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Biomedical subjects

I Sander

Publications and source records attributed to I Sander.

At least 19 recordsLinked to original sources
PubMed2006

Occupational immunoglobulin E-mediated asthma due to Penicillium camemberti in a dry-sausage packer.

A 62-year-old female sausage packer reported progressive work-related asthma, rhinitis and contact urticaria after contact to dry sausages refined by moulds. Whereas skin prick tests with commercial mould extracts were negative, the patient showed weak skin sensitization to a cultivated mould sample from a dry sausage. Specific immunoglobulin E antibodies to various moulds were demonstrated by ImmunoCAP and antibodies to the cultivated mould sample were demonstrated by enzyme allergosorbent test. The mould was identified by pheno- and genotyping as Penicillium camemberti. Five atopic controls did not show sensitization with the same tests. Crossreactivity of P. camemberti and Penicillium notatum was shown by enzyme allergosorbent inhibition tests. Although no challenge tests were considered due to the patient's airway obstruction, a diagnosis of allergic occupational asthma was made. We conclude that immunoglobulin E-mediated allergic occupational asthma due to moulds may occur in dry sausage packers.

Allergens↗
PubMed2006

Airborne exposure to wheat allergens: measurement by human immunoglobulin G4 and rabbit immunoglobulin G immunoassays.

BACKGROUND: Exposure to airborne wheat allergens in the bakery trade is associated with a high risk of occupational allergy and asthma. Control and reduction of allergen exposure require relatively simple but reliable monitoring techniques. We developed new rabbit IgG-based enzyme immunoassays (EIA) for wheat allergens, which might be a convenient alternative for the thus far used human IgG4 inhibition assay. METHODS: The reactivity and specificity of rabbit antibodies were assessed by EIA and immunoblotting, and compared with those of IgE from wheat-sensitized bakers, and with the antibodies used in the IgG4 inhibition EIA. An IgG inhibition and a sandwich EIA were developed for analysis of airborne dust samples. RESULTS: Human IgG4 and rabbit IgG inhibition EIAs had comparable sensitivities, with limits of detection (LOD) between 18 and 88 ng/mL, while the sandwich EIA was much more sensitive (LOD<0.2 ng/mL). Human IgG4 and rabbit IgG reacted in immunoblotting with most of the IgE-binding wheat proteins, although with quantitative differences. All three assays showed a strong reaction with wheat proteins, and some cross-reactivity with rye and barley, but were further highly specific for cereal flour proteins. Concentrations measured with the three EIAs in 432 airborne dust samples were highly correlated (r>0.95) and their absolute values showed less than 10-20% differences. CONCLUSION: The rabbit IgG EIAs are valid substitutes for the human IgG4 inhibition EIA, with important practical advantages. The inhibition EIA is recommended for routine wheat allergen measurements. The sandwich EIA may be used to measure low allergen levels, as in short task-related exposure measurements or in subfractions of airborne dust samples.

Air Pollutants, Occupational↗
PubMed2005

Identification of an obeche (Triplochiton scleroxylon) wood allergen as a class I chitinase.

BACKGROUND: Wood dust is known to cause allergic occupational asthma and obeche (Triplochiton scleroxylon) is a prominent exponent in this field. However, the knowledge about wood allergens is still limited. The aim of this study was to identify and characterize obeche wood allergens. METHODS: Obeche extracts were prepared from freshly ground in comparison to 7 years stored wood dust and investigated by Sodium dodecyl sulfate-polyacrylamid gel electrophoresis, enzyme-linked allergosorbent test and immunoglobulin (Ig)E-immunoblot. Allergens were detected by specific IgE of seven obeche allergic patients' sera and protein analysis was performed by mass spectrometry. Cross-reactivity was demonstrated by ImmunoCAP-inhibition with sera of seven obeche and four latex-allergic patients. RESULTS: Obeche extracts showed different protein pattern and IgE-binding capacities depend on the age of the wood dust. A 38 kDa protein was identified as major obeche wood allergen, detected by six of seven (85%) obeche allergic patients' sera and was entitled as Trip s 1. Trip s 1 is homologous to plant class I chitinases and exhibited enzyme activity demonstrated by chitinolysis. Co-recognition or cross-reactivity of Trip s 1 according to structural similarity was seen in sera of latex allergic patients. IgE inhibition studies with obeche as solid phase and Trip s 1 and latex hevein as inhibitor demonstrated that Trip s 1 was a more effective inhibitor in obeche as well as in latex allergic patients' sera. CONCLUSIONS: Trip s 1 is a new obeche wood allergen of the plant class I chitinase family. This finding may explain the dominant role of obeche in sensitization against wood dust.

