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

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Investigation of Immunoreactivity Profiles and Epitope Landscape in Divergent COVID-19 Trajectories and SARS-CoV-2 Variants

Bihani, Surbhi; Ray, Arka; Borishetty, Dhanush; Tuckley, Chaitanya; Salkar, Akanksha; Acharjee, Arup; Shrivastav, Prithviraj; Shrivastav, Om; Shastri, Jayanthi; Agrawal, Sachee; Duttagupta, Siddhartha; Srivastava, Sanjeeva
J. Proteome Res..
Jan 2025
This study aimed to elucidate the complexity of the humoral immune response in COVID-19 patients with varying disease trajectories using a SARS-CoV-2 whole proteome peptide microarray chip. The microarray, containing 5347 peptides spanning the entire SARS-CoV-2 proteome and key variants of concern, was used to analyze IgG responses in 10 severe-to-recovered, 9 nonsevere-to-severe cases, and 10 control case (5 pre-pandemic and 5 SARS-CoV-2-negative) plasma samples. We identified 1151 IgG-reactive peptides corresponding to 647 epitopes, with 207 peptides being cross-reactive across 124 epitopes. Nonstructural protein 3 (nsp3) exhibited the highest number of total and unique epitopes, followed by the spike protein. nsp12 had the most number of cross-reactive epitopes. Peptides from the spike protein and nsps 2, 3, 5, and 13 were notably associated with recovery. Additionally, specific mutations in SARS-CoV-2 variants were found to alter peptide immunoreactivity, with some mutations (e.g., G142D, L452R, and N501Y) enhancing and others (e.g., R190S and E484 K) reducing immune recognition. These findings have critical implications for the development of diagnostics, vaccines, and therapeutics. Understanding the distribution of epitopes and the impact of viral mutations on antigenicity provides insights into immune evasion mechanisms, informing strategies for controlling COVID-19 and future coronavirus outbreaks.

High-throughput identification of immunoreactive peptides and corresponding proteins from Anaplasma platys and Ehrlichia canis using peptide microarray chips

Llanes, Alejandro; Madesh, Swetha; Brangulis, Kalvis; Rajeev, Sreekumari
Front Cell Infect Microbiol.
Jan 2025
10.3389/fcimb.2025.1671309
INTRODUCTION: Anaplasma platys and Ehrlichia canis are rickettsial pathogens infecting dogs, with a worldwide distribution. Both species are obligate intracellular pathogens and colonize bone marrow-derived cells, with coinfections frequently reported in dogs. Although E. canis immunodominant proteins have been thoroughly characterized, very few high-throughput studies have been conducted to identify immunogenic proteins from Anaplasma spp. In this study, we used a methodology based on peptide microarray chips to identify immunoreactive peptides, either shared or species-specific, in the complete theoretical proteomes of both pathogens. METHODS: B-cell epitopes were predicted in the corresponding proteins from both species and ranked for synthesis on the peptide microarrays. These microarrays were screened with serum samples from antibody-positive dogs, as well as negative control sera from unexposed dogs. Additionally, we assessed the feasibility of integrating evidence gathered at the level of individual peptides to identify potentially immunogenic proteins contributing to the patterns of immunoreactivity observed on microarrays. RESULTS: Screening of peptide microarrays resulted in complex antibody reactivity patterns against thousands of peptides. After discarding peptides with cross-reactivity to negative control sera, we identified over 1,200 immunoreactive peptides, including ~80 peptides shared between the two species with almost identical sequences. Despite screening linear peptides, we were able to identify proteins previously reported as immunodominant in E. canis, some of which contain predominantly conformational epitopes. DISCUSSION: Our results suggest that a high-throughput strategy based on peptide microarrays is an effective approach for the rapid identification of immunoreactive peptides and the underlying immunogenic proteins. This study provides a foundation for developing novel diagnostic tools and vaccine candidates against A. platys and E. canis, including potential combined or multivalent formulations targeting both pathogens.

