An Intracellular Human Single Chain Antibody to Matrix Protein (M1) of H5N1 Virus

2021 ◽  
Author(s):  
He Sun ◽  
Guangmou Wu ◽  
Jiyuan Zhang ◽  
Yu Wang ◽  
Yue Qiu ◽  
...  
Keyword(s):  
Binding Site ◽  
Matrix Protein ◽  
Recombinant Antibody ◽  
Tat Protein ◽  
Single Chain ◽  
Single Chain Antibody ◽  
M1 Protein ◽  
Phage Antibody Library ◽  
Matrix Protein M1 ◽  
Amino Acid Binding

Abstract Background: Influenza virus matrix protein M1 is encoded by viral RNA fragment 7 and is the most abundant protein in virus particles. M1 is expressed in the late stages of viral replication and exerts functionality by inhibiting viral transcription. The M1 protein sequence is an attractive target for antibody drugs.Methods: The M1 protein sequence was amplified by RT-PCR using cDNA from the H5N1 virus as a template; the M1 protein was then expressed and purified. A human strain, high affinity, and single chain antibody (HuScFv) against M1 protein was obtained by phage antibody library screening using M1 as an antigen. A recombinant TAT-HuScFv protein was expressed by fusion with the TAT protein transduction domain (PTD) gene of HIV to prepare a human intracellular antibody against avian influenza virus. The differences between HuScFv and TAT-HUScFv were verified by various experiments and the amino acid binding site of the M1 protein was determined.Results: The M1 protein of H5N1, HuScFv, and TAT-HuScFv, were successfully purified and expressed by and in E. coli. Further analysis demonstrated that TAT-HuScFv inhibited the hemagglutination activity of the 300TCID50 H1N1 virus, thus providing preliminary validation of the universality of the antibody. After two rounds of M1 protein decomposition, the TAT-HuScFv antigen binding site was identified as Alanine (A) at position 239. Collectively, our data describe a recombinant antibody with high binding activity against the conserved sequences of avian influenza viruses. This intracellular recombinant antibody blocked the M1 protein that infected intracellular viruses, thus inhibiting the replication and reproduction of H5N1 viruses.Conclusion: Recombinant HuScFv was successfully identified using the Tomlinson (I+J) phage antibody library and successfully linked to the TAT protein transductive domain of the HIV virus. Compared with the HuScFv, the addition of the TAT peptide improved its ability to penetrate the cell membrane. A definite amino acid binding site was identified after the decomposition of M1 protein, thus providing a target and reference for the development of antibody drugs and the study of new drugs.

Humanization of a highly stable single-chain antibody by structure-based antigen-binding site grafting

2008 ◽  
Vol 45 (9) ◽  
pp. 2474-2485 ◽  
Author(s):  
Maria Elena Villani ◽  
Veronica Morea ◽  
Valerio Consalvi ◽  
Roberta Chiaraluce ◽  
Angiola Desiderio ◽  
...  
Keyword(s):  
Binding Site ◽  
Antigen Binding ◽  
Single Chain ◽  
Single Chain Antibody ◽  
Antigen Binding Site

Construction and Expression of a Bifunctional Single-Chain Antibody against Bacillus cereusSpores

1998 ◽  
Vol 64 (7) ◽  
pp. 2490-2496 ◽  
Author(s):  
Kai Koo ◽  
Peggy M. Foegeding ◽  
Harold E. Swaisgood
Keyword(s):  
Monoclonal Antibody ◽  
Recombinant Antibody ◽  
Expression System ◽  
Variable Region ◽  
Hybridoma Cells ◽  
Antigen Specificity ◽  
Single Chain ◽  
Single Chain Antibody ◽  
Western Blots ◽  
Variable Region Genes

