Salivary cortisol, alpha-amylase and immunoglobulin a responses to a morning session of basketball or volleyball training in boys aged 14-18 years

This study investigates whether a single session of routine morning basketball or volleyball training affects saliva levels of cortisol, alpha-amylase (sAA) and secretory immunoglobulin A (sIgA) in boys aged 14–18 years. Twenty-nine boys who participate in basketball or volleyball training, recruited from the Marcin Gortat’s Athletic Championship School in Lodz, were enrolled in the study. The 90-minute routine exercise program included 15 minutes of warm-up followed by basketball or volleyball practice. Unstimulated saliva samples were collected prior to and immediately after the exercise, and were analysed using ELISA. One training session resulted in a significant increase of sAA concentration in all participants, as well as in the volleyball and basketball subgroups (p=0.00022; p=0.0029; p=0.0011; respectively). Post-exercise cortisol levels were significantly lower than pre-exercise levels (p=0.00002) throughout the group, as well as in the volleyball and basketball subgroups (p=0.0048; p=0.0019; p=0.0048; respectively). The exercise protocol did not significantly affect sIgA level, either in the whole examined group or the volleyball subgroup, however a weak significant increase of sIgA was observed in the basketball subgroup (p=0.046). The routine morning training session comprising a warm-up followed by basketball or volleyball practice seems to activate the sympatho-adrenal-medullary system, with a subsequent increase of alpha-amylase, but does not affect oral immunity in 14-18-year-old boys.

Exposure to flour dust and sensitization among bakery employees

BACKGROUND

The National Institute for Occupational Safety and Health conducted a study to determine prevalences of sensitization to bakery-associated antigens (BAAs) and work-related respiratory symptoms at a large commercial bakery.

METHODS

The following measurements were carried out: personal breathing zone (PBZ) and general area (GA) monitoring for inhalable flour dust, α-amylase and wheat, a questionnaire, and blood tests for IgE specific to flour dust, wheat, α-amylase, and common aeroallergens.

RESULTS

Of 186 bakery employees present during our site visit, 161 completed the questionnaire and 96 allowed their blood to be drawn. The geometric mean PBZ and GA inhalable flour dust concentrations for the lower-exposure group was 0.235 mg/m(3), and for the higher-exposure group was 3.01 mg/m(3). Employees in the higher-exposure group had significantly higher prevalences of work-related wheezing, runny nose, stuffy nose, and frequent sneezing than the lower-exposure group. The prevalence of IgE specific to wheat was significantly higher among employees who ever had a job in the higher-exposure group or in production at another bakery at both the ≥ 0.10 kU/L and the ≥ 0.35 kU/L cutoffs, and to flour dust and α-amylase at the ≥ 0.10 kU/L cutoff, compared to the lower-exposure group.

CONCLUSIONS

Despite knowledge of the risks of exposure to flour being available for centuries, U.S. employees are still at risk of sensitization and respiratory symptoms from exposure to high levels of BAA.

Determinants of specific sensitization in flour allergens in workers in bakeries with use of skin prick tests

Baker's asthma, like other forms of occupational asthma is probably the most serious manifestation of occupational allergy among bakery workers. It is caused by immunologic sensitization and subsequent allergic reactions in the airways to occupational specific airborne allergens. Skin Prick Tests (SPTs) play an important role in the diagnosis of baker's asthma and epidemiological field studies on frequencies of sensitization to flour. This paper presents a review of the available literature on prevalence of flours sensitization in bakery workers. Atopy and level of exposure appears to be a very strong determinant for sensitization to flour allergens. Prevention strategies and standard setting are discussed.

