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Pollen-allergic Individuals (pollen-allergic + individual)
Selected AbstractsBet,v,1, the major birch pollen allergen, initiates sensitization to Api,g,1, the major allergen in celery: evidence at the T,cell levelEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 12 2003Barbara Bohle Abstract Due to IgE cross-reactivity, birch pollen-allergic individuals frequently develop type,I hypersensitivity reactions to celery tuber. We evaluated the T,cell response to the major allergen in celeriac, Api,g,1, and the cellular cross-reactivity with its homologous major allergen in birch pollen, Bet,v,1. Api,g,1-specific T,cell lines (TCL) and clones (TCC) were established from peripheralblood mononuclear cells of allergic patients. Epitope mapping of Api,g,1 with overlapping Api,g,1-derived peptides revealed one dominant T,cell-activating region, Api,g,1109,126. TCL and TCC generated with Api,g,1 cross-reacted with the birch pollen allergen and, although initially stimulated with the food allergen, cellular responses to Bet,v,1 were stronger than to Api,g,1. Epitopemapping with Bet,v,1-derived peptides revealed that T,cells specific for several distinct epitopes distributed over the complete Bet,v,1 molecule could be activated by Api,g,1. Bet,v,1109,126 was identified as the most important T,cell epitope for cross-reactivity with Api,g,1. This epitope shares 72% amino acid sequence similarity with the major T,cell-activating region of the food allergen, Api,g,1109,126. Our data provide evidence that humoral as well as cellular reactivity to the major celery allergen is predominantly based on cross-reactivity with the major birch pollen allergen. The activation of Bet,v,1-specific Th2 cells by Api,g,1, in particular outside the pollen season, may have consequences for birch pollen-allergic individuals. [source] Identification of B-cell epitopes of Bet v 1 involved in cross-reactivity with food allergensALLERGY, Issue 4 2009E. Klinglmayr Background:, The pollen-food syndrome (PFS) is an association of food allergies to fruits, nuts, and vegetables in patients with pollen allergy. Mal d 1, the major apple allergen, is one of the most commonly associated food allergens for birch pollen-allergic patients suffering from PFS. Although the reactions are due to cross-reactive IgE antibodies originally raised against pollen Bet v 1, not every Bet v 1-allergic patient develops clinical reactions towards apple. Aim of the study:, We speculate that distinct IgE epitopes are responsible for the clinical manifestation of PFS. To test this hypothesis we grafted five Mal d 1 stretches onto Bet v 1. The grafted regions were 7- or 8-amino acids long encompassing amino acids residues previously shown to be crucial for IgE recognition of Bet v 1. Methods:, A Bet v 1-Mal d 1 chimeric protein designated BMC was expressed in Escherichia coli and purified to homogeneity. IgE reactivity of BMC was tested with patients' sera originating from (i) Bet v 1-allergic patients displaying no clinical symptoms upon ingestion of apples; and (ii) Bet v 1-allergic patients displaying allergic symptoms upon ingestion of apples and other Bet v 1-related foods. Results and conclusion:, Compared to birch pollen-allergic individuals, patients suffering from PFS showed significantly higher IgE reactivity with BMC (chimeric protein). The results suggest that the Mal d 1 regions grafted onto the Bet v 1 sequence comprise important IgE epitopes recognized by Bet v 1-allergic patients suffering from allergy to apples. [source] Inhibition of human allergic T-helper type 2 immune responses by induced regulatory T cells requires the combination of interleukin-10-treated dendritic cells and transforming growth factor-, for their inductionCLINICAL & EXPERIMENTAL ALLERGY, Issue 12 2006I Bellinghausen Summary Background In grass pollen-allergic individuals, T cell anergy can be induced by IL-10-treated dendritic cells (IL-10-DC) resulting in the suppression of T helper type 1 (Th1) as well as Th2 cells. This study was performed to analyse whether such IL-10-DC-treated T cells are able to act as regulatory T cells (Treg) suppressing the function of other T cells in the periphery. As transforming growth factor (TGF)-, is also a potential inducer of Treg, we additionally analysed the inhibitory capacity of TGF-,-treated T cells in this system. Materials and Methods Freshly isolated CD4+ or CD4+CD25, T cells from grass pollen-allergic donors were stimulated with autologous mature monocyte-derived allergen-pulsed DC in the presence or absence of T cells previously cultured with IL-10-DC- and/or TGF-,. Results Anergic T cells induced by allergen-pulsed IL-10-treated DC or allergen-pulsed DC and TGF-, enhanced IL-10 production and strongly inhibited IFN-, production of freshly prepared peripheral CD4+ or CD4+CD25, T cells while proliferation and Th2 cytokine production were only slightly reduced. The combination of allergen-pulsed IL-10-treated DC and TGF-, had an additional effect leading to a significant suppression also of Th2 cytokine production and proliferation. Suppression was not antigen-specific and was mainly mediated by cell-to-cell contact and by the molecule-programmed death-1 and only partially by CTLA-4, TGF-, and IL-10. Conclusion These data demonstrate