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

Induced Polyspecificity of Human Secretory Immunoglobulin A Antibodies: Is It Possible to Improve Their Ability to Bind Pathogens?

Gorshkova, Ekaterina N.; Pashova, Shina; Vasilenko, Ekaterina A.; Tchurina, Tatiana S.; Razzorenova, Elizaveta A.; Starkina, Olga V.; Dimitrova, Petya; Pashov, Anastas; Vassilev, Tchavdar Lubenov
Pharmacology.
Dec 2021
Introduction: As has been shown previously, various protein-modifying agents can change the antigen-binding properties of immunoglobulins. However, induced polyspecificity of human secretory immunoglobulin A (sIgA) has not been previously characterized in detail. Methods: In the present study, human secretory immunoglobulin A (IgA) was exposed to buffers with acidic pH, to free heme, or to pro-oxidative ferrous ions, and the antigen-binding behavior of the native and modified IgA to viral and bacterial antigens was compared using Western blotting and enzyme-linked immunosorbent assay. The ability of these agents to modulate the antigen-binding properties of human sIgA toward a wide range of pathogen peptides was investigated using an epitope microarray. Results: We have shown that acidic pH, heme, and pro-oxidative ferrous ions influenced the binding of secretory IgA in opposite directions (either increasing or decreasing); however, the strongest effect was observed when using buffers with low pH. This fraction had the highest number of affected reactivities; most of them were increased and most of the new ones were toward common pathogens. Conclusions: Thus, it was shown that all investigated treatments can alter to some degree the antigen-binding of secretory IgA, but acidic pH has the most potentially beneficial effect by increasing binding to a largest number of common pathogens’ antigens.

Influenza‐associated thrombotic thrombocytopenic purpura: A report of two cases and a brief review of the literature

Onkarappa Mangala, Yashvin; Sweeney, Joseph D.
Vox Sanguinis.
Nov 2021
Background and Objectives Thrombotic thrombocytopenic purpura (TTP) is often preceded by a recent history of an acute infection and influenza is the most implicated virus. Materials and Methods We identified two cases of TTP, which were preceded by influenza between 2010 and 2021. In one patient, we epitope mapped the binding specificity of antibodies using an overlapping peptide approach of the stalk protein of Influenza B and the cysteine-rich spacer domain (CRSD) of ADAMTS13. A literature search was performed for reports of influenza-associated TTP over the period 1980–2021. Results Two patients were identified in which TTP was preceded by influenza, one Influenza A and the other Influenza B. Epitope mapping of the latter’s plasma identified target epitopes in both the stalk protein of Influenza B and CRSD of ADAMTS13. The literature review revealed only seven case reports, all but one from Europe or Asia and associated with Influenza A. Severe ADAMTS13 deficiency was demonstrated in only four cases. Conclusion We report the first small case series of influenza-associated TTP. Moreover, it is the first case implicating Influenza B and a mechanism favouring polyclonal B-cell proliferation rather than molecular mimicry as the stimulus to form anti-ADAMTS13 auto-antibodies is suggested.

A high-throughput pipeline for design and selection of peptides targeting the SARS-Cov-2 Spike protein

Wolfe, Monica; Webb, Sean; Chushak, Yaroslav; Krabacher, Rachel; Liu, Yi; Swami, Nathan; Harbaugh, Svetlana; Chávez, Jorge
Sci Rep.
Nov 2021
Rapid design, screening, and characterization of biorecognition elements (BREs) is essential for the development of diagnostic tests and antiviral therapeutics needed to combat the spread of viruses such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To address this need, we developed a high-throughput pipeline combining in silico design of a peptide library specific for SARS-CoV-2 spike (S) protein and microarray screening to identify binding sequences. Our optimized microarray platform allowed the simultaneous screening of ~ 2.5 k peptides and rapid identification of binding sequences resulting in selection of four peptides with nanomolar affinity to the SARS-CoV-2 S protein. Finally, we demonstrated the successful integration of one of the top peptides into an electrochemical sensor with a clinically relevant limit of detection for S protein in spiked saliva. Our results demonstrate the utility of this novel pipeline for the selection of peptide BREs in response to the SARS-CoV-2 pandemic, and the broader application of such a platform in response to future viral threats.

