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

Mapping the epitopes of Schistosoma japonicum esophageal gland proteins for incorporation into vaccine constructs

Li, Xiao-Hong; Vance, Gillian M.; Cartwright, Jared; Cao, Jian-Ping; Wilson, R Alan; Castro-Borges, William
PLoS ONE.
Feb 2020
Background The development of a schistosome vaccine has proved challenging but we have suggested that characterisation of the self-cure mechanism in rhesus macaques might provide a route to an effective product. The schistosome esophagus is a complex structure where blood processing is initiated by secretions from anterior and posterior glands, achieved by a mixture of ~40 unique proteins. The mechanism of self-cure in macaques involves cessation of feeding, after which worms slowly starve to death. Antibody coats the esophagus lumen and disrupts the secretory processes from the glands, potentially making their secretions ideal vaccine targets. Methodology/Principal findings We have designed three peptide arrays comprising overlapping 15-mer peptides encompassing 32 esophageal gland proteins, and screened them for reactivity against 22-week infection serum from macaques versus permissive rabbit and mouse hosts. There was considerable intra- and inter-species variation in response and no obvious unique target was associated with self-cure status, which suggests that self-cure is achieved by antibodies reacting with multiple targets. Some immuno-dominant sequences/regions were evident across species, notably including: MEGs 4.1C, 4.2, and 11 (Array 1); MEG-12 and Aspartyl protease (Array 2); a Tetraspanin 1 loop and MEG-n2 (Array 3). Responses to MEGs 8.1C and 8.2C were largely confined to macaques. As proof of principle, three synthetic genes were designed, comprising several key targets from each array. One of these was expressed as a recombinant protein and used to vaccinate rabbits. Higher antibody titres were obtained to the majority of reactive regions than those elicited after prolonged infection. Conclusions/Significance It is feasible to test simultaneously the additive potential of multiple esophageal proteins to induce protection by combining their most reactive regions in artificial constructs that can be used to vaccinate suitable hosts. The efficacy of the approach to disrupt esophageal function now needs to be tested by a parasite challenge.

A Protein Epitope Targeted by the Antibody Response to Kawasaki Disease

Rowley, Anne H; Baker, Susan C; Arrollo, David; Gruen, Leah J; Bodnar, Tetyana; Innocentini, Nancy; Hackbart, Matthew; Cruz-Pulido, Yazmin E; Wylie, Kristine M; Kim, Kwang-Youn A; Shulman, Stanford T
Background Kawasaki disease (KD) is the leading cause of childhood acquired heart disease in developed nations and can result in coronary artery aneurysms and death. Clinical and epidemiologic features implicate an infectious cause but specific antigenic targets of the disease are unknown. Peripheral blood plasmablasts are normally highly clonally diverse but the antibodies they encode are approximately 70% antigen-specific 1–2 weeks after infection. Methods We isolated single peripheral blood plasmablasts from children with KD 1–3 weeks after onset and prepared 60 monoclonal antibodies (mAbs). We used the mAbs to identify their target antigens and assessed serologic response among KD patients and controls to specific antigen. Results Thirty-two mAbs from 9 of 11 patients recognize antigen within intracytoplasmic inclusion bodies in ciliated bronchial epithelial cells of fatal cases. Five of these mAbs, from 3 patients with coronary aneurysms, recognize a specific peptide, which blocks binding to inclusion bodies. Sera from 5/8 KD patients day ≥ 8 after illness onset, compared with 0/17 infant controls (P < .01), recognized the KD peptide antigen. Conclusions These results identify a protein epitope targeted by the antibody response to KD and provide a means to elucidate the pathogenesis of this important worldwide pediatric problem.

Pre-clinical characterisation of E2814, a high-affinity antibody targeting the microtubule-binding repeat domain of tau for passive immunotherapy in Alzheimer’s disease

