Effect of structural stability on endolysosomal degradation and T-cell reactivity of major shrimp allergen tropomyosin

BACKGROUND

Tropomyosins are highly conserved proteins, an attribute that forms the molecular basis for their IgE antibody cross-reactivity. Despite sequence similarities, their allergenicity varies greatly between ingested and inhaled invertebrate sources. In this study, we investigated the relationship between the structural stability of different tropomyosins, their endolysosomal degradation patterns, and T-cell reactivity.

METHODS

We investigated the differences between four tropomyosins-the major shrimp allergen Pen m 1 and the minor allergens Der p 10 (dust mite), Bla g 7 (cockroach), and Ani s 3 (fish parasite)-in terms of IgE binding, structural stability, endolysosomal degradation and subsequent peptide generation, and T-cell cross-reactivity in a BALB/c murine model.

RESULTS

Tropomyosins displayed different melting temperatures, which did not correlate with amino acid sequence similarities. Endolysosomal degradation experiments demonstrated differential proteolytic digestion, as a function of thermal stability, generating different peptide repertoires. Pen m 1 (Tm 42°C) and Der p 10 (Tm 44°C) elicited similar patterns of endolysosomal degradation, but not Bla g 7 (Tm 63°C) or Ani s 3 (Tm 33°C). Pen m 1-specific T-cell clones, with specificity for regions highly conserved in all four tropomyosins, proliferated weakly to Der p 10, but did not proliferate to Bla g 7 and Ani s 3, indicating lack of T-cell epitope cross-reactivity.

CONCLUSIONS

Tropomyosin T-cell cross-reactivity, unlike IgE cross-reactivity, is dependent on structural stability rather than amino acid sequence similarity. These findings contribute to our understanding of cross-sensitization among different invertebrates and design of suitable T-cell peptide-based immunotherapies for shrimp and related allergies.

Cutting Edge: Tissue Antigen Expression Levels Fine-Tune T Cell Differentiation Decisions In Vivo

Immune homeostasis in peripheral tissues is, to a large degree, maintained by the differentiation and action of regulatory T cells (Treg) specific for tissue Ags. Using a novel mouse model, we have studied the differentiation of naive CD4⁺ T cells into Foxp3⁺ Treg in response to a cutaneous Ag (OVA). We found that expression of OVA resulted in fatal autoimmunity and in prevention of peripheral Treg generation. Inhibiting mTOR activity with rapamycin rescued the generation of Foxp3⁺ T cells. When we varied the level of Ag expression to modulate TCR signaling, we found that low Ag concentrations promoted the generation of Foxp3⁺ T cells, whereas high levels expanded effector T cells and caused severe autoimmunity. Our findings indicate that the expression level of tissue Ag is a key determinant of the balance between tissue-reactive effector and peripheral Foxp3⁺ T cells, which determines the choice between tolerance and autoimmunity.

Macrophages and Fibroblasts Differentially Contribute to Tattoo Stability

BACKGROUND

Little information is available about the complexity and function of skin cells contributing to the high stability of tattoos. It has been shown that dermal macrophages play an important role in the storage and maintenance of pigment particles. By contrast, the impact of dermal fibroblasts, forming the connective tissue of the skin, on the stability of the tattoo is not known.

METHOD

In this study, we compared the cell number and the particle load in dermal macrophages versus dermal fibroblasts, isolated from tail skin of tattooed mice.

RESULTS

Microscopic analysis revealed that both cell populations contained the tattoo particles, although in largely different amounts. A small number of macrophages with high side scatter intensity contained a large quantity of pigment particles, whereas a high number of dermal fibroblasts harbored only a few pigment particles. Using the CD64dtr mouse model that allows for selective, diphtheria toxin-mediated depletion of macrophages, we have previously shown that macrophages hold the tattoo in place by capture-release and recapture cycles. In the tattooed skin of macrophage-depleted mice, the content of pigment particles in fibroblasts did not change; however, the total number of fibroblasts carrying particles increased.

CONCLUSION

The present study demonstrates that dermal macrophages and fibroblasts contribute in different ways to the tattoo stability and further improves our knowledge on tattoo persistence.

A novel vaccination platform for epicutaneous allergen-specific immunotherapy based on beta-glucan neoglycoconjugates

Coupling of long chain carbohydrates to allergens can mask IgE epitopes and thus reduce the allergenicity of the neoglycoconjugates. The resulting molecules can target and activate dendritic cells via C-type lectin receptors. Neoglycoconjugates therefore have a high potential for epicutaneous immunotherapy (EPIT) by delivering a hypoallergenic vaccine to a tissue rich in dendritic cells. In the current study we test the therapeutic efficiency of the beta-glucan laminarin conjugated to ovalbumin (LamOVA) in a mouse model of allergic asthma.

Sensitized Balb/C mice were treated epicutaneously via micropores created by fractional laser ablation. Humoral and cellular responses were evaluated by ELISA, RBL assay and BAT. Lung function was analyzed by whole body plethysmography.

Laminarin remained biologically active after coupling to ovalbumin as indicated by binding to Dectin-1 receptor. IgE epitopes were successfully masked according to in vitro IgE binding aasay and skin reaction scores in therapeutic setup.LamOVA was more potent in stimulating humoral immune responses in comparison to OVA and induced the highest IgG1 and IgG2a production. Epicutaneous treatment with OVA and LamOVA reduced lung inflammation and improved lung function of sensitized mice more efficiently compared to s.c. injection with OVA/alum.

Epicutaneous immunotherapy can alleviate lung inflammation and reduce airway hyperresponsiveness in sensitized mice more efficiently than s.c. injection with alum. Coupling of allergen to laminarin reduces local side effects and increases the immunogenicity, resulting in a safer therapy.

Fusion proteins consisting of Bet v 1 and Phl p 5 form IgE-reactive aggregates with reduced allergenic activity

The cross-linking of effector cell-bound IgE antibodies by allergens induces the release of inflammatory mediators which are responsible for the symptoms of allergy. We demonstrate that a recombinant hybrid molecule consisting of the major birch (Bet v 1) and grass (Phl p 5) pollen allergen exhibited reduced allergenic activity as compared to equimolar mixes of the isolated allergens in basophil activation experiments. The reduced allergenic activity of the hybrid was not due to reduced IgE reactivity as demonstrated by IgE binding experiments using sera from allergic patients. Physicochemical characterization of the hybrid by size exclusion chromatography, dynamic light scattering, negative-stain electron microscopy and circular dichroism showed that the hybrid occurred as folded aggregate whereas the isolated allergens were folded monomeric proteins. IgG antibodies raised in rabbits against epitopes of Bet v 1 and Phl p 5 showed reduced reactivity with the hybrid compared to the monomeric allergens. Our results thus demonstrate that aggregation can induce changes in the conformation of allergens and lead to the reduction of allergenic activity. This is a new mechanism for reducing the allergenic activity of allergens which may be important for modifying allergens to exhibit reduced side effects when used for allergen-specific immunotherapy.

Allograft rejection is associated with development of functional IgE specific for donor MHC antigens

BACKGROUND

Donor-specific antibodies of the IgG isotype are measured routinely for diagnostic purposes in renal transplant recipients and are associated with antibody-mediated rejection and long-term graft loss.

OBJECTIVE

This study aimed to investigate whether MHC-specific antibodies of the IgE isotype are induced during allograft rejection.

METHODS

Anti-MHC/HLA IgE levels were measured in sera of mice grafted with skin or heart transplants from various donor strains and in sera of kidney transplant patients with high levels of HLA IgG. Mediator release was triggered in vitro by stimulating basophils that were coated with murine or human IgE-positive serum, respectively, with specific recombinant MHC/HLA antigens. Kidney tissue samples obtained from organ donors were analyzed by using flow cytometry for cells expressing the high-affinity receptor for IgE (FcεRI).

RESULTS

Donor MHC class I- and MHC class II-specific IgE was found on acute rejection of skin and heart grafts in several murine strain combinations, as well as during chronic antibody-mediated heart graft rejection. Anti-HLA IgE, including donor HLA class I and II specificities, was identified in a group of sensitized transplant recipients. Murine and human anti-MHC/HLA IgE triggered mediator release in coated basophils on stimulation with specific MHC/HLA antigens. HLA-specific IgE was not linked to atopy, and allergen-specific IgE present in allergic patients did not cross-react with HLA antigens. FcεRI+ cells were found in the human renal cortex and medulla and provide targets for HLA-specific IgE.

CONCLUSION

These results demonstrate that MHC/HLA-specific IgE develops during an alloresponse and is functional in mediating effector mechanisms.

DNA and mRNA vaccination against allergies

Allergen-specific immunotherapy, which is performed by subcutaneous injection or sublingual application of allergen extracts, represents an effective treatment against type I allergic diseases. However, due to the long duration and adverse reactions, only a minority of patients decides to undergo this treatment. Alternatively, early prophylactic intervention in young children has been proposed to stop the increase in patient numbers. Plasmid DNA and mRNA vaccines encoding allergens have been shown to induce T helper 1 as well as T regulatory responses, which modulate or counteract allergic T helper 2-biased reactions. With regard to prophylactic immunization, additional safety measurements are required. In contrast to crude extracts, genetic vaccines provide the allergen at high purity. Moreover, by targeting the encoded allergen to subcellular compartments for degradation, release of native allergen can be avoided. Due to inherent safety features, mRNA vaccines could be the candidates of choice for preventive allergy immunizations. The subtle priming of T helper 1 immunity induced by this vaccine type closely resembles responses of non-allergic individuals and-by boosting via natural allergen exposure-could suffice for long-term protection from type I allergy.

Synergistic effects of dendritic cell targeting and laser-microporation on enhancing epicutaneous skin vaccination efficacy

Due to its unique immunological properties, the skin is an attractive target tissue for allergen-specific immunotherapy. In our current work, we combined a dendritic cell targeting approach with epicutaneous immunization using an ablative fractional laser to generate defined micropores in the upper layers of the skin. By coupling the major birch pollen allergen Bet v 1 to mannan from S. cerevisiae via mild periodate oxidation we generated hypoallergenic Bet-mannan neoglycoconjugates, which efficiently targeted CD14⁺ dendritic cells and Langerhans cells in human skin explants. Mannan conjugation resulted in sustained release from the skin and retention in secondary lymphoid organs, whereas unconjugated antigen showed fast renal clearance. In a mouse model, Bet-mannan neoglycoconjugates applied via laser-microporated skin synergistically elicited potent humoral and cellular immune responses, superior to intradermal injection. The induced antibody responses displayed IgE-blocking capacity, highlighting the therapeutic potential of the approach. Moreover, application via micropores, but not by intradermal injection, resulted in a mixed TH1/TH17-biased immune response. Our data clearly show that applying mannan-neoglycoconjugates to an organ rich in dendritic cells using laser-microporation is superior to intradermal injection. Due to their low IgE binding capacity and biodegradability, mannan neoglycoconjugates therefore represent an attractive formulation for allergen-specific epicutaneous immunotherapy.