HSP70iQ435A to subdue autoimmunity and support anti-tumor responses

Jaishankar, Dinesh; Cosgrove, Cormac; Ramesh, Prathyaya; Mahon, James; Shivde, Rohan; Dellacecca, Emilia R.; Yang, Shiayin F.; Mosenson, Jeffrey; Guevara-Patiño, José A.; Le Poole, I. Caroline
Cell Stress and Chaperones.
Sep 2021
Developing immunosuppressive therapies for autoimmune diseases comes with a caveat that immunosuppression may promote the risk of developing other conditions or diseases. We have previously shown that biolistic delivery of an expression construct encoding inducible HSP70 (HSP70i) with one amino acid modification in the dendritic cell (DC) activating moiety 435–445 (HSP70iQ435A) to mouse skin resulted in significant immunosuppressive activity of autoimmune vitiligo, associated with fewer tissue infiltrating T cells. To prepare HSP70iQ435A as a potential therapeutic for autoimmune vitiligo, in this study we evaluated whether and how biolistic delivery of HSP70iQ435A in mice affects anti-tumor responses. We found that HSP70iQ435A in fact supports anti-tumor responses in melanoma-challenged C57BL/6 mice. Biolistic delivery of the HSP70iQ435A-encoding construct to mice elicited significant anti-HSP70 titers, and anti-HSP70 IgG and IgM antibodies recognize surface-expressed and cytoplasmic HSP70i in human and mouse melanoma cells. A peptide scan revealed that the anti-HSP70 antibodies recognize a specific C-terminal motif within the HSP70i protein. The antibodies elicited surface CD107A expression among mouse NK cells, representative of antibody-mediated cellular cytotoxicity (ADCC), supporting the concept, that HSP70iQ435A-encoding DNA elicits a humoral response to the stress protein expressed selectively on the surface of melanoma cells. Thus, besides limiting autoimmunity and inflammation, HSP70iQ435A elicits humoral responses that limit tumor growth and may be used in conjunction with immune checkpoint inhibitors to not only control tumor but to also limit adverse events following tumor immunotherapy.

Location and expression kinetics of Tc24 in different life stages of Trypanosoma cruzi

Versteeg, Leroy; Adhikari, Rakesh; Poveda, Cristina; Villar-Mondragon, Maria Jose; Jones, Kathryn M.; Hotez, Peter J.; Bottazzi, Maria Elena; Tijhaar, Edwin; Pollet, Jeroen
PLoS Negl Trop Dis.
Sep 2021
Tc24-C4, a modified recombinant flagellar calcium-binding protein of Trypanosoma cruzi, is under development as a therapeutic subunit vaccine candidate to prevent or delay progression of chronic Chagasic cardiomyopathy. When combined with Toll-like receptor agonists, Tc24-C4 immunization reduces parasitemia, parasites in cardiac tissue, and cardiac fibrosis and inflammation in animal models. To support further research on the vaccine candidate and its mechanism of action, murine monoclonal antibodies (mAbs) against Tc24-C4 were generated. Here, we report new findings made with mAb Tc24-C4/884 that detects Tc24-WT and Tc24-C4, as well as native Tc24 in T. cruzi on ELISA, western blots, and different imaging techniques. Surprisingly, detection of Tc24 by Tc24-C/884 in fixed T. cruzi trypomastigotes required permeabilization of the parasite, revealing that Tc24 is not exposed on the surface of T. cruzi, making a direct role of antibodies in the induced protection after Tc24-C4 immunization less likely. We further observed that after immunostaining T. cruzi–infected cells with mAb Tc24-C4/884, the expression of Tc24 decreases significantly when T. cruzi trypomastigotes enter host cells and transform into amastigotes. However, Tc24 is then upregulated in association with parasite flagellar growth linked to re-transformation into the trypomastigote form, prior to host cellular escape. These observations are discussed in the context of potential mechanisms of vaccine immunity.

