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Papers by Wolf-Meinhard Becker
Allergo Journal, 2004
ZusammenfassungDie möglicherweise zukünftig größte Quelle für Novel Foods werden gentechnisch ver... more ZusammenfassungDie möglicherweise zukünftig größte Quelle für Novel Foods werden gentechnisch veränderte Organismen (GVOs) der Flora und Fauna sein. Der Haupteinwand gegen Novel Foods ist die Behauptung, sie könnten vermehrt Allergien verursachen. Um sich dieser Frage nähern zu können, muss zwischen dem potenziellen Allergierisiko, das von einem GVO ausgeht, und der Risikowahrscheinlichkeit, bei Verzehr des GVO-Produkts eine Allergie zu entwickeln, unterschieden werden. Für die Abschätzung eines potenziellen Allergierisikos von GVOs wurde 1996 vom International Life Sciences Institute/International Food Biotechnology Council (ILSI/IFBC) ein Entscheidungsbaum entwickelt, der im Jahre 2001 von einem Expertenteam, einberufen von der World Health Organization/Food and Agricultural Organization of the United Nations (WHO/FAO), modifiziert wurde. Die einzelnen Entscheidungsschritte dieses Entscheidungsbaums werden kritisch beleuchtet und diskutiert. Danach erscheint deren Stringenz eher fraglich.AbstractIn future, the possibly biggest source of novel foods will be genetically modified organisms (GMOs) of flora and fauna. In the public discussion about novel foods, the strongest argument against them is the reproach that such food would elicit additional allergies. In order to assess this problem, one has to differentiate between allergy hazard potentially elicited by GMOs and allergy risk when eating products derived from GMOs. In 1996, the International Life Sciences Institute/International Food Biotechnology Council (ILSI/IFBC) decision tree was set up to assess the allergenic hazard of genetically modified food. This decision tree was modified by the joint World Health Organization/Food and Agricultural Organization of the United Nations (WHO/FAO) expert consultation on allergenicity of foods derived from biotechnology, Rome, 2001. The single decision steps on the right side of the decision tree are investigated and discussed. In conclusion, the stringency of each decision step is not convincing.
Klinische Pädiatrie, 1979
The clinical application of an antiserum recognizing common ALL associated antigen (cALL-AG) is v... more The clinical application of an antiserum recognizing common ALL associated antigen (cALL-AG) is very useful in classifying leukemias and diagnosing bone marrow relapse as well as CNS-leukemia. We could demonstrate that sera of common ALL (cALL) patients contain cALL-AG; its partial biochemical characterization is described. The anti cALL serum (cALL-AS) was raised in rabbits with cALL-cells precoated with rabbit antiserum against normal human lymphocytes. After appropriate absorbtion the cALL-AS was highly specific for cALL cells. The isolation of serum cALL-AG was performed by ammoniumsulfat precipitation, gel chromatography and affinity chromatography on agarose lens culinaris hemagglutinin A (lentil lectin). The apparent molecular-weight of the serum glycoprotein is 125 000. Two cALL-AG active structures could be solubilized from cALL cell membrane. The apparent molecular-weights were calculated to be 55 000 and 110 000.
Molecular Nutrition & Food Research, 2004
Peanut allergy is a significant health problem because of its prevalence and the potential severi... more Peanut allergy is a significant health problem because of its prevalence and the potential severity of the allergic reaction. The characterization of peanut allergens is crucial to the understanding of the mechanism of peanut allergy. Recently, we described cloning of the peanut allergen Ara h 6. The aim of this study was isolation and further characterization of nAra h 6. We purified nAra h 6 from crude peanut extract using gel filtration and anion exchange chromatography. The preparation was further characterized by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) with subsequent immunoblotting. Stability of nAra h 6 was studied by an in vitro digestibility assay as well as by resistance against thermal processing. Sequencing of nAra h 6 identified the N-terminal amino acid sequence as MRRERGRQGDSSS. Further results clearly demonstrated stability of nAra h 6 against pepsin digestion and heating. Immunoglobulin G (IgE) binding analysis and its biological activity shown by RBL 25/30-test of natural Ara h 6 supported the importance of this peanut allergen. Investigation of nAra h 6 revealed evidence for a further peanut allergen with putative clinical relevance based on resistance to pepsin digestion and heat.
