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Background: Approximately 70% of individuals allergic to birch pollen (Bet v 1.01 [Bet]) develop a secondary food allergy (e.g., hazelnut: Cor a 1.04 [Cor]), due to allergen cross‐reactivity. However, standard immunotherapy for type I allergies often does not improve the food allergy sufficiently. We analyzed the allergen‐specific and cross‐reactive suppressive capacity of primary human regulatory T cells (Treg) induced by autologous IL‐10‐modulated dendritic cells (IL‐10 DC) in vitro and in vivo. Methods: CD4+ T cells of patients with birch pollen and associated hazelnut allergies were differentiated into Bet‐specific or non‐specific induced Treg (iTreg). After Bet‐ or Cor‐specific restimulation the phenotype, proliferation, and suppressive capacity of iTreg subsets were analyzed. iTreg function was further investigated in humanized mouse models of airway and intestinal allergy, generated by engraftment of peripheral blood mononuclear cells from allergic donors into immunodeficient animals. Results: After IL‐10 DC priming and allergen‐specific restimulation (Bet or Cor), non‐specific control iTreg remained anergic, whereas Bet‐specific iTreg proliferated extensively and exhibited a regulatory phenotype (enhanced expression of CTLA‐4, PD‐1, TNFR2, IL‐10). Accordingly, activated Bet‐specific iTreg displayed a high capacity to suppress Bet‐ and Cor‐induced responder Th2 cell responses in vitro, indicating induction of both allergen‐specific (birch) and cross‐reactive tolerance (hazelnut). In vivo, the beneficial effect of Bet‐specific iTreg was verified in humanized mouse models of allergic airway and intestinal inflammation, resulting in reduced allergen‐induced clinical symptoms, and immune responses. Conclusion: Human IL‐10 DC‐induced iTreg facilitate allergen‐specific and cross‐reactive tolerance. Therefore, they are potential candidates for regulatory cell therapy in allergic and autoimmune diseases. [ABSTRACT FROM AUTHOR]

Introduction: Allergen‐specific IgE‐blocking IgG antibodies contribute to successful allergen immunotherapy (AIT), however, not much is known about their affinity. Since affinity measurements of polyclonal antibodies in serum are technically challenging we evaluated the applicability of acidic disruption of antibody‐allergen complexes by a modified ELISA protocol with monoclonal antibodies (mAbs) specific for the relevant major allergens Betv1 and Mald1. Then, AIT‐induced blocking and non‐blocking Mald1‐specific antibodies in sera from individuals with or without reduced apple allergy were compared. Methods: After testing their pH stability coated recombinant allergens were incubated with (i) mAbs diluted in PBS or human serum and (ii) sera from individuals after sublingual administration of Mald1 or Betv1 for 16 weeks. Immune complexes were exposed to buffers in the pH range of 6.4–3.4 and residual antibodies were measured. Avidity indexes (AI), defined as the pH removing 50% of antibodies, were compared to the dissociation constants (KD) of mAbs determined by surface plasmon resonance. Results: The selected pH range was applicable to disrupt allergen complexes with highly affine mAbs without compromising allergen integrity. AIs of mAbs accorded with KD values and were unaffected by epitope specificity or the presence of serum proteins. The inter‐assay variability was <4% CV. Protective Mald1‐specific IgG antibodies from individuals with reduced apple allergy showed a higher collective binding strength than that of the non‐protective antibodies of individuals without reduced apple allergy. Conclusion: Acidic disruption of allergen‐antibody complexes may be used to estimate the net‐binding force of polyclonal serum antibodies and eases the investigation of affinity‐related research questions in AIT. [ABSTRACT FROM AUTHOR]