Neoantigen Expression in Steady-State Langerhans Cells Induces CTL Tolerance

The skin hosts a variety of dendritic cells (DCs), which act as professional APC to control cutaneous immunity. Langerhans cells (LCs) are the only DC subset in the healthy epidermis. However, due to the complexity of the skin DC network, their relative contribution to either immune activation or immune tolerance is still not entirely understood. To specifically study the function of LCs in vivo, without altering the DC subset composition in the skin, we have generated transgenic mouse models for tamoxifen-inducible de novo expression of Ags in LCs but no other langerin⁺ DCs. Therefore, this system allows for LC-restricted Ag presentation to T cells. Presentation of nonsecreted OVA (GFPOVA) by steady-state LCs resulted in transient activation of endogenous CTL in transgenic mice. However, when these mice were challenged with OVA by gene gun immunization in the contraction phase of the primary CTL response they did not respond with a recall of CTL memory but, instead, with robust Ag-specific CTL tolerance. We found regulatory T cells (T_regs) enriched in the skin of tolerized mice, and depletion of T_regs or adoptive experiments revealed that T_regs were critically involved in CTL tolerance. By contrast, when OVA was presented by activated LCs, a recallable CTL memory response developed in transgenic mice. Thus, neoantigen presentation by epidermal LCs results in either robust CTL tolerance or CTL memory, and this decision-making depends on the activation state of the presenting LCs.

Influence of protein fold stability on immunogenicity and its implications for vaccine design

INTRODUCTION

In modern vaccinology and immunotherapy, recombinant proteins more and more replace whole organisms to induce protective or curative immune responses. Structural stability of proteins is of crucial importance for efficient presentation of antigenic peptides on MHC, which plays a decisive role for triggering strong immune reactions. Areas covered: In this review, we discuss structural stability as a key factor for modulating the potency of recombinant vaccines and its importance for antigen proteolysis, presentation, and stimulation of B and T cells. Moreover, the impact of fold stability on downstream events determining the differentiation of T cells into effector cells is reviewed. We summarize studies investigating the impact of protein fold stability on the outcome of the immune response and provide an overview on computational methods to estimate the effects of point mutations on protein stability. Expert commentary: Based on this information, the rational design of up-to-date vaccines is discussed. A model for predicting immunogenicity of proteins based on their conformational stability at different pH values is proposed.

Infant milk formulas differ regarding their allergenic activity and induction of T-cell and cytokine responses

Background

Several hydrolyzed cow's milk (CM) formulas are available for avoidance of allergic reactions in CM‐allergic children and for prevention of allergy development in high‐risk infants. Our aim was to compare CM formulas regarding the presence of immunoreactive CM components, IgE reactivity, allergenic activity, ability to induce T‐cell proliferation, and cytokine secretion.

Methods

A blinded analysis of eight CM formulas, one nonhydrolyzed, two partially hydrolyzed (PH), four extensively hydrolyzed (EH), and one amino acid formula, using biochemical techniques and specific antibody probes was conducted. IgE reactivity and allergenic activity of the formulas were tested with sera from CM‐allergic patients (n = 26) in RAST‐based assays and with rat basophils transfected with the human FcεRI, respectively. The induction of T‐cell proliferation and the secretion of cytokines in Peripheral blood mononuclear cell (PBMC) culture from CM allergic patients and nonallergic individuals were assessed.

Results

Immune‐reactive α‐lactalbumin and β‐lactoglobulin were found in the two PH formulas and casein components in one of the EH formulas. One PH formula and the EH formula containing casein components showed remaining IgE reactivity, whereas the other hydrolyzed formulas lacked IgE reactivity. Only two EH formulas and the amino acid formula did not induce T‐cell proliferation and proinflammatory cytokine release. The remaining formulas varied regarding the induction of Th2, Th1, and proinflammatory cytokines.

Conclusion

Our results show that certain CM formulas without allergenic and low proinflammatory properties can be identified and they may also explain different outcomes obtained in clinical studies using CM formulas.

Skin vaccination via fractional infrared laser ablation - Optimization of laser-parameters and adjuvantation

BACKGROUND

Methods to deliver an antigen into the skin in a painless, defined, and reproducible manner are essential for transcutaneous immunization (TCI). Here, we employed an ablative fractional infrared laser (P.L.E.A.S.E. Professional) to introduce clinically relevant vaccines into the skin. To elicit the highest possible antibody titers with this system, we optimized different laser parameters, such as fluence and pore number per area, and tested various adjuvants.

METHODS

BALB/c mice were immunized with Hepatitis B surface antigen (HBsAg) by laser-microporation. Adjuvants used were alum, CRM₁₉₇, monophosphoryl lipid A, heat-labile enterotoxin subunit B of E. coli (LT-B), and CpG ODN1826. The influence of different fluences (2.1 to 16.8J/cm²) and pore densities (5-15%) was investigated. Furthermore, immunogenicity of HBsAg and the commercially available conjugate vaccines ActHIB® and Menveo® applied via TCI was compared to standard i.m. injection. Antigen-specific antibody titers were assessed by luminometric ELISA.

RESULTS

Antibody titers against HBsAg were dependent on pore depth and peaked at a fluence of 8.4J/cm². Immunogenicity was independent of pore density. Adjuvantation with alum significantly reduced antibody titers after TCI, whereas other adjuvants only induced marginal changes in total IgG titers. LT-B and CpG shifted the polarization of the immune response as indicated by decreased IgG1/IgG2a ratios. HBsAg/LT-B applied via TCI induced similar antibody titers compared to i.m. injection of HBsAg/alum. In contrast to i.m. injection, we observed a dose response from 5 to 20μg after TCI. Both, ActHIB® and Menveo® induced high antibody titers after TCI, which were comparable to i.m. injection.

CONCLUSIONS

Alum, the most commonly used adjuvant, is contraindicated for transcutaneous vaccination via laser-generated micropores. TCI with optimized laser parameters induces high antibody titers, which cannot be significantly increased by the tested adjuvants. Commercially available vaccines formulated without alum have the potential for successful TCI via laser-generated micropores, without the need for reformulation.

Does waterfall aerosol influence mucosal immunity and chronic stress? A randomized controlled clinical trial

BACKGROUND

The specific microclimate of alpine waterfalls with high levels of ionized water aerosols has been suggested to trigger beneficial immunological and psychological effects. In the present three-armed randomized controlled clinical study, we focused on effects on (i) immunological reagibility, on (ii) physiological stress responses, and on (iii) stress-related psychological parameters.

METHODS

People with moderate to high stress levels (n = 65) spent an active sojourn with daily hiking tours in the National Park Hohe Tauern (Großkirchheim, Austria). Half of the group was exposed to water aerosol of an alpine waterfall for 1 h/day (first arm, n = 33), whereas the other half spent the same time at a distant site (second arm, n = 32). A third arm (control, n = 26) had no intervention (except vaccination) and stayed at home, maintaining their usual lifestyle. The effect of the interventions on the immune system was tested by oral vaccination with an approved cholera vaccine and measuring specific salivary IgA antibody titers. Lung function was determined by peak expiratory flow measurement. Electric skin conductance, heart rate, and adaption of respiration rate were assessed as physiological stress parameters. Psychological stress-related parameters were analyzed by questionnaires and scales.

RESULTS

Compared to the control group, both intervention groups showed improvement of the lung function and of most physiological stress test parameters. Analysis of the mucosal immune response revealed a waterfall-specific beneficial effect with elevated IgA titers in the waterfall group. In line with these results, exposure to waterfall revealed an additional benefit concerning psychological parameters such as subjective stress perception (measured via visual analog scale), the Global Severity Index (GSI), and the Positive Symptom Total (PST).

CONCLUSIONS

Our study provides new data, which strongly support an "added value" of exposure to waterfall microclimate when combined with a therapeutic sojourn at high altitude including regular physical activity.

Generation and Evaluation of Prophylactic mRNA Vaccines Against Allergy

Due to the worldwide increase in allergies and a limited efficacy of therapeutic interventions, the need for prophylactic vaccination against allergies has been recognized. mRNA and DNA vaccines have demonstrated their high potential for preventing allergic sensitization by inducing an immunological bias that prevents TH2 sensitization. However, only mRNA vaccines fulfill the stringent safety requirements for vaccination of healthy children. In this chapter, we describe the generation of conventional as well as self-replicating mRNA vaccines and methods to test their prophylactic efficacy in animal models.

6th International Symposium on Molecular Allergology (ISMA)

ORAL ABSTRACTS

Symposium 1: Biochemistry, structure and environment of the allergen: what makes a protein an allergen?

O1 Two cell-membrane peptidases carrying galactose-alpha-1,3-galactose are implicated in delayed anaphylactic reactions upon pork kidney ingestion in patients with IgE-antibodies to alpha-Gal

Christiane Hilger, Kyra Swiontek, Jörg Fischer, François Hentges, Christiane Lehners, Martine Morisset, Bernadette Eberlein, Tilo Biedermann, Markus Ollert

O2 Structure solution of Pla l 1 suggests similar folding of Ole e 1-like family members but distinct immunological properties

Sabrina Wildner, Teresa Stemeseder, Regina Freier, Peter Briza, Roland Lang, Eva Batanero, Mayte Villalba, Jonas Lidholm, Thomas Hawranek, Fatima Ferreira, Hans Brandstetter, Gabriele Gadermaier

Symposium 2: New allergen molecules in the spotlight

O3 Identification of the cysteine protease Amb a 11 as a novel major allergen from short ragweed (Ambrosia artemisiifolia)

Philippe Moingeon, Rachel Groeme, Julien Bouley, Véronique Bordas, Maxime Le Mignon, Laetitia Bussières, Aurélie Lautrette, Laurent Mascarell, Vincent Lombardi, Véronique Baron-Bodo, Henri Chabre, Thierry Batard, Emmanuel Nony

O4 Production and characterization of polybia paulista recombinant antigen 5: a valuable diagnostic tool

Karine Marafigo De Amicis, Alexandra Sayuri Watanabe, Daniele Danella Figo, José Roberto Aparecido Dos Santos-Pinto, Mario Sergio Palma, Fabio Fernandes Morato Castro, Jorge Kalil, Therese Wohlschlager, Peter Briza, Sabrina Wildner, Fatima Ferreira-Briza, Gabriele Gadermaier, Keity Souza Santos

Symposium 3: Progress in molecular and cellular diagnosis

O5 Basophil activation test with recombinant Pru p 3; identifying genuine peach allergic patients

Margaretha Faber, Athina Van Gasse, Vito Sabato, Margo M. Hagendorens, Chris H. Bridts, Luc S. De Clerck, Araceli Diaz Perales, Didier Ebo

O6 Nanofluidic technology enables rapid, near-patient quantification of allergen-specific IgE

Petra Zavadakova, Aurélie Buchwalder, Fabien Rebeaud, Iwan Märki

Symposium 4: Relevance of molecular diagnostics for intervention and treatment

O7 Longitudinal analysis of Bet v 1-specific epitope repertoires during birch pollen immunotherapy

Barbara Gepp, Nina Lengger, Christian Möbs, Wolfgang Pfützner, Christian Radauer, Barbara Bohle

O8 A natural CCD-free tool: is polistes sp. venom suitable for polybia paulista diagnosis and therapy?

