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

Immunity to Influenza is dependent on MHC II polymorphism: study with 2 HLA transgenic strains

Luckey, David; Weaver, Eric A.; Osborne, Douglas G.; Billadeau, Daniel D.; Taneja, Veena
Sci Rep.
Dec 2019
Major histocompatibility complex II (MHC II) molecules are involved in antigen presentation and the development of a functional adaptive immune response. Evolutionary selection for MHC molecules that effectively clear infectious agents provides an advantage to humans. However, certain class II molecules are associated with autoimmune diseases. In this study we infected autoimmune-susceptible DRB1*0401.AEo and non-susceptible *0402.AEo mice with H1N1 influenza and determined clearance and protective immunity to H3N2 virus. *0401 mice generated a robust TLR-triggered immune response and cleared H1N1 influenza virus infection. After vaccination and challenge with H1N1, *0401 mice, when challenged with H3N2, generated cross-protective immunity to heterosubtypic H3N2 influenza strain whereas *0402 mice cleared the H1N1 infection but did not generate cross-protective immunity against the H3N2 influenza strain. The intracellular trafficking route of MHCII revealed that *0401 molecules traffic through the late endosome/lysosomes while *0402 molecules traffic into early endosomes. This suggested that trafficking of MHCII could affect the functional output of the innate immune response and clearance of viral infections. Also, DRB1*0401 mice live longer than HLA-DRB1*0402 mice. The study provides a potential hypothesis for evolutionary selection of *0401 molecule, even though it is associated with autoreactivity, which may be dependent on the availability of peptide repertoire of self-antigens.

Analysis of humoral immune responses in chikungunya virus (CHIKV) infected patients and individuals vaccinated with a candidate CHIKV vaccine

Henss, Lisa; Yue, Constanze; von Rhein, Christine; Tschismarov, Roland; Lewis-Ximenez, Lia Laura; Dölle, Albert; Baylis, Sally A; Schnierle, Barbara S
Abstract Background Chikungunya virus (CHIKV) is a mosquito-transmitted alphavirus that causes severe flu like symptoms. The acute symptoms disappear after one week, but chronic arthralgia can persist for years. Here, humoral immune responses in CHIKV-infected patients and vaccinees were analyzed. Methods Alphavirus neutralization activity was analyzed with pseudotyped lentiviral vectors and antibody epitope mapping was performed with a peptide array. Results Greatest CHIKV neutralization activity was observed 60-92 days after onset of symptoms. The amount of CHIKV-specific antibodies, their binding avidity and cross-reactivity with other alphaviruses increased over time. CHIKV and o’nyong-nyong virus (ONNV) were both neutralized to a similar extent. Linear antibody binding epitopes were mainly found in E2 domain B and the acid-sensitive regions (ASRs). In addition, serum samples from healthy volunteers vaccinated with a measles-vectored chikungunya vaccine candidate, MV-CHIK, were analyzed. Neutralization activity in the samples from the vaccine cohort was 2–6-fold lower than in samples from CHIKV-infected patients. In contrast to infection, vaccination only induced cross-neutralization with ONNV and the E2 ASR1 was the major antibody target. Conclusion These data could assist vaccine design and enable the identification of correlates of protection necessary for vaccine efficacy.

Diagnostic Profiling of the Human Public IgM Repertoire With Scalable Mimotope Libraries