Leukemia Research, 1979
Ai~'traet-Sera of patients with common-ALL were found to contain a glycoprotein reacting with ant... more Ai~'traet-Sera of patients with common-ALL were found to contain a glycoprotein reacting with antibodies directed to common-ALL associated antigen (Ag cALL). The identification of this protein which has an apparent molecular weight of 125,000 and a binding specificity to lens culinaris lectin is reported. These data are in good accordance with those estimated for the corresponding antigen solubilized from cALL cells as well as those obtained from cultured cell-lines established from leukemic cells and indicate an in vivo shedding or secretion of the molecule.
Journal of Allergy and Clinical Immunology, 2004
ABSTRACT RationaleSpecific immunotherapy with pollen extract bears risks which may be overcome by... more ABSTRACT RationaleSpecific immunotherapy with pollen extract bears risks which may be overcome by using alternative strategies such as DNA vaccination.
Journal of Allergy and Clinical Immunology, 1993
Using Phl p V-depleted timothy grass pollen extract (Phleum pratense) as immunogen, we obtained a... more Using Phl p V-depleted timothy grass pollen extract (Phleum pratense) as immunogen, we obtained a monoclonal antibody QG 4, which recognized proteins of 33, 35, and 37 kd as determined by Western blottmg. The antibody cross-reacted with pollen proteins of other grass species in the molecular weight range of 30 to 37 kd. By means of two-dimensional polyacrylamide gel electrophoresis blot of timothy grass pollen extract, we demonstrated at least seven protein spots: two of 37 kd with isoelectric points of 6.4 and 6.6; four of 35 kd with isoelectric points of 6.5, 6.8, 7.1, and 7.3; and one of 33 kd with an isoelechic point of 8.5. These protein spots were also detected by patients' pooled serum. Microsequencing of the 20 N-terminal amino acid residues revealed structures with sequence identities up to 90% to the well-established allergen, Lo1 p I of ryegrass (Ldium perenne). Therefore we assume that the monoclonal antibody QG 4 recognized the corresponding allergen Phl p I in timothy grass pollen.
Journal of Allergy and Clinical Immunology, 2004
Background: Cor a 1.04 has been identified as the major hazelnut allergen in 65 European patients... more Background: Cor a 1.04 has been identified as the major hazelnut allergen in 65 European patients with positive double-blind, placebo-controlled food challenge results to hazelnut. Recently, the 11S globulin Cor a 9 was shown to be a pollen-independent hazelnut allergen in the United States, whereas preliminary data suggest the lipid transfer protein (LTP) as an important birch pollen-unrelated hazelnut allergen in Europe. Objective: We sought to recruit a group of European patients allergic to hazelnut without birch pollen allergy and to identify and clone the major food allergen(s) in this study population. Methods: We recruited 26 such Spanish patients, including 10 patients with anaphylaxis. IgE immunoblotting was performed with hazelnut extract. Hazelnut LTP Cor a 8 was cloned by using a PCR strategy, purified, and subjected to IgE immunoblotting. Recombinant Cor a 8, rCor a 1.0401, and rCor a 2 (profilin) were further investigated by means of enzyme allergosorbent test. Immunoblot inhibition experiments were used to compare the immunologic properties of natural and recombinant LTP. Results: A 9-kd major allergen was identified in hazelnut extract. Cloning, sequencing, heterologous expression, and inhibition experiments identified it as an LTP. The prevalence of specific IgE antibody reactivity to LTP was 62% in hazelnut extract and 77% when recombinant LTP was tested by means of immunoblotting. IgE immunoblot inhibition with hazelnut extract showed that natural Cor a 8 and rCor a 8 shared identical epitopes. Only one patient had positive reactivity to Cor a 1.04, and no patients had positive reactivity to Cor a 2. Two sera bound to high-molecular-weight allergens. The LTP was denominated as Cor a 8 and submitted to the allergen database of the World Health Organization/International Union of Immunological Societies Allergen Nomenclature Subcommittee. Conclusions: Cor a 8 is a relevant allergen for a majority of Spanish patients with hazelnut allergy that can cause severe allergic reactions. (J Allergy Clin Immunol 2004;113:141-7.)