Serum Peptide Immunoglobulin G Autoantibody Response in Patients with Different Central Nervous System Inflammatory Demyelinating Disorders

Lee, Hye Lim; Park, Jin-Woo; Seok, Jin Myoung; Jeon, Mi Young; Kim, Hojin; Lim, Young-Min; Shin, Ha Young; Kang, Sa-Yoon; Kwon, Oh-Hyun; Lee, Sang-Soo; Seok, Hung Youl; Min, Ju-Hong; Lee, Sung-Hyun; Kim, Byung-Jo; Kim, Byoung Joon
Diagnostics.
Jul 2021
Previous efforts to discover new surrogate markers for the central nervous system (CNS) inflammatory demyelinating disorders have shown inconsistent results; moreover, supporting evidence is scarce. The present study investigated the IgG autoantibody responses to various viral and autoantibodies-related peptides proposed to be related to CNS inflammatory demyelinating disorders using the peptide microarray method. We customized a peptide microarray containing more than 2440 immobilized peptides representing human and viral autoantigens. Using this, we tested the sera of patients with neuromyelitis optica spectrum disorders (NMOSD seropositive, n = 6; NMOSD seronegative, n = 5), multiple sclerosis (MS, n = 5), and myelin-oligodendrocyte glycoprotein antibody-associated disease (MOGAD, n = 6), as well as healthy controls (HC, n = 5) and compared various peptide immunoglobulin G (IgG) responses between the groups. Among the statistically significant peptides based on the pairwise comparisons of IgG responses in each disease group to HC, cytomegalovirus (CMV)-related peptides were most clearly distinguishable among the study groups. In particular, the most significant differences in IgG response were observed for HC vs. MS and HC vs. seronegative NMOSD (p = 0.064). Relatively higher IgG responses to CMV-related peptides were observed in patients with MS and NMOSD based on analysis of the customized peptide microarray.

Identification of a Zika NS2B epitope as a biomarker for severe clinical phenotypes

Loeffler, Felix F.; Viana, Isabelle F. T.; Fischer, Nico; Coêlho, Danilo F.; Silva, Carolina S.; Purificação, Antônio F.; Araújo, Catarina M. C. S.; Leite, Bruno H. S.; Durães-Carvalho, Ricardo; Magalhães, Tereza; Morais, Clarice N. L.; Cordeiro, Marli T.; Lins, Roberto D.; Marques, Ernesto T. A.; Jaenisch, Thomas
RSC Med. Chem..
Jul 2021
The identification of specific biomarkers for Zika infection and its clinical complications is fundamental to mitigate the infection spread, which has been associated with a broad range of neurological sequelae. , The identification of specific biomarkers for Zika infection and its clinical complications is fundamental to mitigate the infection spread, which has been associated with a broad range of neurological sequelae. We present the characterization of antibody responses in serum samples from individuals infected with Zika, presenting non-severe (classical) and severe (neurological disease) phenotypes, with high-density peptide arrays comprising the Zika NS1 and NS2B proteins. The data pinpoints one strongly IgG-targeted NS2B epitope in non-severe infections, which is absent in Zika patients, where infection progressed to the severe phenotype. This differential IgG profile between the studied groups was confirmed by multivariate data analysis. Molecular dynamics simulations and circular dichroism have shown that the peptide in solution presents itself in a sub-optimal conformation for antibody recognition, which led us to computationally engineer an artificial protein able to stabilize the NS2B epitope structure. The engineered protein was used to interrogate paired samples from mothers and their babies presenting Zika-associated microcephaly and confirmed the absence of NS2B IgG response in those samples. These findings suggest that the assessment of antibody responses to the herein identified NS2B epitope is a strong candidate biomarker for the diagnosis and prognosis of Zika-associated neurological disease.

Landscape and selection of vaccine epitopes in SARS-CoV-2

Smith, Christof C.; Olsen, Kelly S.; Gentry, Kaylee M.; Sambade, Maria; Beck, Wolfgang; Garness, Jason; Entwistle, Sarah; Willis, Caryn; Vensko, Steven; Woods, Allison; Fini, Misha; Carpenter, Brandon; Routh, Eric; Kodysh, Julia; O’Donnell, Timothy; Haber, Carsten; Heiss, Kirsten; Stadler, Volker; Garrison, Erik; Sandor, Adam M.; Ting, Jenny P. Y.; Weiss, Jared; Krajewski, Krzysztof; Grant, Oliver C.; Woods, Robert J.; Heise, Mark; Vincent, Benjamin G.; Rubinsteyn, Alex
Genome Medicine.
Jun 2021
Early in the pandemic, we designed a SARS-CoV-2 peptide vaccine containing epitope regions optimized for concurrent B cell, CD4+ T cell, and CD8+ T cell stimulation. The rationale for this design was to drive both humoral and cellular immunity with high specificity while avoiding undesired effects such as antibody-dependent enhancement (ADE).

