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

A Trifunctional Linker for Purified 3D Assembled Peptide Structure Arrays

Mattes, Daniela S.; Rentschler, Simone; Foertsch, Tobias C.; Münch, Stephan W.; Loeffler, Felix F.; Nesterov-Mueller, Alexander; Bräse, Stefan; Breitling, Frank
Small Methods.
Feb 2018
Microarrays are an important tool in modern research that allow the rapid screening of many different interactions simultaneously. Peptide arrays, which bear different peptides arranged in separate spots, permit high-throughput screening to investigate linear and cyclic binding sites. To study conformational or discontinuous binding sites, protein arrays are the major choice. However, the tremendous costs for the generation of high-density protein arrays of high purity restrict progress in protein research. Therefore, peptide-based arrays, which can mimic assembled peptide structures, have an enormous potential. Here, a method is presented to create such structures in the array format as an alternative to protein arrays. A trifunctional linker is developed with an azide, a protected alkyne, and a carboxyl group, which can react with two or three different peptides. Due to the spatial proximity, the peptides interact and can form an assembled peptide structure. As a proof of concept, assembled peptide structures are demonstrated on beads and on a polymer surface and the approach can be validated via matrix-assisted laser desorption/ionization spectrometry. Furthermore, a multistep transfer of peptide arrays is shown, generating purified assembled peptide structure arrays in high density.

Characterization of a sandwich ELISA for the quantification of all human periostin isoforms

Gadermaier, Elisabeth; Tesarz, Manfred; Suciu, Andreea Ana-Maria; Wallwitz, Jacqueline; Berg, Gabriela; Himmler, Gottfried
J Clin Lab Anal.
Feb 2018
Background Periostin (osteoblast-specific factor OSF-2) is a secreted protein occurring in seven known isoforms, and it is involved in a variety of biological processes in osteology, tissue repair, oncology, cardiovascular and respiratory systems or allergic manifestations. To analyze functional aspects of periostin, or the ability of periostin as potential biomarker in physiological and pathological conditions, there is the need for a precise, well-characterized assay that detects periostin in peripheral blood. Methods In this study the development of a sandwich ELISA using monoclonal and affinity-purified polyclonal anti-human periostin antibodies was described. Antibodies were characterized by mapping of linear epitopes with microarray technology, and by analyzing cross-reactive binding to human periostin isoforms with western blot. The assay was validated according to ICH/EMEA guidelines. Results The monoclonal coating antibody binds to a linear epitope conserved between the isoforms. The polyclonal detection antibody recognizes multiple conserved linear epitopes. Therefore, the periostin ELISA detects all known human periostin isoforms. The assay is optimized for human serum and plasma and covers a calibration range between 125 and 4000 pmol/L for isoform 1. Assay characteristics, such as precision (intra-assay: ≤3%, inter-assay: ≤6%), spike-recovery (83%-106%), dilution linearity (95%-126%), as well as sample stability meet the standards of acceptance. Periostin levels of apparently healthy individuals are 864±269 pmol/L (serum) and 817±170 pmol/L (plasma) respectively. Conclusion This ELISA is a reliable and accurate tool for determination of all currently known periostin isoforms in human healthy and diseased samples.

Development and characterization of a human monoclonal antibody targeting the N-terminal region of hepatitis C virus envelope glycoprotein E1

Mesalam, Ahmed Atef; Desombere, Isabelle; Farhoudi, Ali; Van Houtte, Freya; Verhoye, Lieven; Ball, Jonathan; Dubuisson, Jean; Foung, Steven K.H.; Patel, Arvind H.; Persson, Mats A.A.; Leroux-Roels, Geert; Meuleman, Philip
Virology.
Jan 2018
Monoclonal antibodies (mAbs) targeting the hepatitis C virus (HCV) envelope have been raised mainly against envelope protein 2 (E2), while the antigenic epitopes of envelope protein 1 (E1) are not fully identified. Here we describe the detailed characterization of a human mAb, designated A6, generated from an HCV genotype 1b infected patient. ELISA results showed reactivity of mAb A6 to full-length HCV E1E2 of genotypes 1a, 1b and 2a. Epitope mapping identified a region spanning amino acids 230–239 within the N-terminal region of E1 as critical for binding. Antibody binding to this epitope was not conformation dependent. Neutralization assays showed that mAb A6 lacks neutralizing capacity and does not interfere with the activity of known neutralizing antibodies. In summary, mAb A6 is an important tool to study the structure and function of E1 within the viral envelope, a crucial step in the development of an effective prophylactic HCV vaccine.