Stabilization of Bacillus licheniformis alpha-amylase by specific antibody which recognizes the N-terminal fragment of the enzyme

Bacillus licheniformis alpha-amylase (BLA) is an industrially important extracellular enzyme with a number of applications. In the present work, an investigation was carried out on the tryptolytic digestion of BLA which produced two fragments, TF18K and TF38K, and no further fragments could be seen after 6h incubation of BLA with trypsin. The fragments were isolated by preparative gel electrophoresis and reverse phase HPLC. The N-terminal sequencing of fragments showed that trypsin attacks on Arg(127)-Val(128) peptide bond in BLA. Intrinsic and acrylamide quenching fluorescence experiments and Far-UV circular dichroism studies showed that substantial changes in the secondary and tertiary structures of the TF18K and TF38K have occurred. Subsequently, polyclonal antibody was raised against TF18K. After purification of the antibody by protein A Sepharose, thermal stability of BLA in the presence of this antibody was determined. Results showed that the presence of antiTF18K leads to significant stabilization of BLA. For example, after 30 min incubation at 90 degrees C, residual activity of the enzyme in the presence of antibody (40 microg/ml) was determined as 40% while the enzyme showed no activity in the absence of antibody after incubating in the same condition. In addition, it has been proved that calcium enhances the thermal stability of BLA and a synergistic stabilization of BLA has been seen with antiTF18K and calcium, simultaneously.

Mechanistic analysis of experimental food allergen-induced cutaneous reactions

Individuals with food allergy often present with uritcaria and atopic dermatitis. Indeed, susceptibility to food allergy may predispose to the development of these cutaneous allergic disorders. Recently, we developed a model of food allergy, whereby oral consumption of food [pea Pisum sativum L.; expressing alpha-amylase inhibitor-1 (alphaAI) from the common bean Phaseolus vulgaris L. cv Tendergreen (pea-alphaAI)] promotes a T helper cell type 2 (Th2) inflammatory response and predisposes to cutaneous allergic reactions following subsequent food allergen (alphaAI) exposure. To delineate the kinetics of food allergen-induced cutaneous reactions and examine the inflammatory mechanisms involved in this allergic reaction, we used interleukin (IL)-13-, IL-4 receptor alpha-, and eotaxin-1-deficient mice and performed serum transfer and CD4+ T cell depletion studies. We demonstrate that consumption of pea-alphaAI promotes an alphaAI-specific immunoglobulin G1 (IgG1) and IgE antibody response. Furthermore, we show that subsequent food allergen (alphaAI) challenge in the skin induced an early (3 h)- and late-phase (24 h) cutaneous allergic reaction. The early-phase response was associated with mast cell degranulation and the presence of Ig, whereas the late-phase response was characterized by a lymphoid and eosinophilic infiltrate, which was critically regulated by CD4+ T cells, IL-13, and eotaxin-1. Collectively, these studies demonstrate that food allergy can predispose to cutaneous inflammatory reactions, and these processes are critically regulated by Th2 immune factors.

A rapid lateral flow immunoassay for the detection of fungal alpha-amylase at the workplace

Fungal alpha-amylase is a flour supplement which is added to improve the quality of bakery products. Various studies have shown that exposure to this enzyme is an important risk factor for the development of bakers' allergy and this allergy is reported to be one of the most frequent causes of occupational asthma. A rapid assay was developed to monitor exposure to occupational allergens directly at the workplace. The sensitivity of the developed assay is 0.32 ng amylase mL(-1) in a buffer system with the commercially available alpha-amylase preparation Fungamyl 1600S as the standard. Initial validation tests (n = 33) were performed with airborne and settled dust from an industrial bakery. The new lateral flow immunoassay detected amylase in 22 of the 26 samples regarded as positive in an enzyme immunoassay, and was negative for all seven enzyme immunoassay-negative samples, while the four lateral flow immunoassay-negative/enzyme immunoassay-positive samples all had levels below 2 ng mL(-1). The sensitivity of 2 ng mL(-1) of the amylase lateral flow immunoassay is sufficient for first screening purposes and, therefore, this simple and rapid assay may allow direct on-site demonstration of work-related hazards of bio-allergen exposure. This would be particularly useful in occupational hygiene practice, especially in traditional or small-scale bakeries which lack the technological skills for testing the exposure to respiratory allergens.

Evaluation of the prevalence of antiwheat-, anti-flour dust, and anti-alpha-amylase specific IgE antibodies in US blood donors

BACKGROUND

Asthma in bakery workers is one of the most frequently occurring forms of occupational asthma in the world. Experience from other countries has shown the prevalence of sensitization (IgE) to bakery-associated allergens (BAAs) (wheat [W], flour dust [FD], alpha-amylase [AA]) in bakery workers to be 5% to 53%, whereas the prevalence in nonoccupationally exposed individuals was estimated to be 1.2% to 6.4%.