that regulatory T cells that also suppress Th2 cytokine production are induced by two signals: TGF-, and IL-10-DC. This is of importance for the regulation of allergic immune responses and might be exploited for future therapeutic strategies for allergic diseases. [source] Characterization of the T cell response to the major hazelnut allergen, Cor a 1.04: evidence for a relevant T cell epitope not cross-reactive with homologous pollen allergensCLINICAL & EXPERIMENTAL ALLERGY, Issue 10 2005B. Bohle Summary Background IgE antibodies specific for the major birch-pollen allergen, Bet v 1, cross-react with homologous allergens in particular foods, e.g. apples, carrots and hazelnuts. In a high number of tree pollen-allergic individuals, this cross-reactivity causes clinical symptoms, commonly known as the ,birch-fruit-syndrome'. Objective To characterize the T cell response to the Bet v 1-related major allergen in hazelnuts, Cor a 1.04, and its cellular cross-reactivity with Bet v 1 and the homologous hazel pollen allergen, Cor a 1. Methods Using recombinant Cor a 1.04, T cell lines (TCL) and T cell clones (TCC) were established from peripheral blood mononuclear cells of tree pollen-allergic patients with associated food allergy. T cell epitopes were determined using overlapping synthetic peptides in Cor a 1.04-reactive TCL and TCC. In parallel, reactivity to Bet v 1 and Cor a 1 was tested. Results In total, 20 distinct T cell epitopes on the hazelnut allergen were identified. Several Cor a 1.04-specific TCL and TCC reacted with pollen allergens albeit less pronounced than with the hazelnut allergen. Several Cor a 1.04-specific TCC did not react with pollen allergens. Interestingly, these clones were found to react with the Bet v 1-related major allergen in carrots, Dau c 1. The cellular cross-reactivity between both food allergens could be associated with the most frequently recognized T cell epitope of Cor a 1.04, Cor a 1.04142,153. Conclusions The major hazelnut allergen cross-reacts with the major allergens of birch and hazel pollen but apparently contains a relevant T cell epitope not shared with pollen allergens. Our finding may have important implications for the specific immunotherapy of tree pollen-allergic patients suffering from concomitant hazelnut allergy. [source] Sensitization to cross-reactive carbohydrate determinants and the ubiquitous protein profilin: mimickers of allergyCLINICAL & EXPERIMENTAL ALLERGY, Issue 1 2004D. G. Ebo Summary Background During the last decade, evidence has been provided for profilins and cross-reactive carbohydrate determinants (CCDs) to be capable of inducing cross-reactive IgE antibodies with little clinical relevance. Objective To investigate the prevalence of sensitization to CCD and profilin in isolated allergies (birch, timothy grass, house dust mite, pets (cat and/or dog), natural rubber latex (NRL) and hymenoptera venom). To study the contribution of anti-CCD and anti-profilin IgE antibodies as a cause of clinically irrelevant IgE for NRL and apple. Methods For the first part of the study, 100 patients with inhalant allergy, 17 patients with NRL allergy and 40 patients with venom anaphylaxis were enrolled. Diagnosis was based on a questionnaire and a positive IgE determination and skin test for relevant allergen. Patients were identified as sensitized to CCD if they had a negative prick test and positive IgE for the glycoprotein bromelain. Sensitization to profilin was assessed by IgE for rBet v 2 (recombinant birch profilin). For the second part of the study, sera containing IgE against apple (n=82) or NRL (n=38) were classified as true-negative or false-positive according to the presence or absence of an oral allergy syndrome (OAS) or NRL-induced anaphylaxis. In these patients, sensitization to CCD and profilin was evaluated as described above. Results No sensitization to bromelain-type CCD and profilin was found in isolated birch pollen or NRL allergy. In contrast, sensitization to bromelain-type CCD was found in 4/17 patients with isolated grass pollinosis, 5/24 patients with combined pollinosis (birch, timothy, mugwort) and 7/33 patients with venom anaphylaxis. Sensitization to profilin was almost restricted to patients with combined pollen allergy (5/24). In pollen-allergic individuals with a false-positive IgE against NRL the prevalence of sensitization to bromelain-type CCD and profilin IgE was higher than in NRL-allergic patients (P<0.00001 and P=0.0006, respectively). In pollen-allergic individuals with a false-positive IgE to apple, the frequency of sensitization to bromelain-type CCD was higher than in OAS patients (P=0.004). Clinically irrelevant NRL and apple were also found in four and five out of the seven patients sensitized to venom CCD, respectively. In pollinosis, clinically irrelevant NRL and apple IgE antibodies were inhibited by bromelain and recombinant birch profilin, whereas in isolated venom anaphylaxis these antibodies were inhibited by bromelain. Conclusions Patients monoallergic to NRL or birch pollen showed no sensitization to bromelain-type CCD or profilin. Sensitization to profilin and/or bromelain-type CCD, caused by pollen (timothy grass, mugwort) or hymenoptera venom allergens, can elicit false-positive IgE antibodies against NRL and apple. [source] | ||||||||||