Pashov, Anastas; Shivarov, Velizar; Hadzhieva, Maya; Kostov, Victor; Ferdinandov, Dilyan; Heintz, Karen-Marie; Pashova, Shina; Todorova, Milena; Vassilev, Tchavdar; Kieber-Emmons, Thomas; Meza-Zepeda, Leonardo A.; Hovig, Eivind
Front. Immunol..
Dec 2019
Specific antibody reactivities are routinely used as biomarkers, but the antibody repertoire reactivity (igome) profiles are still neglected. Here, we propose rationally designed peptide arrays as efficient probes for these system level biomarkers. Most IgM antibodies are characterized by few somatic mutations, polyspecificity, and physiological autoreactivity with housekeeping function. Previously, probing this repertoire with a set of immunodominant self-proteins provided a coarse analysis of the respective repertoire profiles. In contrast, here, we describe the generation of a peptide mimotope library that reflects the common IgM repertoire of 10,000 healthy donors. In addition, an appropriately sized subset of this quasi-complete mimotope library was further designed as a potential diagnostic tool. A 7-mer random peptide phage display library was panned on pooled human IgM. Next-generation sequencing of the selected phage yielded 224,087 sequences, which clustered in 790 sequence clusters. A set of 594 mimotopes, representative of the most significant sequence clusters, was shown to probe symmetrically the space of IgM reactivities in patients’ sera. This set of mimotopes can be easily scaled including a greater proportion of the mimotope library. The trade-off between the array size and the resolution can be explored while preserving the symmetric sampling of the mimotope sequence and reactivity spaces. BLAST search of the non-redundant protein database with the mimotopes sequences yielded significantly more immunoglobulin J region hits than random peptides, indicating a considerable idiotypic connectivity of the targeted igome. The proof of principle predictors for random diagnoses was represented by profiles of mimotopes. The number of potential reactivity profiles that can be extracted from this library is estimated at more than 1070. Thus, a quasi-complete IgM mimotope library and a scalable representative subset thereof are found to address very efficiently the dynamic diversity of the human public IgM repertoire, providing informationally dense and structurally interpretable IgM reactivity profiles.

Predicting HBsAg clearance in genotype A chronic hepatitis B using HBsAg epitope profiling: A biomarker for functional cure

Walsh, Renae; Hammond, Rachel; Yuen, Lilly; Deerain, Joshua; O’Donnell, Tanya; Leary, Thomas; Cloherty, Gavin; Gaggar, Anuj; Kitrinos, Kathryn; Subramanian, Mani; Wong, Darren; Locarnini, Stephen
Liver Int.
Nov 2019
Background and Aim Functional cure is the major goal of chronic hepatitis B (CHB) therapy though few biomarkers predict this outcome. HBsAg epitope occupancy can be influenced by therapeutic and immune pressure. The aim of this study was to map the HBsAg epitope profiles during long-term nucleos(t)ide analogue therapy in patients with genotype A CHB, in the context of HBsAg loss (SL)/seroconversion. Methods We evaluated 25 genotype A CHB patients in the GS-US-174-0103 trial of HBeAg-positive CHB patients treated with tenofovir or adefovir for 4 years, 14 who achieved SL whilst 11 had no change. We epitope mapped the major domains of HBsAg to identify those patients with HBsAg clearance profile (CP) (loss of binding at both loops 1 and 2 epitopes of the ‘a’ determinant) vs non-clearance profile (no change in epitope recognition, or loss of epitope binding at one loop only), correlating this to on-treatment HBsAg responses. Complexed anti-HBs was also measured. Results Analysis of the HBsAg epitope profiles of the 25 patients at baseline identified no predictive correlation with SL. In contrast, analysis at week 48 and end of study (week 192) or prior to SL identified significant predictive associations between development of HBsAg CPs and outcome of functional cure. The detection of a CP also correlated with the development of an alanine aminotransferase flare and detection of anti-HBs complexed with HBsAg. Conclusion The detection of HBsAg CPs by epitope mapping represents a novel viral biomarker, reflecting an emerging anti-HBs selection pressure prior to functional cure.

A Low‐Cost Laser‐Based Nano‐3D Polymer Printer for Rapid Surface Patterning and Chemical Synthesis of Peptide and Glycan Microarrays