ABSTRACT The variable-region genes of monoclonal antibody againstBacillus cereus spores were cloned from mouse hybridoma cells by reverse transcription-PCR. The heavy- and light-chain variable-region genes were connected by a 45-base linker DNA to allow folding of the fusion protein into a functional tertiary structure. For detection of protein expression, a 10-amino-acid strep tag (biotin-like peptide) was attached to the C terminus of recombinant antibody as the reporter peptide. The single-chain antibody construct was inserted into the expression vector and expressed in Escherichia coliunder the control of the T7 RNA polymerase-T7 promoter expression system. The expressed single-chain antibody was detected on Western blots by using a streptavidin-conjugated enzyme system. This small recombinant antibody fragment (ca. 28,000 Da by calculation) hadB. cereus spore binding ability and antigen specificity similar to those of its parent native monoclonal antibody.

scholarly journals Identification of a Novel Marker for Primordial Smooth Muscle and Its Differential Expression Pattern in Contractile vs Noncontractile Cells

1997 ◽  
Vol 137 (4) ◽  
pp. 925-937 ◽  
Author(s):  
Jill E. Hungerford ◽  
James P. Hoeffler ◽  
Chauncey W. Bowers ◽  
Lisa M. Dahm ◽  
Rocco Falchetto ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vessel Wall ◽  
Recombinant Antibody ◽  
Muscle Cells ◽  
Cytoskeletal Proteins ◽  
Single Chain ◽  
Single Chain Antibody ◽  
Differential Expression Pattern ◽  
Extracellular Matrix Components

The assembly of the vessel wall from its cellular and extracellular matrix components is an essential event in embryogenesis. Recently, we used the descending aorta of the embryonic quail to define the morphological events that initiate the formation of a multilayered vessel wall from a nascent endothelial cell tube (Hungerford, J.E., G.K. Owens, W.S. Argraves, and C.D. Little. 1996. Dev. Biol. 178:375–392). We generated an mAb, 1E12, that specifically labels smooth muscle cells from the early stages of development to adulthood. The goal of our present study was to characterize further the 1E12 antigen using both cytological and biochemical methods. The 1E12 antigen colocalizes with the actin cytoskeleton in smooth muscle cells grown on planar substrates in vitro; in contrast, embryonic vascular smooth muscle cells in situ contain 1E12 antigen that is distributed in threadlike filaments and in cytoplasmic rosette-like patterns. Initial biochemical analysis shows that the 1E12 mAb recognizes a protein, Mr = 100,000, in lysates of adult avian gizzard. An additional polypeptide band, Mr = 40,000, is also recognized in preparations of lysate, when stronger extraction conditions are used. We have identified the 100-kD polypeptide as smooth muscle α-actinin by tandem mass spectroscopy analysis. The 1E12 antibody is an IgM isotype. To prepare a more convenient 1E12 immunoreagent, we constructed a single chain antibody (sFv) using recombinant protein technology. The sFv recognizes a single 100-kD protein in gizzard lysates. Additionally, the recombinant antibody recognizes purified smooth muscle α-actinin. Our results suggest that the 1E12 antigen is a member of the α-actinin family of cytoskeletal proteins; furthermore, the onset of its expression defines a primordial cell restricted to the smooth muscle lineage.

scholarly journals Rapid Isolation of a Single-Chain Antibody against the Cyanobacterial Toxin Microcystin-LR by Phage Display and Its Use in the Immunoaffinity Concentration of Microcystins from Water

2002 ◽  
Vol 68 (11) ◽  
pp. 5288-5295 ◽  
Author(s):  
Jacqui McElhiney ◽  
Mathew Drever ◽  
Linda A. Lawton ◽  
Andy J. Porter
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Phage Display ◽  
High Performance ◽  
Recombinant Antibody ◽  
World Health ◽  
Enzyme Linked Immunosorbent Assay ◽  
Single Chain ◽  
Single Chain Antibody ◽  
Cyanobacterial Toxin