Signal Peptide-Binding Drug as a Selective Inhibitor of Co-Translational Protein Translocation

Vermeire, Kurt; Bell, Thomas W.; Van Puyenbroeck, Victor; Giraut, Anne; Noppen, Sam; Liekens, Sandra; Schols, Dominique; Hartmann, Enno; Kalies, Kai-Uwe; Marsh, Mark
PLoS Biol.
Dec 2014
In eukaryotic cells, surface expression of most type I transmembrane proteins requires translation and simultaneous insertion of the precursor protein into the endoplasmic reticulum (ER) membrane for subsequent routing to the cell surface. This co-translational translocation pathway is initiated when a hydrophobic N-terminal signal peptide (SP) on the nascent protein emerges from the ribosome, binds the cytosolic signal recognition particle (SRP), and targets the ribosome-nascent chain complex to the Sec61 translocon, a universally conserved protein-conducting channel in the ER-membrane. Despite their common function in Sec61 targeting and ER translocation, SPs have diverse but unique primary sequences. Thus, drugs that recognise SPs could be exploited to inhibit translocation of specific proteins into the ER. Here, through flow cytometric analysis the small-molecule macrocycle cyclotriazadisulfonamide (CADA) is identified as a highly selective human CD4 (hCD4) down-modulator. We show that CADA inhibits CD4 biogenesis and that this is due to its ability to inhibit co-translational translocation of CD4 into the lumen of the ER, both in cells as in a cell-free in vitro translation/translocation system. The activity of CADA maps to the cleavable N-terminal SP of hCD4. Moreover, through surface plasmon resonance analysis we were able to show direct binding of CADA to the SP of hCD4 and identify this SP as the target of our drug. Furthermore, CADA locks the SP in the translocon during a post-targeting step, possibly in a folded state, and prevents the translocation of the associated protein into the ER lumen. Instead, the precursor protein is routed to the cytosol for degradation. These findings demonstrate that a synthetic, cell-permeable small-molecule can be developed as a SP-binding drug to selectively inhibit protein translocation and to reversibly regulate the expression of specific target proteins.

Antigenic characteristics of glycosylated protein 3 of highly pathogenic porcine reproductive and respiratory syndrome virus

Wang, Xinglong; Dang, Ruyi; Liu, Wenkai; Yang, Zengqi; Du, Enqi; Zhang, Shuxia
Virus Research.
Aug 2014
Highly pathogenic (HP)-porcine reproductive and respiratory syndrome virus (PRRSV) emerged in 2006 and has now become a global threat to pig farms. Despite extensive characterization of HP-PRRSV proteins by direct analysis and comparison with typical PRRSV, immune recognition remain poorly understood. Glycosylated protein 3 (GP3) has an important function in inducing protective immune response. To analyze the antigenic character of HP-PRRSV GP3, a total of 217 peptides were printed on a chip and used to react with HP-PRRSV specific serum. The reactions of these peptides to HP-PRRSV specific pig serum were scanned and quantified using the software PepSlide® Analyzer by fluorescence intensity. The intensity plots showed various reactions in different parts of GP3. The highest reaction intensity value reached 29,184.5 with the peptide sequence of CSENDHDELGFMVPP. Conversely, 88 peptides showed no reaction with 0 florescence intensity. A further analysis based on the result of the peptide microarray revealed an antigen reaction active region (AR) from Y51 to S106 in GP3. The AR had four parts of variation that may be a significant mutation of the typical PRRSV to HP-PRRSV. Acquired data may be useful for understanding HP-PRRSV variation and its GP3 immune recognition.