Adult↗
PubMed2004

Comparison of wheat and rye flour skin prick test solutions for diagnosis of baker's asthma.

BACKGROUND: Skin prick tests (SPTs) play an important role in the diagnosis of baker's asthma and in the investigation of sensitization frequencies in field studies. It was the aim of our study to compare different SPT solutions for wheat and rye flour sensitization and to assess the validity of test results. METHODS: Skin prick tests with wheat and rye flour were performed in parallel with extracts from different companies and compared with the results of bronchial challenge tests with both flours (69 rye flour and 51 wheat flour challenge tests). Additionally, specific immunoglobulin E (sIgE) to wheat and rye flour were tested. SPT solutions were analysed for protein content and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). RESULTS: Skin prick test solutions for diagnosis of wheat and rye flour sensitization from three companies differed in protein concentrations and composition with the consequence of widely differing SPT results. Sensitivity of SPTs in comparison with allergen-specific bronchial challenge as a gold standard was between 40 and 67%, specificity was between 86 and 100%, the positive predictive value (PPV) ranged from 81 to 100% and the negative predictive value (NPV) from 44 to 70%. These numbers were only marginally affected by using a combination of challenge test result and sIgE value as a more specific gold standard. CONCLUSION: Improvement and standardization of SPT extracts for wheat and rye flour is highly recommended.

Adult↗
PubMed2001

B-cell epitopes of the allergen Chi t 1.01: peptide mapping of epitopes recognized by rabbit, murine, and human antibodies.

BACKGROUND: Chi t 1.01, a hemoglobin of the midge Chironomus thummi thummi, is a widespread environmental and occupational allergen. The aim of the present investigation was to identify and compare peptides involved in B-cell epitopes of Chi t 1.01 recognized by 15 human IgE sera, six murine monoclonal antibodies (mAbs), and a polyclonal rabbit antiserum. METHODS: Synthetic peptides 19-21 amino acids long covering the whole Chi t 1.01-sequence were covalently coupled to activated paper disks as well as adsorbed to wells of immunoplates and used for enzyme-linked immunosorbent assay. For fine epitope mapping, we used overlapping synthetic octapeptides with one amino-acid offset. RESULTS: Peptides containing the amino acids 13-17, 23-29, and 40-50 were recognized by three of the mAbs, while three other mAbs reacting with none of the peptides obviously recognized conformational epitopes. Binding sites for rabbit antibodies and for human IgE antibodies were scattered over the whole molecule. The peptide 80-100 seemed to comprise at least one important IgE epitope. Depending on the method of antigen binding to the solid phase, differing results were obtained. CONCLUSIONS: Several linear epitopes in Chi t 1.01 are recognized by human IgE antibodies, by mAbs, and by polyclonal rabbit antibodies. In addition, the results indicate the presence of conformational epitopes.

Amino Acid Sequence↗
PubMed2001

Identification of wheat flour allergens by means of 2-dimensional immunoblotting.

