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

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Systematic analysis of the RGS2 degron reveals characteristics of substrate recognition by the F-box protein FBXO44

McNabb, Harrison J.; Cho, Eugene; Pitman, Mary; Rushton, Phillip S.; Mobley, David; Sjögren, Benita
Journal of Biological Chemistry.
Nov 2025
10.1016/j.jbc.2025.110757
Regulator of G protein signaling 2 (RGS2) negatively modulates signaling downstream of G protein–coupled receptors by accelerating GTP hydrolysis at Gα subunits of heterotrimeric G proteins. Decreased RGS2 levels are implicated in numerous diseases, including cardiovascular disease and asthma. Thus, identifying selective means of enhancing RGS2 protein levels would be a viable therapeutic strategy. RGS2 is rapidly degraded through the ubiquitin–proteasomal pathway, and we previously identified F-box only protein 44 (FBXO44) as the substrate recognition component of the E3 ligase responsible for facilitating RGS2 degradation. As such, the RGS2–FBXO44 interaction is a potential target for pharmacological intervention. Detailed information on the FBXO44 recognition site (degron) in RGS2 will aid in structure-based small-molecule inhibitor design, as well as in identifying additional FBXO44 targets, which would help predict possible side effects of targeting this interaction. Thus, the goal of this study was to dissect the molecular properties for FBXO44 binding of the RGS2 degron. We used a peptide array utilizing systematic residue substitution, combined with AlphaFold modeling and molecular dynamics simulations, to identify several amino acid changes that altered binding both positively and negatively. Finally, we experimentally confirmed our results in cells through coimmunoprecipitation and proteasomal inhibition, using full-length RGS2. Altogether, these results provide structural insights into RGS2–FBXO44 binding, which will aid in structure-guided drug discovery efforts. It also provides a framework for building a consensus recognition motif for FBXO44, which could aid in identifying more substrates for this understudied F-box protein.

Preclinical characterization of an active immunotherapy targeting calcitonin gene-related peptide

Boyd, Justin D.; Wang, Shixia; Lin, Hsiao-Wen; Hsieh, Yueh-Ting; Sun, Yu Shuang; Thibodeaux, Brett A.; Lu, Hanxin; Sahni, Jaya; Wiggins, Jonathan; Longo, Matthew S.; Brooks, Jeanne K.; Vroom, Madeline M.; Chang, Yi-Pin; Liu, Zhi; Ding, Shuang; Dodart, Jean-Cosme
Commun Med.
Apr 2025
10.1038/s43856-025-00870-2
Abstract **Background** The success of passive immunotherapies targeting Calcitonin gene-related peptide (CGRP) for managing migraine has prompted our efforts towards developing an active immunotherapy that induces the production of endogenous antibodies against CGRP. Achieving efficacious antibody titers via immunization could provide a more convenient and cost-effective treatment alternative to anti-CGRP monoclonal antibody (mAb) therapies. However, immunization against endogenous CGRP faces multiple challenges such as breaking immune tolerance, inducing sufficient antibody titers, and avoiding immune response-associated toxicity. **Methods** Synthetic peptide immunogens formulated in adjuvants were delivered intramuscularly. Serum samples were collected post immunization and used to measure antibody titers as well as for the isolation of antibodies specific to CGRP. Antibodies were characterized for their binding affinities and specificities. The capsaicin-induced increase in dermal blood flow model was used in rats for the assessment of the pharmacodynamic effect of immunization. **Results** Here we demonstrate that a peptide-based active immunotherapy designed to induce antibodies against CGRP promotes robust antibody titers across preclinical species. Characterization of the immune response strongly suggests that this peptide immunogen primarily stimulates a humoral response and only induced CGRP-specific antibodies. Antibodies produced by immunization are primarily IgG1 and demonstrate binding and activity potencies similar to marketed monoclonal antibodies against CGRP. Finally, immunization demonstrates in vivo efficacy in a rat pharmacodynamic model. **Conclusion** Our results strongly suggest that a peptide-based active immunotherapy against CGRP could provide an affordable and convenient therapeutic for the prevention of migraine.

A tumor-binding antibody with cross-reactivity to viral antigens

Campa, Michael J.; Gottlin, Elizabeth B.; Wiehe, Kevin; Patz, Edward F.
Cancer Immunol Immunother.
Feb 2025
10.1007/s00262-025-03975-8
**Background** We previously identified in non-small cell lung cancer (NSCLC) patients an autoantibody to complement factor H (CFH) that is associated with non-metastatic disease and longer time to progression in patients with stage I disease. A recombinant human antibody, GT103, was cloned from single B cells isolated from patients with the autoantibody. GT103 inhibits tumor growth and establishes an antitumor microenvironment. The anti-CFH autoantibody and GT103 recognize the epitope PIDNGDIT within the SCR19 domain of CFH. Here, we asked if this autoantibody could have originally arisen as a humoral response to a similar epitope in a viral protein from a prior infection. **Methods** Homologous viral peptides with high sequence identity to the core PIDNGDIT epitope sequence were identified and synthesized. NSCLC patient plasma containing anti-CFH autoantibodies were assayed by ELISA against these peptides. GT103 was assayed on a 4345-peptide pathogen microarray. **Results** Epitopes similar to the GT103 epitope are present in several viruses, including human metapneumovirus-1 (HMPV-1) that contains a sequence within attachment glycoprotein G that differs by one amino acid. Anti-CFH autoantibodies in NSCLC patient plasma weakly bound to an HMPV-1 peptide containing the epitope. GT103 cross-reacted with multiple viral epitopes on a peptide microarray, with the top hits being peptides in the human endogenous retrovirus-K polymerase (HERV-K pol) protein and measles hemagglutinin glycoprotein. GT103 bound the viral HMPV-1, HERV-K pol, and measles epitope peptides but with lower affinity compared to the GT103 epitope peptide. **Conclusion** These findings suggest that memory B cells against a viral target could have affinity matured to produce an antibody that recognizes a similar epitope on tumor cells and exhibits antitumor properties.

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
10.1038/ncomms13627
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
10.1016/j.clim.2016.09.003
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
10.1371/journal.pone.0165135
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 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
10.1186/s12985-016-0586-3
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
10.1038/srep24757
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.

High-Density Peptide Arrays for Malaria Vaccine Development

Loeffler, Felix F.; Pfeil, Johannes; Heiss, Kirsten
Apr 2016
10.1007/978-1-4939-3387-7_32
The development of an efficacious and practicable vaccine conferring sterile immunity towards a Plasmodium infection represents a not yet achieved goal. A crucial factor for the impact of a given anti-plasmodial subunit vaccine is the identification of the most potent parasitic components required to induce protection from both infection and disease. Here, we present a method based on a novel high-density peptide array technology that allows for a flexible readout of malaria antibodies. Peptide arrays applied as a screening method can be used to identify novel immunogenic antibody epitopes under a large number of potential antigens/peptides. Ultimately, discovered antigen candidates and/or epitope sequences can be translated into vaccine prototype design. The technology can be further utilized to unravel antibody-mediated immune responses (e.g., involved in the establishment of semi-immunity) and moreover to confirm vaccine potency during the process of clinical development by verifying the induced antibody responses following vaccination.

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
10.1212/NXI.0000000000000204
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
10.1016/j.jevs.2016.02.028

Non-invasive glioblastoma immunoprofiling by printed peptide arrays

Mock, Andreas; Herold-Mende, Christel
OncoImmunology.
Feb 2016
10.1080/2162402X.2015.1069941
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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