Background: The experimental fusion protein rFlaA:Betv1 was shown to efficiently suppress allergen‐specific sensitization in mice. However, the detailed mechanism of rFlaA:Betv1‐mediated immune modulation is not fully understood. In this study, we investigated the effect of rFlaA:Betv1 on naïve murine B cells. Methods: Immune modulating capacity of rFlaA:Betv1 was screened in IL‐10 reporter mice. B cells were isolated from spleens of naïve C57Bl/6, TLR5−/−, or MyD88−/− mice, stimulated with rFlaA:Betv1 and controls, and monitored for the expression of the regulatory B cell markers CD1d, CD24, CD38, and surface IgM by flow cytometry. Secreted cytokines, antibodies, and reactivity of the induced antibodies were investigated by ELISA and intracellular flow cytometry. Suppressive capacity of rFlaA:Betv1‐stimulated B cells was tested in mDC:CD4+ T cell:B cell triple cultures. Results: Upon in vivo application of rFlaA:Betv1 into IL‐10‐GFP reporter mice, CD19+ B cells were shown to produce anti‐inflammatory IL‐10, suggesting B cells to contribute to the immune‐modulatory properties of rFlaA:Betv1. rFlaA:Betv1‐induced IL‐10 secretion was confirmed in human B cells isolated from buffy coats. In vitro stimulation of naïve murine B cells with rFlaA:Betv1 resulted in an mTOR‐ and MyD88‐dependent production of IL‐10 and rFlaA:Betv1 induced Bet v 1‐reactive IgG production, which was not observed for IgA. rFlaA:Betv1‐stimulated B cells formed a CD19+CD24+CD1d+IgM+CD38+ Breg subpopulation capable of suppressing Bet v 1‐induced TH2 cytokine secretion in vitro. Conclusion: rFlaA:Betv1 can act as a thymus‐independent B cell antigen, stimulating the mTOR‐ and MyD88‐dependent differentiation of B cells displaying a regulatory phenotype, IL‐10 secretion, antigen‐binding antibody production, and a suppressive capacity in vitro. [ABSTRACT FROM AUTHOR]

However, celeriac allergic patients often show sensitization to mugwort defensin Art v 1 (Table S1).6 This prompted us to investigate the potential presence and role of a defensin-related allergen in allergy to celeriac. IgE-binding capacity and allergenicity of celeriac defensin (officially named Api g 7, www.allergen.org4) was investigated by immunoblotting and ImmunoCAP testing in eight celeriac allergic patients, two celeriac-tolerant controls with mugwort pollen allergy and a non-atopic control. Celeriac allergy is often accompanied by respiratory allergy to mugwort ( I Artemisia vulgaris i ) pollen,5 which cannot be explained by IgE cross-reactivity to known homologous celeriac allergens. [Extracted from the article]

Background: Common wheat (Triticum aestivum) and durum wheat (T. turgidum) are both involved in Baker's asthma (BA) and food allergy (FA) including wheat‐dependent exercise‐induced asthma (WDEIA). However, allergens in durum wheat have not been described, and the over‐expression of T. turgidum non‐specific lipid‐transfer protein (nsLTPs) is considered to increase resistance to phytopathogens. Objective: To identify and assess the allergenicity of nsLTP from T. turgidum. Methods: Recombinant T. turgidum nsLTP Tri tu 14 was generated and tested for structural integrity (circular dichroism‐spectroscopy) and purity (SDS‐PAGE). Thirty‐two wheat allergic patients were enrolled: 20 Spanish patients (BA) with positive bronchial challenge to wheat flour, and 12 Italian patients (wheat FA/WDEIA) with positive double‐blind placebo‐controlled food challenge/open food challenge (OFC) to pasta. IgE values to wheat, Tri tu 14, Tri a 14 (T. aestivum) and Pru p 3 (P. persica) were determined by ImmunoCAP testing. Allergenic potency (in vitro mediator release) and IgE cross‐reactivity were investigated. Results: Tri tu 14 was found to share 49% and 52% amino acid identity with Tri a 14 and Pru p 3, respectively. Among 25 Tri a 14 CAP positive sera, 23 (92%) were reactive to wheat extract, 22 (88%) to Tri tu 14 and 20 (80%) to Pru p 3. The correlation between Tri a 14 and Tri tu 14 specific IgE levels was r = 0.97 (BA) and r = 0.93 (FA/WDEIA), respectively. FA/WDEIA patients showed higher specific IgE values to Tri tu 14 and Pru p 3 than BA patients. Tri tu 14 displayed allergenic activity by mediator release from effector cells and IgE cross‐reactivity with Pru p 3. The degree of IgE cross‐reactivity between the two wheat nsLTPs varied between individual patients. Conclusions and Clinical Relevance: Sensitization to Tri tu 14 likely appears to be more important in wheat FA/WDEIA than in BA. Over‐expression of Tri tu 14 in wheat would represent a risk for patients with nsLTP‐mediated FA. [ABSTRACT FROM AUTHOR]