Karine Marafigo De Amicis, Alexandra Sayuri Watanabe, Clovis Eduardo Galvao, Daniele Danella Figo, Jose Roberto Aparecido Santos-Pinto, Mario Sergio Palma, Fabio Fernandes Morato Castro, Jorge Kalil, Fatima Ferreira, Gabriele Gadermaier, Keity Souza Santos

Symposium 5: The advent of molecular allergology in epidemiology

O9 Peanut oleosins: from identification to diagnostic testing

Christian Schwager, Skadi Kull, Frauke Schocker, Jochen Behrends, Wolf-Meinhard Becker, Uta Jappe

O10 Endotypes of oral allergy syndrome in childhood: a molecular diagnostic approach

Carla Mastrorilli, Salvatore Tripodi, Carlo Caffarelli, Riccardo Asero, Arianna Dondi, Giampaolo Ricci, Carlotta Povesi Dascola, Elisabetta Calamelli, Andrea Di Rienzo Businco, Annamaria Bianchi, Tullio Frediani, Carmen Verga, Iride Dello Iacono, Diego Peroni, Giuseppe Pingitore, Roberto Bernardini, Paolo Maria Matricardi

Symposium 6: Molecular AIT: which approaches will make it to market?

O11 Mbc4: an innovative molecule to tackle birch pollen and concomitant food allergies

Heidi Hofer, Claudia Asam, Michael Hauser, Peter Briza, Martin Himly, Christof Ebner, Fatima Ferreira

O12 Challenges and solutions associated with the production of recombinant Bet v 1 allergen as a therapeutic protein

Emmanuel Nony, Maxime Le Mignon, Pierrick Lemoine, Karine Jain, Kathy Abiteboul, Monica Arvidsson, Sabina Rak, Philippe Moingeon

Clinical Cases: Breakthroughs and headaches from CRD: interactive session

CC1 Anaphylaxis caused by lipid transfer proteins: a complex clinical pattern syndrome

Inês Mota, Filipe Benito Garcia, Angela Gaspar, Cristina Arêde, Susana Piedade, Graça Sampaio, Graça Pires, Luís Miguel Borrego, Cristina Santa-Marta, Mário Morais-Almeida

CC2 IgE sensitization profile in a patient with asteraceae pollen-exotic fruits association

Florin-Dan Popescu, Mariana Vieru, Florin-Adrian Secureanu

CC3 Food-dependent: exercise induced anaphylaxis. Which component to blame?

Rosa Anita Rodrigues Fernandes, Isabel Carrapatoso, Raquel Gomes, Celso Pereira, Ana Todo-Bom

CC4 Anaphylaxis to intravenous iron preparations in a patient that tolerates oral administration

María Cecilia Martín Fernández De Basoa, Javier Barrios Regio, Juan De Castro Cordova, Antón Fernández Ferreiro

CC5 IgE sensitization pattern in an adult patient with oral allergy syndrome to peanuts and pollinosis from southern Romania

Florin-Dan Popescu, Mariana Vieru, Florin-Adrian Secureanu

CC6 Evidence of specific IgE to plant-derived cross-reactive carbohydrate determinant in a patient with delayed anaphylaxis to red meat

Mariana Vieru, Florin-Dan Popescu, Florin-Adrian Secureanu

POSTER PRESENTATIONS

Poster Session 1: Molecular allergology and epidemiology

P1 Atopic children produce stronger and more frequent IgG responses than non-atopic children: longitudinal data from the German MAS birth cohort

Olympia Tsilochristou, Serena Perna, Alina Schwarz, Alexander Rohrbach, Antonio Cappella, Laura Hatzler, Carl-Peter Bauer, Ute Hoffmann, Johannes Forster, Fred Zepp, Antje Schuster, Raffael D’amelio, Ulrich Wahn, Thomas Keil, Susanne Lau, Paolo Maria Matricardi

P2 The IgG sensitization profiles against 112 allergenic components support the absence of a protective role of IgG in allergic individuals, outside of the context of SIT

Pol André Apoil, Claire Mailhol, Anne Broué-Chabbert, Agnès Juchet, Alain Didier, Elodie Carrer, Thomas Lanot, Antoine Blancher

P3 The immune response against the timothy grass pollen allergen Phl p 5 in non-allergic humans

Almedina Kurtaj, Christoph Hillebrand, Gerda Fichtinger, Martin Danzer, Christian Gabriel, Theresa Thalhamer, Sandra Scheiblhofer, Josef Thalhamer, Richard Weiss

P4 Analyzing the cross-reactivity profile of the major ragweed allergen Amb a 1

Martin Wolf, Michael Hauser, Ulrike Pichler, Teresa Twaroch, Gabriele Gadermaier, Christof Ebner, Hidenori Yokoi, Toshiro Takai, Alain Didierlaurent, Adriano Mari, Peter Briza, Heidrun Behrendt, Angela Neubauer, Frank Stolz, Fátima Ferreira, Michael Wallner

P5 LTP (Pru p 3) sensitisation in skin prick test: which means in clinical practice?

Sara Carvalho, Tatiana Lourenço, Joana Cosme, Fátima Cabral Duarte, Amélia Spínola Santos, Ana Célia Costa, Manuel Pereira Barbosa

P6 IgE profiles, allergen exposure and lifestyle of 501 Austrian pupils: investigation of influences on the development of allergic sensitizations

Teresa Stemeseder, Eva Klinglmayr, Bettina Schweidler, Lisa Lueftenegger, Stephanie Moser, Patrick Doppler, Roland Lang, Martin Himly, Gertie J. Oostingh, Arne Bathke, Joerg Zumbach, Thomas Hawranek, Gabriele Gadermaier

P7 Molecular profiles of sensitization to perennial inhalant allergens in a middle European region

Petr Panzner, Martina Vachova, Tomas Vlas, Marek Maly

P8 Evolution of the IgE response to house dust mite allergen molecules in childhood

Daniela Posa, Serena Perna, Stephanie Hofmaier, Laura Hatzler, Alexander Rohrbach, Carl-Peter Bauer, Ute Hoffmann, Johannes Forster, Fred Zepp, Antje Schuster, Philippe Stock, Ulrich Wahn, Linus Grabenhenrich, Thomas Keil, Susanne Lau, Kuan-Wei Chen, Yvonne Resch, Susanne Vrtala, Rudolf Valenta, Paolo Maria Matricardi

P9 Tropomyosin (Pen a1): to include or not to include in skin prick testing?

Joana Cosme, Sara Carvalho, Tatiana Lourenço, Amélia Spínola Santos, Manuel Pereira Barbosa

Immunoallergy Department - Hospital de Santa Maria – Centro Hospitalar Lisboa Norte, Lisbon, Portugal, Lisbon, Portugal; Immunoallergy Department - Hospital de Santa Maria – Centro Hospitalar Lisboa Norte, Lisbon, Portugal; Faculdade de Medicina de Lisboa, Lisbon, Portugal

P10 Component-resolved IgE profiles in Georgian patients

Tamar Abramidze, Nino Lomidze, Maia Gotua

P11 Cross reactivity between food and pollen allergens in Lithuania according to spIgE evaluation

Austeja Dapkeviciute, Ruta Einikyte, Jolita Norkuniene, Laima Skrickiene, Asta Miskiniene, Violeta Kvedariene

P12 Distribution of inhalant allergy in the population of Lithuania

Ruta Einikyte, Austeja Dapkeviciute, Jolita Norkuniene, Laima Skrickiene, Asta Miskiniene, Violeta Kvedariene

Poster Session 2: Allergen molecules: identification, characterization, structure and function

P13 Interference of antigen 5-based cross-reactivity in the diagnosis of hymenoptera venom allergy

Maximilian Schiener, Bernadette Eberlein, Carmen Moreno-Aguilar, Gunilla Pietsch, Mareike Mc Intyre, Lea Schwarze, Dennis Rußkamp, Tilo Biedermann, Edzard Spillner, Ulf Darsow, Carsten Schmidt-Weber, Markus Ollert, Simon Blank

P14 IgE cross-reactivity between European Hymenoptera and Asian hornet (Vespa velutina) venom allergens

Cyril Longé, Andrea Brazdova, Jean-Louis Brunet, Claire Schwartz, Bruno Girodet, François Lavaud, Joelle Birnbaum, Nhân Pham Thi, Magalie Duchateau, Julia Chamot-Rooke, Laurence Guilloux, Marie-Ange Selva, Rémy Couderc, Hélène Sénéchal, Jean-Pierre Sutra, Pascal Poncet

P15 Carbohydrate composition of house dust mite extracts and major group 1 and group 2 allergens

Steffen Augustin, Linda Pump, Martin Wald, Thomas Eichhorn, Frank Fischer, Christoph Willers

P16 Specificity of monoclonal antibodies against cross-reactive carbohydrate determinants

Michaela Miehe, Melanie Plum, Sara Wolf, Frederic Jabs, Tim Raiber, Frank Bantleon, Henning Seismann, Thilo Jakob, Edzard Spillner

P17 Red meat allergic patients have a selective IgE response to the a-Gal glycan

Danijela Apostolovic, Anh Thu Tran, Sara Sanchez-Vidaurre, Tanja Cirkovic Velickovic, Maria Starkhammar, Carl Hamsten, Marianne Van Hage

P18 Specificity of non-specific lipid transfer proteins and influence of the ligands on their three-dimensional structure

Pawel Dubiela, Piotr Humeniuk, Sabine Pfeifer, Merima Bublin, Tomasz Borowski, Karin Hoffmann-Sommergruber

P19 Real-time PCR analysis of Pru av 1 and Pru av 3 allergens

Martie C.M. Verschuren, Shanna Bastiaan-Net, Defien Depoortere, Kay Foetisch, Stephan Scheurer, Harry J Wichers, Theo Noij

P20 Specificity of anti-Pru av 1 antibodies for the detection of Pru av 1 isoallergens

Martie C.M. Verschuren, Shanna Bastiaan-Net, Nikki M.E. Van Uden, Karel Vandenberghe, Kay Foetisch, Stephan Scheurer, Harry J. Wichers H.J., Theo H.M. Noij

P21 Enhancing recombinant production yield of Bet v 1 through codon usage harmonization

Anargyros Roulias, Maria Alejandra Parigiani, Heidi Hofer, Claudia Asam, Christof Ebner, Fátima Ferreira

P22 Structural and dynamic insights into the world of PR-10 allergens

Linda Ahammer, Sarina Grutsch, Martin Tollinger

Poster Session 3: Allergen molecules: identification, characterization, structure and function

P23 Purification of polcalcin from different pollen allergenic sources by antibody-affinity chromatography

Raquel Moya, Mª Angeles López-Matas, Raquel Reyes, Jerónimo Carnés

P24 Variations of wheat allergens in cultivars measured through a targeted quantitative mass spectrometry approach

Colette Larré, Hélène Rogniaux, Roberta Lupi, Sandra Denery-Papini

P25 Art v 1, Amb a 4 and Par h 1 defensin-like proteins share similar structural features but distinct immunological and allergenic properties

Isabel Maria Pablos, Stephanie Eichhorn, Yoan Machado, Peter Briza, Christof Ebner, Jung-Won Park, Alain Didierlaurent, Naveen Arora, Stefan Vieths, Gabriele Gadermaier, Fatima Ferreira

P26 Homogeneity or diversity of IgE-binding proteins in wheat dependant exercise induced anaphylaxis?