Anti-ADAMTS13 IgG autoantibodies present in healthy individuals share linear epitopes with those in patients with thrombotic thrombocytopenic purpura

Grillberger, R.; Casina, V. C.; Turecek, P. L.; Zheng, X. L.; Rottensteiner, H.; Scheiflinger, F.
Haematologica.
Apr 2014

Analysis of Autoantibodies to 3-Hydroxy-3-methylglutaryl-coenzyme A Reductase Using Different Technologies

Musset, Lucile; Miyara, Makoto; Benveniste, Olivier; Charuel, Jean-Luc; Shikhman, Alexander; Boyer, Olivier; Fowler, Richard; Mammen, Andrew; Phillips, Joe; Mahler, Michael
Journal of Immunology Research.
Mar 2014
Diagnostic tests are needed to aid in the diagnosis of necrotizing myopathies associated with statin use. This study aimed to compare different technologies for the detection of anti-HMGCR antibodies and analyze the clinical phenotype and autoantibody profile of the patients. Twenty samples from myositis patients positive for anti-HMGCR antibodies using a research addressable laser bead assay and 20 negative controls were tested for autoantibodies to HMGCR: QUANTA Lite HMGCR ELISA and QUANTA Flash HMGCR CIA. All patients were also tested for antibodies to extractable nuclear antigens and myositis related antibodies. To verify the specificity of the ELISA, 824 controls were tested. All three assays showed qualitative agreements of 100% and levels of anti-HMGCR antibodies showed significant correlation: Spearman’s rho > 0.8. The mean age of the anti-HMGCR antibody positive patients was 54.4 years, 16/20 were females, and 18/20 had necrotizing myopathy (two patients were not diagnosed). Nine out of 20 anti-HMGCR positive patients were on statin. All patients with anti-HMGCR antibodies were negative for all other autoantibodies tested. Testing various controls showed high specificity (99.3%). Anti-HMGCR antibodies are not always associated with the use of statin and appear to be the exclusive autoantibody specificity in patients with statin associated myopathies.

Histatin 5 binds to Porphyromonas gingivalis hemagglutinin B (HagB) and alters HagB-induced chemokine responses

Borgwardt, Derek S.; Martin, Aaron D.; Van Hemert, Jonathan R.; Yang, Jianyi; Fischer, Carol L.; Recker, Erica N.; Nair, Prashant R.; Vidva, Robinson; Chandrashekaraiah, Shwetha; Progulske-Fox, Ann; Drake, David; Cavanaugh, Joseph E.; Vali, Shireen; Zhang, Yang; Brogden, Kim A.
Sci Rep.
Jan 2014
Histatins are human salivary gland peptides with anti-microbial and anti-inflammatory activities. In this study, we hypothesized that histatin 5 binds to Porphyromonas gingivalis hemagglutinin B (HagB) and attenuates HagB-induced chemokine responses in human myeloid dendritic cells. Histatin 5 bound to immobilized HagB in a surface plasmon resonance (SPR) spectroscopy-based biosensor system. SPR spectroscopy kinetic and equilibrium analyses, protein microarray studies and I-TASSER structural modeling studies all demonstrated two histatin 5 binding sites on HagB. One site had a stronger affinity with a KD1 of 1.9 μM and one site had a weaker affinity with a KD2 of 60.0 μM. Binding has biological implications and predictive modeling studies and exposure of dendritic cells both demonstrated that 20.0 μM histatin 5 attenuated (p < 0.05) 0.02 μM HagB-induced CCL3/MIP-1α, CCL4/MIP-1β and TNFα responses. Thus histatin 5 is capable of attenuating chemokine responses, which may help control oral inflammation.

