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ALLERGY IS AN IMMUNE DISORDER RELATED TO A LACK OF REGULATION: THE GLUING ROLE OF IL-2. Immunol Lett 2022; 251-252:103-106. [DOI: 10.1016/j.imlet.2022.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 11/09/2022] [Accepted: 11/13/2022] [Indexed: 11/16/2022]
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Ligabue-Braun R. Hello, kitty: could cat allergy be a form of intoxication? J Venom Anim Toxins Incl Trop Dis 2020; 26:e20200051. [PMID: 33456448 PMCID: PMC7781471 DOI: 10.1590/1678-9199-jvatitd-2020-0051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Background The relationship between slow loris (Nycticebus spp.) venom (BGE protein) and the major cat allergen (Fel d 1) from domestic cat (Felis catus) is known for about two decades. Along this time, evidence was accumulated regarding convergences between them, including their almost identical mode of action. Methods Large-scale database mining for Fel d 1 and BGE proteins in Felidae and Nycticebus spp., alignment, phylogeny proposition and molecular modelling, associated with directed literature review were assessed. Results Fel d 1 sequences for 28 non-domestic felids were identified, along with two additional loris BGE protein sequences. Dimer interfaces are less conserved among sequences, and the chain 1 shows more sequence similarity than chain 2. Post-translational modification similarities are highly probable. Conclusions Fel d 1 functions beyond allergy are discussed, considering the great conservation of felid orthologs of this protein. Reasons for toxicity being found only in domestic cats are proposed in the context of domestication. The combination of the literature review, genome-derived sequence data, and comparisons with the venomous primate slow loris may point to domestic cats as potentially poisonous mammals.
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Affiliation(s)
- Rodrigo Ligabue-Braun
- Department of Pharmacosciences, Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil
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Tyagi N, Farnell EJ, Fitzsimmons CM, Ryan S, Tukahebwa E, Maizels RM, Dunne DW, Thornton JM, Furnham N. Comparisons of Allergenic and Metazoan Parasite Proteins: Allergy the Price of Immunity. PLoS Comput Biol 2015; 11:e1004546. [PMID: 26513360 PMCID: PMC4626114 DOI: 10.1371/journal.pcbi.1004546] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 08/24/2015] [Indexed: 12/03/2022] Open
Abstract
Allergic reactions can be considered as maladaptive IgE immune responses towards environmental antigens. Intriguingly, these mechanisms are observed to be very similar to those implicated in the acquisition of an important degree of immunity against metazoan parasites (helminths and arthropods) in mammalian hosts. Based on the hypothesis that IgE-mediated immune responses evolved in mammals to provide extra protection against metazoan parasites rather than to cause allergy, we predict that the environmental allergens will share key properties with the metazoan parasite antigens that are specifically targeted by IgE in infected human populations. We seek to test this prediction by examining if significant similarity exists between molecular features of allergens and helminth proteins that induce an IgE response in the human host. By employing various computational approaches, 2712 unique protein molecules that are known IgE antigens were searched against a dataset of proteins from helminths and parasitic arthropods, resulting in a comprehensive list of 2445 parasite proteins that show significant similarity through sequence and structure with allergenic proteins. Nearly half of these parasite proteins from 31 species fall within the 10 most abundant allergenic protein domain families (EF-hand, Tropomyosin, CAP, Profilin, Lipocalin, Trypsin-like serine protease, Cupin, BetV1, Expansin and Prolamin). We identified epitopic-like regions in 206 parasite proteins and present the first example of a plant protein (BetV1) that is the commonest allergen in pollen in a worm, and confirming it as the target of IgE in schistosomiasis infected humans. The identification of significant similarity, inclusive of the epitopic regions, between allergens and helminth proteins against which IgE is an observed marker of protective immunity explains the ‘off-target’ effects of the IgE-mediated immune system in allergy. All these findings can impact the discovery and design of molecules used in immunotherapy of allergic conditions. Allergy is an increasingly widespread clinical problem that leads to various conditions such as allergic asthma and susceptibility to anaphylactic shock. These conditions arise from exposure to a range of environmental and food proteins (‘allergens’) that are recognised by a form of immune system antibody called IgE. This part of the immune system is thought to have evolved to provide mammals with additional rapid response mechanisms to combat metazoan parasites. Here, we address the pertinent question, ‘what makes an Allergen an Allergen’ as, although they constitute a very small percentage of known proteins, they appear to be diverse and unrelated. Using computational studies, we have established molecular similarity between parasite proteins and allergens that affect the nature of immune response and are able to predict the regions of parasite proteins that potentially share similarity with the IgE-binding region(s) of the allergens. Our experimental studies support the computational predictions, and we can present the first confirmed example of a plant pollen-like protein in a worm that is targeted by IgE. The results of this study will enable us to predict likely allergens in food and environmental organisms and to help design protein molecules to treat allergy in the future.
