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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.

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.

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.

Immunization of cats to induce neutralizing antibodies against Fel d 1, the major feline allergen in human subjects

Thoms, Franziska; Jennings, Gary T.; Maudrich, Melanie; Vogel, Monique; Haas, Stefanie; Zeltins, Andris; Hofmann-Lehmann, Regina; Riond, Barbara; Grossmann, Jonas; Hunziker, Peter; Fettelschoss-Gabriel, Antonia; Senti, Gabriela; Kündig, Thomas M.; Bachmann, Martin F.
Journal of Allergy and Clinical Immunology.
Jul 2019
Background Cat allergy in human subjects is usually caused by the major cat allergen Fel d 1 and is found in approximately 10% of the Western population. Currently, there is no efficient and safe therapy for cat allergy available. Allergic patients usually try to avoid cats or treat their allergy symptoms. Objective We developed a new strategy to treat Fel d 1–induced allergy in human subjects by immunizing cats against their own major allergen, Fel d 1. Methods A conjugate vaccine consisting of recombinant Fel d 1 and a virus-like particle derived from the cucumber mosaic virus containing the tetanus toxin–derived universal T-cell epitope tt830-843 (CuMVTT) was used to immunize cats. A first tolerability and immunogenicity study, including a boost injection, was conducted by using the Fel-CuMVTT vaccine alone or in combination with an adjuvant. Results The vaccine was well tolerated and had no overt toxic effect. All cats induced a strong and sustained specific IgG antibody response. The induced anti–Fel d 1 antibodies were of high affinity and exhibited a strong neutralization ability tested both in vitro and in vivo. A reduction in the endogenous allergen level and a reduced allergenicity of tear samples, were observed. Conclusion Vaccination of cats with Fel-CuMVTT induces neutralizing antibodies and might result in reduced symptoms of allergic cat owners. Both human subjects and animals could profit from this treatment because allergic cat owners would reduce their risk of developing chronic diseases, such as asthma, and become more tolerant of their cats, which therefore could stay in the households and not need to be relinquished to animal shelters.

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.

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.

A high-sensitivity enzyme immunoassay for the quantification of soluble human semaphorin 4D in plasma

Laber, Anna; Gadermaier, Elisabeth; Wallwitz, Jacqueline; Berg, Gabriela; Himmler, Gottfried
Analytical Biochemistry.
Jun 2019
Human semaphorin 4D (SEMA4D), a type I integral membrane glycoprotein, regulates key cellular functions (e.g. cell-cell communication, platelet activation). Its 120 kDa extracellular region can be shed from the membrane to release soluble SEMA4D (sSEMA4D). Studies on circulating sSEMA4D levels are mostly performed with poorly characterized assays and use serum and plasma as matrix. We developed and validated a sandwich ELISA utilizing two monoclonal antibodies with resolved epitopes and determined affinities. Human serum and plasma samples were analyzed, and the influence of protease activity on sSEMA4D concentration was tested by collecting samples in the presence of the protease inhibitor TAPI-1. Both antibodies recognize conformational epitopes in the sema domain. Validation for plasma (EDTA, citrate, heparin) showed valid specificity, precision, accuracy, dilution linearity, and robustness. The assay shows a calibration range from 62.5 to 2000 pmol/L with a quantification limit of 31 pmol/L. sSEMA4D was significantly higher in serum than in plasma, whereas serum and plasma levels from samples collected in the presence of TAPI-1 showed no statistical difference. This ELISA provides a reliable tool for the quantification of sSEMA4D in human plasma. Serum is not recommended as matrix due to the accumulation of shed SEMA4D during blood coagulation altering serum sSEMA4D levels.

High-density Peptide Arrays Help to Identify Linear Immunogenic B-cell Epitopes in Individuals Naturally Exposed to Malaria Infection

Jaenisch, Thomas; Heiss, Kirsten; Fischer, Nico; Geiger, Carolin; Bischoff, F. Ralf; Moldenhauer, Gerhard; Rychlewski, Leszek; Sié, Ali; Coulibaly, Boubacar; Seeberger, Peter H.; Wyrwicz, Lucjan S.; Breitling, Frank; Loeffler, Felix F.
Mol Cell Proteomics.
Apr 2019
High-density peptide arrays are an excellent means to profile anti-plasmodial antibody responses. Different protein intrinsic epitopes can be distinguished, and additional insights are gained, when compared with assays involving the full-length protein. Distinct reactivities to specific epitopes within one protein may explain differences in published results, regarding immunity or susceptibility to malaria. We pursued three approaches to find specific epitopes within important plasmodial proteins, (1) twelve leading vaccine candidates were mapped as overlapping 15-mer peptides, (2) a bioinformatical approach served to predict immunogenic malaria epitopes which were subsequently validated in the assay, and (3) randomly selected peptides from the malaria proteome were screened as a control. Several peptide array replicas were prepared, employing particle-based laser printing, and were used to screen 27 serum samples from a malaria-endemic area in Burkina Faso, West Africa. The immunological status of the individuals was classified as “protected” or “unprotected” based on clinical symptoms, parasite density, and age. The vaccine candidate screening approach resulted in significant hits in all twelve proteins and allowed us (1) to verify many known immunogenic structures, (2) to map B-cell epitopes across the entire sequence of each antigen and (3) to uncover novel immunogenic epitopes. Predicting immunogenic regions in the proteome of the human malaria parasite Plasmodium falciparum, via the bioinformatics approach and subsequent array screening, confirmed known immunogenic sequences, such as in the leading malaria vaccine candidate CSP and discovered immunogenic epitopes derived from hypothetical or unknown proteins.

Active vaccination against interleukin-5 as long-term treatment for insect-bite hypersensitivity in horses

Fettelschoss-Gabriel, Antonia; Fettelschoss, Victoria; Olomski, Florian; Birkmann, Katharina; Thoms, Franziska; Bühler, Maya; Kummer, Martin; Zeltins, Andris; Kündig, Thomas M.; Bachmann, Martin F.
Allergy.
Mar 2019
Background Insect-bite hypersensitivity (IBH) in horses is a chronic allergic dermatitis caused by insect bites. Horses suffer from pruritic skin lesions, caused by type-I/type-IV allergic reactions accompanied by prominent eosinophil infiltration into the skin. Interleukin-5 (IL-5) is the key cytokine for eosinophils and we have previously shown that targeting IL-5 by vaccination reduces disease symptoms in horses. Objective Here, we analyzed the potential for long-term therapy by assessing a second follow-up year of the previously published study. Methods The vaccine consisted of equine IL-5 (eIL-5) covalently linked to a cucumber mosaic virus-like particle (VLP) containing a universal T cell epitope (CuMVTT) using a semi-crossover design to follow vaccinated horses during a second treatment season. Thirty Icelandic horses were immunized with 300 μg of eIL-5-CuMVTT without adjuvant. Results The vaccine was well tolerated and did not reveal any safety concerns throughout the study. Upon vaccination, all horses developed reversible anti-eIL-5 auto-antibody titers. The mean course of eosinophil levels was reduced compared to placebo treatment leading to significant reduction of clinical lesion scores. Horses in their second vaccination year showed a more pronounced improvement of disease symptoms when compared to first treatment year, most likely due to more stable antibody titers induced by a single booster injection. Hence, responses could be maintained over two seasons and the horses remained protected against disease symptoms. Conclusion Yearly vaccination against IL-5 may be a long-term solution for the treatment of IBH and other eosinophil-mediated diseases in horses and other species including humans.

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