International Archives of Allergy and Immunology, 2005
Molecules and Cells in Allergy 103 Evaluation of Cross-Reactivity between Holoptelea integrifolia... more Molecules and Cells in Allergy 103 Evaluation of Cross-Reactivity between Holoptelea integrifolia and Parietaria judaica
International Archives of Allergy and Immunology, 1992
... Address of Corresponding Author. Int Arch Allergy Immunol 1992;99:425-428 (DOI: 10.1159/00023... more ... Address of Corresponding Author. Int Arch Allergy Immunol 1992;99:425-428 (DOI: 10.1159/000236303). goto top of page Key Words. Grass pollen; Allergen release; Airborne particulate matter; Pollution; Electron microscopy. goto top of page Abstract. ...
International Archives of Allergy and Immunology, 1997
Peanut allergy belongs to the food allergies which are not associated with aeroallergens. It perm... more Peanut allergy belongs to the food allergies which are not associated with aeroallergens. It permanently affects children as well as adults. Peanuts can cause IgE-mediated life-threatening hypersensitivity reactions of the immediate type. The identification and characterization of peanut allergens are preconditions for answering the question how the allergens, which interact with the gastrointestinal tract, are presented to the immune system. This would be an important contribution to the clarification of the pathomechanism of food allergy. The identification and characterization of peanut allergens are performed by electrophoresis/immunoblot techniques with patient IgE, monoclonal antibodies and the lectin ConA. Ara h 1 is identified by N-terminal sequencing of the whole molecule and LysC cleavage products. Ara h 1 is a ConA-reactive 66-kD glycoprotein which consists of a variety of isoallergens and isoforms. Peanut experiments mimicking digestion in the gastrointestinal tract clearly demonstrate the releasability of peanut allergens in the mouth and the resistance of Ara h 1 to degradation under treatment with artificial gastric fluid.
Immunology Letters, 2005
Allergen-specific IgE and IgG antibodies coexist in allergic individuals, but only IgE has anaphy... more Allergen-specific IgE and IgG antibodies coexist in allergic individuals, but only IgE has anaphylactogenic capacity. This study aimed to determine the association, dissociation and equilibrium constants for the interaction of allergen-specific IgE and IgG with the major grass and birch pollen allergens Phl p 5a and Bet v 1a. We isolated specific IgE and IgG antibodies from pollen allergic patients' sera by a two-step affinity chromatography protocol and controlled the high purity in a recombinant allergen chip microarray. Surface plasmon resonance measurements of polyclonal IgE and IgG species revealed that their affinities diverge widely, being in the range of 10(-10) and 10(-11) M for IgE, but only 10(-6)-10(-7) M for IgG. Moreover, murine monoclonal IgG1 antibodies against the allergens showed affinities of 10(-7)-10(-8) M. Thus, we conclude from our data that even stringently affinity matured IgG cannot score the superior affinity of IgE antibodies to allergens.