Sandra Denery-Papini, Charlene Tanaka, Florence Pineau, Roberta Lupi, Martine Drouet, Etienne Beaudouin, Martine Morisset, Susan Altenbach

P27 Deciphering the role of disulfide bonds and of repetitive epitopes in immunoglobulin E binding to wheat gliadins

Sandra Denery-Papini, Hamza Mameri, Chantal Brossard, Roberta Lupi, Florence Pineau, Jean Charles Gaudin, Denise Anne Moneret-Vautrin, Etienne Beaudouin, Evelyne Paty, Martine Drouet, Olivier Tranquet, Colette Larré

P28 Assessment of the allergenicity of soluble fractions from bread and durum wheats genotypes

Roberta Lupi, Stefania Masci, Olivier Tranquet, Denise-Anne Moneret-Vautrin, Sandra Denery-Papini, Colette Larré

P29 Isolation and characterization of Ara h 12 and Ara h 13: defensins, a novel class of peanut allergens

Skadi Kull, Arnd Petersen, Marisa Böttger, Sandra Rennert, Wolf-Meinhard Becker, Susanne Krause, Martin Ernst, Thomas Gutsmann, Johann Bauer, Buko Lindner, Uta Jappe

P30 Allergenicity attributes of different peanut market types

Stef Koppelman, Shyamali Jayasena, Dion Luykx, Erik Schepens, Danijela Apostolovic, Govardus De Jong, Tom Isleib, Julie Nordlee, Joe Baumert, Steve Taylor, Soheila Maleki

P31 The impact of peanut lipids on Ara h 1-induced immune responses in monocytes-derived dendritic cells

Chiara Palladino, Barbara Gepp, Sofía Sirvent, Alba Angelina, Merima Bublin, Christian Radauer, Nina Lengger, Thomas Eiwegger, Oscar Palomares, Heimo Breiteneder

P32 Compared allergenicity of native and thermally aggregated ovalbumin as large agglomerated particles

Mathilde Claude, Roberta Lupi, Grégory Bouchaud, Marie Bodinier, Chantal Brossard, Sandra Denery-Papini

P33 Simulation of the gastrointestinal digestion of the hazelnut allergens Cor a 9 and Cor a 11 by an in-vitro model and characterisation of peptidic products including epitopes by HPLC-MS/MS

Robin Korte, Julia Bräcker, Jens Brockmeyer

P34 Analysis of distribution of rice allergens in brown rice grain and allergenicity of the products containing rice bran

Rie Satoh, Reiko Teshima

Poster Session 4: Molecular approaches in AIT

P35 Production of a recombinant hypoallergenic variant of the major peanut allergen Ara h 2 for allergen-specific immunotherapy

Angelika Tscheppe, Dieter Palmberger, Merima Bublin, Christian Radauer, Chiara Palladino, Barbara Gepp, Nina Lengger, Reingard Grabherr, Heimo Breiteneder

P36 Mutagenesis of amino acids critical for calcium-binding leads to the generation of a hypoallergenic Phl p 7 variant

Marianne Raith, Linda Sonnleitner, Doris Zach, Konrad Woroszylo, Margit Focke-Tejkl, Herbert Wank, Thorsten Graf, Annette Kuehn, Ines Swoboda

P37 Are birch pollen allergen immunotherapy induced blocking antibodies protective for cross-reactive allergens?

Claudia Asam, Sara Huber, Heidi Hofer, Roland Lang, Thomas Hawranek, Fátima Ferreira, Michael Wallner

P38 High success of 58 subcutaneous immunotherapy for pets allergy in a polyallergic cohort of patients: a component resolved individually adapted treatment (CRIAT)

Fabienne Gay-Crosier

P39 Neutrophils are potential antigen presenting cells in IgE- mediated allergy

Dominika Polak, Birgit Nagl, Claudia Kitzmüller, Barbara Bohle

P40 Characterization of allergen-specific CD8+ T cells in type I allergy

Nazanin Samadi, Claudia Kitzmüller, Rene Geyeregger, Barbara Bohle, Beatrice Jahn-Schmid

Poster Session 5: Molecular and cellular diagnostic tests

P41 Nanofluidic-based biosensors allow quantification of total circulating IgE from a drop of blood in 5 minutes

Aurélie Buchwalder, Ariel Gomez, Fabien Rebeaud, Iwan Märki

P42 Allergen microarray for the analysis of serum IgE binding profile and allergenic activity

Jaana Haka, Liisa Hattara, Marika Heikkinen, Merja H Niemi, Juha Rouvinen, Petri Saviranta, Pekka Mattila, Kristiina Takkinen, Marja-Leena Laukkanen

P43 Generation of a well-characterized panel of periplaneta americana allergens for component resolved diagnosis

Stephanie Eichhorn, Isabel Pablos, Bianca Kastner, Bettina Schweidler, Sabrina Wildner, Peter Briza, Jung-Won Park, Naveen Arora, Stefan Vieths, Gabriele Gadermaier, Fatima Ferreira

P44 Improved diagnostic sensitivity of recombinant Api m 1 and Ves v 5 in diagnosis of Hymenoptera venom allergy

Mira Silar, Julij Selb, Rok Kogovsek, Mitja Kosnik, Peter Korosec

P45 Added value of biomarkers of primary sensitization and cross-reactivity in patients with hymenoptera venom allergy

Leticia Pestana, Alcinda Campos Melo, Ana Mendes, Maria Elisa Pedro, Manuel Pereira Barbosa, Maria Conceição Pereira Santos

P46 Cosensitization to Alt a 1 and Act d 2: more than a fortuitous association?

Françoise Bienvenu, Claire Goursaud, Lorna Garnier, Sandrine Jacquenet, Michaël Degaud, Sébastien Viel, Annick Barre, Pierre Rougé, Jacques Bienvenu, Joana Vitte

P47 Molecular diagnosis for peanut allergy: ALFA method performs as well as established methods for Ara h 1, Ara h 2, Ara h 6, Ara h 9 and CCD

Amel Bensalah, Isabelle Cleach, Laurent Mousseau, Chantal Agabriel, Valérie Liabeuf, Joëlle Birnbaum, Jean-Louis Mège, Joana Vitte

P48 Evaluation of a food challenge service in relation to specific IgE to molecular components in children with suspected peanut allergy

James Gardner, Minal Gandhi, Harsha Kariyawasam, Giuseppina Rotiroti

P49 Component resolved diagnosis in cereal allergy

Isabel Carrapatoso, Celso Pereira, Frederico Regateiro, Emília Faria, Ana Todo-Bom

Poster Session 6: Molecular diagnosis in prevention and therapy

P50 Pretreatment molecular sensitizations determine the sIgG4 induction during the updosing of SCIT and may be useful to identify clinically relevant additional sensitizations

Johannes Martin Schmid, Ronald Dahl, Hans Juergen Hoffmann

P51 Usefulness of recombinant latex allergens in immunotherapy’s decision and follow-up

Inês Mota, Filipe Benito Garcia, Angela Gaspar, Mário Morais-Almeida

P52 Omega-5-gliadin in the diagnosis of wheat-dependent anaphylaxis induced by ibuprofen but not by exercise

Joana Cosme, Letícia Pestana, Amélia Spínola Santos, Manuel Pereira Barbosa

P53 Food dependent exercise-induced anaphylaxis: a component-resolved and in vitro depletion approach to access IgE cross-reactivity

Diana Silva, Teresa Vieira, Ana Maria Pereira, André Moreira, Luís Delgado

P54 Olive pollen allergens: what are we missing?

Sara Prates, Cátia Alves, Elena Finelli, Paula Leiria Pinto

P55 Purified Alt a 1 extract in Alternaria alternata allergy diagnosis

Bárbara Kong Cardoso, Cíntia Cruz, Filipa Semedo, Elza Tomaz, Filipe Inácio

P56 Use of specific IgE Bos d8 (casein) to aid early introduction of dietary baked milk in children with cows’ milk allergy

James Gardner, Santanu Maity, Giuseppina Rotiroti, Minal Gandhi

P57 Molecular characterisation and immunoreactivity of a peanut ingredient for use in oral food challenges

Ivona Baricevic-Jones, Justin T. Marsh, Phil E. Johnson, Anuradha Balasundaram, Anya-May Hope, Aafke Taekema, Angela Simpson, Aida Semic-Jusufagic, E.N. Clare Mills

P58 Specific IgE to recombinant allergens of hazelnut and oral food challenge in children

Gourdon Dubois Nelly, Sellam Laetitia, Pereira Bruno, Michaud Elodie, Messaoudi Khaled, Evrard Bertrand, Fauquert Jean-Luc

Poster session 7/8: miscellaneous

P59 What defines a protein as an allergen? A discussion of sources and sufficiency

Richard E. Goodman

P60 Cat allergy: relationship between clinical and molecular diagnostic

María Cecilia Martín Fernández De Basoa, Antón Fernández Ferreiro, Elena Rodríguez Plata

P61 Anaphylaxis to rabbit: the cat came in last

Luis Amaral, Borja Bartolomé, Alice Coimbra, Jose L Placido

P62 Dog allergy: relationship between clinical and molecular diagnostic

María Cecilia Martín Fernández De Basoa, Antón Fernández Ferreiro, Elena Rodríguez Plata

P63 Correlation of serum timothy grass-pollen specific IgE levels determined by two immunoblot test systems

