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  • 1
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background Ribosome-inactivating proteins (RIPs) are expressed in many plants. Because of their anti-infectious and anti-proliferative effects, intensive research is going on for applying these toxins in therapy against viral infections or malignancies. Recently, we demonstrated that type I allergy against RIPs from elderberry can occur.Objective Stimulated by our study, a group of RIP researchers reported that some of the employees had suspected allergy to RIPs.Methods and Results We tested their sera in ELISA on natural RIPs. Specific IgE in four subjects were found against dianthin30, gelonin, momordin, PAP-S, saporin, ricin and volkensin. In contrast, asparin and lychnin did not show any IgE binding. When separating extracts of plants containing the toxins in SDS-PAGE, RIPs appeared to be the predominant constituents. Interestingly, among the other plant proteins, they were exclusively recognized by IgE in immunoblot. RIPs derived from close botanical families share high sequence homologies. Nevertheless, in IgE inhibition experiments with human sera, cross-reactivity between RIPs also derived from non-related plants could be demonstrated.Conclusion We conclude that sensitization and IgE induction to RIPs may occur upon exposure. This has to be considered when applying them in therapy against malignancies or viral infections.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background and objective Biocompatible and biodegradable microparticles have gained interest as antigen delivery systems during the recent years. We investigated whether biodegradable poly(d,l-lactic-co-glycolic) acid (PLGA) nanospheres could be used as allergen vehicles for few-shot therapy of type I allergy.Methods The major birch pollen allergen Bet v 1 was encapsulated in PLGA nanospheres (PLGA-Bet v 1). We examined the antigenicity and the immune response to PLGA-Bet v 1 in a BALB/c mouse model.Results The antigenicity of Bet v 1 was largely unaffected by PLGA entrapment. When BALB/c mice were immunized subcutaneously with PLGA-Bet v 1, they formed allergen-specific IgG antibodies, but did not develop hypersensitivity to Bet v 1, as shown by type I skin tests. To evaluate their therapeutic potential, PLGA-Bet v 1 with or without Al(OH)3 or non-entrapped Bet v 1 with Al(OH)3 were used for single-shot treatment of sensitized mice. Both groups treated with PLGA-Bet v 1 developed high levels of Bet v 1-specific IgG2a antibodies (P〈0.01), whereas IgG1 levels decreased significantly (P〈0.01). Moreover, T cells from mice treated with PLGA-Bet v 1 showed IFN-γ and IL-10 production. The synthesis of these cytokines was enhanced in the groups where Al(OH)3 had been added to the vaccine formulation.Conclusion Allergen-loaded PLGA nanoparticles modulate an ongoing Th2 response in the BALB/c mouse model, as demonstrated by down-regulation of IgG1 and production of IFN-γ and IL-10. Our data strongly suggest that PLGA nanospheres can advantageously be used for formulations of allergen extracts or allergen derivatives for the few-shot treatment of type I allergy.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background Patients suffering from allergic rhinoconjunctivitis and dyspnoea during summer may exhibit these symptoms after contact with flowers or dietary products of the elderberry tree Sambucus nigra.Objective Patients with a history of summer hayfever were tested in a routine setting for sensitization to elderberry. Nine patients having allergic symptoms due to elderberry and specific sensitization were investigated in detail. We studied the responsible allergens in extracts from elderberry pollen, flowers and berries, and investigated cross-reactivity with allergens from birch, grass and mugwort.Methods Sera from patients were tested for IgE reactivity to elderberry proteins by one-dimensional (1D) and 2D electrophoresis/immunoblotting. Inhibition studies with defined allergens and elderberry-specific antibodies were used to evaluate cross-reactivity. The main elderberry allergen was purified by gel filtration and reversed-phase HPLC, and subjected to mass spectrometry. The in-gel-digested allergen was analysed by the MS/MS sequence analysis and peptide mapping. The N-terminal sequence of the predominant allergen was analysed.Results 0.6% of 3668 randomly tested patients showed positive skin prick test and/or RAST to elderberry. IgE in patients' sera detected a predominant allergen of 33.2 kDa in extracts from elderberry pollen, flowers and berries, with an isoelectric point at pH 7.0. Pre-incubation of sera with extracts from birch, mugwort or grass pollen rendered insignificant or no inhibition of IgE binding to blotted elderberry proteins. Specific mouse antisera reacted exclusively with proteins from elderberry. N-terminal sequence analysis, as well as MS/MS spectrometry of the purified elderberry allergen, indicated homology with ribosomal inactivating proteins (RIPs).Conclusion We present evidence that the elderberry plant S. nigra harbours allergenic potency. Independent methodologies argue for a significant homology of the predominant 33.2 kDa elderberry allergen with homology to RIPs. We conclude that this protein is a candidate for a major elderberry allergen with designation Sam n 1.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background and objective In previous studies we have generated mimotopes of Bet v 1, the major birch pollen allergen, by biopannings of phage-display random peptide libraries. In the present study, we analysed the humoral and cellular immune response to Bet v 1-mimotopes.Methods The mimotope CFPYCYPSESA, designated Bet mim 1, was used for intraperitoneal immunizations of BALB/c mice in phage-displayed form. For examination of the humoral immune response, enzyme-linked immunosorbent assay (ELISA) experiments were applied. Stimulation capacities were investigated in cultured mouse splenocytes and in humoral Bet v 1-specific T cell clones.Results We demonstrated that the Bet mim 1-induced murine antibody response against Bet v 1 was predominated by the IgG1 isotype. In these mice only the phage-displayed mimotopes, but neither the allergen nor the synthetic Bet mim 1-mimotopes were able to stimulate proliferation of cultured splenocytes. Using Bet v 1-specific T cell clones of allergic patients, phage-displayed and synthetic mimotopes were unable to stimulate T cell proliferation. Moreover, tolerance induction to Bet v 1 in mice by intranasal administration of Bet mim 1-phages or Bet mim 1-peptide failed.Conclusion Taking these results together, our data indicate that Bet mim 1 mimics a Bet v 1-epitope on the B cell but not on the T cell level. We suggest that the phage itself is responsible for the recruitment of T cells providing bystander help in the formation of a mimotope-specific humoral response.
    Type of Medium: Electronic Resource
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