European Journal of Nutrition, 2000
European Food Research and Technology, 2000
Hazelnuts (HNs), widely distributed in sweets, provoke one of the most frequent pollen-associated... more Hazelnuts (HNs), widely distributed in sweets, provoke one of the most frequent pollen-associated food allergies. In this study HN allergens were investigated and immunologically characterized, focussing on their heat stability and cross-reactivity with known allergenic structures. Therefore, 27 sera from HN-allergic patients and 28 sera from children with positive CAP classes for HN and birch pollen were submitted to immunoblot and immunoblot inhibition. The major HN allergen was found to present a molecular mass of about 17-18 kDa, and to share IgE epitopes with Bet v 1, the major birch pollen allergen. This allergen was recognized by IgE of 93% of our HN-allergic patients and by 79% of sensitized children. A 48 kDa glycoprotein was identified as a minor HN allergen with cross-reactive carbohydrate determinants. The major N-glycan species was determined by matrixassisted laser desorption mass spectrometry to be Man 3 XylGlcNAc 2. IgE binding to this protein was detected in sera of 41% of the allergic patients and 61% of the children. Partial N-terminal sequencing demonstrated similarity to legume storage proteins. The IgE reactivity of this structure was partially resistant to heating. The rat basophil leukaemia cell mediator release assay was used for estimation of cross-sensitiza-tion between HN and birch pollen, confirming the finding that HNs contain a heat-resistant allergenicity without cross-reactivity to birch pollen allergens. Keywords Hazelnut allergens 7 Cross-reactivity 7 Cross-reactive carbohydrate determinants 7 Heat-stable allergens 7 Rat basophil leukaemia cell assay
Electrophoresis, 1992
The separation of timothy pollen extract by two-dimensional immunoblotting revealed microheteroge... more The separation of timothy pollen extract by two-dimensional immunoblotting revealed microheterogeneity of the major allergens PhI p I and PhI p V. There was not only a diversity in size, 38 and 32 kDa for PhI p V and 37, 35, and 33 kDa for PhI p I, but also a separation into proteins of identical sizes but different pIs. Since former studies on the protein structure by amino acid analysis and N-terminal microsequencing did not reveal any differences, we examined other possibilities that might cause microheterogeneity. In allergens belonging to the PhI p I group, the variability in pI can be due to the carbohydrate structure and to the fact that charges are hidden in the interior of the protein, as shown by varying concentrations of urea. On the other hand we were not able to detect any such reasons for the existence of PhI p V isoallergens. Thus, we assume that they are stable conformational isomers of the proteins (allomorphism) or that there are only slight variations in the internal sequences of these proteins (polymorphism) causing distinct pIs.
Current Opinion in Allergy & Clinical Immunology, 2006
Purpose of review The current state of the art in allergen standardization and recent progress in... more Purpose of review The current state of the art in allergen standardization and recent progress in the field is summarized, and future developments are discussed. Recent findings The main focus of recent research in allergen standardization was on sandwich enzyme-linked immunosorbent assays or competitive tests for the quantification of individual allergens in extracts. New assays for quantifying major or minor allergens have been developed for tree and weed pollens from the Mediterranean area, grass pollens, and foods such as peanut and apple. In several cases, a good correlation with allergenic activity, measured by inhibition tests, was obtained. In addition, the potential of cellular mediator release assays in allergen standardization was evaluated in one study. Summary Several new tests have been developed to make more major and minor allergens from various allergen sources accessible to allergen standardization programmes such as the CREATE project. It is expected that assays to determine the majority of all clinically relevant major allergens from aeroallergen sources will be available in the near future. Standardized and validated mediator release assays may be a complementary tool for evaluating the biological potency of reference allergens and for correlating allergen concentrations to biological potency.
Biochemical and Biophysical Research Communications, 2005
Grass pollen allergy is one of the most important allergic diseases worldwide. Several meadow gra... more Grass pollen allergy is one of the most important allergic diseases worldwide. Several meadow grasses, like timothy grass and rye grass, contribute to allergic sensitizations, but also allergens from extensively cultivated cereals, especially rye, make a profound contribution. The group 4 allergens are well known as important major allergens of grasses. We have cloned for the first time group 4 sequences from Phleum pratense, Lolium perenne, Secale cereale, Triticum aestivum, and Hordeum vulgare, and investigated the IgE-reactivity of recombinant Phl p 4 as a candidate for allergy diagnostic and therapeutic applications.
