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

High-resolution mapping of linear epitopes from LiNTPDase2: Advancing leishmaniasis detection using optimized protein and peptide antigens

Castro, Raissa Barbosa De; Badaró De Moraes, João Victor; De Souza, Anna Cláudia Alves; Favarato, Evandro Silva; Voorwald, Fabiana Azevedo; Dos Santos, Fabiane Matos; Bressan, Gustavo Costa; Vasconcellos, Raphael De Souza; Fietto, Juliana Lopes Rangel
Diagnostic Microbiology and Infectious Disease.
Oct 2024
Visceral Leishmaniasis, caused by Leishmania infantum, is a tropical neglected disease and the most dangerous form of Leishmaniasis. It occurs zoonotically, with domestic transmission posing risks to humans as dogs have high susceptibility and are natural reservoirs of the parasite. Given their epidemiological role, improvements are needed in diagnosing Canine Visceral Leishmaniasis (CVL). Thus, we mapped linear epitopes from the rLiNTPDase2 antigen through peptide microarray and identified six positive epitopes. Validation through peptide ELISA revealed three promising peptides with accuracies of 78.6%, 85.92%, and 79.59%. Their combination yielded 97.58% accuracy. Negative epitopes were also found, which interacted with CVL-negative and Chagas Disease positive samples. Their removal from the rLiNTPDase2 sequence resulted in the rNT2.neg, which obtained enhanced specificity over rLiNTPDase2. The rNT2.neg validation achieved 87.50% sensitivity, 90.55% specificity, and 93.5% accuracy within 127 CVL-positive and 96 CVL-negative samples. Therefore, three peptides and rNT2.neg show significant promise for CVL diagnosis.

Bivalent chromatin accommodates survivin and BRG1/SWI complex to activate DNA damage response in CD4+ cells

Chandrasekaran, Venkataragavan; Andersson, Karin M. E.; Erlandsson, Malin; Li, Shuxiang; Olsson, Torbjörn Nur; Garcia-Bonete, Maria-Jose; Malmhäll-Bah, Eric; Johansson, Pegah; Katona, Gergely; Bokarewa, Maria I.
Cell Commun Signal.
Sep 2024
Background: Bivalent regions of chromatin (BvCR) are characterized by trimethylated lysine 4 (H3K4me3) and lysine 27 on histone H3 (H3K27me3) deposition which aid gene expression control during cell differentiation. The role of BvCR in post-transcriptional DNA damage response remains unidentified. Oncoprotein survivin binds chromatin and mediates IFNγ effects in CD4+ cells. In this study, we explored the role of BvCR in DNA damage response of autoimmune CD4+ cells in rheumatoid arthritis (RA). Methods: We performed deep sequencing of the chromatin bound to survivin, H3K4me3, H3K27me3, and H3K27ac, in human CD4+ cells and identified BvCR, which possessed all three histone H3 modifications. Protein partners of survivin on chromatin were predicted by integration of motif enrichment analysis, computational machine-learning, and structural modeling, and validated experimentally by mass spectrometry and peptide binding array. Survivin-dependent change in BvCR and transcription of genes controlled by the BvCR was studied in CD4+ cells treated with survivin inhibitor, which revealed survivin-dependent biological processes. Finally, the survivin-dependent processes were mapped to the transcriptome of CD4+ cells in blood and in synovial tissue of RA patients and the effect of modern immunomodulating drugs on these processes was explored. Results: We identified that BvCR dominated by H3K4me3 (H3K4me3-BvCR) accommodated survivin within cis-regulatory elements of the genes controlling DNA damage. Inhibition of survivin or JAK-STAT signaling enhanced H3K4me3-BvCR dominance, which improved DNA damage recognition and arrested cell cycle progression in cultured CD4+ cells. Specifically, BvCR accommodating survivin aided sequence-specific anchoring of the BRG1/SWI chromatin-remodeling complex coordinating DNA damage response. Mapping survivin interactome to BRG1/SWI complex demonstrated interaction of survivin with the subunits anchoring the complex to chromatin. Co-expression of BRG1, survivin and IFNγ in CD4+ cells rendered complete deregulation of DNA damage response in RA. Such cells possessed strong ability of homing to RA joints. Immunomodulating drugs inhibited the anchoring subunits of BRG1/SWI complex, which affected arthritogenic profile of CD4+ cells. Conclusions: BvCR execute DNA damage control to maintain genome fidelity in IFN-activated CD4+ cells. Survivin anchors the BRG1/SWI complex to BvCR to repress DNA damage response. These results offer a platform for therapeutic interventions targeting survivin and BRG1/SWI complex in autoimmunity.

