Bet v 1(142-156) is the dominant T-cell epitope of the major birch pollen allergen and important for cross-reactivity with Bet v 1-related food allergens
ABSTRACT Individuals with birch pollen allergy frequently experience hypersensitivity reactions to certain foods, primarily because of IgE antibodies specific for the major birch pollen allergen Bet v 1 that cross-react with homologous food allergens.
We sought to characterize the major T-cell epitopes of Bet v 1 and to investigate their involvement in the cellular cross-reactivity with homologous food allergens.
T-cell epitope mapping of Bet v 1 was performed by testing Bet v 1-specific T-cell lines derived from 57 individuals with birch pollen allergy, with overlapping peptides representing the entire allergen. T-cell lines and T-cell clones were stimulated with Bet v 1-related major allergens from apple (Mal d 1), cherry (Pru av 1), hazelnut (Cor a 1), celery (Api g 1), carrot (Dau c 1), and soybean (Gly m 4) and with peptides deduced from the C-terminal amino acid sequences of these molecules. Results Bet v 1 142-156 , positioned in the highly conserved C-terminal region of Bet v 1, was identified as the major T-cell epitope recognized by 61% of individuals. Most T lymphocytes specific for Bet v 1 142-156 were activated by one or more homologous food proteins or the respective peptides, as indicated by proliferation and cytokine production.
The major T-cell epitope of Bet v 1, Bet v 1 142-156 , plays an important role in the cellular cross-reactivity between this respiratory allergen and related food allergens. Thus T lymphocytes specific for Bet v 1 142-156 might be activated by various Bet v 1-related food allergens in vivo, even out of the pollen season.
- SourceAvailable from: Karl-Heinz Kogel
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- "PR10 proteins show a high degree of amino acid sequence identity with the birch pollen allergens of the Bet v 1 family and are the most important elicitors of pollen-related food allergy. Approximately 90% of patients allergic to birch pollen have IgE antibodies against Bet v 1 (Jahn-Schmid et al. 2005). Carrot (Daucus carota) allergy is also a common phenomenon in patients with birch pollen allergy. "
ABSTRACT: Pathogenesis-related protein-10 (PR10) is a ubiquitous small plant protein induced by microbial pathogens and abiotic stress that adversely contributes to the allergenic potency of many fruits and vegetables, including carrot. In this plant, two highly similar genes encoding PR10 isoforms have been isolated and designated as allergen Dau c 1.01 and Dau c 1.02. The aim of the study was to generate PR10-reduced hypoallergenic carrots by silencing either one of these genes in transgenic carrots by means of RNA interference (RNAi). The efficiency of gene silencing by stably expressed hairpin RNA (hnRNA) was documented by means of quantitative RT-PCR (qPCR) and immunoblotting. Quantification of the residual protein revealed that PR10 accumulation was strongly decreased compared with untransformed controls. Treatment of carrot plants with the PR protein-inducing chemical salicylic acid resulted in an increase of PR10 isoforms only in wild-type but not in Dau c 1-silenced mutants. The decrease of the allergenic potential in Dau c 1-silenced plants was sufficient to cause a reduced allergenic reactivity in patients with carrot allergy, as determined with skin prick tests (SPT). However, simultaneous silencing of multiple allergens will be required to design hypoallergenic carrots for the market. Our findings demonstrate the feasibility of creating low-allergenic food by using RNAi. This constitutes a reasonable approach to allergen avoidance.Transgenic Research 06/2011; 20(3):547-56. DOI:10.1007/s11248-010-9435-0 · 2.28 Impact Factor
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ABSTRACT: ABSTRACT Exosomes are nano-sized vesicles of endosomal origin which are secreted from several different cell types. Depending on their cellular source they have been suggested to have different functions, like having a role in antigen delivery and T cell activation (antigen presenting cell-derived exosomes) or a role in tolerance induction (epithelial cell-derived exosomes). In addition, exosomes have shown potential to be used in immunotherapy,both against infections and cancer. This thesis aimed at elucidating the presence of exosomes in vivo, develop methods to asses their function as immune regulators and to investigate if they may have a role in inflammatory responses such as allergies. Alot of investigations have been published on exosomes,derived from in vitro culture supernatants but very few studies have been performed,showing,the presence of exosomes,in vivo. Since the lung contain many,antigen presenting cells (APCs) and is a site of antigen entry we hypothesized,that bronchoalveolar lavage fluid (BALF) might contain exosomes. By flow cytometry analysis and immune electron microscopy we describe the novel finding ofexosomes,in BALF. These exosomes,expressed the antigen presenting molecules MHC class I and II, the co-stimulatory molecule CD86 and the tetraspanin protein CD63, suggesting them to be of APC origin, and to have a role in the immune defense of the lung. Exosomes from APCs have been proposed to have a role in T cell activation. However, there are