Allergo Journal, 2004
ZusammenfassungDie möglicherweise zukünftig größte Quelle für Novel Foods werden gentechnisch ver... more ZusammenfassungDie möglicherweise zukünftig größte Quelle für Novel Foods werden gentechnisch veränderte Organismen (GVOs) der Flora und Fauna sein. Der Haupteinwand gegen Novel Foods ist die Behauptung, sie könnten vermehrt Allergien verursachen. Um sich dieser Frage nähern zu können, muss zwischen dem potenziellen Allergierisiko, das von einem GVO ausgeht, und der Risikowahrscheinlichkeit, bei Verzehr des GVO-Produkts eine Allergie zu entwickeln, unterschieden werden. Für die Abschätzung eines potenziellen Allergierisikos von GVOs wurde 1996 vom International Life Sciences Institute/International Food Biotechnology Council (ILSI/IFBC) ein Entscheidungsbaum entwickelt, der im Jahre 2001 von einem Expertenteam, einberufen von der World Health Organization/Food and Agricultural Organization of the United Nations (WHO/FAO), modifiziert wurde. Die einzelnen Entscheidungsschritte dieses Entscheidungsbaums werden kritisch beleuchtet und diskutiert. Danach erscheint deren Stringenz eher fraglich.AbstractIn future, the possibly biggest source of novel foods will be genetically modified organisms (GMOs) of flora and fauna. In the public discussion about novel foods, the strongest argument against them is the reproach that such food would elicit additional allergies. In order to assess this problem, one has to differentiate between allergy hazard potentially elicited by GMOs and allergy risk when eating products derived from GMOs. In 1996, the International Life Sciences Institute/International Food Biotechnology Council (ILSI/IFBC) decision tree was set up to assess the allergenic hazard of genetically modified food. This decision tree was modified by the joint World Health Organization/Food and Agricultural Organization of the United Nations (WHO/FAO) expert consultation on allergenicity of foods derived from biotechnology, Rome, 2001. The single decision steps on the right side of the decision tree are investigated and discussed. In conclusion, the stringency of each decision step is not convincing.
Klinische Pädiatrie, 1979
The clinical application of an antiserum recognizing common ALL associated antigen (cALL-AG) is v... more The clinical application of an antiserum recognizing common ALL associated antigen (cALL-AG) is very useful in classifying leukemias and diagnosing bone marrow relapse as well as CNS-leukemia. We could demonstrate that sera of common ALL (cALL) patients contain cALL-AG; its partial biochemical characterization is described. The anti cALL serum (cALL-AS) was raised in rabbits with cALL-cells precoated with rabbit antiserum against normal human lymphocytes. After appropriate absorbtion the cALL-AS was highly specific for cALL cells. The isolation of serum cALL-AG was performed by ammoniumsulfat precipitation, gel chromatography and affinity chromatography on agarose lens culinaris hemagglutinin A (lentil lectin). The apparent molecular-weight of the serum glycoprotein is 125 000. Two cALL-AG active structures could be solubilized from cALL cell membrane. The apparent molecular-weights were calculated to be 55 000 and 110 000.
Molecular Nutrition & Food Research, 2004
Peanut allergy is a significant health problem because of its prevalence and the potential severi... more Peanut allergy is a significant health problem because of its prevalence and the potential severity of the allergic reaction. The characterization of peanut allergens is crucial to the understanding of the mechanism of peanut allergy. Recently, we described cloning of the peanut allergen Ara h 6. The aim of this study was isolation and further characterization of nAra h 6. We purified nAra h 6 from crude peanut extract using gel filtration and anion exchange chromatography. The preparation was further characterized by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) with subsequent immunoblotting. Stability of nAra h 6 was studied by an in vitro digestibility assay as well as by resistance against thermal processing. Sequencing of nAra h 6 identified the N-terminal amino acid sequence as MRRERGRQGDSSS. Further results clearly demonstrated stability of nAra h 6 against pepsin digestion and heating. Immunoglobulin G (IgE) binding analysis and its biological activity shown by RBL 25/30-test of natural Ara h 6 supported the importance of this peanut allergen. Investigation of nAra h 6 revealed evidence for a further peanut allergen with putative clinical relevance based on resistance to pepsin digestion and heat.