Identification of Schistosoma haematobium and Schistosoma mansoni linear B-cell epitopes with diagnostic potential using in silico immunoinformatic tools and peptide microarray technology

Vengesai, Arthur; Manuwa, Marble; Midzi, Herald; Mandeya, Masimba; Muleya, Victor; Mujeni, Keith; Chipako, Isaac; Mduluza, Takafira
PLoS Negl Trop Dis.
Aug 2024
Introduction: Immunoinformatic tools can be used to predict schistosome-specific B-cell epitopes with little sequence identity to human proteins and antigens other than the target. This study reports an approach for identifying schistosome peptides mimicking linear B-cell epitopes using in-silico tools and peptide microarray immunoassay validation. Method: Firstly, a comprehensive literature search was conducted to obtain published schistosome-specific peptides and recombinant proteins with the best overall diagnostic performances. For novel peptides, linear B-cell epitopes were predicted from target recombinant proteins using ABCpred, Bcepred and BepiPred 2.0 in-silico tools. Together with the published peptides, predicted peptides with the highest probability of being B-cell epitopes and the lowest sequence identity with proteins from human and other pathogens were selected. Antibodies against the peptides were measured in sera, using peptide microarray immunoassays. Area under the ROC curve was calculated to assess the overall diagnostic performances of the peptides. Results: Peptide AA81008-19-30 had excellent and acceptable diagnostic performances for discriminating S. mansoni and S. haematobium positives from healthy controls, with AUC values of 0.8043 and 0.7326 respectively for IgG. Peptides MS3_10186-123-131, MS3_10385-339-354, SmSPI-177-193, SmSPI-379-388, MS3-10186-40-49 and SmS-197-214 had acceptable diagnostic performances for discriminating S. mansoni positives from healthy controls with AUC values ranging from 0.7098 to 0.7763 for IgG. Peptides SmSPI-359-372, Smp126160-438-452 and MS3 10186-25-41 had acceptable diagnostic performances for discriminating S. mansoni positives from S. mansoni negatives with AUC values of 0.7124, 0.7156 and 0.7115 respectively for IgG. Peptide MS3-10186-40-49 had an acceptable diagnostic performance for discriminating S. mansoni positives from healthy controls, with an AUC value of 0.7413 for IgM. Conclusion: One peptide with a good diagnostic performance and nine peptides with acceptable diagnostic performances were identified using the immunoinformatic approach and peptide microarray validation. There is need for evaluation of the peptides with true negatives and a good standard positive reference.

Alzheimer’s disease risk associated with changes in Epstein-Barr virus nuclear antigen 1-specific epitope targeting antibody levels