Functional screening for anti-CMV biologics identifies a broadly neutralizing epitope of an essential envelope protein

Gardner, Thomas J.; Stein, Kathryn R.; Duty, J. Andrew; Schwarz, Toni M.; Noriega, Vanessa M.; Kraus, Thomas; Moran, Thomas M.; Tortorella, Domenico
Nat Commun.
Dec 2016
The prototypic β-herpesvirus human cytomegalovirus (CMV) establishes life-long persistence within its human host. The CMV envelope consists of various protein complexes that enable wide viral tropism. More specifically, the glycoprotein complex gH/gL/gO (gH-trimer) is required for infection of all cell types, while the gH/gL/UL128/130/131a (gH-pentamer) complex imparts specificity in infecting epithelial, endothelial and myeloid cells. Here we utilize state-of-the-art robotics and a high-throughput neutralization assay to screen and identify monoclonal antibodies (mAbs) targeting the gH glycoproteins that display broad-spectrum properties to inhibit virus infection and dissemination. Subsequent biochemical characterization reveals that the mAbs bind to gH-trimer and gH-pentamer complexes and identify the antibodies’ epitope as an ‘antigenic hot spot’ critical for virus entry. The mAbs inhibit CMV infection at a post-attachment step by interacting with a highly conserved central alpha helix-rich domain. The platform described here provides the framework for development of effective CMV biologics and vaccine design strategies.

Identification of novel antigens contributing to autoimmunity in cardiovascular diseases

Müller, Anna-Maria; Bockstahler, Mariella; Hristov, Georgi; Weiß, Christel; Fischer, Andrea; Korkmaz-Icöz, Sevil; Giannitsis, Evangelos; Poller, Wolfgang; Schultheiss, Heinz-Peter; Katus, Hugo A.; Kaya, Ziya
Clinical Immunology.
Dec 2016
In myocarditis and dilated cardiomyopathy (DCM) patients the immune system may play an important role in disease progression. In this study, we aimed to identify new antigens as a target for autoimmune response that might play a crucial role in these diseases. Therefore, a peptide-array was used to investigate antibody binding profiles in patients with autoimmune myocarditis or DCM compared to healthy controls and thus to identify disease relevant antigens. To analyze the pathogenicity of the identified antigens, an experimental autoimmune myocarditis (EAM) model was used. Hereby, 3 peptide sequences, derived from myosin-binding-protein-C (MYBPC) fast-type, RNA-binding-protein 20 (RBM20), and dystrophin, showed pathogenic effects on the myocardium of mice. In summary, 3 potentially cardiopathogenic peptides (MYBPC fast-type, RBM20, dystrophin) were identified. Thus, this study could serve as a basis for future investigations aimed at determining further antigens leading to pathogenic effects on the myocardium of DCM as well as myocarditis patients.

Antibody Binding Studies Reveal Conformational Flexibility of the Bacillus cereus Non-Hemolytic Enterotoxin (Nhe) A-Component

Didier, A.; Dietrich, R.; Märtlbauer, E.
PLoS ONE.
Oct 2016
The non-hemolytic enterotoxin complex (Nhe) is supposed to be the main virulence factor of B. cereus causing a diarrheal outcome of food poisoning. This tripartite toxin consists of the single components NheA, -B and -C all of them being necessary for maximum toxicity. In the past, research activities aiming to elucidate the mode-of-action of Nhe were mostly focused on the B- and C-component. In this study the generation of novel monoclonal antibodies (mAb) and their thorough characterization enabled the determination of key features for NheA. By the means of immunoaffinity chromatography it could be shown that NheA does not interact with -B and -C in solution. Additionally, the establishment of a highly sensitive sandwich-EIA now enables the detection of NheA in B. cereus supernatants down to 20 pg ml-1.Peptide-based epitope mapping in combination with partially deleted recombinant NheA fragments allowed the allocation of the binding regions for the three mAbs under study. Furthermore, by different EIA set-ups the conformational flexibility of NheA could be shown. For two of the antibodies under study different mechanisms of NheA neutralization were proven. Due to prevention of complete pore formation by one of the antibodies, NheA could be detected in an intermediate stage of the tripartite complex on the cell surface. Taken together, the results obtained in the present study allow a refinement of the mode-of-action for the Nhe toxin-complex.