Leukemia Research, 1979
Ai~'traet-Sera of patients with common-ALL were found to contain a glycoprotein reacting with ant... more Ai~'traet-Sera of patients with common-ALL were found to contain a glycoprotein reacting with antibodies directed to common-ALL associated antigen (Ag cALL). The identification of this protein which has an apparent molecular weight of 125,000 and a binding specificity to lens culinaris lectin is reported. These data are in good accordance with those estimated for the corresponding antigen solubilized from cALL cells as well as those obtained from cultured cell-lines established from leukemic cells and indicate an in vivo shedding or secretion of the molecule.
Journal of Allergy and Clinical Immunology, 2004
ABSTRACT RationaleSpecific immunotherapy with pollen extract bears risks which may be overcome by... more ABSTRACT RationaleSpecific immunotherapy with pollen extract bears risks which may be overcome by using alternative strategies such as DNA vaccination.
Journal of Allergy and Clinical Immunology, 1993
Using Phl p V-depleted timothy grass pollen extract (Phleum pratense) as immunogen, we obtained a... more Using Phl p V-depleted timothy grass pollen extract (Phleum pratense) as immunogen, we obtained a monoclonal antibody QG 4, which recognized proteins of 33, 35, and 37 kd as determined by Western blottmg. The antibody cross-reacted with pollen proteins of other grass species in the molecular weight range of 30 to 37 kd. By means of two-dimensional polyacrylamide gel electrophoresis blot of timothy grass pollen extract, we demonstrated at least seven protein spots: two of 37 kd with isoelectric points of 6.4 and 6.6; four of 35 kd with isoelectric points of 6.5, 6.8, 7.1, and 7.3; and one of 33 kd with an isoelechic point of 8.5. These protein spots were also detected by patients' pooled serum. Microsequencing of the 20 N-terminal amino acid residues revealed structures with sequence identities up to 90% to the well-established allergen, Lo1 p I of ryegrass (Ldium perenne). Therefore we assume that the monoclonal antibody QG 4 recognized the corresponding allergen Phl p I in timothy grass pollen.
Journal of Allergy and Clinical Immunology, 2004
Background: Cor a 1.04 has been identified as the major hazelnut allergen in 65 European patients... more Background: Cor a 1.04 has been identified as the major hazelnut allergen in 65 European patients with positive double-blind, placebo-controlled food challenge results to hazelnut. Recently, the 11S globulin Cor a 9 was shown to be a pollen-independent hazelnut allergen in the United States, whereas preliminary data suggest the lipid transfer protein (LTP) as an important birch pollen-unrelated hazelnut allergen in Europe. Objective: We sought to recruit a group of European patients allergic to hazelnut without birch pollen allergy and to identify and clone the major food allergen(s) in this study population. Methods: We recruited 26 such Spanish patients, including 10 patients with anaphylaxis. IgE immunoblotting was performed with hazelnut extract. Hazelnut LTP Cor a 8 was cloned by using a PCR strategy, purified, and subjected to IgE immunoblotting. Recombinant Cor a 8, rCor a 1.0401, and rCor a 2 (profilin) were further investigated by means of enzyme allergosorbent test. Immunoblot inhibition experiments were used to compare the immunologic properties of natural and recombinant LTP. Results: A 9-kd major allergen was identified in hazelnut extract. Cloning, sequencing, heterologous expression, and inhibition experiments identified it as an LTP. The prevalence of specific IgE antibody reactivity to LTP was 62% in hazelnut extract and 77% when recombinant LTP was tested by means of immunoblotting. IgE immunoblot inhibition with hazelnut extract showed that natural Cor a 8 and rCor a 8 shared identical epitopes. Only one patient had positive reactivity to Cor a 1.04, and no patients had positive reactivity to Cor a 2. Two sera bound to high-molecular-weight allergens. The LTP was denominated as Cor a 8 and submitted to the allergen database of the World Health Organization/International Union of Immunological Societies Allergen Nomenclature Subcommittee. Conclusions: Cor a 8 is a relevant allergen for a majority of Spanish patients with hazelnut allergy that can cause severe allergic reactions. (J Allergy Clin Immunol 2004;113:141-7.)
