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  • 11
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Clinical & experimental allergy 33 (2003), S. 0 
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We suggest that the coapplication of recombinant allergens and microarray technology can lead to the development of new forms of multi-allergen tests which allow the determining and monitoring of complex sensitization profiles of allergic patients in single assays. The allergen extracts which have so far been used for diagnosis only allowed the determining of whether an allergic patient is sensitized against a particular allergen source, but the disease-eliciting allergens could not be identified. Through the application of recombinant DNA technology a rapidly growing panel of recombinant allergen molecules has become available which meanwhile comprises the epitope spectrum of most of the important allergen sources. We demonstrate that microarray technology can be used to establish multi-allergen tests consisting of microarrayed recombinant allergen molecules. Microarrayed recombinant allergens can be used to determine and monitor the profile of disease-eliciting allergens using single tests that require minute amounts of serum from allergic patients. The wealth of diagnostic information gained through microarray-based allergy testing will likely improve diagnosis, prevention and treatment of allergy.
    Type of Medium: Electronic Resource
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  • 12
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background Almost no information is available regarding the prevalence of IgE-mediated allergies and the disease-eliciting allergens in tropical Africa.Objective To study IgE-mediated allergies and the allergen profile in allergic patients from Zimbabwe.Methods The frequency of sensitization to common environmental allergen sources was determined by skin prick testing in 650 allergic patients from Zimbabwe. Fifty representative sera were analysed for IgE reactivity to 20 respiratory and 20 food allergen extracts by multiallergen extract testing. The IgE reactivity profiles to recombinant pollen and mite allergens were compared between grass pollen- and mite-sensitized patients from Zimbabwe and central Europe. Sera from grass pollen-allergic patients were also analysed for IgE reactivity to nitrocellulose-blotted natural timothy grass and Bermuda grass pollen allergens.Results IgE-mediated allergies were found to be common in Zimbabwe. Similar to the situation in central Europe, mites and grass pollens represented the most prevalent allergen sources. However, the IgE reactivity profiles determined with single recombinant pollen and mite allergens revealed interesting differences between the European and African patients, which most likely reflect the local allergen exposure.Conclusions The striking differences regarding sensitization to grass pollen and mite allergens between African and European patients revealed by recombinant allergen-based testing emphasize the need for component-resolved allergy testing to optimize allergy prevention and therapy in different populations.
    Type of Medium: Electronic Resource
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  • 13
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background Type I allergy represents a severe health problem in industrialized countries where up to 20% of the population suffer froin allergic rhinitis, conjunctivitis and allergic asthma bronchiale and in severe cases from anaphylaxis. leading to death.Objective The aim of this study was to evaluate recombinant Bet v I, the major birch pollen allergen for in vivo and in vitro diagnosis of birch pollen allergy.Methods A group of 51 birch pollen allergic patients and eight non-allergic control individuals were tested for birch pollen allergy by skin-prick and intradennal testing, comparing commercial birch pollen extracts with recombinant Bet v I. Quantitative and qualitative serological testing was done with natural and recombinant allergens by radioallergosorbent test (RAST), enzyme-linked immunosorbent assay (ELISA) and immunoblotting.Results Recombinant Bet v I allowed accurate in vivo and in vitro diagnosis of tree pollen allergy in 49/51 patients tested. No false positive results were obtained in any in vitro assay system (ELISA. Westernblot) or by skin testing (skin-prick, intradermal test) with recombinant Bet v I.Conclusion Our results document that recombinant Bet v I produced in bacterial expression systems allows accurate in vitro and in vivo diagnosis of birch pollen allergy in 〉 95% of birch pollen allergic patients.
    Type of Medium: Electronic Resource
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  • 14
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background The allergens of the house dust mite (Dermatophagoides pteronyssinus, Der p), one of the most important indoor allergen sources, occur as isoallergens that differ in their amino acid sequence. These variations may influence allergenic activity and thus may have impact on diagnostic tests and specific immunotherapy.Objective We investigated whether single purified recombinant mite allergens contain the IgE epitopes of the natural Der p isoallergens.Methods A panel of purified recombinant (rDer p 2, 5, 7, 8, 10 and 14) and two natural (nDer p 1 and 4) mite allergens were used to establish IgE reactivity profiles of Der p allergic patients and to inhibit IgE reactivity to two-dimensionally separated Der p isoallergens. In addition, we determined the percentage of Der p extract-specific IgE which could be preadsorbed with a mixture of purified mite allergens (nDer p 1, rDer p 2, 5, 7, 8 and 10) from sera of mite-allergic patients (n=18) in a non-denaturing RAST-based inhibition.Results We demonstrate that single recombinant mite allergens inhibit IgE reactivity to the corresponding natural isoallergens. A mixture of purified mite allergens (nDer p 1, rDer p 2, 5, 7, 8 and 10) bound on an average 76% of Der p-specific IgE antibodies.Conclusion The studied recombinant and natural mite allergens contain a large portion of Der p-specific IgE and may be used for diagnostic tests and therapy of Der p allergy.
