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Discover how PEPperPRINT Peptide Microarray products have been used in different fields of research.

Detection of specific IgE against linear epitopes from Gal d 1 has additional value in diagnosing hen’s egg allergy in adults

Ehlers, Anna M.; Otten, Henny G.; Wierzba, Eva; Flügge, Ulrike; Le, Thuy-My; Knulst, André C.; Suer, Waltraud
Background Although hen’s egg allergy is more prevalent in children, up to 0.6% of adults from different European countries suffers from a persistent or newly-onset hen’s egg allergy, making accurate diagnosis in adults necessary. However, sensitisation to hen’s egg extracts, components and linear epitopes are solely studied in children. Methods Hen’s egg allergic (n=16) and tolerant (n=20) adults were selected by sensitisation towards recombinant components rGal d 1 and/or 3. Sensitisation profiles towards egg white and yolk extract and the native components Gal d 1, 2, 3 and 4 were respectively evaluated with the ImmunoCAP or the EUROLINE system. Characterisation of linear epitopes was performed with a peptide microarray containing 15mer peptides representing the entire sequence of mature Gal d 1 and 3. Results Overall, sIgE titres against hen’s egg extracts and single components overlapped largely between allergic and tolerant adults. Although the median sIgE/sIgG4 ratio to Gal d 1 was increased in allergic adults, the range was comparable between both groups. Clinically relevant sensitisation to Gal d 1 was confirmed by sIgE-binding to the linear epitopes aa30-41, aa39-50 or aa84-95 in 6/13 allergic adults, mainly suffering from objective symptoms. In comparison, these epitopes were recognized by 1/15 tolerant patient. Only a few linear epitopes were detected for Gal d 3, suggesting a greater importance of conformational epitopes for the recognition of Gal d 3. Conclusion and Clinical Relevance Specific IgE-binding to linear epitopes of Gal d 1 is highly specific in identifying hen’s egg allergic adults with objective symptoms.

Rapid response to pandemic threats: immunogenic epitope detection of pandemic pathogens for diagnostics and vaccine development using peptide microarrays

Heiss, Kirsten; Heidepriem, Jasmin; Fischer, Nico; Weber, Laura K; Dahlke, Christine; Jaenisch, Thomas; Loeffler, Felix F
J. Proteome Res..
Sep 2020
Emergence and re-emergence of pathogens bearing the risk of becoming a pandemic threat are on the rise. Increased travel and trade, growing population density, changes in urbanization, and climate have a critical impact on infectious disease spread. Currently, the world is confronted with the emergence of a novel coronavirus SARS-CoV-2, responsible for yet more than 500 000 deaths globally. Outbreaks caused by viruses such as SARS-CoV-2, HIV, Ebola, influenza, and Zika have increased over the last decade, underlining the urgent need for a rapid development of diagnostics and vaccines. Hence, the rational identification of biomarkers for diagnostic measures on the one hand, and antigenic targets for vaccine development on the other, are of utmost importance. Peptide microarrays can display large numbers of putative target proteins translated into overlapping linear (and cyclic) peptides. Using these highly diverse libraries, covering tens of thousands of peptides, allow for the in-depth analysis of antibody signatures in a multiplexed, high-throughput fashion. In this review, we highlight synthesis platforms that facilitate fast and highly flexible generation of high-density peptide microarrays. We further outline the multifaceted applications of these peptide array platforms for the development of serological tests and vaccines, to quickly encounter pandemic threats.

On‐Chip Neo‐Glycopeptide Synthesis for Multivalent Glycan Presentation

Mende, Marco; Tsouka, Alexandra; Heidepriem, Jasmin; Paris, Grigori; Mattes, Daniela S.; Eickelmann, Stephan; Bordoni, Vittorio; Wawrzinek, Robert; Fuchsberger, Felix F.; Seeberger, Peter H.; Rademacher, Christoph; Delbianco, Martina; Mallagaray, Alvaro; Loeffler, Felix F
Chem. Eur. J..
Apr 2020
Single glycan–protein interactions are often weak, such that glycan binding partners commonly utilize multiple, spatially defined binding sites to enhance binding avidity and specificity. Current array technologies usually neglect defined multivalent display. Laser-based array synthesis technology allows for flexible and rapid on-surface synthesis of different peptides. By combining this technique with click chemistry, neo-glycopeptides were produced directly on a functionalized glass slide in the microarray format. Density and spatial distribution of carbohydrates can be tuned, resulting in well-defined glycan structures for multivalent display. The two lectins concanavalin A and langerin were probed with different glycans on multivalent scaffolds, revealing strong spacing-, density-, and ligand-dependent binding. In addition, we could also measure the surface dissociation constant. This approach allows for a rapid generation, screening, and optimization of a multitude of multivalent scaffolds for glycan binding.