International Archives of Allergy and Immunology, 2005
Molecules and Cells in Allergy 103 Evaluation of Cross-Reactivity between Holoptelea integrifolia... more Molecules and Cells in Allergy 103 Evaluation of Cross-Reactivity between Holoptelea integrifolia and Parietaria judaica
International Archives of Allergy and Immunology, 1992
... Address of Corresponding Author. Int Arch Allergy Immunol 1992;99:425-428 (DOI: 10.1159/00023... more ... Address of Corresponding Author. Int Arch Allergy Immunol 1992;99:425-428 (DOI: 10.1159/000236303). goto top of page Key Words. Grass pollen; Allergen release; Airborne particulate matter; Pollution; Electron microscopy. goto top of page Abstract. ...
International Archives of Allergy and Immunology, 1997
Peanut allergy belongs to the food allergies which are not associated with aeroallergens. It perm... more Peanut allergy belongs to the food allergies which are not associated with aeroallergens. It permanently affects children as well as adults. Peanuts can cause IgE-mediated life-threatening hypersensitivity reactions of the immediate type. The identification and characterization of peanut allergens are preconditions for answering the question how the allergens, which interact with the gastrointestinal tract, are presented to the immune system. This would be an important contribution to the clarification of the pathomechanism of food allergy. The identification and characterization of peanut allergens are performed by electrophoresis/immunoblot techniques with patient IgE, monoclonal antibodies and the lectin ConA. Ara h 1 is identified by N-terminal sequencing of the whole molecule and LysC cleavage products. Ara h 1 is a ConA-reactive 66-kD glycoprotein which consists of a variety of isoallergens and isoforms. Peanut experiments mimicking digestion in the gastrointestinal tract clearly demonstrate the releasability of peanut allergens in the mouth and the resistance of Ara h 1 to degradation under treatment with artificial gastric fluid.
Immunology Letters, 2005
Allergen-specific IgE and IgG antibodies coexist in allergic individuals, but only IgE has anaphy... more Allergen-specific IgE and IgG antibodies coexist in allergic individuals, but only IgE has anaphylactogenic capacity. This study aimed to determine the association, dissociation and equilibrium constants for the interaction of allergen-specific IgE and IgG with the major grass and birch pollen allergens Phl p 5a and Bet v 1a. We isolated specific IgE and IgG antibodies from pollen allergic patients' sera by a two-step affinity chromatography protocol and controlled the high purity in a recombinant allergen chip microarray. Surface plasmon resonance measurements of polyclonal IgE and IgG species revealed that their affinities diverge widely, being in the range of 10(-10) and 10(-11) M for IgE, but only 10(-6)-10(-7) M for IgG. Moreover, murine monoclonal IgG1 antibodies against the allergens showed affinities of 10(-7)-10(-8) M. Thus, we conclude from our data that even stringently affinity matured IgG cannot score the superior affinity of IgE antibodies to allergens.