Sim, Kyu-Young; An, Jaekyeung; Bae, So-Eun; Yang, Taewoo; Ko, Gwang-Hoon; Hwang, Jeong-Ryul; Choi, Kyu Yeong; Park, Jung Eun; Lee, Jung Sup; Kim, Byeong C.; Lee, Kun Ho; Park, Sung-Gyoo
Journal of Infection and Public Health.
Jul 2024
*Background* Alzheimer’s disease (AD) is a neurodegenerative disorder influenced by age, sex, genetic factors, immune alterations, and infections. Multiple lines of evidence suggest that changes in antibody response are linked to AD pathology. *Methods* To elucidate the mechanisms underlying AD development, we investigated antibodies that target autoimmune epitopes using high-resolution epitope microarrays. Our study compared two groups: individuals with AD (n = 19) and non-demented (ND) controls (n = 19). To validate the results, we measured antibody levels in plasma samples from AD patients (n = 96), mild cognitive impairment (MCI; n = 91), and ND controls (n = 97). To further explore the invlovement of EBV, we performed epitope masking immunofluorescence microscopy analysis and tests to induce lytic replication using the B95–8 cell line. *Results* In this study, we analyzed high-resolution epitope-specific serum antibody levels in AD, revealing significant disparities in antibodies targeting multiple epitopes between the AD and control groups. Particularly noteworthy was the significant down-regulation of antibody (anti-DG#29) targeting an epitope of Epstein-Barr virus nuclear antigen 1 (EBNA1). This down-regulation increased AD risk in female patients (odds ratio up to 6.6), but not in male patients. Our investigation further revealed that the down-regulation of the antibody (anti-DG#29) is associated with EBV reactivation in AD, as indicated by the analysis of EBV VCA IgG or IgM levels. Additionally, our data demonstrated that the epitope region on EBNA1 for the antibody is hidden during the EBV lytic reactivation of B95–8 cells. *Conclusion* Our findings suggest a potential relationship of EBV in the development of AD in female. Moreover, we propose that antibodies targeting the epitope (DG#29) of EBNA1 could serve as valuable indicators of AD risk in female.

Discovery of putative breast cancer antigens using an integrative platform of genomics-driven immunoproteomics

Qendro, Veneta; Lundgren, Deborah H.; Palczewski, Samuel; Hegde, Poornima; Stevenson, Christina; Perpetua, Laurie; Latifi, Ardian; Merriman, Jesse; Bugos, Grace; Han, David K.
Proteomics.
Aug 2018
Recent advances in cancer immuno-therapeutics such as checkpoint inhibitors, chimeric antigen-receptor T cells, and tumor infiltrating T cells (TIL) are now significantly impacting cancer patients in a positive manner. Although very promising, reports indicate no more than 25% of cases result in complete remission. One of the limitations of these treatments is the identity of putative cancer antigens in each patient, as it is technically challenging to identify cancer antigens in a rapid fashion. Thus, identification of cancer antigens followed by targeted treatment will increase the efficacy of cancer immunotherapies. To achieve this goal, a combined technologies platform of deep genomic sequencing and personalized immune assessment was devised, termed Genomics Driven Immunoproteomics (GDI). Using this technological platform, we report the discovery of 149 tumor antigens from human breast cancer patients. Significant number of these putative cancer antigens arise from single nucleotide variants (SNVs), as well as insertions and deletions that results into frame-shift mutations. We propose a general model of anti-cancer immunity and suggest that the GDI platform may help identify patient-specific tumor antigens in a timely fashion for precision immunotherapies.

Circulating GRP78 antibodies from ovarian cancer patients: a promising tool for cancer cell targeting drug delivery system?

Van Hoesen, Kylie; Meynier, Sonia; Ribaux, Pascale; Petignat, Patrick; Delie, Florence; Cohen, Marie
Oncotarget.
Dec 2017
Glucose-regulated protein 78 (GRP78) is a chaperone protein that has a high frequency in tumor cells. Normally it is found in the endoplasmic reticulum to assist in protein folding, but under cellular stress, GRP78 influences proliferative signaling pathways at the cell surface. The increased expression elicits autoantibody production, providing a biomarker of ovarian cancer, as well as other types of cancer. This study aims to determine the epitope recognition of GRP78 autoantibodies isolated from serum of ovarian cancer patients and use the identified antibodies to design new drug delivery systems to specifically target cancer cells. We first confirmed that the membrane GRP78 levels are increased in ovarian cancer cells and positively correlate with proliferation. However, the level of circulating GRP78 autoantibodies did not correlate with membrane GRP78 expression in ovarian cancer cells and was lower, although not significantly, compared to control patients. We then determined the epitope recognition of GRP78 autoantibodies and showed that treatment with paclitaxel-loaded nanoparticles coated with anti-GRP78 antibodies significantly decreased tumor development in chick embryo culture of ovarian cancer cell tumors compared to paclitaxel treatment alone. This evidence suggests that nanoparticle drug delivery systems coupled with antibodies against GRP78 has potential as a powerful therapy against ovarian cancer.

