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| 3. |
- Gustavsson, Elin, et al.
(författare)
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Surrogate antigens as targets for proteome-wide binder selection
- 2011
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Ingår i: New Biotechnology. - : Elsevier BV. - 1871-6784 .- 1876-4347. ; 28:4, s. 302-311
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Tidskriftsartikel (refereegranskat)abstract
- In the last decade, many initiatives have been taken to develop antibodies for proteome-wide studies, as well as characterization and validation of clinically relevant disease biomarkers. Phage display offers many advantages compared to conventional antibody generation by immunization and hybridoma technology, since it is an unlimited resource of affinity reagents without batch-to-batch variation and is amendable for high throughput. One of the major bottlenecks to proteome-wide binder selection is the limited supply of suitable target antigens representative of the human proteome. Here, we provide proof of principle of using easily accessible, cancer-associated protein epitope signature tags (PrESTs), routinely generated within the Human Protein Atlas project, as surrogate antigens in phage selectionsfor the retrieval of target specific binders. These binders were subsequently tested in western blot, immunohistochemistry and protein microarray application to demonstrate their functionality.
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| 4. |
- Hu, Francis Jingxin, 1986-, et al.
(författare)
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Combination of phage and Gram-positive bacterial display of human antibody repertoires enables isolation of functional high affinity binders
- 2018
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Ingår i: New Biotechnology. - : Elsevier. - 1871-6784 .- 1876-4347. ; 45, s. 80-88
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Tidskriftsartikel (refereegranskat)abstract
- Surface display couples genotype with a surface exposed phenotype and thereby allows screening of gene-encoded protein libraries for desired characteristics. Of the various display systems available, phage display is by far the most popular, mainly thanks to its ability to harbour large size libraries. Here, we describe the first use of a Gram-positive bacterial host for display of a library of human antibody genes which, when combined with phage display, provides ease of use for screening, sorting and ranking by flow cytometry. We demonstrate the utility of this method by identifying low nanomolar affinity scFv fragments towards human epidermal growth factor receptor 2 (HER2). The ranking and performance of the scFv isolated by flow sorting in surface-immobilised form was retained when expressed as soluble scFv and analysed by biolayer interferometry, as well as after expression as full-length antibodies in mammalian cells. We also demonstrate the possibility of using Gram-positive bacterial display to directly improve the affinity of the identified binders via an affinity maturation step using random mutagenesis and flow sorting. This combined approach has the potential for a more complete scan of the antibody repertoire and for affinity maturation of human antibody formats.
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- Hu, Francis Jingxin, et al.
(författare)
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Generation of HER2 monoclonal antibodies using epitopes of a rabbit polyclonal antibody
- 2014
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Ingår i: New Biotechnology. - : Elsevier BV. - 1871-6784 .- 1876-4347. ; 31:1, s. 35-43
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Tidskriftsartikel (refereegranskat)abstract
- One of the issues in using polyclonal antibodies is the limited amount of reagent available from an immunisation, leading to batch-to-batch variation and difficulties in obtaining the same antibody performance when the same antigen is re-immunised into several separate animals. This led to the development of hybridoma technology allowing, at least theoretically, for an unlimited production of a specific binder. Nevertheless, polyclonal antibodies are widely used in research and diagnostics and there exists a need for robust methods to convert a polyclonal antibody with good binding performance into a renewable monoclonal with identical or similar binding specificity. Here we have used precise information regarding the functional recognition sequence (epitope) of a rabbit polyclonal antibody with attractive binding characteristics as the basis for generation of a renewable mouse monoclonal antibody. First, the original protein fragment antigen was used for immunisation and generation of mouse hybridoma, without obtaining binders to the same epitope region. Instead a peptide designed using the functional epitope and structural information was synthesised and used for hybridoma production. Several of the monoclonal antibodies generated were found to have similar binding characteristics to those of the original polyclonal antibody. These monoclonal antibodies detected native HER2 on cell lines and were also able to stain HER2 in immunohistochemistry using xenografted mice, as well as human normal and cancer tissues.
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| 6. |
- Hu, Francis Jingxin, 1986-, et al.
(författare)
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Phage and Gram-positive bacterial display of human antibody repertoires enables isolation of functional high affinity binders
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Ingår i: New Biotechnology. - 1871-6784 .- 1876-4347.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Surface display couples genotype with a surface exposed phenotype and thereby allows for screening of gene-encoded protein libraries for desired characteristics. Of the various display systems, phage display is by far the most popular, mainly thanks to its ability to harbor large library sizes. Here, we describe the first use of a grampositive host for display of a library of human antibody genes. The method allows for swift generation of binders by combining phage and gram-positive display, for its ease of use for screening, sorting and ranking by flow cytometry. We demonstrate the utility of this method by identifying specific low nanomolar scFv towards human HER2. The ranking and performance of the scFv isolated by flow sorting in surface immobilized form was retained when expressed as soluble scFv and analyzed by biolayer interferometry as well as after expression as full-length antibodies in mammalian cells. We also show the possibility to use gram-positive display to directly improve the affinity of the identified binders via an affinity maturation step using random mutagenesis and flow sorting. We believe this combined approach has the potential for a more complete scan of the antibody repertoire and for swift affinity maturation of human antibody formats.