    Type of Medium: Electronic Resource
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  • 15
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background Allergen-specific immunotherapy represents a causal form of treatment for IgE-mediated allergies. The allergen extract-based analyses of immunotherapy-induced effects yielded highly controversial results regarding a beneficial role of therapy-induced IgG antibodies.Objective We analysed allergen-specific IgE, IgG subclass, and IgM responses in patients treated with a grass pollen allergy vaccine adjuvanted with monophosphoryl lipid A (MPL), a Th1-inducing agent, and in a placebo group using recombinant timothy grass pollen allergen molecules (rPhl p 1, rPhl p 2, rPhl p 5).Results The strong induction of allergen-specific IgG1 and IgG4 antibodies observed only in the actively treated group was associated with significant clinical improvement. Therapy-induced allergen-specific IgM and IgG2 responses were also noted in several actively treated patients. An inhibition of allergen-dependent basophil histamine release was only obtained with sera containing therapy-induced allergen-specific IgG, but not with sera obtained before therapy or from placebo-treated patients. Moreover, patients with therapy-induced allergen-specific IgG antibodies showed a reduced induction of allergen-specific IgE responses during seasonal grass pollen exposure.Conclusion Successful immunotherapy with the MPL-adjuvanted grass pollen allergy vaccine is associated with the production of allergen-specific IgG antibodies. These blocking antibodies may have protective effects by inhibiting immediate-type reactions and systemic increases of IgE responses caused by seasonal allergen exposure.
    Type of Medium: Electronic Resource
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  • 16
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background Genetic engineering of the major birch pollen allergen (Bet v 1) has led to the generation of recombinant Bet v 1 derivatives with markedly reduced IgE-binding capacity, but with retained T cell activating ability.Objective To compare the mucosal reactivity to rBet v 1 derivatives with rBet v 1 wild-type as basis for new therapeutic strategies for birch pollen allergy based on mucosal tolerance induction.Methods Outside the pollen season, 10 patients with birch pollen allergic rhinitis and mild asthma underwent four nasal challenge-sessions in a randomized, double-blind, and cross-over design, employing increasing doses of rBet v 1 fragment mix, rBet v 1 trimer, rBet v 1 wild-type and diluent (albumin). Nasal lavage fluids (NAL) were collected before the challenge-series as well as 10 min, 4 and 24 h thereafter. Nasal lavage fluid levels of tryptase as well as EPO and ECP were measured as indices of mast cell and eosinophil activity, respectively.Results All 10 patients tolerated the highest accumulated dose, 8.124 µg, when challenged with rBet v 1 trimer, eight with rBet v 1 fragments compared to one when challenged with rBet v 1 wild-type. No late phase reactions were observed. The change in tryptase levels (pre-challenge vs. 10 min) was significantly lower after challenges with rBet v 1 trimer and rBet v 1 fragments than with rBet v 1 wild-type. The change in EPO/ECP concentration pre-challenge versus 4 h post-challenge was lower for rBet v 1 trimer and the change was significantly lower when pre-challenge versus 24 h post-challenge to rBet v 1 fragments and rBet v 1 wild-type was examined.Conclusion The derivatives induced significantly fewer symptoms and lower mast cell and eosinophil activation than rBet v 1 wild-type upon application to the nasal mucosa. They could in the future be candidates for immunotherapy based on mucosal tolerance induction.
    Type of Medium: Electronic Resource
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  • 17
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Clinical & experimental allergy 25 (1995), S. 0 
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Considering the high occurrence of profilin as an allergen in many plant species, the assumption was made that profilin might be an allergen in Hevea brasiliensis, a member of the latex producing Euphorbiaceae family. Using IgE-binding inhibition by purified profilins we demonstrated that profilin is an IgE-binding component in the cytosolic fraction of natural latex and, to a lower extent, in the rubber fraction. Thirty-five out of 36 sera containing IgE to ragweed-profilin reacted with profilin from latex, indicating structural homologies between profilins from latex and ragweed. A large percentage (59%) of these sera were found to be positive in CAP latex assay. The preincubation of these sera with purified ragweed profilin greatly inhibited the CAP latex. Because profilin is also present in banana extract, it is likely to be involved in cross-sensitivity to banana and latex. In a group of 19 individuals allergic to latex only two had antiprofilin IgE antibodies. Profilin was barely detectable on glove extract immunoblots, whereas some sera from patients allergic to latex reacted with a 15 kDa allergen which was not profilin. Consequently, IgE antibodies to latex-profilin is a questionable factor for sensitization of occupationally-exposed patients; however, sensitization to profilin should be taken into account when interpreting the results of latex IgE antibody assays.