Immunity to Influenza is dependent on MHC II polymorphism: study with 2 HLA transgenic strains

Luckey, David; Weaver, Eric A.; Osborne, Douglas G.; Billadeau, Daniel D.; Taneja, Veena
Sci Rep.
Dec 2019
Major histocompatibility complex II (MHC II) molecules are involved in antigen presentation and the development of a functional adaptive immune response. Evolutionary selection for MHC molecules that effectively clear infectious agents provides an advantage to humans. However, certain class II molecules are associated with autoimmune diseases. In this study we infected autoimmune-susceptible DRB1*0401.AEo and non-susceptible *0402.AEo mice with H1N1 influenza and determined clearance and protective immunity to H3N2 virus. *0401 mice generated a robust TLR-triggered immune response and cleared H1N1 influenza virus infection. After vaccination and challenge with H1N1, *0401 mice, when challenged with H3N2, generated cross-protective immunity to heterosubtypic H3N2 influenza strain whereas *0402 mice cleared the H1N1 infection but did not generate cross-protective immunity against the H3N2 influenza strain. The intracellular trafficking route of MHCII revealed that *0401 molecules traffic through the late endosome/lysosomes while *0402 molecules traffic into early endosomes. This suggested that trafficking of MHCII could affect the functional output of the innate immune response and clearance of viral infections. Also, DRB1*0401 mice live longer than HLA-DRB1*0402 mice. The study provides a potential hypothesis for evolutionary selection of *0401 molecule, even though it is associated with autoreactivity, which may be dependent on the availability of peptide repertoire of self-antigens.

Diagnostic Profiling of the Human Public IgM Repertoire With Scalable Mimotope Libraries

Pashov, Anastas; Shivarov, Velizar; Hadzhieva, Maya; Kostov, Victor; Ferdinandov, Dilyan; Heintz, Karen-Marie; Pashova, Shina; Todorova, Milena; Vassilev, Tchavdar; Kieber-Emmons, Thomas; Meza-Zepeda, Leonardo A.; Hovig, Eivind
Front. Immunol..
Dec 2019
Specific antibody reactivities are routinely used as biomarkers, but the antibody repertoire reactivity (igome) profiles are still neglected. Here, we propose rationally designed peptide arrays as efficient probes for these system level biomarkers. Most IgM antibodies are characterized by few somatic mutations, polyspecificity, and physiological autoreactivity with housekeeping function. Previously, probing this repertoire with a set of immunodominant self-proteins provided a coarse analysis of the respective repertoire profiles. In contrast, here, we describe the generation of a peptide mimotope library that reflects the common IgM repertoire of 10,000 healthy donors. In addition, an appropriately sized subset of this quasi-complete mimotope library was further designed as a potential diagnostic tool. A 7-mer random peptide phage display library was panned on pooled human IgM. Next-generation sequencing of the selected phage yielded 224,087 sequences, which clustered in 790 sequence clusters. A set of 594 mimotopes, representative of the most significant sequence clusters, was shown to probe symmetrically the space of IgM reactivities in patients’ sera. This set of mimotopes can be easily scaled including a greater proportion of the mimotope library. The trade-off between the array size and the resolution can be explored while preserving the symmetric sampling of the mimotope sequence and reactivity spaces. BLAST search of the non-redundant protein database with the mimotopes sequences yielded significantly more immunoglobulin J region hits than random peptides, indicating a considerable idiotypic connectivity of the targeted igome. The proof of principle predictors for random diagnoses was represented by profiles of mimotopes. The number of potential reactivity profiles that can be extracted from this library is estimated at more than 1070. Thus, a quasi-complete IgM mimotope library and a scalable representative subset thereof are found to address very efficiently the dynamic diversity of the human public IgM repertoire, providing informationally dense and structurally interpretable IgM reactivity profiles.