Mariana Vieru, Florin-Dan Popescu, Florin-Adrian Secureanu, Carmen Saviana Ganea

P64 Development of oral food challenge formulations for diagnosis of fish allergy using powdered fish ingredients

Carol Ann Costello, Ivona Baricevic-Jones, Martin Sorensen, Clare Mills, Adrian Rogers, Aage Otherhals

P65 Fish and peanut allergens interact with plasma membranes of intestinal and bronchial epithelial cells and induce differential gene expression of cytokines and chemokines

Tanja Kalic, Isabella Ellinger, Chiara Palladino, Barbara Gepp, Eva Waltl, Verena Niederberger-Leppin, Heimo Breiteneder

P66 Interleukin 4 affects fat tissue metabolism and expression of pro-inflammatory factors in isolated rat adipocytes

Dawid Szczepankiewicz, Ewa Pruszynska-Oszmalek, Marek Skrzypski, Krzysztof W. Nowak, Aleksandra Szczepankiewicz

P67 Ozone induced airway hyperreactivity in PD-L2−/− mice model

Gwang-Cheon Jang

P68 Thymic stromal lymphopoietin (TSLP) and its receptor as targets for the development of anti-inflammatory inhibitory agents

Iva Markovic, Andreas Borowski, Tina Vetter, Andreas Wohlmann, Michael Kuepper, Karlheinz Friedrich

P69 The mononuclear phagocyte system in experimentally-induced allergic rhinitis

Ibon Eguiluz Gracia, Anthony Bosco, Ralph Dollner, Guro Reinholt Melum, Anya C Jones, Maria Lexberg, Patrick G Holt, Espen Sønderaal Bækkevold, Frode Lars Jahnsen

P70 Expression of histamine metabolizing enzymes is increased in allergic children

Aleksandra Szczepankiewicz, Paulina Sobkowiak, Marta Rachel, Beata Narozna, Dorota Jenerowicz, Witold Swiatowy, Anna Breborowicz

P71 Modifying the glycosylation of human IgE towards oligomannosidic structures does not affect its biological activity

Melanie Plum, Sara Wolf, Frank Bantleon, Henning Seismann, Frederic Jabs, Michaela Miehe, Thilo Jakob, Edzard Spillner

P72 Flying Labs: an educational initiative to transfer allergy research into high-school settings

Michael Wallner, Heidi Hofer, Fatima Ferreira, Reinhard Nestelbacher

P73 Clinical significance of antihistamines and Kujin, an anti-allergic Kampo medicine

Hiroyuki Fukui

Potential of nanoparticles for allergen-specific immunotherapy - use of silica nanoparticles as vaccination platform

INTRODUCTION

Allergen-specific immunotherapy is the only curative approach for the treatment of allergies. There is an urgent need for improved therapies, which increase both, efficacy and patient compliance. Novel routes of immunization and the use of more advanced vaccine platforms have gained heightened interest in this field. Areas covered: The current status of allergen-specific immunotherapy is summarized and novel routes of immunization and their challenges in the clinics are critically discussed. The use of nanoparticles as novel delivery system for allergy vaccines is comprehensively reviewed. Specifically, the advantages of silica nanoparticles as vaccine carriers and adjuvants are summarized. Expert opinion: Future allergen-specific immunotherapy will combine engineered hypoallergenic vaccines with novel routes of administration, such as the skin. Due to their biodegradability, and the easiness to introduce surface modifications, silica nanoparticles are promising candidates for tailor-made vaccines. By covalently linking allergens and polysaccharides to silica nanoparticles, a versatile vaccination platform can be designed to specifically target antigen-presenting cells, render the formulation hypoallergenic, and introduce immunomodulatory functions. Combining potent skin vaccination methods, such as fractional laser ablation, with nanoparticle-based vaccines addresses all the requirements for safe and efficient therapy of allergic diseases.

Allergy Enhances Neurogenesis and Modulates Microglial Activation in the Hippocampus

Allergies and their characteristic T_H2-polarized inflammatory reactions affect a substantial part of the population. Since there is increasing evidence that the immune system modulates plasticity and function of the central nervous system (CNS), we investigated the effects of allergic lung inflammation on the hippocampus—a region of cellular plasticity in the adult brain. The focus of the present study was on microglia, the resident immune cells of the CNS, and on hippocampal neurogenesis, i.e., the generation of new neurons. C57BL/6 mice were sensitized with a clinically relevant allergen derived from timothy grass pollen (Phl p 5). As expected, allergic sensitization induced high serum levels of allergen-specific immunoglobulins (IgG1 and IgE) and of T_H2 cytokines (IL-5 and IL-13). Surprisingly, fewer Iba1⁺ microglia were found in the granular layer (GL) and subgranular zone (SGZ) of the hippocampal dentate gyrus and also the number of Iba1⁺MHCII⁺ cells was lower, indicating a reduced microglial surveillance and activation in the hippocampus of allergic mice. Neurogenesis was analyzed by labeling of proliferating cells with bromodeoxyuridine (BrdU) and determining their fate 4 weeks later, and by quantitative analysis of young immature neurons, i.e., cells expressing doublecortin (DCX). The number of DCX⁺ cells was clearly increased in the allergy animals. Moreover, there were more BrdU⁺ cells present in the hippocampus of allergic mice, and these newly born cells had differentiated into neurons as indicated by a higher number of BrdU⁺NeuN⁺ cells. In summary, allergy led to a reduced microglia presence and activity and to an elevated level of neurogenesis in the hippocampus. This effect was apparently specific to the hippocampus, as we did not observe these alterations in the subventricular zone (SVZ)/olfactory bulb (OB) system, also a region of high cellular plasticity and adult neurogenesis.

No Concentration Decrease of House Dust Mite Allergens With Rising Altitude in Alpine Regions

Purpose

Several studies over the past 4 decades have indicated a significant reduction in house dust mite (HDM) and HDM allergen concentration in areas higher than 1,500 m above sea level. These have served as basis of allergen avoidance therapies for HDM allergy and asthma. However, modern construction techniques used in the insulation, heating, and glazing of buildings as well as global warming have changed the environmental parameters for HDM living conditions. The present study revisits the paradigm of decreasing HDM allergen concentrations with increasing altitude in the alpine region of Germany and Austria.

Methods

A total of 122 dust samples from different abodes (hotels, privates and mountain huts) at different altitudes (400-2,600 m) were taken, and concentrations of HDM allergens were analyzed. Humidity and temperature conditions, and numerous indoor environmental parameters such as fine dust, type of flooring, age of building, and frequency of cleaning were determined.

Results

HDM allergen concentrations did not significantly change with increasing altitude or relative humidity. At the level of indoor parameters, correlations could be found for different flooring types and the concentration of HDM allergens.

Conclusions

In contrast to the widespread view of the relationship between altitude and HDM allergen concentrations, clinically relevant concentrations of HDM allergens could be detected in high-lying alpine regions in Austria and Germany. These results indicate that improvement in conditions of asthmatic patients sensitized against HDMs during a stay at high altitude can no longer be ascribed to decreased levels of HDM allergens, instead, other mechanisms may trigger the beneficial effect.

Fold stability during endolysosomal acidification is a key factor for allergenicity and immunogenicity of the major birch pollen allergen

BACKGROUND

The search for intrinsic factors, which account for a protein's capability to act as an allergen, is ongoing. Fold stability has been identified as a molecular feature that affects processing and presentation, thereby influencing an antigen's immunologic properties.

OBJECTIVE

We assessed how changes in fold stability modulate the immunogenicity and sensitization capacity of the major birch pollen allergen Bet v 1.

METHODS

By exploiting an exhaustive virtual mutation screening, we generated mutants of the prototype allergen Bet v 1 with enhanced thermal and chemical stability and rigidity. Structural changes were analyzed by means of x-ray crystallography, nuclear magnetic resonance, and molecular dynamics simulations. Stability was monitored by using differential scanning calorimetry, circular dichroism, and Fourier transform infrared spectroscopy. Endolysosomal degradation was simulated in vitro by using the microsomal fraction of JAWS II cells, followed by liquid chromatography coupled to mass spectrometry. Immunologic properties were characterized in vitro by using a human T-cell line specific for the immunodominant epitope of Bet v 1 and in vivo in an adjuvant-free BALB/c mouse model.

RESULTS

Fold stabilization of Bet v 1 was pH dependent and resulted in resistance to endosomal degradation at a pH of 5 or greater, affecting presentation of the immunodominant T-cell epitope in vitro. These properties translated in vivo into a strong allergy-promoting TH2-type immune response. Efficient TH2 cell activation required both an increased stability at the pH of the early endosome and efficient degradation at lower pH in the late endosomal/lysosomal compartment.

CONCLUSIONS

Our data indicate that differential pH-dependent fold stability along endosomal maturation is an essential protein-inherent determinant of allergenicity.

Immune Reactions against Gene Gun Vaccines Are Differentially Modulated by Distinct Dendritic Cell Subsets in the Skin

The skin accommodates multiple dendritic cell (DC) subsets with remarkable functional diversity. Immune reactions are initiated and modulated by the triggering of DC by pathogen-associated or endogenous danger signals. In contrast to these processes, the influence of intrinsic features of protein antigens on the strength and type of immune responses is much less understood. Therefore, we investigated the involvement of distinct DC subsets in immune reactions against two structurally different model antigens, E. coli beta-galactosidase (betaGal) and chicken ovalbumin (OVA) under otherwise identical conditions. After epicutaneous administration of the respective DNA vaccines with a gene gun, wild type mice induced robust immune responses against both antigens. However, ablation of langerin+ DC almost abolished IgG1 and cytotoxic T lymphocytes against betaGal but enhanced T cell and antibody responses against OVA. We identified epidermal Langerhans cells (LC) as the subset responsible for the suppression of anti-OVA reactions and found regulatory T cells critically involved in this process. In contrast, reactions against betaGal were not affected by the selective elimination of LC, indicating that this antigen required a different langerin+ DC subset. The opposing findings obtained with OVA and betaGal vaccines were not due to immune-modulating activities of either the plasmid DNA or the antigen gene products, nor did the differential cellular localization, size or dose of the two proteins account for the opposite effects. Thus, skin-borne protein antigens may be differentially handled by distinct DC subsets, and, in this way, intrinsic features of the antigen can participate in immune modulation.

Natural clinical tolerance to peanut in African patients is caused by poor allergenic activity of peanut IgE

BACKGROUND

In Africa, peanuts are frequently consumed, but severe allergic reactions are rare. We investigated immunological patterns of clinical tolerance to peanut in peanut-sensitized but asymptomatic patients from central Africa compared to peanut-allergic and peanut-sensitized but asymptomatic patients from Sweden.