ABSTRACT A naïve (unimmunized) human semisynthetic phage display library was employed to isolate recombinant antibody fragments against the cyanobacterial hepatotoxin microcystin-LR. Selected antibody scFv genes were cloned into a soluble expression vector and expressed in Escherichia coli for characterization against purified microcystin-LR by competition enzyme-linked immunosorbent assay (ELISA). The most sensitive single-chain antibody (scAb) isolated was capable of detecting microcystin-LR at levels below the World Health Organization limit in drinking water (1 μg liter−1) and cross-reacted with three other purified microcystin variants (microcystin-RR, -LW, and -LF) and the related cyanotoxin nodularin. Extracts of the cyanobacterium Microcystis aeruginosa were assayed by ELISA, and quantifications of microcystins in toxic samples showed good correlation with analysis by high-performance liquid chromatography. Immobilized scAb was also used to prepare immunoaffinity columns, which were assessed for the ability to concentrate microcystin-LR from water for subsequent analysis by high-performance liquid chromatography. Anti-microcystin-LR scAb was immobilized on columns via a hexahistidine tag, ensuring maximum exposure of antigen binding sites, and the performance of the columns was evaluated by directly applying 150 ml of distilled water spiked with 4 μg of purified microcystin-LR. The procedure was simple, and a recovery rate of 94% was achieved following elution in 1 ml of 100% methanol. Large-scale, low-cost production of anti-microcystin-LR scAb in E. coli is an exciting prospect for the development of biosensors and on-line monitoring systems for microcystins and will also facilitate a range of immunoaffinity applications for the cleanup and concentration of these toxins from environmental samples.

scholarly journals AI179 single-chain antibody recognizes the Myc tag by Western blotting

2019 ◽  
Vol 2 (2) ◽  
pp. e27
Author(s):  
Zsofia Keszei ◽  
Didier Picard
Keyword(s):  
Western Blotting ◽  
Recombinant Antibody ◽  
Human Cells ◽  
Single Chain ◽  
Single Chain Antibody

The recombinant antibody AI179 against the Myc tag detects a Myc-tagged protein exogenously expressed in human cells by Western blotting.

scholarly journals Optimal Neutralization of Centruroides noxius Venom Is Understood through a Structural Complex between Two Antibody Fragments and the Cn2 Toxin

2015 ◽  
Vol 291 (4) ◽  
pp. 1619-1630 ◽  
Author(s):  
Lidia Riaño-Umbarila ◽  
Luis M. Ledezma-Candanoza ◽  
Hugo Serrano-Posada ◽  
Guillermo Fernández-Taboada ◽  
Timoteo Olamendi-Portugal ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Recombinant Antibody ◽  
Current Trend ◽  
Cross Reactivity ◽  
Antibody Fragments ◽  
Crystallographic Structure ◽  
Single Chain ◽  
Single Chain Antibody ◽  
Neutralizing Capacity ◽  
Centruroides Noxius

The current trend of using recombinant antibody fragments in research to develop novel antidotes against scorpion stings has achieved excellent results. The polyclonal character of commercial antivenoms, obtained through the immunization of animals and which contain several neutralizing antibodies that recognize different epitopes on the toxins, guarantees the neutralization of the venoms. To avoid the use of animals, we aimed to develop an equivalent recombinant antivenom composed of a few neutralizing single chain antibody fragments (scFvs) that bind to two different epitopes on the scorpion toxins. In this study, we obtained scFv RU1 derived from scFv C1. RU1 showed a good capacity to neutralize the Cn2 toxin and whole venom of the scorpion Centruroides noxius. Previously, we had produced scFv LR, obtained from a different parental fragment (scFv 3F). LR also showed a similar neutralizing capacity. The simultaneous administration of both scFvs resulted in improved protection, which was translated as a rapid recovery of previously poisoned animals. The crystallographic structure of the ternary complex scFv LR-Cn2-scFv RU1 allowed us to identify the areas of interaction of both scFvs with the toxin, which correspond to non-overlapping sites. The epitope recognized by scFv RU1 seems to be related to a greater efficiency in the neutralization of the whole venom. In addition, the structural analysis of the complex helped us to explain the cross-reactivity of these scFvs and how they neutralize the venom.