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Affiliation(s)
- Nidhi Tyagi
- The EMBL-European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
- * E-mail:
| | - Edward J Farnell
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | | | - Stephanie Ryan
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Rick M Maizels
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| | - David W Dunne
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Janet M Thornton
- The EMBL-European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Nicholas Furnham
- London School of Hygiene and Tropical Medicine, London, United Kingdom
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Affiliation(s)
- S. Scheurer
- Molecular Allergology; Paul-Ehrlich-Institut; Langen Germany
| | - M. Toda
- Molecular Allergology; Paul-Ehrlich-Institut; Langen Germany
| | - S. Vieths
- Molecular Allergology; Paul-Ehrlich-Institut; Langen Germany
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Farnell EJ, Tyagi N, Ryan S, Chalmers IW, Pinot de Moira A, Jones FM, Wawrzyniak J, Fitzsimmons CM, Tukahebwa EM, Furnham N, Maizels RM, Dunne DW. Known Allergen Structures Predict Schistosoma mansoni IgE-Binding Antigens in Human Infection. Front Immunol 2015; 6:26. [PMID: 25691884 PMCID: PMC4315118 DOI: 10.3389/fimmu.2015.00026] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 01/12/2015] [Indexed: 12/21/2022] Open
Abstract
The IgE response has been associated with both allergic reactions and immunity to metazoan parasites. Recently, we hypothesized that all environmental allergens bear structural homology to IgE-binding antigens from metazoan parasites and that this homology defines the relatively small number of protein families containing allergenic targets. In this study, known allergen structures (Pfam domains) from major environmental allergen families were used to predict allergen-like (SmProfilin, SmVAL-6, SmLipocalin, SmHSP20, Sm triosephosphate isomerase, SmThioredoxin, Sm superoxide dismutase, SmCyclophilin, and Sm phosphoglycerate kinase) and non-allergen-like [Sm dynein light chain (SmDLC), SmAldolase SmAK, SmUbiquitin, and Sm14-3-3] proteins in Schistosoma mansoni. Recombinant antigens were produced in Escherichia coli and IgG1, IgG4, and IgE responses against them measured in a cohort of people (n = 222) infected with S. mansoni. All allergen-like antigens were targeted by IgE responses in infected subjects, whilst IgE responses to the non-allergen-like antigens, SmAK, SmUbiquitin, and Sm14-3-3 were essentially absent being of both low prevalence and magnitude. Two new IgE-binding Pfam domain families, not previously described in allergen family databases, were also found, with prevalent IgE responses against SmDLC (PF01221) and SmAldolase (PF00274). Finally, it was demonstrated that immunoregulatory serological processes typically associated with allergens also occurred in responses to allergen-like proteins in S. mansoni infections, including the production of IgG4 in people responding with IgE and the down-regulation of IgE in response to increased antigen exposure from S. mansoni eggs. This study establishes that structures of known allergens can be used to predict IgE responses against homologous parasite allergen-like molecules (parallergens) and that serological responses with IgE/IgG4 to parallergens mirror those seen against allergens, supporting our hypothesis that allergenicity is rooted in expression of certain protein domain families in metazoan parasites.
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Affiliation(s)
- Edward J Farnell
- Department of Pathology, University of Cambridge , Cambridge , UK
| | - Nidhi Tyagi
- European Bioinformatics Institute , Cambridge , UK
| | - Stephanie Ryan
- Institute of Immunology and Infection Research, The University of Edinburgh , Edinburgh , UK
| | - Iain W Chalmers
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University , Aberystwyth , UK
| | | | - Frances M Jones
- Department of Pathology, University of Cambridge , Cambridge , UK
| | - Jakub Wawrzyniak
- Department of Pathology, University of Cambridge , Cambridge , UK
| | | | | | - Nicholas Furnham
- European Bioinformatics Institute , Cambridge , UK ; Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine , London , UK
| | - Rick M Maizels
- Institute of Immunology and Infection Research, The University of Edinburgh , Edinburgh , UK
| | - David W Dunne
- Department of Pathology, University of Cambridge , Cambridge , UK
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