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Introduction: Severe equine asthma (SEA) is a common, chronic respiratory disease of horses characterized by hyperreactivity to hay dust which has many similarities to severe neutrophilic asthma in humans. SEA-provoking antigens have not been comprehensively characterized, but molds and mites have been suggested as relevant sources. Here, we identified relevant antigen candidates using immunoproteomics with IgG isotype-binding analyses. Methods: Proteins from Dermatophagoides pteronyssinus (Der p) were separated by two-dimensional gel electrophoresis followed by immunoblotting (2D immunoblots) resulting in a characteristic pattern of 440 spots. After serum incubation, antibody (Ig)-binding of all Ig (Pan-Ig) and IgG isotypes (type-2-associated IgG3/5, type-1-associated IgG4/7) was quantified per each spot and compared between asthmatic and healthy horses' sera (n=5 per group). Results: Ig binding differences were detected in 30 spots. Pan-Ig binding was higher with asthmatics compared to healthy horses' sera on four spots, and IgG3/5 binding was higher on 18 spots. Small IgG4/7 binding differences were detected on 10 spots with higher binding with asthmatics' sera on four but higher binding with healthy horses' sera on six spots. Proteins from the spots with group differences including mite and yeast proteins were identified by liquid chromatography mass spectrometry. The latter likely originated from the feeding substrate of the Der p culture. Prioritized antigen candidates amongst the proteins identified were Der p 1, Der p 11, group 15 allergens, myosin heavy chain, and uncharacterized Der p proteins. Additionally, yeast enolases, alcohol dehydrogenase (ADH), phosphoglycerate kinase (PGK), glyceraldehyde-3-phosphate dehydrogenase, and heat shock proteins were prioritized. Eleven antigen candidates were tested for confirmation by ELISAs using the respective proteins separately. Differences in asthmatics vs. healthy horses' serum Ig binding to Der p 1, Der p 18, and three yeast enzymes (enolase, ADH, and PGK) confirmed these as promising antigens of immune responses in SEA. Discussion: Antigens with relevance in SEA were newly identified by immunoproteomics, and yeast antigens were considered for SEA for the first time. Serum IgG3/5 binding to relevant antigens was increased in SEA and is a novel feature that points to increased type-2 responses in SEA but requires confirmation of the corresponding cellular responses. [ABSTRACT FROM AUTHOR]

Background: The domestic mite Blomia tropicalis is a major source of allergens in tropical and subtropical regions. Despite its great medical importance, the allergome of this mite has not been sufficiently studied. Only 14 allergen groups have been identified in B. tropicalis thus far, even though early radioimmunoelectrophoresis techniques (27 uncharacterized allergen complexes) and comparative data based on 40 allergen groups officially recognized by the World Health Organization (WHO)/IUIS in domestic astigmatid mites suggest the presence of a large set of additional allergens. Methods: Here, we employ a multiomics approach to assess the allergome of B. tropicalis using genomic and transcriptomic sequence data and perform highly sensitive protein abundance quantification. Findings: Among the 14 known allergen groups, we confirmed 13 (one WHO/IUIS allergen, Blo t 19, was not found) and identified 16 potentially novel allergens based on sequence similarity. These data indicate that B. tropicalis shares 27 known/deduced allergen groups with pyroglyphid house dust mites (genus Dermatophagoides). Among these groups, five allergen‐encoding genes are highly expressed at the transcript level: Blo t 1, Blo t 5, Blo t 21 (known), Blo t 15, and Blo t 18 (predicted). However, at the protein level, a different set of most abundant allergens was found: Blo t 2, 10, 11, 20 and 21 (mite bodies) or Blo t 3, 4, 6 and predicted Blo t 13, 14 and 36 (mite feces). Interpretation: We report the use of an integrated omics method to identify and predict an array of mite allergens and advanced, label‐free proteomics to determine allergen protein abundance. Our research identifies a large set of novel putative allergens and shows that the expression levels of allergen‐encoding genes may not be strictly correlated with the actual allergenic protein abundance in mite bodies. [ABSTRACT FROM AUTHOR]