BACKGROUND: Wheat flour proteins are allergens for 60% to 70% of bakers with workplace-related respiratory symptoms. OBJECTIVE: The aim of the study was to investigate the variability of IgE antibody patterns of wheat flour-sensitized bakers and to identify the most frequently recognized allergens. METHODS: Water/salt-soluble wheat flour proteins from the cultivar Bussard were separated by using 2-dimensional gel electrophoresis with immobilized pH gradients. IgE-reactive proteins were identified by means of immunoblotting with sera of 10 subjects with baker's asthma. Mass spectrometric fingerprinting was used to identify the proteins most frequently recognized by IgE. RESULTS: The IgE immunoblots obtained with 10 different sera exhibited a remarkable heterogeneity. Each patient showed an individual IgE-binding pattern with 4 to 50 different allergen spots. Altogether, more than 100 IgE-binding protein spots were detected. Nine of the predominant IgE-binding protein spots were identified by using mass spectrometric fingerprinting. The obtained masses matched 2 different isoforms of glycerinaldehyde-3-phosphate dehydrogenase from Hordeum vulgare, triosephosphate isomerase from H vulgare, and serpin, a serine proteinase inhibitor from Triticum aestivum. CONCLUSIONS: The results show a great interindividual variation of IgE-binding patterns of wheat flour proteins in baker's asthma. The clinical relevance of the identified 4 new allergens will be further investigated in the near future.

Allergens↗
PubMed2001

Baker's asthma due to xylanase and cellulase without sensitization to alpha-amylase and only weak sensitization to flour.

BACKGROUND: The baking additives xylanase and cellulase were described as baking additives causing baker's asthma. It is not known whether monosensitization to these enzymes may occur. METHODS: We present a case report of a baker with work-related asthma evaluated by skin prick test (SPT), enzyme-linked immunosorbent assay (EAST), immunoblot, EAST and immunoblot inhibition, and specific bronchial challenge. Fungal xylanase and alpha-amylase were measured by two-site enzyme immunoassays in products used by the patient at work. RESULTS: Allergy to xylanase and cellulase was demonstrated by SPT, EAST, immunoblot and specific bronchial challenge (for xylanase only). No sensitization to alpha-amylase could be demonstrated, but there was a weak flour allergy as documented by EAST and immunoblot and a positive occupational-type challenge with high concentrations of rye flour. Four baking additives contained measurable amounts of fungal alpha-amylase and xylanase, without a correlation between these enzymes. CONCLUSIONS: We conclude that occupational asthma due to the baking additives xylanase and cellulase may occur without concomitant sensitization to alpha-amylase and only weak sensitization to flour.

Adult↗
PubMed2000

Is fungal alpha-amylase in bread an allergen?

BACKGROUND: The enzyme alpha-amylase from Aspergillus oryzae used in bakeries to improve the bread quality has been identified as an inhalative allergen in baker's asthma. It is doubtful whether this enzyme can induce allergic sensitization in regular bread consumers. OBJECTIVE: To find out whether fungal alpha-amylase in bread and rolls retains its antibody-binding capacity and allergenicity after the baking procedure. METHODS: Rabbit antibodies directed to fungal alpha-amylase were used for the development of a two-site enzyme-linked immunosorbent assay (ELISA). This assay was used to analyse different fractions of bread and rolls baked with the usual amounts of alpha-amylase in comparison with control products without added enzyme. Competitive experiments between bakers' sera containing specific immunoglobulin (Ig) E to alpha-amylase and the rabbit antibodies were performed. Additionally, specific IgE binding to fungal alpha-amylase was inhibited by native or heated alpha-amylase. RESULTS: With the highly specific two-site ELISA for native alpha-amylase in the crust of bread bottom and sides, 2.3-7 ng antigenic alpha-amylase per gram crust were measured. No alpha-amylase could be detected in the crumb fractions. Rabbit antibodies to native alpha-amylase completely inhibited human IgE binding to alpha-amylase allergen disks. CONCLUSION: The results prove residual antibody-binding capacity of alpha-amylase in bread crusts and in the crust of some rolls. In comparison with the content of alpha-amylase in dough, between 0.1 and 20% of the antibody-binding capacity remained.

Animals↗
PubMed2000

Development of a monoclonal antibody-based sandwich ELISA for detection of the latex allergen Hev b 1.