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| 7. |
- Häggmark, Anna, et al.
(författare)
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Classification of protein profiles from antibody microarrays using heat and detergent treatment.
- 2011
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Ingår i: New Biotechnology. - : Elsevier BV. - 1871-6784 .- 1876-4347. ; 29:5, s. 564-570
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Tidskriftsartikel (refereegranskat)abstract
- Antibody microarrays offer new opportunities for exploring the proteome and to identify biomarker candidates in human serum and plasma. Here, we have investigated the effect of heat and detergents on an antibody-based suspension bead array (SBA) assay using polyclonal antibodies and biotinylated plasma samples. With protein profiles from more than 2300 antibodies generated in 384-plex antibody SBAs, three major classes of heat and detergent susceptibility could be described. The results show that washing of the beads with SDS (rather than Tween) after target binding lowered intensity levels of basically all profiles and that about 50% of the profiles appeared to be lowered to a similar extent by heating of the sample. About 33% of the profiles appeared to be insensitive to heat treatment while another 17% showed a positive influence of heat to yield elevated profiles. The results suggest that the classification of antibodies is driven by the molecular properties of the antibody-antigen interaction and can generally not be predicted based on protein class or Western blot data. The experimental scheme presented here can be used to systematically categorize antibodies and thereby combine antibodies with similar properties into targeted arrays for analysis of plasma and serum.
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| 8. |
- Jönsson, Malin, et al.
(författare)
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CaRA – A multi-purpose phage display library for selection of calcium-regulated affinity proteins
- 2022
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Ingår i: New Biotechnology. - : Elsevier B.V.. - 1871-6784 .- 1876-4347. ; 72, s. 159-167
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Tidskriftsartikel (refereegranskat)abstract
- Protein activity regulated by interactions with metal ions can be utilized for many different purposes, including biological therapies and bioprocessing, among others. Calcium ions are known to interact with the frequently occurring EF-hand motif, which can alter protein activity upon binding through an induced conformational change. The calcium-binding loop of the EF-hand motif has previously been introduced into a small protein domain derived from staphylococcal Protein A in a successful effort to render antibody binding dependent on calcium. Presented here, is a combinatorial library for calcium-regulated affinity, CaRA, based on this domain. CaRA is the first alternative scaffold library designed to achieve novel target specificities with metal-dependent binding. From this library, several calcium-dependent binders could be isolated through phage display campaigns towards a set of unrelated target proteins (IgE Cε3-Cε4, TNFα, IL23, scFv, tPA, PCSK9 and HER3) useful for distinct applications. Overall, these monomeric CaRA variants showed high stability and target affinities within the nanomolar range. They displayed considerably higher melting temperatures in the presence of 1 mM calcium compared to without calcium. Further, all discovered binders proved to be calcium-dependent, with the great majority showing complete lack of target binding in the absence of calcium. As demonstrated, the CaRA library is highly capable of providing protein-binding domains with calcium-dependent behavior, independent of the type of target protein. These binding domains could subsequently be of great use in gentle protein purification or as novel therapeutic modalities.
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| 10. |
- Sjöberg, Ronald, et al.
(författare)
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Exploration of high-density protein microarrays for antibody validation and autoimmunity profiling
- 2016
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Ingår i: New Biotechnology. - : Elsevier. - 1871-6784 .- 1876-4347. ; 33:5, s. 582-592
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Tidskriftsartikel (refereegranskat)abstract
- High-density protein microarrays of recombinant human protein fragments, representing 12,412 unique Ensembl Gene IDs, have here been produced and explored. These protein microarrays were used to analyse antibody off-target interactions, as well as for profiling the human autoantibody repertoire in plasma against the antigens represented by the protein fragments. Affinity-purified polyclonal antibodies produced within the Human Protein Atlas (HPA) were analysed on microarrays of three different sizes, ranging from 384 antigens to 21,120 antigens, for evaluation of the antibody validation criteria in the HPA. Plasma samples from secondary progressive multiple sclerosis patients were also screened in order to explore the feasibility of these arrays for broad-scale profiling of autoantibody reactivity. Furthermore, analysis on these near proteome-wide microarrays was complemented with analysis on HuProt (TM) Human Proteome protein microarrays. The HPA recombinant protein microarray with 21,120 antigens and the HuProt (TM) Human Proteome protein microarray are currently the largest protein microarray platforms available to date. The results on these arrays show that the Human Protein Atlas antibodies have few off-target interactions if the antibody validation criteria are kept stringent and demonstrate that the HPA-produced high-density recombinant protein fragment microarrays allow for a high-throughput analysis of plasma for identification of possible autoantibody targets in the context of various autoimmune conditions.
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