Allergic disorders are caused by a combination of hereditary and environmental factors. The hygiene hypothesis postulates that early-life microbial exposures impede the development of subsequent allergic disease. Recently developed "wildling" mice are genetically identical to standard laboratory specific pathogen–free (SPF) mice but are housed under seminatural conditions and have rich microbial exposures from birth. Thus, by comparing conventional SPF mice with wildlings, we can uncouple the impact of lifelong microbial exposures from genetic factors on the allergic immune response. We found that wildlings developed larger populations of antigen-experienced T cells than conventional SPF mice, which included interleukin-10–producing CD4 T cells specific for commensal Lactobacilli strains and allergy-promoting T helper 2 (TH2) cells. In models of airway exposure to house dust mite (HDM), recombinant interleukin-33, or Alternaria alternata, wildlings developed strong allergic inflammation, characterized by eosinophil recruitment, goblet cell metaplasia, and antigen-specific immunoglobulin G1 (IgG1) and IgE responses. Wildlings developed robust de novo TH2 cell responses to incoming allergens, whereas preexisting TH2 cells could also be recruited into the allergic immune response in a cytokine-driven and TCR-independent fashion. Thus, wildling mice, which experience diverse and lifelong microbial exposures, were not protected from developing pathological allergic immune responses. Instead, wildlings mounted robust allergic responses to incoming allergens, shedding new light on the hygiene hypothesis. Editor's summary: The hygiene hypothesis proposes that early-life exposure to microbes protects against the development of allergies, a possible explanation for the alarming rise in allergic disorders in developed countries. However, a causal link between early-life infections and allergies is lacking. To uncover the impact of lifelong microbial exposure on the development of allergic inflammation, Ma and Urgard et al. compared experimental wildling mice, which have a representative breadth of naturally occurring pathogens, to specific pathogen–free mice. Surprisingly, when challenged with allergens, wildlings developed robust signs of pathological inflammation and allergic responses, with rapid expansion of TH2 cells in the lungs. The study identifies that increased microbial biodiversity in wildlings did not protect against allergic inflammation, in contrast to what would be predicted by the hygiene hypothesis. —Hannah Isles [ABSTRACT FROM AUTHOR]

Background: Understanding differences in sensitization profiles at the molecular allergen level is important for diagnosis, personalized treatment and prevention strategies in allergy. Methods: Immunoglobulin E (IgE) sensitization profiles were determined in more than 2800 sera from children in nine population‐based cohorts in different geographical regions of Europe; north [BAMSE (Sweden), ECA (Norway)], west/central [PIAMA (the Netherlands), BiB (the United Kingdom), GINIplus (Germany)], and south [INMA Sabadell and Gipuzkoa (Spain) and ROBBIC Rome and Bologna (Italy)] using the MeDALL‐allergen chip. Results: Sensitization to grass pollen allergen, Phl p 1, and to major cat allergen, Fel d 1, dominated in most European regions whereas sensitization to house dust mite allergens Der p 1, 2 and 23 varied considerably between regions and were lowest in the north. Less than half of children from Sabadell which has a hot and dry climate were sensitized to respiratory allergens, in particular house dust mite allergens as compared to Gipuzkoa nearby with a more humid climate. Peanut allergen Ara h 1 was the most frequently recognized class 1 food allergen in Northern/Western Europe, while the fruit allergens Pru p 3, Act d 1 and 2 were prominent in Southern and Western/Central Europe. Ves v 5‐sensitization dominated in North and West/Central Europe. Conclusion: We show regional, exposome‐ and climate‐dependent differences in molecular IgE‐reactivity profiles in Northern, Western/Central and Southern Europe which may form a molecular basis for precision medicine‐based approaches for treatment and prevention of allergy. [ABSTRACT FROM AUTHOR]

Background: Asthma is not well investigated in equatorial Africa and little is known about the disease-associated allergen molecules recognized by IgE from patients in this area. The aim was to study the molecular IgE sensitization profile of asthmatic children and young adults in a semi-rural area (Lambaréné) of an equatorial African country (Gabon), to identify the most important allergen molecules associated with allergic asthma in equatorial Africa. Methods: Fifty-nine asthmatic patients, mainly children and few young adults, were studied by skin prick testing to Dermatophagoides pteronyssinus (Der p), D. farinae (Der f), cat, dog, cockroach, grass, Alternaria and peanut. Sera were obtained from a subset of 35 patients, 32 with positive and 3 with negative skin reaction to Der p and tested for IgE reactivity to 176 allergen molecules from different allergen sources by ImmunoCAP ISAC microarray technology and to seven recombinant Blomia tropicalis (Blo t) allergens by IgE dot blot assay. Results: Thirty-three of the 59 patients (56%) were sensitized to Der p and 23 of them (39%) were also sensitized to other allergen sources, whereas 9 patients (15%) were only sensitized to allergen sources other than Der p. IgE serology analyses (n=35) showed high IgE-binding frequencies to the Blo t allergens Blo t 5 (43%), Blo t 21 (43%) and Blo t 2 (40%), whereas the Der p allergens rDer p 2, rDer p 21 and rDer p 5 (34%, 29% and 26%) were less frequently recognized. Only few patients showed IgE reactivity to allergens from other allergen sources, except to allergens containing carbohydrate determinants (CCDs) or to wasp venom allergens (i.e., antigen 5). Conclusion: Our results thus demonstrate that IgE sensitization to mite allergens is very prevalent in asthmatics in Equatorial Africa with B. tropicalis allergen molecules representing the most important ones associated with allergic asthma. [ABSTRACT FROM AUTHOR]