METHODS

Sera from allergic patients (n = 54) from Zimbabwe sensitized to peanut but without allergic symptoms to peanut, and sera from peanut-allergic (n = 25) and peanut-sensitized but asymptomatic (n = 25) patients from Sweden were analyzed toward peanut allergen components (Ara h 1-3, 6, 8-9) and other allergen molecules from important allergen sources using microarray. IgE to Ara h 2 peptide epitopes was analyzed, and allergenic activity was assessed by basophil activation assay.

RESULTS

Forty-six percent of the African and all peanut-allergic Swedish patients showed IgE toward one of the highly allergenic peanut allergens (Ara h 1-3, 6, 9). However, 48% of the African patients had IgE to cross-reactive carbohydrate determinants (CCDs) with low allergenic activity and 60% of the Swedish asymptomatic patients had IgE against the PR protein Ara h 8. IgG and IgG4 specificities and levels could not discriminate between the African asymptomatic and Swedish peanut-allergic patients. Asymptomatic patients almost lacked IgE to Ara h 2 peptides, which were recognized by peanut-allergic patients. Peanut IgE from peanut asymptomatic patients showed poor allergenic activity compared with IgE from peanut-allergic patients.

CONCLUSIONS

Natural clinical tolerance to peanut in the African patients can be caused by IgE to low allergenic peanut components and by poor allergenic activity of peanut-specific IgE.

Hypoallergenic derivatives of Fel d 1 obtained by rational reassembly for allergy vaccination and tolerance induction

BACKGROUND AND OBJECTIVE

The major cat allergen Fel d 1 represents one of the most important respiratory allergens. Aim of this study was to engineer recombinant Fel d 1 derivatives with reduced IgE reactivity and preserved T cell epitopes for vaccination and tolerance induction.

METHODS

Seven recombinant mosaic proteins were generated by reassembly of non-IgE-reactive peptides of Fel d 1 which contained the sequence elements for induction of allergen-specific blocking IgG antibodies and T cell epitopes. Mosaic proteins were expressed in Escherichia coli using codon-optimized synthetic genes and compared with Fel d 1 regarding structural fold by circular dichroism, IgE-binding capacity, activation of allergic patients' basophils and ability to induce allergen-specific blocking IgG antibodies upon immunization.

RESULTS

Although each of the mosaic proteins had lost the alpha-helical fold typical for Fel d 1, a strong reduction in IgE reactivity as well as allergenic activity in basophil activation assays was only obtained for three constructs, two reassembled fragments (Fel d 1 MB, Fel d 1 MC) and a fusion of the latter two (Fel d 1 MF) in which the cysteines of Fel d 1 MC were replaced by serines. Immunization of rabbits with Fel d 1 MB, MC and MF induced high levels of IgG antibodies that inhibited IgE reactivity of cat-allergic patients to Fel d 1 in a comparable manner as IgG induced with the wild-type allergen.

CONCLUSIONS

We report the development of hypoallergenic reassembled Fel d 1 proteins suitable for vaccination and tolerance induction in cat-allergic patients.

Development and characterization of a recombinant, hypoallergenic, peptide-based vaccine for grass pollen allergy

Background

Grass pollen is one of the most important sources of respiratory allergies worldwide.

Objective

This study describes the development of a grass pollen allergy vaccine based on recombinant hypoallergenic derivatives of the major timothy grass pollen allergens Phl p 1, Phl p 2, Phl p 5, and Phl p 6 by using a peptide-carrier approach.

Methods

Fusion proteins consisting of nonallergenic peptides from the 4 major timothy grass pollen allergens and the PreS protein from hepatitis B virus as a carrier were expressed in Escherichia coli and purified by means of chromatography. Recombinant PreS fusion proteins were tested for allergenic activity and T-cell activation by means of IgE serology, basophil activation testing, T-cell proliferation assays, and xMAP Luminex technology in patients with grass pollen allergy. Rabbits were immunized with PreS fusion proteins to characterize their immunogenicity.

Results

Ten hypoallergenic PreS fusion proteins were constructed, expressed, and purified. According to immunogenicity and induction of allergen-specific blocking IgG antibodies, 4 hypoallergenic fusion proteins (BM321, BM322, BM325, and BM326) representing Phl p 1, Phl p 2, Phl p 5, and Phl p 6 were included as components in the vaccine termed BM32. BM321, BM322, BM325, and BM326 showed almost completely abolished allergenic activity and induced significantly reduced T-cell proliferation and release of proinflammatory cytokines in patients' PBMCs compared with grass pollen allergens. On immunization, they induced allergen-specific IgG antibodies, which inhibited patients' IgE binding to all 4 major allergens of grass pollen, as well as allergen-induced basophil activation.

Conclusion

A recombinant hypoallergenic grass pollen allergy vaccine (BM32) consisting of 4 recombinant PreS-fused grass pollen allergen peptides was developed for safe immunotherapy of grass pollen allergy.

The high molecular weight glutenin subunit Bx7 allergen from wheat contains repetitive IgE epitopes

BACKGROUND

Wheat is one of the most common food allergen sources for children and adults. The aim of this study was to characterize new wheat allergens using an IgE discovery approach and to investigate their IgE epitopes.

METHODS

A cDNA expression library representing the wheat transcriptome was constructed in phage lambda gt11 and screened with IgE antibodies from wheat food allergic patients. IgE-reactive cDNA clones coding for portions of high molecular weight (HMW) glutenin subunits were identified by sequence analysis of positive clones. IgE epitopes were characterized using recombinant fragments from the HMW Bx7 and synthetic peptides thereof for testing of allergic patients' sera and in basophil degranulation assays.

RESULTS

We found that the major IgE-reactive areas of HMW glutenins are located in the repetitive regions of the protein and could show that two independent IgE-reactive fragments from HMW Bx7 contained repetitive IgE epitopes.

CONCLUSIONS

Our results demonstrate that IgE antibodies from wheat food allergic patients can recognize repetitive epitopes in one of the important wheat food allergens. Recombinant HMW Bx7 may be included into the panel of allergens for component-resolved diagnosis of wheat food allergy.

Structural integrity of the antigen is a determinant for the induction of T-helper type-1 immunity in mice by gene gun vaccines against E. coli beta-galactosidase

The type of immune response is critical for successful protection and typically determined by pathogen-associated danger molecules. In contrast, protein antigens are usually regarded as passive target structures. Here, we provide evidence that the structure of the antigen can profoundly influence the type of response that is elicited under else identical conditions. In mice, gene gun vaccines induce predominantly Th2-biased immune reactions against most antigens. One exception is E. coli beta-galactosidase (βGal) that induces a balanced Th1/Th2 response. Because both, the delivered material (plasmid DNA-coated gold particles) as well as the procedure (biolistic delivery to the skin surface) is the same as for other antigens we hypothesized that Th1 induction could be a function of βGal protein expressed in transfected cells. To test this we examined gene gun vaccines encoding structural or functional variants of the antigen. Employing a series of gene gun vaccines encoding individual structural domains of βGal, we found that neither of them induced IgG2a antibodies. Even disruption of the homo-tetramer association of the native protein by deletion of a few N-terminal amino acids was sufficient to abrogate IgG2a production. However, enzymatically inactive βGal with only one point mutation in the catalytic center retained the ability to induce Th1 reactions. Thus, structural but not functional integrity of the antigen must be retained for Th1 induction. βGal is not a Th1 adjuvant in the classical sense because neither were βGal-transgenic ROSA26 mice particularly Th1-biased nor did co-administration of a βGal-encoding plasmid induce IgG2a against other antigens. Despite this, gene gun vaccines elicited Th1 reactions to antigens fused to the open reading frame of βGal. We interpret these findings as evidence that different skin-borne antigens may be differentially handled by the immune system and that the three-dimensional structure of an antigen is an important determinant for this.

Allergens are not pathogens: why immunization against allergy differs from vaccination against infectious diseases

Vaccination against infectious diseases has been one of the major breakthroughs in human medical history, saving the lives of millions of people each year. More recently, prophylactic vaccination against non-infectious diseases such as cancer, Alzheimer’s disease, diabetes, and type I allergy is being investigated. Particularly in case of IgE-driven allergic disorders, which afflict almost a quarter of the population in highly developed countries, preventative measures would represent a major improvement for patients’ health as well as an economic relief for public health services. As an alternative to allergen-specific immunotherapy, prophylactic vaccination against type I allergic diseases could slow down or even stop the progress of the allergy pandemic. Allergen-encoding gene-based vaccines, i.e., plasmid DNA and mRNA vaccines, provide the advantage of purity over crude allergen extracts, which involve the risk of de novo sensitizations. Furthermore, these formulations have been demonstrated to induce T helper 1 as well as T regulatory immune responses—a pre-requisite for prophylactic intervention against allergies. However, prophylactic vaccines against environmental allergens strikingly differ from conventional vaccines against infectious diseases or therapeutic approaches concerning the underlying immunological mechanisms.

The influence of antigen targeting to sub-cellular compartments on the anti-allergic potential of a DNA vaccine

•

DNA vaccine targeting affected humoral and cellular immunity.

•

Elevated Th1 immunity did not correlate with superior protection from sensitization.

•

Plasmid vaccination boosted Treg numbers within re-stimulated splenocyte cultures.

Background

Gene vaccines offer attractive rationales for prophylactic as well as therapeutic treatments of type I allergies. DNA and mRNA vaccines have been shown to prevent from allergic sensitization and to counterbalance established allergic immune reactions. Recent advances in gene vaccine manipulation offer additional opportunities for modulation of T helper cell profiles by specific targeting of cellular compartments.

Methods

DNA vaccines encoding the major birch pollen allergen Bet v 1.0101 were equipped with different leader sequences to shuttle the antigen to lysosomes (LIMP-II), to trigger cellular secretion (hTPA), or to induce proteasomal degradation via forced ubiquitination (ubi). Mice were pre-vaccinated with these constructs and the protective efficacy was tested by subcutaneous Th2-promoting challenges, followed by allergen inhalation. IgG antibody subclass distribution and allergen-specific IgE as well as cytokine profiles from re-stimulated splenocytes and from BALFs were assessed. The cellular composition of BALFs, and lung resistance and compliance were determined.

Results

Immunization with all targeting variants protected from allergic sensitization, i.e. IgE induction, airway hyperresponsiveness, lung inflammation, and systemic and local Th2 cytokine expression. Surprisingly, protection did not clearly correlate with the induction of a systemic Th1 cytokine profile, but rather with proliferating CD4+ CD25+ FoxP3+ T regulatory cells in splenocyte cultures. Targeting the allergen to proteasomal or lysosomal degradation severely down-regulated antibody induction after vaccination, while T cell responses remained unaffected. Although secretion of antigen promoted the highest numbers of Th1 cells, this vaccine type was the least efficient in suppressing the establishment of an allergic immune response.