BACKGROUND: Natural rubber latex (NRL) products are complex mixtures consisting of different allergenic components. Among them, Hev b 1 belongs to the important and well-characterized ones. To quantify the relevant allergen Hev b 1 in NRL products, a two-site monoclonal antibody (mAb)-based assay was developed. METHODS: Two Hev b 1-specific mAbs with different epitope recognition and ability to bind simultaneously to an Hev b 1 molecule were used in the study. Both mAbs (II4F9 and II4G9) were enriched by in vitro production in a modular minifermenter and affinity purified. Wells of micro-ELISA plates coated with captured mAb II4G9 were incubated with samples containing Hev b 1. Bound Hev b 1 was detected by a combination of biotinylated mAb II4F9 as detection antibody and peroxidase-labeled avidin. RESULTS: The optimized sandwich ELISA was highly reproducible in the linear range of the standard curve and Hev b 1 concentrations ranging from 12.5 to 400 ng/100 microl could be detected. The assay was suitable for the detection of Hev b 1 concentrations in latex sap and latex products, e.g. gloves, with a detection limit of 1.25 microg of Hev b 1/g of rubber. In a preliminary study with five different brands of latex gloves, Hev b 1 concentrations were found to be in the range of 18-40 microg per gram of rubber material, corresponding to 2-4% of the total extractable protein content in latex glove extracts. CONCLUSIONS: A sensitive sandwich assay was developed to quantify the latex allergen Hev b 1. This assay can be used to standardize latex extracts with regard to the content of the major allergen Hev b 1.

Allergens↗
PubMed2000

Identification and characterization of cross-reactive natural rubber latex and Ficus benjamina allergens.

BACKGROUND: An association between allergy to Ficus benjamina and natural rubber latex (NRL) has been suspected based on clinical and immunological observations. The responsible cross-reactive allergens have not been identified yet. This study was undertaken to investigate the cross-reactivity between hevein (Hev b 6.02, 4.7 kD), a major allergen of NRL, and F. benjamina and identify its counterpart in F. benjamina. METHODS: 89 serum samples from subjects allergic to NRL were used in the study. Skin prick tests were performed with highly purified hevein and sap extract of F. benjamina. Specific IgE antibodies to NRL, F. benjamina and Hev b 6.02 were determined by the Pharmacia CAP method. Cross-reactivity among these allergens was investigated by means of CAP and immunoblot inhibition experiments. Two-dimensional gel electrophoresis separation and protein microsequencing were performed to identify the cross-reactive allergens in F. benjamina. RESULTS: 67 out of 89 (75%) sera showed elevated IgE to hevein. Specific IgE to Ficus were found in 22 (24.7%) sera, and with 1 exception, all these sera also had IgE to Hev b 6.02. Results of CAP inhibition assays using 11 sera showing IgE to both Hev b 6.02 and Ficus demonstrated that the IgE to Ficus could be completely inhibited by Hev b 6.02 in 6 of 11 sera. Immunoblots and immunoblot inhibition assays revealed that a protein of about 45 kD in F. benjamina is strongly recognized by serum IgE. In addition, the IgE-binding reactivity to this 45-kD protein could be completely inhibited by preincubation of the sera with Hev b 6.02. N-terminal protein sequencing of 14 amino acids indicated that this 45-kD protein has a hevein-like domain at the N-terminal region and may belong to the endochitinase family. CONCLUSION: Latex-allergic patients are at higher risk of becoming sensitized to Ficus. Hev b 6.02 in latex is a major cross-reactive allergen and its counterpart in F. benjamina is an acidic protein with a molecular weight of about 45 kD and a hevein-like N-terminal domain.

Adult↗
PubMed2000

Comparison of four methods to assess fungal alpha-amylase in flour dust.