Of the 73 patients, 53 (72.6%) were positive for at least one of the four allergen components; only 30 (41.1%) were positive for mango extract in ImmunoCAP, suggesting low or lacking presence of relevant allergens in the mango extract. Mango allergy is frequently associated with pollinosis by I Artemisia i and I Betula i pollens.[[1]] Immunoglobulin E (IgE)-mediated mango allergy is the leading cause of fruit allergies in China.[3] Although several mango allergens have been identified with IgE-binding bands around 14, 17, 30, 40, 50, 60, and 67 kDa,[[2], [4], [6]] their molecular characterization is absent from the International Union of Immunological Societies (IUIS) allergen database. Specific IgE positivity against mango extract and allergen components was higher in children and teenagers than in adults (Figure 1G), indicating the increasing trend of mango allergy in younger people. [Extracted from the article]

Background: Molecular antibody reactivity profiles have not yet been studied in depth in patients treated by sublingual house dust mite (HDM) tablet immunotherapy. Humoral immune responses to a large panel of HDM mite allergens were studied using allergen microarray technology in a subset of clinically defined high and low responder patients from a double‐blind placebo‐controlled allergen‐specific immunotherapy (AIT) trial using sublingual 300 IR HDM tablets. Methods: Serum levels of IgE, IgG and IgG4 to 13 Dermatophagoides pteronyssinus molecules were measured at baseline and after 1‐year AIT, using allergen microarrays in 100 subjects exhibiting high or low clinical benefit. Results: Der p 1, Der p 2 and Der p 23 were the most frequently recognized allergens in the study population. Patients with HDM‐related asthma had significantly higher allergen‐specific IgE levels to Der p 1 and Der p 23. No significant difference in the distribution of allergen sensitization pattern was observed between high and low responders. An increase in serum allergen‐specific IgG and IgG4 occurred upon AIT, in particular to allergens Der p 1, Der p 2 and Der p 23 (p < 0.0001). Conclusions: We confirm for our study population that Der p 1‐ and Der p 23‐specific IgE levels are associated with asthma. IgE reactivity profiles were not predicitive of sublingual AIT outcomes, with 300 IR tablets as efficacious in pauci‐ and multi‐sensitized subjects. Our study is the first to demonstrate the induction of IgG and IgG4 specific for the HDM allergens Der p 1, Der p 2 and Der p 23 by sublingual AIT. [ABSTRACT FROM AUTHOR]

Background: The Dermatophagoides pteronyssinus molecule Der p 23 is a major allergen whose clinical relevance has been shown in cross‐sectional studies. We longitudinally analysed the trajectory of Der p 23‐specific IgE antibody (sIgE) levels throughout childhood and youth, their early‐life determinants and their clinical relevance for allergic rhinitis and asthma. Methods: We obtained sera and clinical data of 191 participants of the German Multicentre Allergy Study, a prospective birth cohort. Serum samples from birth to 20 years of age with sIgE reactivity to Der p 23 in a customised semiquantitative microarray were newly analysed with a singleplex quantitative assay. Early mite exposure was assessed by measuring the average content of Der p 1 in house dust at 6 and 18 months. Results: Der p 23‐sIgE levels were detected at least once in 97/191 participants (51%). Prevalence of Der p 23 sensitisation and mean sIgE levels increased until age 10 years, plateaued until age 13 years and were lowest at age 20 years. Asthma, allergic rhinitis (AR) and atopic dermatitis (AD) were more prevalent in Der p 23‐sensitised children, including those with monomolecular but persistent sensitisation (11/97, 11%). A higher exposure to mites in infancy and occurrence of AD before 5 years of age preceded the onset of Der p 23 sensitisation, which in turn preceded a higher incidence of asthma. Conclusions: Der p 23 sensitisation peaks in late childhood and then decreases. It is preceded by early mite exposure and AD. Asthma and AR can occur in patients persistently sensitised to Der p 23 as the only mite allergen, suggesting the inclusion of molecular testing of Der p 23‐sIgE for subjects with clinical suspicion of HDM allergy but without sIgE to other major D.pt. allergens. [ABSTRACT FROM AUTHOR]