SARS-CoV-2 spike protein stabilized in the closed state induces potent neutralizing responses.

Carnell, George W.; Ciazynska, Katarzyna A.; Wells, David A.; Xiong, Xiaoli; Aguinam, Ernest T.; McLaughlin, Stephen H.; Mallery, Donna; Ebrahimi, Soraya; Ceron-Gutierrez, Lourdes; Asbach, Benedikt; Einhauser, Sebastian; Wagner, Ralf; James, Leo C.; Doffinger, Rainer; Heeney, Jonathan L.; Briggs, John A. G.
The majority of SARS-CoV-2 vaccines in use or advanced development are based on the viral spike protein (S) as their immunogen. S is present on virions as pre-fusion trimers in which the receptor binding domain (RBD) is stochastically open or closed. Neutralizing antibodies have been described against both open and closed conformations. The long-term success of vaccination strategies depends upon inducing antibodies that provide long-lasting broad immunity against evolving SARS-CoV-2 strains. Here we have assessed the results of immunization in a mouse model using an S protein trimer stabilized in the closed state to prevent full exposure of the receptor binding site and therefore interaction with receptor. We compared this with other modified S protein constructs, including representatives used in current vaccines. We found that all trimeric S proteins induced a T cell response and long-lived, strongly neutralizing antibody responses against 2019 SARS-CoV-2 and variants of concern B.1.248 and B.1.351. Notably, the protein binding properties of sera induced by the closed spike differed from those induced by standard S protein constructs. Closed S proteins induced more potent neutralizing responses than expected based on the degree to which they inhibit interactions between the RBD and ACE2. These observations suggest that closed spikes recruit different, but equally potent, immune responses than open spikes, and that this is likely to include neutralizing antibodies against conformational epitopes present in the closed conformation. Together with their improved stability and storage properties we suggest that closed spikes may be a valuable component of refined, next-generation vaccines. Importance Vaccines in use against SARS-CoV-2 induce immune responses against the spike protein. There is intense interest in whether the antibody response induced by vaccines will be robust against new variants, as well as in next-generation vaccines for use in previously infected or immunized individuals. We assessed the use as an immunogen of a spike protein engineered to be conformationally stabilized in the closed state where the receptor binding site is occluded. Despite occlusion of the receptor binding site, the spike induces potently neutralizing sera against multiple SARS-CoV-2 variants. Antibodies are raised against a different pattern of epitopes to those induced by other spike constructs, preferring conformational epitopes present in the closed conformation. Closed spikes, or mRNA vaccines based on their sequence, can be a valuable component of next generation vaccines.

Longitudinal Development of Antibody Responses in COVID-19 Patients of Different Severity with ELISA, Peptide, and Glycan Arrays: An Immunological Case Series

Heidepriem, Jasmin; Dahlke, Christine; Kobbe, Robin; Santer, René; Koch, Till; Fathi, Anahita; Seco, Bruna M. S.; Ly, My L.; Schmiedel, Stefan; Schwinge, Dorothee; Serna, Sonia; Sellrie, Katrin; Reichardt, Niels-Christian; Seeberger, Peter H.; Addo, Marylyn M.; Loeffler, Felix F.; on behalf of the ID-UKE COVID-19 Study Group
The current COVID-19 pandemic is caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). A better understanding of its immunogenicity can be important for the development of improved diagnostics, therapeutics, and vaccines. Here, we report the longitudinal analysis of three COVID-19 patients with moderate (#1) and mild disease (#2 and #3). Antibody serum responses were analyzed using spike glycoprotein enzyme linked immunosorbent assay (ELISA), full-proteome peptide, and glycan microarrays. ELISA immunoglobulin A, G, and M (IgA, IgG, and IgM) signals increased over time for individuals #1 and #2, whereas #3 only showed no clear positive IgG and IgM result. In contrast, peptide microarrays showed increasing IgA/G signal intensity and epitope spread only in the moderate patient #1 over time, whereas early but transient IgA and stable IgG responses were observed in the two mild cases #2 and #3. Glycan arrays showed an interaction of antibodies to fragments of high-mannose and core N-glycans, present on the viral shield. In contrast to protein ELISA, microarrays allow for a deeper understanding of IgA, IgG, and IgM antibody responses to specific epitopes of the whole proteome and glycans of SARS-CoV-2 in parallel. In the future, this may help to better understand and to monitor vaccination programs and monoclonal antibodies as therapeutics.