Ara h 7 isoforms share many linear epitopes: Are 3D epitopes crucial to elucidate divergent abilities?

Ehlers, Anna M.; Klinge, Marco; Suer, Waltraud; Weimann, Yvonne; Knulst, André C.; Besa, Frithjof; Le, Thuy‐My; Otten, Henny G.
Clin Exp Allergy.
Nov 2019
Background The peanut allergens Ara h 2, h 6, and h 7 are potent allergens and can trigger severe reactions. Ara h 7 consists of three isoforms differing in their ability to induce basophil degranulation, whereas the ability of Ara h 7.0201 is comparable to Ara h 2 and 6 as shown in previous literature. Objective To identify linear epitopes of Ara h 7.0101, Ara h 7.0201 and Ara h 7.0301 recognized by IgE and IgG4 from patients sensitized to Ara h 7 and to investigate their potential to elucidate divergent abilities of the Ara h 7 isoforms in inducing basophil activation. Methods Linear epitopes recognized by IgE and IgG4 were mapped by peptide microarray analysis containing 15-mer peptides of Ara h 2.0201, 6, 7.0101, 7.0201 and 7.0301 and 39 peanut allergic patients sensitized to Ara h 7 (discovery). For validation, 20-mer peptides containing the minimal epitope and surrounding amino acids were incubated with 25 sensitized patients and 10 controls (validation). Results Three out of 14 linear epitopes were unique for each isoform (Ara h 7.0101: aa 97-109; Ara h 7.0201: aa 122-133; Ara h 7.0301: aa 65-74) but scarcely recognized by IgE. The main linear IgE epitope (aa 51-57) located in the long flexible loop of all Ara h 7 isoforms was bound by antibodies from 31% of the patients (discovery and validation cohort). Regarding IgG4, 55% of the patients recognized an epitope present on all isoforms (aa 55-65), whereas epitope aa 129-137, only present on Ara h 7.0101/0.0301, was recognized by 38% of the patients. Recognition was highly individual, although 20% of the patients recognized any linear epitope neither by IgE nor by IgG4 despite a low mean z-score of ≥ 1.7. Remarkably, only 50% of the patients recognized one or more epitopes by IgE. Conclusion & Clinical Relevance Ara h 7 isoforms share many linear epitopes being easily accessible for antibody binding. Unique epitopes, essential to elucidate divergent potencies, were scarcely recognized, suggesting a crucial involvement of conformational epitopes.

A Low‐Cost Laser‐Based Nano‐3D Polymer Printer for Rapid Surface Patterning and Chemical Synthesis of Peptide and Glycan Microarrays

Eickelmann, Stephan; Tsouka, Alexandra; Heidepriem, Jasmin; Paris, Grigori; Zhang, Junfang; Molinari, Valerio; Mende, Marco; Loeffler, Felix F.
Adv. Mater. Technol..
Nov 2019
A low-cost laser-based printing setup is presented, which allows for the spot-wise patterning of surfaces with defined polymer nanolayers. These nanolayer spots serve as a “solid solvent,” embedding different chemicals, chemical building blocks, materials, or precursors and can be stacked on top of each other. By melting the spot pattern, the polymer-embedded molecules are released for chemical reaction. This enables researchers to quickly pattern a surface with different molecules and materials, mixing them directly on the surface for high-throughput chemical synthesis to generate and screen diverse microarray libraries. In contrast to expensive ink-jet or contact printing, this approach does not require premixing of inks, which enables in situ combinatorial mixing. Easy access and versatility of this patterning approach are shown by generating microarrays of various biomolecules, such as glycans for the first time, to screen interactions of antibodies and lectins. In addition, a layer-by-layer solid-phase synthesis of peptides directly on the microarray is presented. Amino acid–containing nanolayers are repeatedly laser-transferred and reacted with the functionalized acceptor surface in defined patterns. This simple system enables a reproducible array production, down to spot-to-spot distances of 100 µm, and offers a flexible and cheap alternative to expensive spotting robot technology.

