BL21 (DE3) was transformed with selected clones and was induced with IPTG for the expression of recombinant proteins.The nanobody was purified by nickel ion affinity chromatography column.The affinity of the nanobodies to Her2 was tested.Results After the second round of screening, two antibody clones were selected, H3 and H5.The affinity of H5 was 8.106×10-10mol/L.Histochemistry results showed that H5 could recognize Her2 antigen in breast tumor tissue.Conclusion An Her2 specific nanobody derived from alpaca is obtained through phage display library screening, which can recognize human Her2 antibody in human breast tumor tissue.

Screening and identification of cell-penetrating peptides by display technology / 国际药学研究杂志

Screening and identification of cell-penetrating peptides(CPP)which have different functions by display technolo?gy are hot topics in recent years. Currently the most widely used display technology is phage display and mRNA display technology. This paper describes the principle and application of display technology such as phage display and mRNA display and reviews in detail the advance in study on the screening and identification of CPP by display technology in recent years.

Screening and identification of cell-penetrating peptides by display technology / 国际药学研究杂志

Screening and identification of cell-penetrating peptides, CPP which have different functions by display technology are hot topics in recent years. Currently the most widely used display technology is phage display and mRNA display technology. This paper describes the principle and application of display technology such as phage display and mRNA display and reviews in detail the advance in study on the screening and identification of CPP by display technology in recent years.

Screening and Characterization of Human Phage Antibody to Permethrin / 现代检验医学杂志

Objective To do screening acute lymphoblastic leukemia patients scFv antibody single chain variable region to cre-ate conditions for the expression and obtain further specificity of antibody fragments.Methods In this study,patients with newly diagnosed acute lymphoblastic leukemia serum as coating antigen using phage display technology,screening phage an-tibody specificity from the semi-synthetic human phage antibody libraries,the first to target the immune antigen-coated tab-let,phage library was added,so that with the target antigen-specific binding phage antibody was immobilized on plates immu-nization,could not be specifically bound phages were rinsed.The eluted specific binding phage,E.coli infection.Could get the specific antibody gene containing phagemid.Results After three “adsorption-elution-amplification”screening process,got stronger leukemia patient antigen-specific phage antibody variable region fragment and identification.Conclusion Got better strain affinity antibody fragments,to create the conditions for the next fragment expression,identification and clinical appli-cation.

Progress of phage display technology in cancer / 国际肿瘤学杂志

Phage display technology describes a genetic engineering technique in which a library of peptide or protein variants is expressed on the outside of a phage virion,while the genetic material encodes each variant resides on the inside and maintains the relatively independent spatial structure and biological activity. Studies have shown that the phage display technology can be used to screen tumor homing peptides,target trans-porting anti-substances,develop vaccines,research diagnostic regents and image in blood vessels.Thus phage display technology is a powerful method to overcome the challenge of tumor disease.

Selection of peptide specifically binding to bladder carcinoma by using phage display in vivo / 中国免疫学杂志

Objective:To screen the peptide binding to human bladder carcinoma cells specifically by using phage display technology in vivo.Methods: Nude mice were inoculated with bladder carcinoma cells BIU87 for establishing tumor-bearing mice model.The Ph.D.-C7CTM Peptide Library was injected intravenously via tail vein.Then we screened Phage containing exogenous peptides binding to bladder transitional carcinoma cells specifically.The phage peptide homed to the tumor tissues was obtained after 3 rounds screening in vivo.The phage clones affinity to BIU87 were identified by immunohistochemistry and ELISA.The positive peptide was synthetized by chemical methods after sequencing the positive monoclonal phage DNA.The tumor cell specificity of target peptide was identified by confocal laser scanning microscope and flow cytometry.Results:After 3 rounds screening in vivo,enrichment rate of phage was 4.334×102 times.Immunohistochemistry results showed that the dyeing of the tumor tissue had a rising trend following each round of phage screening,while liver had a lot of non-specific binding phage because the phages were metabolized through liver and kid-ney.The 30 phage clones were identified by ELISA and 10 clones had a strong affinity on BIU87 among 24 positive clones.Three amino acid sequences of positive phage clones were obtained.The highest rate of repeat sequences CSSPIGRHC(8/10) named NYZL1 and the FITC-C6-NYZL1 peptide was synthesized.Our results showed that it could bind to bladder carcinoma cells BIU87 specifically.Conclusion:We obtained the small molecular peptide NYZL1 binding to human bladder carcinoma specifically by means of phage display in vivo,which provide a theoretical basis for bladder carcinoma early diagnosis and targeted therapy.