SARS-CoV-2 proteome-wide analysis revealed significant epitope signatures in COVID-19 patients

Schwarz, Tatjana; Heiss, Kirsten; Mahendran, Yuvaraj; Casilag, Fiordiligie; Kurth, Florian; Sander, Leif; Wendtner, Clemens-Martin; Hoechstetter, Manuela A.; Müller, Marcel A.; Sekul, Renate; Drosten, Christian; Stadler, Volker; Corman, Victor M.
Front. Immunol..
Mar 2021
The WHO declared the COVID-19 outbreak a public health emergency of international concern. The causative agent of this acute respiratory disease is a newly emerged coronavirus, named SARS-CoV 2, which originated in China in late 2019. Exposure to SARS‑CoV‑2 leads to multifaceted disease outcomes from asymptomatic infection to severe pneumonia, acute respiratory distress and potentially death. Understanding the host immune response is crucial for the development of interventional strategies. Humoral responses play an important role in defending viral infections and are therefore of particular interest. With the aim to resolve SARS-CoV-2-specific humoral immune responses at the epitope level, we screened clinically well-characterized sera from COVID-19 patients with mild and severe disease outcome using high-density peptide microarrays covering the entire proteome of SARS-CoV-2. Moreover, we determined the longevity of epitope-specific antibody responses in a longitudinal approach. Here we present IgG and IgA-specific epitope signatures from COVID-19 patients, which may serve as discriminating prognostic or predictive markers for disease outcome and/or could be relevant for intervention strategies

Immunodominant B cell epitope in SARS-CoV-2 RBD comprises a B.1.351 and P.1 mutation hotspot: implications for viral spread and antibody escape

Santos, Keity Souza; Oliveira, Jamille Ramos; Machado, Rafael Rahal G.; Arcuri, Helen Andrade; Magawa, Jhosiene Yukari; Daher, Isabela Pazotti; Urbanski, Alysson Henrique; Schmitz, Gabriela Justamante Händel; Silva, Roberto Carlos Vieira; Durigon, Edison Luiz; Boscardin, Silvia Beatriz; Rosa, Daniela Santoro; Schechtman, Deborah; Nakaya, Helder I.; Cunha-Neto, Edecio; Gadermaier, Gabriele; Coelho, Verônica; Kalil, Jorge; Team, on behalf of COVID-19 SP-Brazil

Recent SARS-CoV-2 variants pose important concerns due to their higher transmissibility (1) and escape (2) from previous infections or vaccine-induced neutralizing antibodies (nAb). The receptor binding domain (RBD) of the Spike protein is a major nAb target (3), but data on its B cell epitopes are still lacking. Using a peptide microarray, we identified an immunodominant epitope (S415-429) recognized by 68% of sera from 71 convalescent Brazilians infected with the ancestral variant. In contrast with previous studies, we have identified a linear IgG and IgA antibody binding epitope within the RBD. IgG and IgA antibody levels for this epitope positively correlated with nAb titers, suggesting a potential target of antibody neutralizing activity. Interestingly, this immunodominant RBD region harbors the mutation hotspot site K417 present in P.1 (K417T) and B.1.351 (K417N) variants. In silico simulation analyses indicate impaired RBD binding to nAb in both variants and that glycosylation in the B.1.351 417N could further hinder antibody binding as compared to the K417T mutation in P.1. This is in line with published data showing that nAb from either convalescents or anti-CoV-2 vaccinees are less effective towards B.1.351 than for P.1. Our data support the occurrence of immune pressure and selection involving this immunodominant epitope that may have critically contributed to the recent COVID-19 marked rise in Brazil and South Africa, and pinpoint a potential additional immune escape mechanism for SARS-CoV-2.

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