Roberts, Malcolm; Sevastou, Ioanna; Imaizumi, Yoichi; Mistry, Kavita; Talma, Sonia; Dey, Madhurima; Gartlon, Jane; Ochiai, Hiroshi; Zhou, Zhi; Akasofu, Shigeru; Tokuhara, Naoki; Ogo, Makoto; Aoyama, Muneo; Aoyagi, Hirofumi; Strand, Kate; Sajedi, Ezat; Agarwala, Kishan Lal; Spidel, Jared; Albone, Earl; Horie, Kanta; Staddon, James M.; de Silva, Rohan
Acta Neuropathologica Communications.
Feb 2020
Tau deposition in the brain is a pathological hallmark of many neurodegenerative disorders, including Alzheimer’s disease (AD). During the course of these tauopathies, tau spreads throughout the brain via synaptically-connected pathways. Such propagation of pathology is thought to be mediated by tau species (“seeds”) containing the microtubule binding region (MTBR) composed of either three repeat (3R) or four repeat (4R) isoforms. The tau MTBR also forms the core of the neuropathological filaments identified in AD brain and other tauopathies. Multiple approaches are being taken to limit tau pathology, including immunotherapy with anti-tau antibodies. Given its key structural role within fibrils, specifically targetting the MTBR with a therapeutic antibody to inhibit tau seeding and aggregation may be a promising strategy to provide disease-modifying treatment for AD and other tauopathies. Therefore, a monoclonal antibody generating campaign was initiated with focus on the MTBR. Herein we describe the pre-clinical generation and characterisation of E2814, a humanised, high affinity, IgG1 antibody recognising the tau MTBR. E2814 and its murine precursor, 7G6, as revealed by epitope mapping, are antibodies bi-epitopic for 4R and mono-epitopic for 3R tau isoforms because they bind to sequence motif HVPGG. Functionally, both antibodies inhibited tau aggregation in vitro. They also immunodepleted a variety of MTBR-containing tau protein species. In an in vivo model of tau seeding and transmission, attenuation of deposition of sarkosyl-insoluble tau in brain could also be observed in response to antibody treatment. In AD brain, E2814 bound different types of tau filaments as shown by immunogold labelling and recognised pathological tau structures by immunohistochemical staining. Tau fragments containing HVPGG epitopes were also found to be elevated in AD brain compared to PSP or control. Taken together, the data reported here have led to E2814 being proposed for clinical development.

Immunization with full-length Plasmodium falciparum merozoite surface protein 1 is safe and elicits functional cytophilic antibodies in a randomized first-in-human trial

Blank, Antje; Fürle, Kristin; Jäschke, Anja; Mikus, Gerd; Lehmann, Monika; Hüsing, Johannes; Heiss, Kirsten; Giese, Thomas; Carter, Darrick; Böhnlein, Ernst; Lanzer, Michael; Haefeli, Walter E.; Bujard, Hermann
npj Vaccines.
Jan 2020
A vaccine remains a priority in the global fight against malaria. Here, we report on a single-center, randomized, double-blind, placebo and adjuvant-controlled, dose escalation phase 1a safety and immunogenicity clinical trial of full-length Plasmodium falciparum merozoite surface protein 1 (MSP1) in combination with GLA-SE adjuvant. Thirty-two healthy volunteers were vaccinated at least three times with MSP1 plus adjuvant, adjuvant alone, or placebo (24:4:4) to evaluate the safety and immunogenicity. MSP1 was safe, well tolerated and immunogenic, with all vaccinees sero-converting independent of the dose. The MSP1-specific IgG and IgM titers persisted above levels found in malaria semi-immune humans for at least 6 months after the last immunization. The antibodies were variant- and strain-transcending and stimulated respiratory activity in granulocytes. Furthermore, full-length MSP1 induced memory T-cells. Our findings encourage challenge studies as the next step to evaluate the efficacy of full-length MSP1 as a vaccine candidate against falciparum malaria (EudraCT 2016-002463-33).

The Myc tag monoclonal antibody 9E10 displays highly variable epitope recognition dependent on neighboring sequence context

Schüchner, Stefan; Behm, Christian; Mudrak, Ingrid; Ogris, Egon
Sci. Signal..
Jan 2020
Epitope tags are short, linear antibody recognition sequences that enable detection of tagged fusion proteins by antibodies. Epitope tag position and neighboring sequences potentially affect its recognition by antibodies, and such context-dependent differences in tag binding may have a wide-ranging effect on data interpretation. We tested by Western blotting six antibodies that recognize the c-Myc epitope tag, including monoclonal antibodies 9E10, 4A6, 9B11, and 71D10 and polyclonal antibodies 9106 and A-14. All displayed context-dependent differences in their ability to detect N- or C-terminal Myc-tagged proteins. In particular, clone 9E10, the most cited Myc-tag antibody, displayed high context-dependent detection variability, whereas others, notably 4A6 and 9B11, showed much less context sensitivity in their detection of Myc-tagged proteins. The very high context sensitivity of 9E10 was further substantiated by peptide microarray analyses. We conclude that recently developed, purpose-made monoclonal antibodies specific for Myc have much more uniform reactivity in diverse assays and are much less context sensitive than is the legacy antibody 9E10.