Eickelmann, Stephan; Tsouka, Alexandra; Heidepriem, Jasmin; Paris, Grigori; Zhang, Junfang; Molinari, Valerio; Mende, Marco; Loeffler, Felix F.
Adv. Mater. Technol..
Nov 2019
A low-cost laser-based printing setup is presented, which allows for the spot-wise patterning of surfaces with defined polymer nanolayers. These nanolayer spots serve as a “solid solvent,” embedding different chemicals, chemical building blocks, materials, or precursors and can be stacked on top of each other. By melting the spot pattern, the polymer-embedded molecules are released for chemical reaction. This enables researchers to quickly pattern a surface with different molecules and materials, mixing them directly on the surface for high-throughput chemical synthesis to generate and screen diverse microarray libraries. In contrast to expensive ink-jet or contact printing, this approach does not require premixing of inks, which enables in situ combinatorial mixing. Easy access and versatility of this patterning approach are shown by generating microarrays of various biomolecules, such as glycans for the first time, to screen interactions of antibodies and lectins. In addition, a layer-by-layer solid-phase synthesis of peptides directly on the microarray is presented. Amino acid–containing nanolayers are repeatedly laser-transferred and reacted with the functionalized acceptor surface in defined patterns. This simple system enables a reproducible array production, down to spot-to-spot distances of 100 µm, and offers a flexible and cheap alternative to expensive spotting robot technology.

Immunization of mice with chimeric antigens displaying selected epitopes confers protection against intestinal colonization and renal damage caused by Shiga toxin-producing Escherichia coli

Montero, David A.; Del Canto, Felipe; Salazar, Juan C.; Cespedes, Sandra; Cádiz, Leandro; Arenas-Salinas, Mauricio; Reyes, José; Oñate, Ángel; Vidal, Roberto M.
Sep 2019
Abstract Shiga toxin-producing Escherichia coli (STEC) cause diarrhea and dysentery, which may progress to hemolytic uremic syndrome (HUS). Vaccination has been proposed as a preventive approach against STEC infection; however, there is no vaccine for humans and those used in animals reduce but do not eliminate the intestinal colonization of STEC. The OmpT, Cah and Hes proteins are widely distributed among clinical STEC strains and are recognized by serum IgG and IgA in patients with HUS. Here, we develop a vaccine formulation based on two chimeric antigens containing epitopes of OmpT, Cah and Hes proteins against STEC strains. Intramuscular and intranasal immunization of mice with these chimeric antigens elicited systemic and local long-lasting humoral responses. However, the class of antibodies generated was dependent on the adjuvant and the route of administration. Moreover, while intramuscular immunization with the combination of the chimeric antigens conferred protection against colonization by STEC O157:H7 and the intranasal conferred protection against renal damage caused by STEC O91:H21. This pre-clinical study supports the potential use of this formulation based on recombinant chimeric proteins as a preventive strategy against STEC infections.

Characterization of a sandwich ELISA for quantification of total human soluble neuropilin‐1

Gadermaier, Elisabeth; Tesarz, Manfred; Wallwitz, Jacqueline; Berg, Gabriela; Himmler, Gottfried
J Clin Lab Anal.
Sep 2019
Background Neuropilin-1 (NRP1) is a highly interactive molecule that exists as transmembrane and soluble isoforms. Measurement of circulating levels of soluble NRP1 (sNRP1) in human serum and plasma has proven to be difficult due to present matrix interferences and due to the lack of a reliable technique. Methods We developed a highly specific and sensitive sandwich ELISA assay for total sNRP1 quantification in peripheral blood, and we validated the test according to ICH guidelines. The linear epitopes of the employed polyclonal and monoclonal anti-human NRP1 antibodies were mapped with microarray technology. We included a sample pre-treatment step with guanidine hydrochloride (GuHCl) to release sNRP1 from existing interferants. Results The ELISA assay which is calibrated with sNRP1 isoform 2 and covers a calibration range from 0.375 to 12 nmol/L detects sNRP1 in human serum and plasma (heparin, EDTA, and citrate). Multiple linear epitopes recognized by the polyclonal coating antibody are distributed over the whole sNRP1 sequence. The monoclonal detection antibody binds to a linear epitope which is in the N-terminal region of the a1 domain of human sNRP1. Assay parameters like precision (intra-assay: 6%), dilution linearity (95%-115%), specificity (98%), and spike recovery (81%-109%) meet the international standards of acceptance. Conclusion Our novel sandwich ELISA provides a reliable tool for the quantitative determination of total human sNRP1. The assay detects free and previous ligand-bound total NRP1.