    Type of Medium: Electronic Resource
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  • 18
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background IgE-dependent activation of mast cells (MCs) is a key pathomechanism of type I allergies. In contrast, allergen-specific IgG Abs are thought to attenuate immediate allergic reactions by blocking IgE binding and by cross-linking the inhibitory Fcγ receptor IIB on MCs.Objectives To establish a defined in vitro system using human MCs to study the biological activity of allergens and to investigate the role of allergen-specific IgE and IgG.Methods Purified human intestinal MCs sensitized with different forms of specific IgE Abs were triggered by monomeric and oligomeric forms of recombinant Bet v 1, the major birch pollen allergen, in the presence or absence of allergen-specific IgG Abs.Results MCs sensitized with an anti-Bet v 1 IgE mAb or sera obtained from birch pollen allergic patients released histamine and sulphidoleukotrienes after exposure to oligomeric Bet v 1. Monomeric Bet v 1 provoked mediator release only in MCs sensitized with patients sera but not in MCs sensitized with anti-Bet v 1 IgE mAb. Interestingly, MC activation could be induced by supercross-linking of monomeric Bet v 1 bound to monovalent IgE on MCs with a secondary allergen-specific IgG pAb. By using IgG F(ab′)2 fragments we provide evidence that this effect is not a result of IgG binding to Fcγ receptors.Conclusion This assay represents a new tool for the in vitro study of MC activation in response to natural and genetically modified allergens. Fcɛ receptor I supercross-linking by allergen-specific IgG Abs provides a possible new mechanism of IgG-dependent enhancement of type I allergic reactions.
    Type of Medium: Electronic Resource
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  • 19
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background Mites belong to the most frequent and potent allergen sources. Immunotherapy with mite allergen extracts is frequently performed if allergen avoidance is not possible or successful. However, highly controversial results have been reported for mite-specific immunotherapy.Objective The aim of this study was to develop diagnostic concepts that may contribute to an improved selection of patients for immunotherapy with Der p allergen extracts and that may be used for immunological monitoring of patients undergoing this treatment.Methods The IgE reactivity profiles to Der p extract were determined in a Middle European mite-allergic population by IgE immunoblotting and by using a panel of seven purified natural or recombinant Der p allergens (nDer p 1, nDer p 4, rDer p 2, rDer p 5, rDer p 7, rDer p 8, rDer p 10). Furthermore, we investigated the sensitization and cross-reactivity to house-dust- and storage-mite allergen extracts by CAP FEIA measurements and by IgE competition studies.Results More than 95% of the patients could be diagnosed with a combination of nDer p 1 and rDer p 2. With the methods used, we could discriminate mite-allergic patients who were mainly sensitized to the major Der p allergens (Der p 1, Der p 2) from patients with a broad sensitization profile, including highly cross-reactive allergens (e.g. Der p 10: tropomyosin) as well as reactivity to storage mites.Conclusions Diagnostic tests containing the major mite allergens (i.e. Der p 1, Der p 2) and highly cross-reactive mite allergens (e.g. Der p 10) may improve the diagnostic selection of patients for immunotherapy with Der p extracts. These tests may also be used for the immunological monitoring of patients undergoing immunotherapy.
    Type of Medium: Electronic Resource
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  • 20
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background Ash, a wind-pollinated tree belonging to the family Oleaceae, is distributed world-wide and has been suggested as a potent allergen source in spring time.Objective The aim of this study was to determine the profile of allergen components in ash pollen in order to refine diagnosis and therapy for patients with sensitivity to ash pollenMethods The IgE reactivity profile of 40 ash pollen-allergic patients was determined by immunoblotting. Antibodies raised to purified pollen allergens from tree and grass pollens were used to identify cross-reactive structures in ash pollen extract. IgE immunoblot inhibition studies were performed with recombinant and natural pollen allergens to characterize ash pollen allergens and to determine the degree of cross-reactivity between pollen allergens from ash, olive, birch, grasses and weeds.Results The allergen profile of ash pollen comprises Fra e 1, a major allergen related to the major olive allergen, Ole e 1, and to group 11 grass pollen allergens, the panallergen profilin, a two EF-hand calcium-binding protein, a pectinesterase-like molecule and an allergen sharing epitopes with group 4 grass pollen allergens. Thus, the relevant allergens of ash are primarily allergens that share epitopes with pollen allergens from other tree, grass and weed species.Conclusions Allergic symptoms to ash pollen can be the consequence of sensitization to cross-reactive allergens from other sources. The fact that ash pollen-allergic patients can be discriminated on the basis of their specific IgE reactivity profile to highly or moderately cross-reactive allergens has implications for the selection of appropriate forms of treatment.
    Type of Medium: Electronic Resource
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