Conclusion

This comparative analysis highlights the modulatory effect of antigen targeting on the resulting immune response, with a special emphasis on prophylactic anti-allergy DNA vaccination. Targeting the antigen to proteasomal or lysosomal degradation reduces the availability of native allergen, thereby rendering the vaccine hypoallergenic without compromising efficacy, an important feature for a therapeutic setting.

Laser microporation of the skin: prospects for painless application of protective and therapeutic vaccines

Introduction:

In contrast to muscle and subcutaneous tissue, the skin is easily accessible and provides unique immunological properties. Increasing knowledge about the complex interplay of skin-associated cell types in the development of cutaneous immune responses has fueled efforts to target the skin for vaccination as well as for immunotherapy.

Areas covered:

This review provides an overview on skin layers and their resident immunocompetent cell types. Advantages and shortcomings of standard methods and innovative technologies to circumvent the outermost skin barrier are addressed. Studies employing fractional skin ablation by infrared lasers for cutaneous delivery of drugs, as well as high molecular weight molecules such as protein antigens or antibodies, are reviewed, and laserporation is introduced as a versatile transcutaneous vaccination platform. Specific targeting of the epidermis or the dermis by different laser settings, the resulting kinetics of uptake and transport and the immune response types elicited are discussed, and the potential of this transcutaneous delivery platform for allergen-specific immunotherapy is demonstrated.

Expert opinion:

Needle-free and painless vaccination approaches have the potential to replace standard methods due to their improved safety and optimal patient compliance. The use of fractional laser devices for stepwise ablation of skin layers might be advantageous for both vaccination against microbial pathogens, as well as immunotherapeutic approaches, such as allergen-specific immunotherapy. Thorough investigation of the underlying immunological mechanisms will help to provide the knowledge for a rational design of transcutaneous protective/therapeutic vaccines.

Transcutaneous delivery of CpG-adjuvanted allergen via laser-generated micropores

BACKGROUND

Two main shortcomings of classical allergen-specific immunotherapy are long treatment duration and low patient compliance. Utilizing the unique immunological features of the skin by transcutaneous application of antigen opens new approaches not only for painless vaccine delivery, but also for allergen-specific immunotherapy. Under certain conditions, however, barrier disruption of the skin favors T helper 2-biased immune responses, which may lead to new sensitizations.

METHODS

In a prophylactic approach, an infra-red laser device was employed, producing an array of micropores of user-defined number, density, and depth on dorsal mouse skin. The grass pollen allergen Phl p 5 was administered by patch with or without the T helper 1-promoting CpG oligodeoxynucleotide 1826 as adjuvant, or was subcutaneously injected. Protection from allergic immune responses was tested by sensitization via injection of allergen adjuvanted with alum, followed by intranasal instillation. In a therapeutic setting, pre-sensitized mice were treated either by the standard method using subcutaneous injection or via laser-generated micropores. Sera were analyzed for IgG antibody subclass distribution by ELISA and for IgE antibodies by a basophil mediator release assay. Cytokine profiles from supernatants of re-stimulated lymphocytes and from bronchoalveolar lavage fluids were assessed by flow cytometry using a bead-based assay. The cellular composition of lavage fluids was determined by flow cytometry.

RESULTS

Application of antigen via micropores induced T helper 2-biased immune responses. Addition of CpG balanced the response and prevented from allergic sensitization, i.e. IgE induction, airway inflammation, and expression of T helper 2 cytokines. Therapeutic efficacy of transcutaneous immunotherapy was equal compared to subcutaneous injection, but was superior with respect to suppression of already established IgE responses.

CONCLUSIONS

Transcutaneous immunotherapy via laser-generated micropores provides an efficient novel platform for treatment of type I allergic diseases. Furthermore, immunomodulation with T helper 1-promoting adjuvants can prevent the risk for new sensitization.

Generation of hypoallergenic neoglycoconjugates for dendritic cell targeted vaccination: a novel tool for specific immunotherapy

The incidence of allergic disorders and asthma continuously increased over the past decades, consuming a considerable proportion of the health care budget. Allergen-specific subcutaneous immunotherapy represents the only intervention treating the underlying causes of type I allergies, but still suffers from unwanted side effects and low compliance. There is an urgent need for novel approaches improving safety and efficacy of this therapy. In the present study we investigated carbohydrate-mediated targeting of allergens to dermal antigen-presenting cells and its influence on immunogenicity and allergenicity. Mannan, high (40 kDa) and low (6 kDa) molecular weight dextran, and maltodextrin were covalently attached to ovalbumin and papain via mild carbohydrate oxidation resulting in neoglycocomplexes of various sizes. In particular, mannan-conjugates were efficiently taken up by dendritic cells in vivo leading to elevated humoral immune responses against the protein moiety and a shift from IgE to IgG. Beyond providing an adjuvant effect, papain glycocomplexes also proved to mask B-cell epitopes, thus rendering the allergen derivative hypoallergenic.

The present data demonstrate that carbohydrate-modified allergens combine targeting of antigen presenting cells with hypoallergenicity, offering the potential for low dose allergen-specific immunotherapy while concomitantly reducing the risk of side effects.

Transcutaneous immunotherapy via laser-generated micropores efficiently alleviates allergic asthma in Phl p 5-sensitized mice

Background

Specific immunotherapy via the subcutaneous or oral route is associated with local and, in some cases, systemic side effects and suffers from low patient compliance. Due to its unique immunological features, the skin represents a promising target tissue for effective and painless treatment of type I allergy. The current study was performed to compare the efficacy of transcutaneous immunotherapy via laser-generated micropores to subcutaneous injection.

Methods

BALB/c mice were sensitized by intraperitoneal injection of recombinant grass pollen allergen Phl p 5 together with alum. Subsequently, lung inflammation was induced by repeated intranasal challenge. During the treatment phase, adjuvant-free Phl p 5 was applied in solution to microporated skin or was subcutaneously injected. Lung function and cellular infiltration; Phl p 5–specific serum levels of IgG1, IgG2a, and IgE; and cytokine levels in bronchoalveolar lavage fluids as well as in supernatants of splenocyte cultures were assessed.

Results

Both therapeutic approaches reduced airway hyperresponsiveness and leukocyte infiltration into the lungs. Whereas subcutaneous immunotherapy induced a systemic increase in Th2-associated cytokine secretion, transcutaneous application revealed a general downregulation of Th1/Th2/Th17 responses. Successful therapy was associated with induction of IgG2a and an increase in FOXP3+ CD4+ T cells.

Conclusions

Transcutaneous immunotherapy via laser microporation is equally efficient compared with conventional subcutaneous treatment but avoids therapy-associated boosting of systemic Th2 immunity. Immunotherapy via laser-microporated skin combines a painless application route with the high efficacy known from subcutaneous injections and therefore represents a promising alternative to established forms of immunotherapy.

Molecular and immunological characterization of Tri a 36, a low molecular weight glutenin, as a novel major wheat food allergen

Wheat is an essential element in our nutrition but one of the most important food allergen sources. Wheat allergic patients often suffer from severe gastrointestinal and systemic allergic reactions after wheat ingestion. In this study, we report the molecular and immunological characterization of a new major wheat food allergen, Tri a 36. The cDNA coding for a C-terminal fragment of Tri a 36 was isolated by screening a wheat seed cDNA expression library with serum IgE from wheat food-allergic patients. Tri a 36 is a 369-aa protein with a hydrophobic 25-aa N-terminal leader peptide. According to sequence comparison it belongs to the low m.w. glutenin subunits, which can be found in a variety of cereals. The mature allergen contains an N-terminal domain, a repetitive domain that is rich in glutamine and proline residues, and three C-terminal domains with eight cysteine residues contributing to intra- and intermolecular disulfide bonds. Recombinant Tri a 36 was expressed in Escherichia coli and purified as soluble protein. It reacted with IgE Abs of ∼80% of wheat food-allergic patients, showed IgE cross-reactivity with related allergens in rye, barley, oat, spelt, and rice, and induced specific and dose-dependent basophil activation. Even after extensive in vitro gastric and duodenal digestion, Tri a 36 released distinct IgE-reactive fragments and was highly resistant against boiling. Thus, recombinant Tri a 36 is a major wheat food allergen that can be used for the molecular diagnosis of, and for the development of specific immunotherapy strategies against, wheat food allergy.

Effects of ionized waterfall aerosol on pediatric allergic asthma

OBJECTIVE

Ionized water aerosols have been suggested to exert beneficial health effects on pediatric allergic asthma. Their effect was evaluated in a randomized controlled clinical trial as part of a summer asthma camp.

METHODS

Asthmatic allergic children (n = 54) spent 3 weeks in an alpine asthma camp; half of the group was exposed to water aerosol of an alpine waterfall for 1 hour per day, whereas the other half spent the same time at a "control site". Immunological analysis, lung function testing, and fractional exhaled nitric oxide (FeNO) testing were performed during the stay, and sustaining effects were evaluated 2 months later. Symptom score testing was done over a period of 140 days.

RESULTS

The water aerosol group showed a significant improvement in all lung function parameters, whereas only the peak expiratory flow improved in the control group. All patients showed a significant improvement in symptom score and a significant decrease in FeNO after the camp. Only the water aerosol group exhibited a long-lasting effect on asthma symptoms, lung function, and inflammation in the follow-up examination. Induction of interleukin (IL)-10 and regulatory T (Treg) cells was measured in both groups, with a pronounced increase in the water aerosol group. IL-13 was significantly decreased in both groups, whereas IL-5 and eosinophil cationic protein were decreased only in the water aerosol group.

CONCLUSIONS

Our findings confirm the induction of Treg cells and reduction in inflammation by climate therapy. They indicate a synergistic effect of water aerosols resulting in a long-lasting beneficial effect on asthma symptoms, lung function, and airway inflammation.

Transcutaneous vaccination via laser microporation

Driven by constantly increasing knowledge about skin immunology, vaccine delivery via the cutaneous route has recently gained renewed interest. Considering its richness in immunocompetent cells, targeting antigens to the skin is considered to be more effective than intramuscular or subcutaneous injections. However, circumvention of the superficial layer of the skin, the stratum corneum, represents the major challenge for cutaneous immunization. An optimal delivery method has to be effective and reliable, but also highly adaptable to specific demands, should avoid the use of hypodermic needles and the requirement of specially trained healthcare workers. The P.L.E.A.S.E.® (Precise Laser Epidermal System) device employed in this study for creation of aqueous micropores in the skin fulfills these prerequisites by combining the precision of its laser scanning technology with the flexibility to vary the number, density and the depth of the micropores in a user-friendly manner. We investigated the potential of transcutaneous immunization via laser-generated micropores for induction of specific immune responses and compared the outcomes to conventional subcutaneous injection. By targeting different layers of the skin we were able to bias polarization of T cells, which could be modulated by addition of adjuvants. The P.L.E.A.S.E.® device represents a highly effective and versatile platform for transcutaneous vaccination.