scholarly journals Structural Determinants of the Interactions Between Influenza A Virus Matrix Protein M1 and Lipid Membranes

2018 ◽  
Author(s):  
C.T. Höfer ◽  
S. Di Lella ◽  
I. Dahmani ◽  
N. Jungnick ◽  
N. Bordag ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Matrix Protein ◽  
Structural Changes ◽  
Full Length ◽  
Image Correlation ◽  
Host Cell Membrane ◽  
M1 Protein ◽  
Animal Populations ◽  
Matrix Protein M1

ABSTRACTInfluenza A virus is a pathogen responsible for severe seasonal epidemics threatening human and animal populations every year. One of the ten proteins encoded by the viral genome, the matrix protein M1, is abundantly produced in infected cells and plays a structural role in determining the morphology of the virus. During assembly of new viral particles, M1 is recruited to the host cell membrane where it associates with lipids and other viral proteins. The structure of M1 is only partially known. In particular, structural details of M1 interactions with the cellular plasma membrane as well as M1–protein interactions and multimerization have not been clarified, yet.In this work, we employed a set of complementary experimental and theoretical tools to tackle these issues. Using raster image correlation, surface plasmon resonance and circular dichroism spectroscopies, we quantified membrane association and oligomerization of full-length M1 and of different genetically engineered M1 constructs (i.e., N- and C-terminally truncated constructs and a mutant of the polybasic region, residues 95-105). Furthermore, we report novel information on structural changes in M1 occurring upon binding to membranes. Our experimental results are corroborated by an all-atom model of the full-length M1 protein bound to a negatively charged lipid bilayer.

scholarly journals Generation of High-Affinity Chicken Single-Chain Fv Antibody Fragments for Measurement of the Pseudonitzschia pungens Toxin Domoic Acid

2006 ◽  
Vol 72 (5) ◽  
pp. 3343-3349 ◽  
Author(s):  
William J. J. Finlay ◽  
Iain Shaw ◽  
Joanna P. Reilly ◽  
Marian Kane
Keyword(s):  
Domoic Acid ◽  
Recombinant Antibody ◽  
Variable Region ◽  
Antibody Fragments ◽  
Enzyme Linked Immunosorbent Assay ◽  
Single Chain ◽  
Single Chain Antibody ◽  
High Affinity ◽  
Single Chain Fv ◽  
Recombinant Antibody Fragments

ABSTRACT Antibody-based assay systems are now accepted by regulatory authorities for detection of the toxins produced by phytoplankton that accumulate in shellfish tissues. However, the generation of suitable antibodies for sensitive assay development remains a major challenge. We have examined the potential of using the chicken immune system to generate high-affinity, high-specificity recombinant antibody fragments against phytotoxins. Following immunization of the chicken with domoic acid-bovine serum albumin, a single-chain antibody variable region (scFv) gene library was generated from single VH and VL genes isolated from the immune cells in the spleen and bone marrow. scFvs reacting with domoic acid were isolated by phage display and affinity matured by light chain shuffling, resulting in an approximate 10-fold increase in sensitivity. The isolated scFvs were effectively expressed in Escherichia coli and readily purified by affinity chromatography. They were then used to develop a convenient and sensitive indirect competitive enzyme-linked immunosorbent assay for domoic acid, with a 50% effective dose of 156 ng/ml, which could be used reliably with shellfish extracts. This study demonstrates that chickens provide a valuable model system for the simplified, rapid generation of high-affinity recombinant antibody fragments with specificity for small toxin molecules.

Bound Tris Confounds the Identification of Binding Site Residues in a Paraquat Single Chain Antibody

1997 ◽  
Vol 122 (1) ◽  
pp. 101-108 ◽  
Author(s):  
M. R. Bowles ◽  
T. D. Mulhern ◽  
R. B. Gordon ◽  
H. R. Inglis ◽  
I. A. Sharpe ◽  
...  
Keyword(s):  
Binding Site ◽  
Single Chain ◽  
Single Chain Antibody
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