European Journal of Nutrition, 2000
European Food Research and Technology, 2000
Hazelnuts (HNs), widely distributed in sweets, provoke one of the most frequent pollen-associated... more Hazelnuts (HNs), widely distributed in sweets, provoke one of the most frequent pollen-associated food allergies. In this study HN allergens were investigated and immunologically characterized, focussing on their heat stability and cross-reactivity with known allergenic structures. Therefore, 27 sera from HN-allergic patients and 28 sera from children with positive CAP classes for HN and birch pollen were submitted to immunoblot and immunoblot inhibition. The major HN allergen was found to present a molecular mass of about 17-18 kDa, and to share IgE epitopes with Bet v 1, the major birch pollen allergen. This allergen was recognized by IgE of 93% of our HN-allergic patients and by 79% of sensitized children. A 48 kDa glycoprotein was identified as a minor HN allergen with cross-reactive carbohydrate determinants. The major N-glycan species was determined by matrixassisted laser desorption mass spectrometry to be Man 3 XylGlcNAc 2. IgE binding to this protein was detected in sera of 41% of the allergic patients and 61% of the children. Partial N-terminal sequencing demonstrated similarity to legume storage proteins. The IgE reactivity of this structure was partially resistant to heating. The rat basophil leukaemia cell mediator release assay was used for estimation of cross-sensitiza-tion between HN and birch pollen, confirming the finding that HNs contain a heat-resistant allergenicity without cross-reactivity to birch pollen allergens. Keywords Hazelnut allergens 7 Cross-reactivity 7 Cross-reactive carbohydrate determinants 7 Heat-stable allergens 7 Rat basophil leukaemia cell assay
Electrophoresis, 1992
The separation of timothy pollen extract by two-dimensional immunoblotting revealed microheteroge... more The separation of timothy pollen extract by two-dimensional immunoblotting revealed microheterogeneity of the major allergens PhI p I and PhI p V. There was not only a diversity in size, 38 and 32 kDa for PhI p V and 37, 35, and 33 kDa for PhI p I, but also a separation into proteins of identical sizes but different pIs. Since former studies on the protein structure by amino acid analysis and N-terminal microsequencing did not reveal any differences, we examined other possibilities that might cause microheterogeneity. In allergens belonging to the PhI p I group, the variability in pI can be due to the carbohydrate structure and to the fact that charges are hidden in the interior of the protein, as shown by varying concentrations of urea. On the other hand we were not able to detect any such reasons for the existence of PhI p V isoallergens. Thus, we assume that they are stable conformational isomers of the proteins (allomorphism) or that there are only slight variations in the internal sequences of these proteins (polymorphism) causing distinct pIs.
Current Opinion in Allergy & Clinical Immunology, 2006
Purpose of review The current state of the art in allergen standardization and recent progress in... more Purpose of review The current state of the art in allergen standardization and recent progress in the field is summarized, and future developments are discussed. Recent findings The main focus of recent research in allergen standardization was on sandwich enzyme-linked immunosorbent assays or competitive tests for the quantification of individual allergens in extracts. New assays for quantifying major or minor allergens have been developed for tree and weed pollens from the Mediterranean area, grass pollens, and foods such as peanut and apple. In several cases, a good correlation with allergenic activity, measured by inhibition tests, was obtained. In addition, the potential of cellular mediator release assays in allergen standardization was evaluated in one study. Summary Several new tests have been developed to make more major and minor allergens from various allergen sources accessible to allergen standardization programmes such as the CREATE project. It is expected that assays to determine the majority of all clinically relevant major allergens from aeroallergen sources will be available in the near future. Standardized and validated mediator release assays may be a complementary tool for evaluating the biological potency of reference allergens and for correlating allergen concentrations to biological potency.
Biochemical and Biophysical Research Communications, 2005
Grass pollen allergy is one of the most important allergic diseases worldwide. Several meadow gra... more Grass pollen allergy is one of the most important allergic diseases worldwide. Several meadow grasses, like timothy grass and rye grass, contribute to allergic sensitizations, but also allergens from extensively cultivated cereals, especially rye, make a profound contribution. The group 4 allergens are well known as important major allergens of grasses. We have cloned for the first time group 4 sequences from Phleum pratense, Lolium perenne, Secale cereale, Triticum aestivum, and Hordeum vulgare, and investigated the IgE-reactivity of recombinant Phl p 4 as a candidate for allergy diagnostic and therapeutic applications.