Serum levels of sclerostin reflect altered bone microarchitecture in patients with hepatic cirrhosis

Wakolbinger, Robert; Muschitz, Christian; Wallwitz, Jacqueline; Bodlaj, Gerd; Feichtinger, Xaver; Schanda, Jakob E.; Resch, Heinrich; Baierl, Andreas; Pietschmann, Peter
Wien Klin Wochenschr.
Jan 2020
Background: Patients with hepatic cirrhosis are at increased risk of bone loss. Recent work on areal bone mineral density has reported contradictory findings. As the assessment of bone microarchitecture is complex, a search was made for correlations with new serum markers of bone turnover. Current data on serum sclerostin levels in patients with increased fracture risk are divergent and to date only one study has examined patients with hepatic cirrhosis. Therefore, the aim of this study was to evaluate serum sclerostin levels and to test for correlations with microarchitecture. Methods: This study was performed in 32 patients with recently diagnosed hepatic cirrhosis and 32 controls. The parameters of bone microarchitecture were assessed by high-resolution peripheral quantitative computed tomography. Sclerostin was detected via a new ELISA that detects the active receptor interaction site at loop 2 of the sclerostin core region. Results: Sclerostin levels were slightly, but not significantly lower in the patient group, compared to controls. In contrast, patients with alcoholic liver cirrhosis had significantly lower levels than the controls. A significant correlation with areal bone mineral density (BMD) and trabecular microarchitecture was observed in the patient group. However, there was hardly any correlation between sclerostin and bone microarchitecture in the controls. Conclusion: In hepatic cirrhosis, sclerostin is related to altered bone microarchitecture and lower areal BMD. In alcoholic liver disease, low sclerostin concentrations were seen.

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 novel neutralizing human monoclonal antibody broadly abrogates hepatitis C virus infection in vitro and in vivo

Desombere, Isabelle; Mesalam, Ahmed Atef; Urbanowicz, Richard A.; Van Houtte, Freya; Verhoye, Lieven; Keck, Zhen-Yong; Farhoudi, Ali; Vercauteren, Koen; Weening, Karin E.; Baumert, Thomas F.; Patel, Arvind H.; Foung, Steven K.H.; Ball, Jonathan; Leroux-Roels, Geert; Meuleman, Philip
Antiviral Research.
Dec 2017
Infections with hepatitis C virus (HCV) represent a worldwide health burden and a prophylactic vaccine is still not available. Liver transplantation (LT) is often the only option for patients with HCV-induced end-stage liver disease. However, immediately after transplantation, the liver graft becomes infected by circulating virus, resulting in accelerated progression of liver disease. Although the efficacy of HCV treatment using direct-acting antivirals has improved significantly, immune compromised LT-patients and patients with advanced liver disease remain difficult to treat. As an alternative approach, interfering with viral entry could prevent infection of the donor liver. We generated a human monoclonal antibody (mAb), designated 2A5, which targets the HCV envelope. The neutralizing activity of mAb 2A5 was assessed using multiple prototype and patient-derived HCV pseudoparticles (HCVpp), cell culture produced HCV (HCVcc), and a human-liver chimeric mouse model. Neutralization levels observed for mAb 2A5 were generally high and mostly superior to those obtained with AP33, a well-characterized HCV-neutralizing monoclonal antibody. Using humanized mice, complete protection was observed after genotype 1a and 4a HCV challenge, while only partial protection was achieved using gt1b and 6a isolates. Epitope mapping revealed that mAb 2A5 binding is conformation-dependent and identified the E2-region spanning amino acids 434 to 446 (epitope II) as the predominant contact domain. Conclusion: mAb 2A5 shows potent anti-HCV neutralizing activity both in vitro and in vivo and could hence represent a valuable candidate to prevent HCV recurrence in LT-patients. In addition, the detailed identification of the neutralizing epitope can be applied for the design of prophylactic HCV vaccines.

Efficacy of an Adenoviral Vectored Multivalent Centralized Influenza Vaccine

Lingel, Amy; Bullard, Brianna L.; Weaver, Eric A.
Sci Rep.
Nov 2017
Mice were immunized with Adenovirus expressing the H1-con, H2-con, H3-con and H5-con HA consensus genes in combination (multivalent) and compared to mice immunized with the traditional 2010–2011 FluZone and FluMist seasonal vaccines. Immunized mice were challenged with 10–100 MLD50 of H1N1, H3N1, H3N2 and H5N1 influenza viruses. The traditional vaccines induced robust levels of HA inhibition (HI) titers, but failed to protect against five different heterologous lethal influenza challenges. Conversely, the multivalent consensus vaccine (1 × 1010 virus particles (vp)/mouse) induced protective HI titers of ≥40 against 8 of 10 influenza viruses that represent a wide degree of divergence within the HA subtypes and protected 100% of mice from 8 of 9 lethal heterologous influenza virus challenges. The vaccine protection was dose dependent, in general, and a dose as low as 5 × 107 vp/mouse still provided 100% survival against 7 of 9 lethal heterologous influenza challenges. These data indicate that very low doses of Adenovirus-vectored consensus vaccines induce superior levels of immunity against a wide divergence of influenza subtypes as compared to traditional vaccines. These doses are scalable and translatable to humans and may provide the foundation for complete and long-lasting anti-influenza immunity.

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