OBJECTIVE

To estimate the prevalence of BAA sensitization by measuring BAA specific IgE in the residual serum tubes of volunteer blood donors.

METHODS

Serum samples from 534 volunteer blood donors were measured for anti-W, anti-FD, and anti-AA specific IgE antibodies (in duplicate) using the AlaSTAT microplate assay. Samples with BAA IgE concentrations of 0.35 kU/L or greater were considered positive.

RESULTS

Nineteen of 530 serum samples (3.6%; 95% confidence interval [CI], 3.3%-3.9%) were positive for W (range, 0.38-3.61 kU/L), whereas 31 of 534 (5.8%; 95% CI, 5.3%-6.3%) were positive for FD (range, 0.35-2.34 kU/L) and 5 of 529 (1.0%; 95% CI, 0.9%-1.1%) were positive for AA (range, 0.38-1.59 kU/L). Thirteen serum samples were positive for both W and FD; 1 sample each was positive for W and AA and FD and AA.

CONCLUSIONS

The prevalence of IgE sensitization in serum samples from a relatively large unselected population of volunteer blood donors is 1.0% for AA, 3.6% for W, and 5.8% for FD, which agrees well with data from other countries for sensitization prevalence rates for nonoccupationally exposed individuals.

Bread eating induced oral angioedema due to alpha-amylase allergy

Inhalation of dust from different enzymes can be the cause of occupational asthma in exposed workers. Enzymes from different sources are being increasingly used in food. Few cases of food allergy to alpha-amylase induced by eating bread have been reported. Those cases were reported in bakery-related patients and in a pharmaceutical-industry worker. A 25-year-old farmer suffered sneezing, rhinorrhea, oropharyngeal itching, hoarseness, cough, and non-wheezy dyspnea after eating white bread. Skin prick tests (SPT) with common aeroallergens and food allergens revealed only sensitization to Olea europaea pollen. SPT response was positive to Aspergillus oryzae alpha-amylase. Specific IgE against alpha-amylase was positive. A double-blind placebo-controlled challenge with 5 mg of uncooked -amylase induced sneezing, cough, oral angioedema within 10 minutes. The provocation test with 50 g of white bread gave similar findings. This case indicates that alpha-amylase contained in bread may provoke IgE-mediated food allergy. It is worth noting that in this case, the only source of alpha-amylases sensitization was bread.

Assessment of blind predictions of protein-protein interactions: current status of docking methods

The current status of docking procedures for predicting protein-protein interactions starting from their three-dimensional structure is assessed from a first major evaluation of blind predictions. This evaluation was performed as part of a communitywide experiment on Critical Assessment of PRedicted Interactions (CAPRI). Seven newly determined structures of protein-protein complexes were available as targets for this experiment. These were the complexes between a kinase and its protein substrate, between a T-cell receptor beta-chain and a superantigen, and five antigen-antibody complexes. For each target, the predictors were given the experimental structures of the free components, or of one free and one bound component in a random orientation. The structure of the complex was revealed only at the time of the evaluation. A total of 465 predictions submitted by 19 groups were evaluated. These groups used a wide range of algorithms and scoring functions, some of which were completely novel. The quality of the predicted interactions was evaluated by comparing residue-residue contacts and interface residues to those in the X-ray structures and by analyzing the fit of the ligand molecules (the smaller of the two proteins in the complex) or of interface residues only, in the predicted versus target complexes. A total of 14 groups produced predictions, ranking from acceptable to highly accurate for five of the seven targets. The use of available biochemical and biological information, and in one instance structural information, played a key role in achieving this result. It was essential for identifying the native binding modes for the five correctly predicted targets, including the kinase-substrate complex where the enzyme changes conformation on association. But it was also the cause for missing the correct solution for the two remaining unpredicted targets, which involve unexpected antigen-antibody binding modes. Overall, this analysis reveals genuine progress in docking procedures but also illustrates the remaining serious limitations and points out the need for better scoring functions and more effective ways for handling conformational flexibility.