Bayesian Analysis of MicroScale Thermophoresis Data to Quantify Affinity of Protein:Protein Interactions with Human Survivin

Garcia-Bonete, Maria-Jose; Jensen, Maja; Recktenwald, Christian V.; Rocha, Sandra; Stadler, Volker; Bokarewa, Maria; Katona, Gergely
Sci Rep.
Dec 2017
A biomolecular ensemble exhibits different responses to a temperature gradient depending on its diffusion properties. MicroScale Thermophoresis technique exploits this effect and is becoming a popular technique for analyzing interactions of biomolecules in solution. When comparing affinities of related compounds, the reliability of the determined thermodynamic parameters often comes into question. The thermophoresis binding curves can be assessed by Bayesian inference, which provides a probability distribution for the dissociation constant of the interacting partners. By applying Bayesian machine learning principles, binding curves can be autonomously analyzed without manual intervention and without introducing subjective bias by outlier rejection. We demonstrate the Bayesian inference protocol on the known survivin:borealin interaction and on the putative protein-protein interactions between human survivin and two members of the human Shugoshin-like family (hSgol1 and hSgol2). These interactions were identified in a protein microarray binding assay against survivin and confirmed by MicroScale Thermophoresis.

Development and analytical performance of a new ARCHITECT automated dipeptidyl peptidase-4 immunoassay

Hemken, Philip M.; Jeanblanc, Nicolette M.; Rae, Tracey; Brophy, Susan E.; Datwyler, Maria J.; Xu, Ying; Manetz, T. Scott; Vainshtein, Inna; Liang, Meina; Xiao, Xiaodong; Chowdhury, Partha S.; Chang, Chien-ying; Streicher, Katie; Greenlees, Lydia; Ranade, Koustubh; Davis, Gerard J.
Practical Laboratory Medicine.
Dec 2017
Background Dipeptidyl peptidase-4 (DPP-4) may be a suitable biomarker to identify people with severe asthma who have greater activation of the interleukin-13 (IL-13) pathway and may therefore benefit from IL-13-targeted treatments. We report the analytical performance of an Investigational Use Only immunoassay and provide data on the biological range of DPP-4 concentrations. Methods We assessed assay performance, utilising analyses of precision, linearity and sensitivity; interference from common endogenous assay interferents, and from asthma and anti-diabetic medications, were also assessed. The assay was used to measure the range of serum DPP-4 concentrations in healthy volunteers and subjects with diabetes and severe, uncontrolled asthma. Results The total precision of DPP-4 concentration measurement (determined using percentage coefficient of variation) was ≤5% over 20 days. Dilution analysis yielded linear results from 30 to 1305 ng/mL; the limit of quantitation was 19.2 ng/mL. No notable endogenous or drug interferences were observed at the expected therapeutic concentration. Median DPP-4 concentrations in healthy volunteers and subjects with asthma or Type 1 diabetes were assessed, with concentrations remaining similar in subjects with diabetes and asthma across different demographics. Conclusion These analyses indicate that the ARCHITECT DPP-4 Immunoassay is a reliable and robust method for measuring serum DPP-4 concentration.

A recombinant BBSome core complex and how it interacts with ciliary cargo

Klink, Björn Udo; Zent, Eldar; Juneja, Puneet; Kuhlee, Anne; Raunser, Stefan; Wittinghofer, Alfred
Cilia are small, antenna-like structures on the surface of eukaryotic cells that harbor a unique set of sensory proteins, including GPCRs and other membrane proteins. The transport of these proteins involves the BBSome, an eight-membered protein complex that is recruited to ciliary membranes by the G-protein Arl6. BBSome malfunction leads to Bardet-Biedl syndrome, a ciliopathy with severe consequences. Short ciliary targeting sequences (CTS) have been identified that trigger the transport of ciliary proteins. However, mechanistic studies that relate ciliary targeting to BBSome binding are missing. Here we used heterologously expressed BBSome subcomplexes to analyze the complex architecture and to investigate the binding of GPCRs and other receptors to the BBSome. A stable heterohexameric complex was identified that binds to GPCRs with interactions that only partially overlap with previously described CTS, indicating a more complex recognition than anticipated. Arl6•GTP does not affect these interactions, suggesting no direct involvement in cargo loading/unloading.