Combinatorial Peptide Synthesis on a Microchip

Schirwitz, Christopher; Block, Ines; König, Kai; Nesterov, Alexander; Fernandez, Simon; Felgenhauer, Thomas; Leibe, Klaus; Torralba, Gloria; Hausmann, Michael; Lindenstruth, Volker; Stadler, Volker; Breitling, Frank; Bischoff, F. Ralf
Current Protocols in Protein Science.
Aug 2009
Microchips are used in the combinatorial synthesis of peptide arrays by means of amino acid microparticle deposition. The surface of custom-built microchips can be equipped with an amino-modified poly(ethylene glycol)methacrylate (PEGMA) graft polymer coating, which permits high loading of functional groups and resists nonspecific protein adsorption. Specific microparticles that are addressed to the polymer-coated microchip surface in a well defined pattern release preactivated amino acids upon melting, and thus allow combinatorial synthesis of high-complexity peptide arrays directly on the chip surface. Currently, arrays with densities of up to 40,000 peptide spots/cm2 can be generated in this way, with a minimum of coupling cycles required for full combinatorial synthesis. Without using any additional blocking agent, specific peptide recognition has been verified by background-free immunostaining on the chip-based array. This unit describes microchip surface modification, combinatorial peptide array synthesis on the chip, and a typical immunoassay employing the resulting high-density peptide arrays.

Particle-Based Synthesis of Peptide Arrays

Breitling, Frank; Felgenhauer, Thomas; Nesterov, Alexander; Lindenstruth, Volker; Stadler, Volker; Bischoff, F. Ralf
ChemBioChem.
Mar 2009
Lithographic methods allow for the combinatorial synthesis of >50,000 oligonucleotides per cm(2), and this has revolutionized the field of genomics. High-density peptide arrays promise to advance the field of proteomics in a similar way, but currently lag behind. This is mainly due to the monomer-by-monomer repeated consecutive coupling of 20 different amino acids associated with lithography, which adds up to an excessive number of coupling cycles. Combinatorial synthesis based on electrically charged solid amino acid particles resolves this problem. A color laser printer or a chip addresses the different charged particles consecutively to a solid support, where, when completed, the whole layer of solid amino acid particles is melted at once. This frees hitherto immobilized amino acids to couple all 20 different amino acids to the support in one single coupling reaction. The method should allow for the translation of entire genomes into sets of overlapping peptides to be used in proteome research.

High-density peptide arrays

Breitling, Frank; Nesterov, Alexander; Stadler, Volker; Felgenhauer, Thomas; Bischoff, F. Ralf
Mol. BioSyst..
Jan 2009
Arrays promise to advance biology by allowing parallel screening for many different binding partners. Meanwhile, lithographic methods enable combinatorial synthesis of >50 000 oligonucleotides per cm2, an advance that has revolutionized the whole field of genomics. A similar development is expected for the field of proteomics, provided that affordable, very high-density peptide arrays are available. However, peptide arrays lag behind oligonucleotide arrays. This review discusses recent developments in the field with an emphasis on methods that lead to very high-density peptide arrays.

A Novel Combinatorial Approach to High-Density Peptide Arrays

Beyer, Mario; Block, Ines; König, Kai; Nesterov, Alexander; Fernandez, Simon; Felgenhauer, Thomas; Schirwitz, Christopher; Leibe, Klaus; Bischoff, Ralf F.; Breitling, Frank; Stadler, Volker
Combinatorial synthesis of peptides on solid supports (1), either as spots on cellulose membranes (2) or with split-pool-libraries on polymer beads (3), substantially forwarded research in the field of peptide-protein interactions. Admittedly, these concepts have specific limitations, on one hand the number of synthesizable peptide sequences per area, on the other hand elaborate decoding/encoding strategies, false-positive results and sequence limitations. We recently established a method to produce high-density peptide arrays on microelectronic chips (4). Solid amino acid microparticles were charged by friction and transferred to defined pixel electrodes onto the chip’s surface, where they couple to a functional polymer coating simply upon melting (Fig. 16.1 A-D,F). By applying standard Fmoc chemistry according to Merrifield, peptide array densities of up to 40,000 spots per square centimetre were achieved (Fig. 16.1G). The term Merrifield synthesis describes the consecutive linear coupling and deprotecting of L-amino acids modified with base-labile fluorenylmethoxy (Fmoc) groups at the N-terminus and different acid-sensitive protecting groups at their side chains. Removing side chain protecting groups takes place only once at the very end of each synthesis and generates the natural peptide sequence thereby.

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