A study of type-1 diabetes associated autoantibodies in schizophrenia

Hallford, Philomena; Clair, David St; Halley, Lorna; Mustard, Colette; Wei, Jun
Schizophrenia Research.
Oct 2016
Epidemiological studies revealed an association between type-1 diabetes (T1D) and schizophrenia but the findings reported to date have been controversial. To clarify the inconsistency across studies, T1D-associated autoantibodies were examined in plasma samples collected from 272 patients with schizophrenia and 276 control subjects. An in-house enzyme-linked immunosorbent assay (ELISA) was developed using three linear peptide antigens, one of which was derived from glutamic acid decarboxylase (GAD) and two were derived from insulinoma-associated antigen 2 (IA2). Mann-Whitney U test showed a significant decrease in the levels of plasma IgG against the IA2b antigen in schizophrenia patients as compared to control subjects (Z = − 3.54, p = 0.0007), while no significant difference was found between these two groups either in anti-IA2a IgG levels (Z = − 1.62, p = 0.105) or in anti-GAD IgG levels (Z = − 1.63, p = 0.104). Linear regression analysis indicated no association of antipsychotic medication with the levels of plasma IgG against IA2a, IA2b or GAD, while the levels of plasma IgG for these 3 peptide antigens were significantly correlated with each other. Binary logistic regression showed that neither the DQ2.5 variant nor the DQ8 variant was associated with circulating levels of 3 T1D-associated autoantibodies in both the patient group and the control group. The coefficient of variation was 10.7% for anti-IA2a IgG assay, 10.1% for anti-IA2b IgG assay and 10.7% for anti-GAD IgG assay. The present work suggests that T1D-associated antibodies are unlikely to confer risk of schizophrenia and that the in-house ELISA developed with linear peptide antigens is highly reproducible.

A single amino acid substitution alter antigenicity of Glycosylated protein 4 of HP-PRRSV

Wang, Xinglong; Wang, Zhenbin; Xu, Hongyu; Biao, Xiang; Yang, Zengqi
Virol J.
Jul 2016
Background Porcine reproductive and respiratory syndrome (PRRS) is an important pig endemic disease in pork-producing countries worldwide. The etiology, porcine reproductive and respiratory syndrome virus (PRRSV), is characterized by fast antigen variability. Glycosylated protein 4 (GP4) is a minor protein in PRRSV virion, but contributes to induce protective immune responses. However, the antigenic characterization of PRRSV GP4 and the role of the mutations in this protein in PRRSV evolution are not clear. Methods Peptides chip scanning and peptide based ELISA was used to analyze the antigenic characterization of HP-PRRSV GP4. A total of 142 peptides printed on a chip were used to reveal the antigen reaction characteristics of the HP-PRRSV. The reactions of these peptides with HP-PRRSV-specific pig serum were scanned and quantified using the software PepSlide® Analyzer by fluorescence intensity. The active reaction regions (AR) were identified based on the scanning results and then the amino acids (aa) sequences of AR(s) is aligned among PRRSV strains for further identify the key aa site(s) impact the antigenicity of the protein. Peptide based ELISA is then reacted with PRRSV positive sera derived from pig inoculated with different PRRSV strains for further analysis the role of specific amino acid in AR. Results The intensity plot was used to show the reactions of the peptides with PRRSV serum and it showed that enormously different response happened to various parts of GP4. The highest reaction intensity value reached 6401.5 against one peptide with the sequence DIKTNTTAASDFVVL. An AR from S29 to G56 was identified. Sequence alignment revealed various mutations in site 43 and possibly played an important role in this AR. Peptides ELISA reaction with sera from pigs inoculated with different PRRSV strain revealed that the change of aa in site 43 reduced the reaction of the peptide with PRRSV positive sera derived from pigs inoculated with the peptide related PRRSV strains. Conclusion In this study, one AR covering S29 to G56 was identified in GP4. The aa in site 43 play an important role in determining the antigenic character of GP4. The continual mutations (S → G → D → N) occurred in this site alter the antigenicity of PRRSV GP4.