House dust mite (HDM) allergens are major elicitors of allergic reactions worldwide. Identification, characterization, and evaluation of diagnostic utility of a new important HDM allergen was performed. A cDNA coding for a new Dermatophagoides pteronyssinus (Dp) allergen, Der p 37, was isolated from a Dp expression library with allergic patients' IgE antibodies. Recombinant Der p 37 (rDer p 37) expressed in Escherichia coli was purified, then characterized by mass spectrometry, circular dichroism, and IgE reactivity by ImmunoCAP ISAC technology with sera from 111 clinically defined HDM-allergic patients. The allergenic activity of rDer p 37 was studied by basophil activation and CD4+ T-cell responses by carboxyfluorescein diacetate succinimidyl ester dilution assays. Specific antibodies raised against rDer p 37 were used for the ultrastructural localization of Der p 37 in mites by immunogold transmission electron microscopy. Der p 37, a 26 kDa allergen with homology to chitin-binding proteins, is immunologically distinct from Der p 15, 18, and 23. It is located in the peritrophic membrane of fecal pellets. Der p 37 reacted with IgE antibodies from a third of HDM-allergic patients and induced specific basophil- and CD4+ T-cell activation. Der p 37 IgE–positive patients had significantly higher IgE levels to major HDM allergens, reacted with more HDM allergens, and had a higher risk (odds ratio = 3.1) of asthma compared to Der p 37–negative patients. Der p 37, a new Dp allergen recognized by a third of HDM-allergic patients, may serve as a surrogate marker for severe HDM sensitization and asthma. [ABSTRACT FROM AUTHOR]

IgE-mediated allergy to birch pollen affects more than 100 million patients world-wide. Bet v 1, a 17 kDa protein is the major allergen in birch pollen responsible for allergic rhinoconjunctivitis and asthma in birch pollen allergic patients. Allergen-specific immunotherapy (AIT) based on therapeutic administration of Bet v 1-containing vaccines is an effective treatment for birch pollen allergy but no allergen-specific forms of prevention are available. We developed a mouse model for IgE sensitization to Bet v 1 based on subcutaneous injection of aluminum-hydroxide adsorbed recombinant Bet v 1 and performed a detailed characterization of the specificities of the IgE, IgG and CD4+ T cell responses in sensitized mice using seven synthetic peptides of 31-42 amino acids length which comprised the Bet v 1 sequence and the epitopes recognized by human CD4+ T cells. We then d.emonstrate that preventive systemic administration of a mix of synthetic non-allergenic Bet v 1 peptides to 3-4 week old mice significantly reduced allergic immune responses, including IgE, IgG, IgE-mediated basophil activation, CD4+ T cell and IL-4 responses to the complete Bet v 1 allergen but not to the unrelated major grass pollen allergen Phl p 5, without inducing Bet v 1-specific allergic sensitization or adaptive immunity. Our results thus demonstrate that early preventive administration of non-allergenic synthetic T cell epitope-containing allergen peptides could be a safe strategy for the prevention of allergen-specific IgE sensitization. [ABSTRACT FROM AUTHOR]

Approximately 30% of the world population suffers from immunoglobulin-E (IgE)-mediated allergy. IgE-mediated allergy affects the respiratory tract, the skin and the gastrointestinal tract and may lead to life-threatening acute systemic manifestations such as anaphylactic shock. The symptoms of allergy are mediated by IgE-recognition of causative allergen molecules from different allergen sources. Today, molecular allergy diagnosis allows determining the disease-causing allergens to develop allergen-specific concepts for prevention and treatment of allergy. Allergen-specific preventive and therapeutic strategies include allergen avoidance, vaccination, and tolerance induction. The implementation of these preventive and therapeutic strategies requires a detailed knowledge of the relevant allergen molecules affecting a given population. China is the world´s most populous country with around 1.4 billion inhabitants and an estimated number of more than 400 million allergic patients. Research in allergy in China has dramatically increased in the last decade. We summarize in this review article what is known about the dominating allergen sources and allergen molecules in China and what further investigations could be performed to draw a molecular map of IgE sensitization for China as a basis for the implementation of systematic and rational allergen-specific preventive and therapeutic strategies to combat allergic diseases in this country. [ABSTRACT FROM AUTHOR]