Background: The use of hypoallergenic derivatives is considered beneficial to promote the safety and efficacy of allergen-specific immunotherapy. We aimed to assess the efficacy of reduced and alkylated (R/A) Pru p 3, a hypoallergenic folding variant of the major peach allergen, in subcutaneous immunotherapy (SCIT) using a murine model of peach allergy.Methods and Results: After sensitization with Pru p 3, BALB/c mice received SCIT with Pru p 3 or R/A Pru p 3 and were challenged with Pru p 3. SCIT with Pru p 3, but not with R/A Pru p 3, suppressed anaphylaxis upon the challenge significantly. SCIT with Pru p 3 did not suppress Pru p 3-specific IgE and IgG1 production, but enhanced IgG2a production. In contrast, SCIT with R/A Pru p 3 suppressed IgE and IgG1 production, but enhanced IgG2a production only moderately. The therapeutic efficacy of SCIT with Pru p 3 was associated with induction of IL-10 and IFN-γ.Conclusion: Hypoallergenic folding variant of Pru p 3 is not likely an efficacious therapeutic component in SCIT of peach allergy. The lower efficacy of R/A Pru p 3 might be attributed to poor antigenicity and/or weak stability due to its unfolded conformation. [ABSTRACT FROM AUTHOR]

Background: TLR ligands can promote Th1-biased immune responses, mimicking potent stimuli of viruses and bacteria.Aim: To investigate the adjuvant properties of dual TLR2/7 ligands compared to those of the mixture of both single ligands.Methods: Dual TLR2/7 ligands: CL401, CL413, and CL531, including CL264 (TLR7-ligand) and Pam2CysK4 (TLR2-ligand), were used. Immune-modulatory capacity of the dual ligands with the individual ligands alone or as a mixture in mouse BMmDCs, BMmDC:TC cocultures, or BMCMCs was compared and assessed in naïve mice and in a mouse model of OVA-induced intestinal allergy.Results: CL413 and CL531 induced BMmDC-derived IL-10 secretion, suppressed rOVA-induced IL-5 secretion from OVA-specific DO11.10 CD4+ TCs, and induced proinflammatory cytokine secretion in vivo. In contrast, CL401 induced considerably less IL-10 secretion and led to IL-17A production in BMmDC:TC cocultures, but not BMCMC IL-6 secretion, or IL-6 or TNF-α production in vivo. No immune-modulating effects were observed with single ligands. All dual TLR2/7 ligands suppressed DNP-induced IgE-and-Ag-specific mast cell degranulation. Compared to vaccination with OVA, vaccination with the mixture CL531 and OVA, significantly suppressed OVA-specific IgE production in the intestinal allergy model.Conclusions: Based on beneficial immune-modulating properties, CL413 and CL531 may have utility as potential adjuvants for allergy treatment. [ABSTRACT FROM AUTHOR]

We investigated the biochemical function of the birch pollen allergen Bet v 6 and its role in the IgE-cross-reactivity between birch pollen and plant foods, and characterized Pyr c 5, a Bet v 6-related food allergen, from pear; the proteins were expressed as His-Tag fusion proteins in Eschershia coli and purified by Ni-chelate affinity chromatography under native conditions. Nonfusion proteins were obtained by factor Xa protease treatment. The highest degree of amino-acid sequence identity of Pyr c 5 and Bet v 6 was found with a plant protein related to a defense mechanism, which we have named phenylcoumaran benzylic ether reductase (PCBER) based on its ability to catalyze the NADPH-dependent reduction of 8–5′ linked lignans such as dehydrodiconiferyl alcohol to give isodihydrodehydrodiconiferyl alcohol. Enzymatic assays with recombinant Pyr c 5 and Bet v 6 showed PCBER catalytic activity for both recombinant allergens. Both Pyr c 5 and Bet v 6 allergens had similar IgE binding characteristics in immunoblotting and enzyme allergosorbent tests (EAST), and bound IgE from 10 sera of birch-pollen-allergic patients including six pear-allergic subjects. EAST inhibition experiments with Pyr c 5 as the solid phase antigen suggested that homologous allergens may be present in many vegetable foods such as apple, peach, orange, lychee fruit, strawberry, persimmon, zucchini (courgette), and carrot. In extracts of pear, apple, orange, and persimmon, the presence of proteins of approximately 30–35 kDa containing Bet v 6 cross-reactive epitopes was demonstrated with two Bet v 6-specific monoclonal antibodies. Recombinant Pyr c 5 triggered a strong, dose-dependent mediator release from basophils of a pear-allergic subject, suggesting that Pyr c 5 has the potential to elicit type I allergic reactions. [ABSTRACT FROM AUTHOR]

Evaluates the use of optimized allergen extracts and recombinant allergens in diagnostic applications. Serological data of patients with pollen-related allergy to cherry; Association between specific immunoglobulin E responses in allergic patients and the pathomechanism of the disease condition; Characterization of various cherry allergens.