The aim of the study was to compare four different immunological methods to analyse fungal alpha-amylase in flour dust samples. Three European research groups have independently developed four immuno assay based methods to measure alpha-amylase in air samples. Three of the methods use polyclonal antibodies and one method uses monoclonal antibodies. Eighty personal samples have been collected during two to three work-shifts in four bakeries. Sampling was performed with PAS-6 inhalable dust samplers and aliquots from each sample were analysed by the three laboratories. The agreement between the four methods was high compared with agreement between immunological methods to measure other allergens in the air, e.g. for rat allergens. For the three methods with polyclonal antibodies the mean differences for individual samples was less than a factor of two. The arithmetic means (AM) of the estimated alpha-amylase exposure were 12.5, 11.3, 8.6 and 25.9ng/m(3) for the respective methods with values ranging from below the detection limit to 192, 215, 207 and 615 ng/m(3). The AM for all samples analysed by the methods with polyclonal antibodies varied by about a factor of 1.5. About one-third of the values were below or at the detection limit for all methods. In a regression analysis the squared correlation coefficients (R(2)) between the methods varied between 0.91 and 0.95 for the log transformed values. For workplace monitoring, results from the methods using polyclonal antibodies will be relatively comparable. High levels of alpha-amylase might differ in absolute numbers with a factor of two or more between the different methods but will anyway be considered as high and should result in preventive actions. On the other hand, this study also shows that despite the relative agreement between methods, there is a clear need for standardization.

Air Pollutants, Occupational↗
PubMed1998

Allergy to Aspergillus-derived enzymes in the baking industry: identification of beta-xylosidase from Aspergillus niger as a new allergen (Asp n 14).

BACKGROUND: Aspergillus-derived enzymes are used in dough improvers in bakeries. Some of these enzymes are identified as causing IgE-mediated sensitization in up to 25% of bakers with workplace-related symptoms. OBJECTIVE: The aim of this study was to compare the frequency of sensitization to Aspergillus xylanase, cellulase, and glucoamylase with the sensitization to alpha-amylase (Asp o 2) and to identify IgE-reactive proteins in enzyme preparations. METHODS: Sensitization to Aspergillus-derived enzymes and cross-reactivity were retrospectively studied by enzyme allergosorbent test (EAST) and EAST-inhibition experiments. IgE-reactive proteins were detected by electrophoretic separation and immunoblotting. Liquid chromatography with electrospray ionization mass spectrometry and Edman degradation of tryptic protein fragments were used for the biochemical identification of an unknown IgE-binding protein. RESULTS: Twenty-three percent of 171 tested bakers had specific IgE to alpha-amylase, 8% reacted to glucoamylase, 13% reacted to cellulase, and 11% reacted to xylanase. Xylanase and cellulase preparations, each containing at least 6 different proteins, showed cross-reactivity in the range of 80%. The main IgE-binding protein in the xylanase preparation recognized in 7 of 8 xylanase-positive subjects was a protein of about 105 kd. This protein was identified as beta-xylosidase by peptide mass spectrometric fingerprinting. The identification was confirmed by matching 12 peptide sequences obtained by N-terminal and mass spectrometric sequencing to this protein. CONCLUSIONS: Beta-Xylosidase from Aspergillus niger is an occupational allergen present in currently used baking additives, which causes sensitization in at least 4% of symptomatic bakers. According to the International Union of Immunological Societies nomenclature, we suggest the term Asp n 14 for this allergen.

Adult↗
PubMed1998

Baker's asthma: still among the most frequent occupational respiratory disorders.

BACKGROUND: Baker's asthma and rhinitis are among the most frequent occupational respiratory disorders. OBJECTIVE: The aim of the study was to evaluate the frequency of work-related symptoms and the clinical relevance of sensitization to allergens in screened and symptomatic bakers. METHODS: Eighty-nine bakers participating in a screening study and 104 bakers filing a claim for compensation were examined with regard to occupational and clinical case history, lung function parameters, and sensitization to bakery allergens by skin prick tests, specific IgE analyses, and inhalative challenge tests. RESULTS: A high prevalence of respiratory disorders, abnormal lung function parameters, and sensitization to bakery allergens exists. Most frequently, bakers with workplace-related respiratory symptoms showed sensitization to wheat flour (64%), rye flour (52%), soy bean flour (25%), and alpha-amylase (21%). The correlation between these sensitizations and asthma case history and inhalative challenge test responses was significant. However, approximately 29% of the bakers with respiratory symptoms showed no sensitization to these bakery allergens, whereas 32% of the sensitized bakers in the screening group had no workplace-related symptoms. Atopic status defined by skin prick test sensitization to common allergens or elevated total IgE levels was found to be a risk factor for the development of sensitization to bakery allergens and respiratory symptoms. On the other hand, there is evidence for an increased frequency of elevated total IgE as the result of occupational allergen exposure because respective findings were observed in bakers without symptoms. CONCLUSION: Sensitization to bakery allergens seems to be the main cause of baker's asthma and rhinitis but cannot explain the asthma case history in each case. Further methods are required to objectively assume irritative pathomechanisms. Our findings indicate the necessity for an improved primary prevention of exposure to inhalative noxae in bakeries.