Molecular characterization of wheat allergens specifically recognized by patients suffering from wheat-induced respiratory allergy

BACKGROUND

Wheat (Triticum aestivum) is an important allergen source responsible for various clinical manifestations of allergy (i.e. food allergy, pollen allergy, respiratory allergy to flour-Baker's asthma).

OBJECTIVE

The objective of this study was the molecular and immunological characterization of new recombinant wheat allergens and to evaluate their usefulness for the diagnosis of allergy to wheat.

METHODS

A T. aestivum cDNA library was constructed and screened with serum IgE from patients suffering from wheat allergy to identify cDNAs coding for new wheat allergens. The allergen-encoding cDNAs were expressed in Escherichia coli and purified to homogeneity. IgE reactivity of recombinant proteins was analysed in RAST-based, non-denaturing dot blot experiments and by ELISA with sera from wheat allergic patients and their allergenic activity was assessed in basophil degranulation experiments.

RESULTS

We report the molecular characterization, recombinant expression and purification of five wheat allergens, a thioredoxin h isoform, glutathione transferase, 1-Cys-peroxiredoxin, profilin and dehydrin. Homologous proteins were identified by sequence comparisons in various plants. 1-Cys-peroxiredoxin appeared to be the most relevant of the newly identified wheat allergens according to prevalence of IgE recognition and results from basophil degranulation experiments. It showed IgE cross-reactivity with seed proteins from barley, rye, rice, maize, soy, oat and spelt. 1-Cys-peroxiredoxin, glutathione transferase and dehydrin were mainly recognized by patients with baker's asthma but not wheat-induced food allergy.

CONCLUSION AND CLINICAL RELEVANCE

The characterized recombinant wheat allergens may be useful for the development of serological tests which allow the discrimination of different clinical manifestations of wheat allergy.

Transcutaneous gene gun delivery of hNC16A Induces BPAG2-specific tolerance

Immune recognition and rejection of tissues expressing transfected genes is a major complication of gene replacement therapy for inherited genetic disorders. Owing to the high immunogenicity of human bullous pemphigoid antigen 2 (hBPAG2), the induction and maintenance of tolerance to this neo-antigen is essential to deliver the gene product to patients with epidermolysis bullosa junctionalis. In a skin grafting mouse model, we used gene gun transfection with a construct encoding hNC16A, the immunodominant domain of hBPAG2, to induce antigen-specific immune tolerance. Eighty percent of wild-type mice transfected with hNC16A showed long-term survival of skin grafts expressing hBPAG2. Tolerance was stable and transferable by T cells but not by B cells of tolerant mice to naive hosts. A dense Foxp3(+) regulatory T-cell (T(reg)) infiltrate was noticed in grafts of tolerant mice and depletion of these cells resulted in a loss of tolerance. Taken together, we show that long-lasting hBPAG2-specific tolerance was induced with gene gun delivery of hNC16A through a T(reg)-dependent mechanism. This is of relevance to patients undergoing gene therapy and has broader implications for the treatment of antigen-specific autoimmune diseases.

Targeting of the hNC16A collagen domain to dendritic cells induces tolerance to human type XVII collagen

Antibodies, specific to murine DEC205, can be used to target antigens to dendritic cells. The immunodominant domain of human type XVII collagen, hNC16A, was fused to this antibody (DEC-hNC16A) and was administered as expression plasmid by gene gun transfection with the aim of inducing tolerance to human type XVII collagen in a skin transplantation model. Mice transfected with DEC-hNC16A were challenged with skin grafts from transgenic mice engineered to express human type XVII collagen. Graft survival was either prolonged or grafts were accepted infinitely (33% and 16%, respectively) upon treatment with DEC-hNC16A while 100% of grafts were rejected in untreated controls. Graft acceptance was associated with the absence of a CD4+ infiltrate and a dense CD8+ T-cell infiltrate and was not strictly dependent on antibody production. Our results show that DEC-hNC16A targets dendritic cells in vivo leading to prolonged survival of transgenic skin grafts. This indicates that DEC205-targeting may be used for the induction of tolerance to skin antigens, which would increase the chances of successful skin gene therapy of epidermolysis bullosa patients.

T cell epitopes of the timothy grass pollen allergen Phl p 5 of mice and men and the detection of allergen-specific T cells using Class II Ultimers

BACKGROUND

Knowledge of allergen-specific T cell epitopes is a prerequisite not only for therapeutic approaches but also for elucidating immunological mechanisms of type I allergy. Ex vivo detection of allergen-specific T cells using class II tetramer technology has become an important tool for investigating immune responses in atopic and healthy individuals.

METHODS

Using (3)H-thymidine incorporation assays, T cell epitopes specific for the major timothy grass pollen allergen Phl p 5.0101 were mapped in 11 allergic donors and two different mouse strains. Different protocols for expansion/restimulation of T cells from the blood of allergic donors and detection of allergen-specific T cells by Class II Ultimer staining were evaluated.

RESULTS

We identified several new Phl p 5.0101 class II T cell epitopes in allergic patients and confirmed previously published ones. Additionally, we discovered the major T cell epitopes in BALB/c and C57BL/6 mice. Using a novel Class II Ultimer, we detected epitope-specific T cells expanded from the blood of an allergic donor.

CONCLUSIONS

Epitope mapping of Phl p 5.0101 revealed an immunodominant epitope in BALB/c and C57BL/6 mice and an immunodominant region in humans (amino acids 259-282), which was recognized by 8 out of 11 allergic donors. Detection of Phl p 5-specific T cells was demonstrated using a Class II Ultimer specific for epitope 196-210. Successful detection of ultimer-positive T cells was strongly dependent on a resting phase after in vitro expansion.

Recombinant allergen-based monitoring of antibody responses during injection grass pollen immunotherapy and after 5 years of discontinuation

BACKGROUND

Subcutaneous injection immunotherapy (SCIT) is considered as antigen-specific and disease-modifying treatment with long-lasting effect.

METHODS

We used a panel of recombinant grass pollen allergens for analyzing allergen-specific IgE, IgG(1) -IgG(4) , IgM, IgA, and light-chain (kappa, lambda) responses in grass pollen-allergic patients who had received one course of injection immunotherapy (SCIT) with an aluminum hydroxide-adsorbed grass pollen extract or only anti-inflammatory treatment. Serum samples were analyzed before and after 5 months of treatment as well as after 5 years.

RESULTS

After 5 months of SCIT but not of anti-inflammatory treatment, IgG(1) > IgG(4) > IgG(2) > IgA antibody responses using both kappa and lambda light chains specific for major grass pollen allergens (Phl p 1, Phl p 5, Phl p 6, Phl p 2) increased significantly, whereas specific IgM or IgG(3) levels were unaltered. Allergen-dependent basophil degranulation was only inhibited with SCIT sera containing therapy-induced allergen-specific IgG antibodies. Likewise, decreases in Phl p 1- and Phl p 5-specific IgE levels and significant (P<0.001) reduction in symptom and medication scores were found only in the SCIT group but not in the group of patients receiving anti-inflammatory treatment. After 5 years, allergen-specific IgG antibody levels in the SCIT group had returned to baseline levels and there was no significant difference regarding symptoms between the SCIT and non-SCIT groups.

CONCLUSION

The results from our observational study demonstrate that only SCIT but not anti-inflammatory treatment induces allergen-specific IgG and reduces boosts of allergen-specific IgE production but that one SCIT course was not sufficient to achieve long-term immunological and clinical effects.

Molecular characterization of Der p 10: a diagnostic marker for broad sensitization in house dust mite allergy

BACKGROUND

Tropomyosins represent clinically relevant seafood allergens but the role of mite tropomyosin, Der p 10, in house dust mite (HDM) allergy has not been studied in detail.

OBJECTIVE

To express and purify a recombinant Der p 10 with equivalent IgE reactivity as natural Der p 10 and to evaluate its IgE reactivity and allergenic activity in HDM-allergic patients.

METHODS

rDer p 10 was expressed in Escherichia coli, purified and characterized by mass spectrometry and circular dichroism. It was tested for IgE reactivity in 1322 HDM-allergic patients. Detailed IgE-reactivity profiles to six HDM allergens (Der p 1, 2, 5, 7, 10, 21) were established for subgroups of Der p 10-positive and -negative patients. The allergenic activity of rDer p 10 was evaluated in basophil degranulation experiments.

RESULTS

rDer p 10 is an α-helical protein sharing IgE epitopes with nDer p 10. It is recognized by 15.2% of HDM-allergic patients. Der p 10-negative patients were primarily sensitized to Der p 1 and/or Der p 2, whereas Der p 10-positive patients reacted to several other HDM allergens besides the major allergens (Der p 1, Der p 2) or showed a rather selective Der p 10 reactivity. The allergenic activity of Der p 10 was generally low but patients could be identified who suffered from clinically relevant HDM allergy due to Der p 10 sensitization.

CONCLUSION AND CLINICAL RELEVANCE

Der p 10 may be a diagnostic marker for HDM-allergic patients with additional sensitization to allergens other than Der p 1 and Der p 2. Such patients may require attention when allergen-specific immunotherapy is considered.

Reshaping the Bet v 1 fold modulates T(H) polarization

BACKGROUND

Several alternative mechanisms have been proposed to explain why some proteins are able to induce a T(H)2-biased and IgE-mediated immune response. These include specific interactions with receptors of the innate immune system, proteolytic activities, allergen-associated carbohydrate structures, and intrinsic structural determinants.

OBJECTIVES

Available data suggest that a fold-dependent allergy-promoting mechanism could be a driving force for the T(H)2-polarization activity of Bet v 1, the major birch pollen allergen.

METHODS

Computer-aided sequence and fold analysis of the Bet v 1 family identified a short stretch susceptible for mutations inducing an altered fold of the entire molecule. With this knowledge, 7 consecutive amino acids of Bet v 1 were replaced with the homologous Mal d 1 sequence, creating the derivative BM4.

RESULTS

The minimal changes of the sequence led to a loss of the Bet v 1-like fold and influenced the immunologic behavior. Compared to wild-type Bet v 1, BM4 induced elevated T-cell proliferation of human PBMCs. In the mouse model, immunization with Bet v 1 absorbed to aluminum hydroxide triggered strong T(H)2 polarization, whereas BM4 immunization additionally recruited T(H)1 cells. Furthermore, the fold variant BM4 showed enhanced uptake by dendritic cells and a decreased susceptibility to endo-/lysosomal proteolysis.

CONCLUSION

Modifications in the 3-dimensional structure of Bet v 1.0101 resulted in a change of its immunologic properties. We observed that the fold alteration led to a modified crosstalk with dendritic cells and a shift of the immune response polarization toward a mixed T(H)1/T(H)2 cytokine production.