A Monoclonal Antibody to M-Phase Phosphoprotein 1/Kinesin-Like Protein KIF20B

Fritzler, Marvin J.; Brown, Rachael D.; Zhang, Meifeng
Monoclonal Antibodies in Immunodiagnosis and Immunotherapy.
Aug 2019
Kinesin-like protein KIF20B, originally named M-phase phosphoprotein 1 (MPP1), is a plus-end-directed kinesin-related protein that exhibits in vitro microtubule-binding and -bundling properties as well as microtubule-stimulated ATPase activity. It has been characterized as a slow molecular motor that moves toward the plus-end of microtubules. Human autoantibodies directed against KIF20B have been described in up to 25% of patients with idiopathic ataxia and less commonly in other neuropathies and autoinflammatory conditions. One of the limitations of research into the structure and function of KIF20B has been a reliable monoclonal antibody that can be used in a variety of applications. To establish a reference standard for anti-KIF20B immunoassays and facilitate studies on the role of KIF20B in developmental cell biology, we developed an IgG1 monoclonal antibody, 10C7, which reacts with the cognate KIF20B protein in Western immunoblots and in addressable laser bead immunoassays. In HEp2 cells, leptomeningeal pericytes, and transfected HEK293T cells, indirect immunofluorescence studies showed that reactivity was mainly localized to a proportion of interphase nuclei, but during metaphase, it was redistributed throughout the cytoplasm and perichromatin mass. Later in telophase/anaphase, KIF20B was localized to the stem body and midzone of the midbody. 10C7 also showed remarkable staining of a subset of cells in the cerebellum, ovary, and testis tissues. KIF20B was shown to have extensive coiled-coil domains. The monoclonal antibody, 10C7, will be of value to diagnostic laboratory scientists interested in having a reliable reference standard for anti-KIF20B immunoassays as well as cell, molecular, and developmental biology researchers.

Immunization of cats to induce neutralizing antibodies against Fel d 1, the major feline allergen in human subjects

Thoms, Franziska; Jennings, Gary T.; Maudrich, Melanie; Vogel, Monique; Haas, Stefanie; Zeltins, Andris; Hofmann-Lehmann, Regina; Riond, Barbara; Grossmann, Jonas; Hunziker, Peter; Fettelschoss-Gabriel, Antonia; Senti, Gabriela; Kündig, Thomas M.; Bachmann, Martin F.
Journal of Allergy and Clinical Immunology.
Jul 2019
Background Cat allergy in human subjects is usually caused by the major cat allergen Fel d 1 and is found in approximately 10% of the Western population. Currently, there is no efficient and safe therapy for cat allergy available. Allergic patients usually try to avoid cats or treat their allergy symptoms. Objective We developed a new strategy to treat Fel d 1–induced allergy in human subjects by immunizing cats against their own major allergen, Fel d 1. Methods A conjugate vaccine consisting of recombinant Fel d 1 and a virus-like particle derived from the cucumber mosaic virus containing the tetanus toxin–derived universal T-cell epitope tt830-843 (CuMVTT) was used to immunize cats. A first tolerability and immunogenicity study, including a boost injection, was conducted by using the Fel-CuMVTT vaccine alone or in combination with an adjuvant. Results The vaccine was well tolerated and had no overt toxic effect. All cats induced a strong and sustained specific IgG antibody response. The induced anti–Fel d 1 antibodies were of high affinity and exhibited a strong neutralization ability tested both in vitro and in vivo. A reduction in the endogenous allergen level and a reduced allergenicity of tear samples, were observed. Conclusion Vaccination of cats with Fel-CuMVTT induces neutralizing antibodies and might result in reduced symptoms of allergic cat owners. Both human subjects and animals could profit from this treatment because allergic cat owners would reduce their risk of developing chronic diseases, such as asthma, and become more tolerant of their cats, which therefore could stay in the households and not need to be relinquished to animal shelters.