Allergens↗
PubMed1998

Baker's asthma due to the enzyme xylanase -- a new occupational allergen.

The asthmatic baker showed IgE-mediated sensitization to xylanase of Aspergillus niger used as a baking additive. Inhalative challenge with approximately 0.5 microg of the enzyme resulted in an immediate-type asthmatic reaction. This case, as well as a preliminary screening of symptomatic bakers, shows that xylanase is a further relevant type I-sensitizer in the baking industry.

Administration, Intranasal↗
PubMed1998

[Quantification of inhaled exposure to alpha-amylase in 2 bakeries].

BACKGROUND: Baker's asthma and baker's rhinitis are among the most frequent occupational diseases. A major cause is the high exposure to flour dust in the workplace and to allergenic enzymes like alpha-amylase from Aspergillus oryzae (allergen name: Asp o 2). METHODS: To quantify allergen exposure in the workplace, 31 personal dust samples in a conventional small bakery (six workers) and in a biobakery (seven workers) were collected. Using a recently developed two-site enzyme-linked immunosorbent assay based on monoclonal antibodies to alpha-amylase from Aspergillus oryzae, the allergen content of these dust samples was determined. RESULTS: Dust exposure in the biobakery was in the range between 3.5 and 12 mg/m3 (median: 5.2 mg/m3) and in the conventional bakery between 0.9 and 118 mg/m3 (median 8.5 mg/m3). 23 out of 31 exposure measurements showed values higher than 4 mg/m3 (threshold limit value for inhalable dust). In the biobakery, no fungal alpha-amylase could be detected. 15 out of 17 samples taken in the conventional bakery contained fungal alpha-amylase in the range between 0.2 and 88 ng per mg dust. The geometric mean of alpha-amylase exposure in this bakery was 13 ng Asp o 2/m3, and the maximum exposure was 4.8 micrograms/m3. In four cases, fungal alpha-amylase was detected although exposure to dust was below the threshold limit of 4 mg/m3. CONCLUSIONS: This study in two German bakeries shows that preventive measures to reduce contact to allergens have not been sufficiently realised. Relevant alpha-amylase exposure occurred at low dust levels illustrating that dust measurements are not adequate to control alpha-amylase exposure. For fungal alpha-amylase an additional threshold limit should be established.

Aspergillus oryzae↗
PubMed1997

Development of a two-site enzyme-linked immunosorbent assay for alpha-amylase from Aspergillus oryzae based on monoclonal antibodies.

A two-site monoclonal antibody ELISA was developed to quantify the allergen Asp o 2 (alpha-amylase from Aspergillus oryzae). Two mAbs recognizing distinct epitopes were selected, enriched by in vitro production in a modular minifermenter and affinity-purified. The first antibody was bound to microtiter plates which were then incubated with samples containing the allergen. Bound allergen was detected using a biotinylated second antibody and peroxidase-polymer-labelled streptavidin. The assay had a sensitivity of 0.6 ng/ml and did not react to high concentrations of wheat and rye flour or yeast proteins. The mAb ELISA will be useful in individual or epidemiological studies of baker's asthma to assess workplace allergen concentrations and the efficacy of allergen exposure prevention. It can be used as a standard assay for the quantification of alpha-amylase and the establishment and control of threshold limits in European bakeries.

Allergens↗