Abstract: Severe equine asthma (SEA) is a common chronic disease of adult horses with characteristic recurrent airway obstruction and similarities to neutrophilic asthma in humans. As an extrinsic stimulus, hay dust exposure is a major risk factor and induces acute exacerbation in susceptible horses. However, single inducing agents of SEA have hardly been identified on a molecular basis. () is a common mold species in hay and has been described as a major provoking agent of SEA. Unassigned: Aiming to identify disease-relevant antigens, we analyzed using an immunoproteomics approach on two-dimensional immunoblots of protein probed with serum from environmentally matched asthmatic and healthy horses (n=5 pairs). binding serum immunoglobulins (Pan-Ig), and the isotypes IgG4/7 and IgG3/5 were quantified for each protein spot and then compared between asthmatic and healthy horses. Unassigned: For 21 out of 289 spots serum immunoglobulin (Ig) binding was different between the two groups for Pan-Ig or the isotypes. If differences were detected, Pan-Ig and IgG4/7 binding to the proteins were lower, while IgG3/5 binding was higher in asthmatic than healthy horse sera. Proteins were extracted from the 21 spots of interest and analyzed by liquid chromatography mass spectrometry. Eight prioritized proteins (candidate antigens) were expressed as recombinant proteins. Some of these have been previously described as major or minor allergens, alongside other proteins, most with hydrolase activity. Recombinant candidate antigens were tested on 1D immunoblots to confirm their relevance as antigens by serum antibody binding. Four proteins (beta-hexosaminidase, class II aldolase/adducin domain protein, glucoamylase, peptide hydrolase B0XX53) showed different antibody binding characteristics between asthmatic and healthy horses and are likely relevant antigens in SEA. Their identification can provide the basis for innovative diagnostics, prevention, or therapeutic approaches. Additionally, a more profound understanding of SEA and its potential underlying mechanisms can be established. Elevated serum IgG3/5 antibodies correlate with T helper cell 2 responses in other equine pathologies, and the recombinant SEA antigens developed here can become instrumental in analyzing the involvement of SEA-specific T cell responses and Ig responses in future studies.
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The research article discusses the identification of new antigenic proteins in a common mold species known as Aspergillus fumigatus, which may play a role in the development of severe equine asthma, a common chronic ailment in adult horses.
Identification of Antigens via Immunoproteomics
The research involved an immunoproteomics approach to identifying antigens, relevant to the disease, from the mold Aspergillus fumigatus. Immunoproteomics is a scientific approach that involves identifying and studying the interactions between proteins and the immune system.
Specifically, the researchers looked for differences in the binding of serum immunoglobulins (antibodies) from asthmatic and healthy horses to proteins of this mold. This was done by comparing signals from 2D immunoblots of the mold’s protein probed with horse serum.
A group of 21 out of 289 protein spots were identified where immunoglobulin (Ig) binding differed between the two groups of horses.
Analysis & Findings
The differences observed were such that pan-immunoglobulins (Pan-Ig) and IgG4/7 binding were generally lower, while IgG3/5 binding was elevated in the asthmatic horses as compared to the healthy ones.
Protein extraction and analysis were conducted on the 21 identified spots to study the different antigens. These were then prioritized and the top eight were expressed as recombinant proteins.
Some of these proteins had been previously identified as being major or minor allergens, while others were first-time findings.
The majority of these proteins were found to have hydrolase activity.
Confirming Antigen Relevance
These recombinant proteins were then further tested using 1D immunoblots to confirm their relevance as antigens by checking if serum antibodies bound to them.
Ultimately, four proteins (beta-hexosaminidase, class II aldolase/adducin domain protein, glucoamylase, and peptide hydrolase B0XX53) displayed different antibody binding characteristics when comparing asthmatic and healthy horses, showing their likely relevance as antigens in severe equine asthma.
Identifying these antigens not only helps develop better diagnostics, prevention strategies, and therapeutic approaches for this disease, but also provides a deeper understanding of its mechanisms.
Future Research
The elevated IgG3/5 antibodies in asthmatic horses likely reveal a correlation with T helper cell 2 responses, as seen in other equine disorders. Thus, the antigens developed in this study could greatly aid future research in exploring their involvement in specific T cell responses and Ig responses associated with severe equine asthma.
Cite This Article
APA
Jentsch MC, Lübke S, Schrödl W, Volke D, Krizsan A, Hoffmann R, Kaiser-Thom S, Gerber V, Marti E, Wagner B, Schnabel CL.
(2024).
Immunoproteomics enable broad identification of new Aspergillus fumigatus antigens in severe equine asthma.
Front Immunol, 15, 1347164.
https://doi.org/10.3389/fimmu.2024.1347164
Institute of Immunology, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany.
Lübke, Sabrina
Institute of Immunology, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany.
Schrödl, Wieland
Institute of Bacteriology and Mycology, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany.
Volke, Daniela
Institute of Bioanalytical Chemistry, Faculty of Chemistry and Mineralogy, Centre for Biotechnology and Biomedicine, Leipzig University, Leipzig, Germany.
Krizsan, Andor
Institute of Bioanalytical Chemistry, Faculty of Chemistry and Mineralogy, Centre for Biotechnology and Biomedicine, Leipzig University, Leipzig, Germany.
Hoffmann, Ralf
Institute of Bioanalytical Chemistry, Faculty of Chemistry and Mineralogy, Centre for Biotechnology and Biomedicine, Leipzig University, Leipzig, Germany.
Kaiser-Thom, Sarah
Swiss Institute of Equine Medicine, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
Gerber, Vinzenz
Swiss Institute of Equine Medicine, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
Marti, Eliane
Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
Wagner, Bettina
Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States.
Schnabel, Christiane L
Institute of Immunology, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany.
MeSH Terms
Humans
Adult
Animals
Horses
Aspergillus fumigatus
Asthma / veterinary
Pulmonary Disease, Chronic Obstructive
Antigens, Fungal
Immunoglobulin G
Conflict of Interest Statement
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
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