Miniaturized and Automated Synthesis of Biomolecules—Overview and Perspectives

Mattes, Daniela S.; Jung, Nicole; Weber, Laura K.; Bräse, Stefan; Breitling, Frank
Adv. Mater..
Jun 2019
Chemical synthesis is performed by reacting different chemical building blocks with defined stoichiometry, while meeting additional conditions, such as temperature and reaction time. Such a procedure is especially suited for automation and miniaturization. Life sciences lead the way to synthesizing millions of different oligonucleotides in extremely miniaturized reaction sites, e.g., pinpointing active genes in whole genomes, while chemistry advances different types of automation. Recent progress in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) imaging could match miniaturized chemical synthesis with a powerful analytical tool to validate the outcome of many different synthesis pathways beyond applications in the life sciences. Thereby, due to the radical miniaturization of chemical synthesis, thousands of molecules can be synthesized. This in turn should allow ambitious research, e.g., finding novel synthesis routes or directly screening for photocatalysts. Herein, different technologies are discussed that might be involved in this endeavor. A special emphasis is given to the obstacles that need to be tackled when depositing tiny amounts of materials to many different extremely miniaturized reaction sites.

A high-sensitivity enzyme immunoassay for the quantification of soluble human semaphorin 4D in plasma

Laber, Anna; Gadermaier, Elisabeth; Wallwitz, Jacqueline; Berg, Gabriela; Himmler, Gottfried
Analytical Biochemistry.
Jun 2019
Human semaphorin 4D (SEMA4D), a type I integral membrane glycoprotein, regulates key cellular functions (e.g. cell-cell communication, platelet activation). Its 120 kDa extracellular region can be shed from the membrane to release soluble SEMA4D (sSEMA4D). Studies on circulating sSEMA4D levels are mostly performed with poorly characterized assays and use serum and plasma as matrix. We developed and validated a sandwich ELISA utilizing two monoclonal antibodies with resolved epitopes and determined affinities. Human serum and plasma samples were analyzed, and the influence of protease activity on sSEMA4D concentration was tested by collecting samples in the presence of the protease inhibitor TAPI-1. Both antibodies recognize conformational epitopes in the sema domain. Validation for plasma (EDTA, citrate, heparin) showed valid specificity, precision, accuracy, dilution linearity, and robustness. The assay shows a calibration range from 62.5 to 2000 pmol/L with a quantification limit of 31 pmol/L. sSEMA4D was significantly higher in serum than in plasma, whereas serum and plasma levels from samples collected in the presence of TAPI-1 showed no statistical difference. This ELISA provides a reliable tool for the quantification of sSEMA4D in human plasma. Serum is not recommended as matrix due to the accumulation of shed SEMA4D during blood coagulation altering serum sSEMA4D levels.

Autoantibodies to a novel Rpp38 (Th/To) derived B-cell epitope are specific for systemic sclerosis and associate with a distinct clinical phenotype

Koenig, Martial; Bentow, Chelsea; Satoh, Minoru; Fritzler, Marvin J; Senécal, Jean-Luc; Mahler, Michael
Abstract Objective Detection of antinuclear antibodies and specific autoantibodies is important in the diagnosis and classification of SSc. Several proteins of the Th/To complex, including Rpp25, Rpp38 and hPop1 are the target of autoantibodies in SSc patients. However, very little is known about the epitope distribution of this autoantigen. Consequently, we screened Rpp25, Rpp38 and hPop1 for B cell epitopes and evaluated their clinical relevance. Methods Serum pools with (n = 2) and without (n = 1) anti-Th/To autoantibodies were generated and used for epitope discovery. Identified biomarker candidate sequences were then utilized to synthesize synthetic, biotinylated, soluble peptides. The peptides were tested to determine reactivity with sera from SSc cohorts (n = 202) and controls (n = 159) using a chemiluminescence immunoassay. Additionally, samples were also tested for antibodies to full-length recombinant Rpp25 antibodies by chemiluminescence immunoassay. Results Several immunodominant regions were found on the three proteins. The strongest reactivity was observed with an Rpp38 peptide (aa 229–243). Autoantibodies to the Rpp38 peptide were detected in 8/149 (5.4%) limited cutaneous SSc patients, but not in any of 159 controls (P = 0.003 by two-sided Fisher’s exact probability test). Although reactivity to the novel antigenic peptide was correlated with the binding to Rpp25 (rho = 0.44; P < 0.0001), subsets of patient sera either reacted strongly with Rpp25 or with the novel Rpp38-derived peptide. Conclusion A novel Rpp38 epitope holds promise to increase the sensitivity in the detection of anti-Th/To autoantibodies, thus enhancing the serological diagnosis of SSc.

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