Performance evaluation of 3 serodiagnostic peptide epitopes and the derived multi-epitope peptide OvNMP-48 for detection of Onchocerca volvulus infection

Lagatie, Ole; Verheyen, Ann; Nijs, Erik; Batsa Debrah, Linda; Debrah, Yaw A.; Stuyver, Lieven J.
Parasitol Res.
Jul 2019
Current diagnostic tools to determine infection with the helminth parasite Onchocerca volvulus have limited performance characteristics. In previous studies, a proteome-wide screen was conducted to identify linear epitopes in this parasite’s proteome, resulting in the discovery of 1110 antigenic peptide fragments. Here, we investigated three of these peptides using peptide ELISA’s and evaluated their sensitivity and specificity. Epitope mapping was performed, and peptides were constructed that contained only the minimal epitope, flanked by a linker. Investigation of the performance of these minimal epitope peptides demonstrated that all three of them have a specificity (as defined by lack of response in non-helminth-infected individuals) of 100%, low cross-reactivity (5.6%, 5.6%, and 9.3%, respectively), but low sensitivity (36.9%, 46.5%, and 41.2%, respectively). Some cross-reactivity was observed in samples from individuals infected with soil-transmitted helminths or Brugia malayi. Combining these three minimal epitopes in a single peptide, called OvNMP-48, resulted in a performance that exceeded the sum of the individual epitopes, with a sensitivity of 76.0%, a specificity of 97.4%, and a cross-reactivity of 11.1%. Cross-reactivity was observed in some STH and Brugia malayi-infected individuals. This work opens the opportunity to start exploring how these novel linear epitope markers might become part of the O. volvulus diagnostic toolbox.

LRPAP1 is a frequent proliferation-inducing antigen of BCRs of mantle cell lymphomas and can be used for specific therapeutic targeting

Thurner, Lorenz; Hartmann, Sylvia; Fadle, Natalie; Kemele, Maria; Bock, Theresa; Bewarder, Moritz; Regitz, Evi; Neumann, Frank; Nimmesgern, Anna; von Müller, Lutz; Pott, Christiane; Kim, Yoo-Jin; Bohle, Rainer Maria; Wasik, Mariusz; Schuster, Stephen J.; Hansmann, Martin-Leo; Preuss, Klaus-Dieter; Pfreundschuh, Michael
Leukemia.
Jun 2019
The predominant usage of VH4-34 and V3-21 and reports of stereotyped CDR3s suggest a shared antigenic target of B-cell receptors (BCR) from mantle cell lymphomas (MCL). To identify the target antigens of MCL–BCRs, BCRs from 21 patients and seven MCL cell lines were recombinantly expressed and used for antigen screening. The BCRs from 8/21 patients and 2/7 MCL cell lines reacted specifically with the autoantigen low-density lipoprotein receptor-related protein-associated protein 1 (LRPAP1). High-titered and light chain-restricted anti-LRPAP1 serum antibodies were found in MCL patients, but not in controls. LRPAP1 induced proliferation by BCR pathway activation, while an LRPAP1–ETA′ toxin-conjugate specifically killed MCL cells with LRPAP1-specific BCRs. Our results suggest a role of LRPAP1 in lymphomagenesis and maintenance of a considerable proportion of MCL cases by chronic autoantigenic stimulation, likely evolving from a chronic autoreactive B-cell response. Importantly, LRPAP1 can be used for a novel therapeutic approach that targets MCL with LRPAP1-reactive BCRs with high specificity.

Miniaturized and Automated Synthesis of Biomolecules—Overview and Perspectives

Mattes, Daniela S.; Jung, Nicole; Weber, Laura K.; Bräse, Stefan; Breitling, Frank
Adv. Mater..
Jun 2019
Chemical synthesis is performed by reacting different chemical building blocks with defined stoichiometry, while meeting additional conditions, such as temperature and reaction time. Such a procedure is especially suited for automation and miniaturization. Life sciences lead the way to synthesizing millions of different oligonucleotides in extremely miniaturized reaction sites, e.g., pinpointing active genes in whole genomes, while chemistry advances different types of automation. Recent progress in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) imaging could match miniaturized chemical synthesis with a powerful analytical tool to validate the outcome of many different synthesis pathways beyond applications in the life sciences. Thereby, due to the radical miniaturization of chemical synthesis, thousands of molecules can be synthesized. This in turn should allow ambitious research, e.g., finding novel synthesis routes or directly screening for photocatalysts. Herein, different technologies are discussed that might be involved in this endeavor. A special emphasis is given to the obstacles that need to be tackled when depositing tiny amounts of materials to many different extremely miniaturized reaction sites.