Screening of receptor that interacted with outer membrane protein 25 during macrophage infection by Brucella abortus / 中华地方病学杂志

Objective Receptor was screened to find out the interaction between outer membrane protein 25 of Brucella(OMP25) and Brucella infected macrophages.Methods Recombinant OMP25 protein was expressed and purified.The 7 peptide was screened out with OMP25 protein by phage display technology.OMP25-7 peptide interactions were further confirmed by enzyme linked immunosorbent assay(ELISA) after candidate peptides were predicted with bioinformatics software.Four potential 7 peptides were synthetized.Their functions were estimated after Brucella abortus 2308 infected murine macrophages RAW264.7.Results Forty-two cyclic 7 peptides were screened out based on purified OMP25 by the M13 Phage Library Kit.Four peptides,named as ST-7,MT-7,TF-7 and SN-7,were confirmed with ELISA.Colony forming unit(CFU) result demonstrated ST-7,MT-7,TF-7 and SN-7 showed some function for inhibition of intracellular parasite.ST-7 inhibition ratio was 14.4％-51.8％ for Brucella abortus 2308; MT-7 inhibition ratio was 49.6％-69.5％ for Brucella abortus 2308; TF-7 inhibition ratio was 43.2％-74.4％ for Brucella abortus 2308; SN-7 inhibition ratio was 57.5％-82.2％ for 2308.ELISA result showed,that compared to control group,tumor necrosis factor α(TNF-α)increased no statistical significance in each time point of ST-7,MT-7 experiment groups (all P ＞ 0.05).There was no statistical significance in 8 h ago of TF-7,SN-7 experiment groups (all P ＞ 0.05),but there was statistical significance in 12,24 h (all P ＜ 0.05).Conclusions We have obtained four effective OMP25 receptors through phage display technology; TF-7 and SN-7 have inhibited Brucella abortus 2308 invasion and intracellular survival in murine macrophage cells,while ST-7 and MT-7 have only prevented the invasion against Brucella abortus 2308.

The Progress of the Proteomic Technology / 航天医学与医学工程

With the rapid development of modern science and technology,the post-genomics period has come with the complement of the sequence of body genome including several tens of human genome,the emphasis of life science transfer from instruction genome to the post-genomics period,functional genome.Proteomics is the most important part of it.The technology of proteomics is advanced day by day.Except the classical two dimensional gel electrophoresis,the technology of multi-dimensional liquid chromatography and the technology of isotope coded-affinity tags have been successively developed,as well as protein chip and phage display have been applied extensively.This article simply summarizes the key technologies of proteomics.

Cloning and expression of human anti-Rh(D) single-chain Fv fragment / 医学研究生学报

Objective: To construct a phage display library of human single-chain Fv antibodies against blood group Rh(D) substance. Methods: Combining phage display library techniques, isolated total RNA from B lymphoblastoid cell lines secreting anti-Rh(D) antibodies was used for the synthesis of the first strand of cDNA, V_ H and V_ L genes were amplified by 2nd PCR and linked together by splicing overlap extension (SOE) with the use of a (Gly_ 4Ser)_ 3 linker. The resulted scFv genes were then cloned into pCANTAB5E vectors and displayed on the phage. Phage clones were selected using intact red cells as a source of antigen. After 4 rounds of "binding-elution-enrichment", each clone was assayed for specificity by Dot ELISA. Results: A phage antibody library, with the sink size being 1.2?107, was obtained. The percentage of full-length scFv gene inserted into phage DNA was 0.80. Rescued by helper phage, a phage scFv library with titer of 3?108 pfu/ml was established. Specific phages with scFv were acquired after 4 rounds of panning, one clone exhibiting specific binding to Rh+ cell was identified by Dot ELISA. Conclusion: A strategy for construction phage antibody library by means of phage display technique was practicable, which would be useful in screening engineered antibodies against human Rh (D) blood group substances.

Construction of Fab fragment phage antibody library and selection of clones expressing anti-human ?_1-AR antibody / 中国免疫学杂志

Objective:To construct a human Fab phage antibody library and to obtain some recombinant clones which can express Fab fragment antibody against ? 1-adrenergic receptor.Methods:Fd heavy chain gene and ??? light chains gene of IgG obtained by RT-PCR from peripheral lymphocytes of DCM patients whose anti ? 1-AR antibodies are present were cloned into pComb3 vector and the human Fab phage antibody library was constructed.The library was panned by phage display technology with ? 1-ARECⅡ as antigen.Results:A human Fab phage antibody library with 1.4?10 6 capability was constructed successfully,a positive clone against human ? 1-AR was screened from the phage antibody library.Conclusion:The recombinant clones which express Fab antibody against ? 1-AR can be obtained by phage display technology.