Background: Sensitization to house dust mite (HDM) is a leading cause of allergic rhinitis and asthma. Despite more than 30 HDM‐derived allergens having been identified to date, specific therapeutic approaches do not yet take into account the local sensitization profiles of patients. This study aimed to identify patterns of HDM sensitization in HDM‐allergic adults living in distinct geographic areas, to inform the development of targeted diagnostic and therapeutic tools. Methods: Serum samples from 685 HDM‐allergic subjects from Canada, Europe, South Africa, and the USA were tested for levels of IgE specific for 17 micro‐arrayed HDM allergens by ImmunoCAP Immuno Solid‐phase Allergen Chip (ISAC) technology. Results: The results confirmed significant geographical variability in sensitization patterns and levels of IgE. In all areas, the major sensitizers were the group 1 and group 2 allergens and Der p 23. Der p 23 was a frequent sensitizer: 64% of the subjects had IgE specific for Der p 23, and 2.3% were monosensitized to it. In South Africa, Der p 23 was the dominant HDM allergen (86% prevalence) and Der p 7 achieved major allergen status (56%). IgE sensitization to HDM was influenced by asthmatic status, levels of allergen exposure, age, race‐ethnicity and smoking status, but not by BMI. Conclusion: Sensitization profiles to HDM allergens differ considerably among distinct geographic areas, with Der p 7 and Der p 23 being major sensitizers in South Africa. Such heterogeneity should be taken into account in the diagnosis and treatment of HDM‐allergic patients. [ABSTRACT FROM AUTHOR]

Background: Several studies indicate that Der p 7 is an important and clinically relevant allergen of Dermatophagoides pteronyssinus which should be included in vaccines for treatment of house dust mite (HDM) allergy. Aim of this study was to characterize the IgE epitopes of Der p 7. Methods: Recombinant Der p 7 was expressed and purified, analyzed for fold by circular dichroism and tested for its allergenic activity by basophil activation. Seven overlapping, surface-exposed peptides (P1–P7) with a length of 27 to 37 amino acids, which spanned the Der p 7 sequence, were synthesized and tested for IgE reactivity and allergenic activity by basophil activation assay. Carrier-bound peptides were studied for their ability to induce allergen-specific IgG antibodies in rabbits. Peptide-specific antibodies were used to inhibit allergic patients' IgE binding to Der p 7 by ELISA for mapping of IgE epitopes. Results: rDer p 7 showed high allergenic activity comparable with Der p 5, Der p 21, and Der p 23. None of the seven tested peptides showed any IgE reactivity or allergenic activity when tested with HDM- allergic patients indicating lack of sequential IgE epitopes on Der p 7. IgE inhibition experiments using anti-peptide specific IgGs and molecular modeling enabled us to identify discontinuous, conformational IgE epitopes of Der p 7. Conclusion and Clinical Relevance: IgE epitopes of Der p 7 belong to the conformational and discontinuous type whereas sequential Der p 7 peptides lack IgE reactivity. It should thus be possible to construct hypoallergenic vaccines for Der p 7 based on carrier-bound allergen peptides. [ABSTRACT FROM AUTHOR]

More than 30% of the world population suffers from allergy. Allergic individuals are characterized by the production of immunoglobulin E (IgE) antibodies against innocuous environmental allergens. Upon allergen recognition IgE mediates allergen-specific immediate and late-phase allergic inflammation in different organs. The identification of the disease-causing allergens by demonstrating the presence of allergen-specific IgE is the key to precision medicine in allergy because it allows tailoring different forms of prevention and treatment according to the sensitization profiles of individual allergic patients. More than 30 years ago molecular cloning started to accelerate the identification of the disease-causing allergen molecules and enabled their production as recombinant molecules. Based on recombinant allergen molecules, molecular allergy diagnosis was introduced into clinical practice and allowed dissecting the molecular sensitization profiles of allergic patients. In 2002 it was demonstrated that microarray technology allows assembling large numbers of allergen molecules on chips for the rapid serological testing of IgE sensitizations with small volumes of serum. Since then microarrayed allergens have revolutionized research and diagnosis in allergy, but several unmet needs remain. Here we show that detection of IgE- and IgG-reactivity to a panel of respiratory allergens microarrayed onto silicon elements is more sensitive than glass-based chips. We discuss the advantages of silicon-based allergen microarrays and how this technology will allow addressing hitherto unmet needs in microarray-based allergy diagnosis. Importantly, it described how the assembly of silicon microarray elements may create different microarray formats for suiting different diagnostic applications such as quick testing of single patients, medium scale testing and fully automated large scale testing. [ABSTRACT FROM AUTHOR]