Properties of Two Enterovirus Antibodies that are Utilized in Diabetes Research

Maccari, Giuseppe; Genoni, Angelo; Sansonno, Silvia; Toniolo, Antonio
Sci Rep.
Apr 2016
Human enteroviruses (EVs) comprise >100 different types. Research suggests a non-chance association between EV infections and type 1 diabetes. Immunohistochemical studies with the anti-EV antibody 5D-8.1 have shown that the EV capsid antigen is present in pancreatic islet cells of diabetic subjects. When it was noticed that 5D-8.1 may cross-react with human proteins, doubt was casted on the significance of the above histopathologic findings. To address this issue, properties of EV antibodies 5D-8.1 and 9D5 have been investigated using peptide microarrays, peptide substitution scanning, immunofluorescence of EV-infected cells, EV neutralization assays, bioinformatics analysis. Evidence indicates that the two antibodies bind to distinct non-neutralizing linear epitopes in VP1 and are specific for a vast spectrum of EV types (not for other human viruses). However, their epitopes may align with a few human proteins at low expected values. When tested by immunofluorescence, high concentrations of 5D-8.1 yelded faint cytoplasmic staining in uninfected cells. At reduced concentrations, both antibodies produced dotted staining only in the cytoplasm of infected cells and recognized both acute and persistent EV infection. Thus, the two monoclonals represent distinct and independent probes for hunting EVs in tissues of patients with diabetes or other endocrine conditions.

Serum peptide reactivities may distinguish neuromyelitis optica subgroups and multiple sclerosis

Metz, Imke; Beißbarth, Tim; Ellenberger, David; Pache, Florence; Stork, Lidia; Ringelstein, Marius; Aktas, Orhan; Jarius, Sven; Wildemann, Brigitte; Dihazi, Hassan; Friede, Tim; Brück, Wolfgang; Ruprecht, Klemens; Paul, Friedemann
Neurol Neuroimmunol Neuroinflamm.
Apr 2016
Objective: To assess in an observational study whether serum peptide antibody reactivities may distinguish aquaporin-4 (AQP4) antibody (Ab)–positive and -negative neuromyelitis optica spectrum disorders (NMOSD) and relapsing-remitting multiple sclerosis (RRMS). Methods: We screened 8,700 peptides that included human and viral antigens of potential relevance for inflammatory demyelinating diseases and random peptides with pooled sera from different patient groups and healthy controls to set up a customized microarray with 700 peptides. With this microarray, we tested sera from 66 patients with AQP4-Ab-positive (n = 16) and AQP4-Ab-negative (n = 19) NMOSD, RRMS (n = 11), and healthy controls (n = 20). Results: Differential peptide reactivities distinguished NMOSD subgroups from RRMS in 80% of patients. However, the 2 NMOSD subgroups were not well-discriminated, although those patients are clearly separated by their antibody reactivities against AQP4 in cell-based assays. Elevated reactivities to myelin and Epstein-Barr virus peptides were present in RRMS and to AQP4 and AQP1 peptides in AQP4-Ab-positive NMOSD. Conclusions: While AQP4-Ab-positive and -negative NMOSD subgroups are not well-discriminated by peptide antibody reactivities, our findings suggest that peptide antibody reactivities may have the potential to distinguish between both NMOSD subgroups and MS. Future studies should thus concentrate on evaluating peptide antibody reactivities for the differentiation of AQP4-Ab-negative NMOSD and MS.

Identification of Equine arteritis virus immunodominant B cell epitopes using a peptide microarray

Mayers, J.; Westcott, D.; Steinbach, F.
Journal of Equine Veterinary Science.
Apr 2016

Non-invasive glioblastoma immunoprofiling by printed peptide arrays

Mock, Andreas; Herold-Mende, Christel
OncoImmunology.
Feb 2016
Immune monitoring assays for patient stratification and treatment efficacy in clinical trials are in demand. We have recently described a cost-effective non-invasive assay to determine the immune status of glioblastoma patients. Profiling antitumor serum antibodies by customized printed peptide arrays identified response against a tenascin-C (TNC) peptide as a robust prognostic biomarker.

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