Clinical expression and antigenic profiles of a Plasmodium vivax vaccine candidate: merozoite surface protein 7 (PvMSP-7)

Cheng, Chew Weng; Jongwutiwes, Somchai; Putaporntip, Chaturong; Jackson, Andrew P.
Malar J.
Jun 2019
Background Vivax malaria is the predominant form of malaria outside Africa, affecting about 14 million people worldwide, with about 2.5 billion people exposed. Development of a Plasmodium vivax vaccine is a priority, and merozoite surface protein 7 (MSP-7) has been proposed as a plausible candidate. The P. vivax genome contains 12 MSP-7 genes, which contribute to erythrocyte invasion during blood-stage infection. Previous analysis of MSP-7 sequence diversity suggested that not all paralogs are functionally equivalent. To explore MSP-7 functional diversity, and to identify the best vaccine candidate within the family, MSP-7 expression and antigenicity during bloodstream infections were examined directly from clinical isolates. Methods Merozoite surface protein 7 gene expression was profiled using RNA-seq data from blood samples isolated from ten human patients with vivax malaria. Differential expression analysis and co-expression cluster analysis were used to relate PvMSP-7 expression to genetic markers of life cycle stage. Plasma from vivax malaria patients was also assayed using a custom peptide microarray to measure antibody responses against the coding regions of 12 MSP-7 paralogs. Results Ten patients presented diverse transcriptional profiles that comprised four patient groups. Two MSP-7 paralogs, 7A and 7F, were expressed abundantly in all patients, while other MSP-7 genes were uniformly rare (e.g. 7J). MSP-7H and 7I were significantly more abundant in patient group 4 only, (two patients having experienced longer patency), and were co-expressed with a schizont-stage marker, while negatively associated with liver-stage and gametocyte-stage markers. Screening infections with a PvMSP-7 peptide array identified 13 linear B-cell epitopes in five MSP-7 paralogs that were recognized by plasma from all patients. Conclusions These results show that MSP-7 family members vary in expression profile during blood infections; MSP-7A and 7F are expressed throughout the intraerythrocytic development cycle, while expression of other paralogs is focused on the schizont. This may reflect developmental regulation, and potentially functional differentiation, within the gene family. The frequency of B-cell epitopes among paralogs also varies, with MSP-7A and 7L consistently the most immunogenic. Thus, MSP-7 paralogs cannot be assumed to have equal potential as vaccines. This analysis of clinical infections indicates that the most abundant and immunogenic paralog is MSP-7A.

Identification of Two Distinct Linear B Cell Epitopes of the Matrix Protein of the Newcastle Disease Virus Vaccine Strain LaSota

Bi, Youkun; Jin, Zhongyuan; Wang, Yanhong; Mou, Sujing; Wang, Wenbin; Wei, Qiaolin; Huo, Na; Liu, Siqi; Wang, Xinglong; Yang, Zengqi; Chen, Hongjun; Xiao, Sa
Viral Immunology.
Jun 2019
Matrix (M) protein of Newcastle disease virus (NDV) is an abundant protein that can induce a robust humoral immune response. However, its antigenic epitopes remain unknown. In this study, we used a pepscan approach to map linear B cell immunodominant epitopes (IDEs) of M protein with NDV-specific chicken antisera. The six epitopes with the highest reactivity by peptide scanning were obtained as IDE candidates. Among them, aa71–85 and aa349–363 were identified by immunological assays with NDV-specific or IDE-specific antisera. The minimal antigenic epitopes of the two IDEs were further characterized as 77MIDDKP82 and 354HTLAKYNPFK363. Moreover, an amino acid sequence alignment and immunoblot analysis revealed the conservation of the two IDEs in the M protein of strains of different genotypes. These two IDEs of M protein could be genetically eliminated as negative markers in recombinant NDV for serologically differential diagnosis in the development of marker vaccines.

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