Identification of two conserved B-cell epitopes in the gp90 of reticuloendothelial virus using peptide microarray

Khairy, Wiaam O.A.; Qian, Kun; Shao, Hongxia; Ye, Jianqiang; Qin, Aijian
Veterinary Microbiology.
Nov 2017
Since the gp90 protein of Reticuloendotheliosis virus (REV) plays vital roles in virus neutralization, so detailed analysis of REV-gp90 epitopes is important for the development of epitope based marker vaccines and diagnostic tools for REV infections. In this study, two monoclonal antibodies (mAbs) namely 6C12 and 09980 were used to map the epitopes in REVgp90 using peptide microarray and ELISA. Peptide microarray revealed that mAbs 6C12 and 09980 recognized 216YHPLA220 and 230DPQTSDILEA239 motifs, respectively. This result was confirmed by ELISA using synthetic peptides. Moreover, homology analysis indicated that mAbs defined epitopes are highly conserved among REV strains used in this study. The mAbs and their epitopes identified in this study may have potential applications in development of diagnostic techniques and epitope-based marker vaccines for control of REV infections.

Antibody fingerprints in lyme disease deciphered with high density peptide arrays

Weber, Laura K.; Isse, Awale; Rentschler, Simone; Kneusel, Richard E.; Palermo, Andrea; Hubbuch, Jürgen; Nesterov-Mueller, Alexander; Breitling, Frank; Loeffler, Felix F.
Eng. Life Sci..
Oct 2017
Lyme disease is the most common tick-borne infectious disease in Europe and North America. Previous studies discovered the immunogenic role of a surface-exposed lipoprotein (VlsE) of Borreliella burgdorferi. We employed high density peptide arrays to investigate the antibody response to the VlsE protein in VlsE-positive patients by mapping the protein as overlapping peptides and subsequent in-depth epitope substitution analyses. These investigations led to the identification of antibody fingerprints represented by a number of key residues that are indispensable for the binding of the respective antibody. This approach allows us to compare the antibody specificities of different patients to the resolution of single amino acids. Our study revealed that the sera of VlsE-positive patients recognize different epitopes on the protein. Remarkably, in those cases where the same epitope is targeted, the antibody fingerprint is almost identical. Furthermore, we could correlate two fingerprints with human autoantigens and an Epstein-Barr virus epitope; yet, the link to autoimmune disorders seems unlikely and must be investigated in further studies. The other three fingerprints are much more specific for B. burgdorferi. Since antibody fingerprints of longer sequences have proven to be highly disease specific, our findings suggest that the fingerprints could function as diagnostic markers that can reduce false positive test results.

Identification of a Tetanus Toxin Specific Epitope in Single Amino Acid Resolution

Palermo, Andrea; Weber, Laura K.; Rentschler, Simone; Isse, Awale; Sedlmayr, Martyna; Herbster, Karin; List, Volker; Hubbuch, Jürgen; Löffler, Felix F.; Nesterov-Müller, Alexander; Breitling, Frank
Biotechnol. J..
Oct 2017
Vaccinations are among the most potent tools to fight infectious diseases. However, cross-reactions are an ongoing problem and there is an urgent need to fully understand the mechanisms of the immune response. For the development of a methodological workflow, the linear epitopes in the immune response to the tetanus toxin is investigated in sera of 19 vaccinated Europeans applying epitope mapping with peptide arrays. The most prominent epitope, appearing in nine different sera (923IHLVNNESSEVIVHK937), is investigated in a substitution analysis to identify the amino acids that are crucial for the binding of the corresponding antibody species − the antibody fingerprint. The antibody fingerprints of different individuals are compared and found to be strongly conserved (929ExxEVIVxK937), which is astonishing considering the randomness of their development. Additionally, the corresponding antibody species is isolated from one serum with batch chromatography using the amino acid sequence of the identified epitope and the tetanus specificity of the isolated antibody is verified by ELISA. Studying antibody fingerprints with peptide arrays should be transferable to any kind of humoral immune response toward protein antigens. Furthermore, antibody fingerprints have shown to be highly disease-specific and, therefore, can be employed as reliable biomarkers enabling the study of cross-reacting antigens.

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