A soft docking algorithm for predicting the structure of antibody-antigen complexes

An efficient soft docking algorithm is described for predicting the mode of binding between an antibody and its antigen based on the three-dimensional structures of the molecules. The basic tools are the "simplified protein" model and the docking algorithm of Wodak and Janin. The side-chain flexibility of Arg, Lys, Asp, Glu, and Met residues on the protein surface is taken into account. A combined filtering technique is used to select candidate binding modes. After energy minimization, we calculate a scoring function, which includes electrostatic and desolvation energy terms. This procedure was applied to targets 04, 05, and 06 of CAPRI, which are complexes of three different camelid antibody VHH variable domains with pig alpha-amylase. For target 06, two native-like structures with a root-mean-square deviation < 4.0 A relative to the X-ray structure were found within the five top ranking structures. For targets 04 and 05, our procedure produced models where more than half of the antigen residues forming the epitope were correctly predicted, albeit with a wrong VHH domain orientation. Thus, our soft docking algorithm is a promising tool for predicting antibody-antigen recognition.

Guided docking: first step to locate potential binding sites

The long-range electrostatic forces of the targets in round 2 of the Critical Assessment of PRediction of Interactions (CAPRI) experiment were examined and a simple guided docking method, based on these forces, was applied. The method described consists of calculating an initial rigid body trajectory and an optional final, fully flexible refinement stage. Although only limited success was found in predicting the final complexes, some interesting information was discovered. In particular, the long-range forces seem to give some insight into the unusual binding mode of target 4 while raising some questions about target 7, which warrant further investigation.

Finding needles in haystacks: Reranking DOT results by using shape complementarity, cluster analysis, and biological information

We present an evaluation of our results for the first Critical Assessment of PRedicted Interaction (CAPRI). The methods used include the molecular docking program DOT, shape analysis tool FADE, cluster analysis and filtering based on biological data. Good results were obtained for most of the seven CAPRI targets, and for two systems, submissions having the highest number of correctly predicted contacts were produced.

Prediction of the unknown: inspiring experience with the CAPRI experiment

We submitted predictions for all seven targets in the CAPRI experiment. For four targets, our submitted models included acceptable, medium accuracy predictions of the structures of the complexes, and for a fifth target we identified the location of the binding site of one of the molecules. We used a weighted-geometric docking algorithm in which contacts involving specified parts of the surfaces of either one or both molecules were up-weighted or down-weighted. The weights were based on available structural and biochemical data or on sequence analyses. The weighted-geometric docking proved very useful for five targets, improving the complementarity scores and the ranks of the nearly correct solutions, as well as their statistical significance. In addition, the weighted-geometric docking promoted formation of clusters of similar solutions, which include more accurate predictions.

Alpha amylase is a major allergenic component in occupational asthma patients caused by porcine pancreatic extract

Porcine pancreatic extracts (PPE) are composed of alpha-amylase and lipase, which are common components of digestive enzymes. They have been known to cause occupational asthma in exposed workers in pharmaceutical and baking industries, as well as in a laboratory technician, but there has been no report of PPE-induced occupational asthma in medical personnel and their IgE binding components to each component. Four asthmatic subjects showing positive results on PPE-bronchoprovocation testing were enrolled. All of them were nurses working in a university hospital. Their job included grinding and mixing PPE powder for admitted patients. Serum-specific IgE antibodies to PPE, alpha-amylase, and lipase were measured by enzyme linked immunosorbent assay (ELISA). To confirm specificity of IgE binding and cross-allergenicity among the three extracts, ELISA inhibition tests were performed. In order to characterize allergenic components within these three extracts, SDS-PAGE and IgE immunoblot analysis were done. Specific IgE antibodies to PPE, alpha-amylase, and lipase were detectable by ELISA in all study subjects. An alpha-amylase ELISA inhibition test showed significant inhibitions by amylase and PPE, and minimal inhibition by lipase. However, a lipase ELISA inhibition test showed significant inhibitions by alpha-amylase and PPE with a lesser degree of inhibition by lipase. Furthermore, IgE immunoblot analysis showed one IgE binding component (55 kDa) within PPE, six components (55 kDa, 43 kDa, 41 kDa, 32 kDa, 31 kDa, 29 kDa) within alpha-amylase and two components (31 kDa, 29 kDa) within lipase extracts. Thesefindings suggest that inhalation of PPE powder can induce IgE-mediated bronchoconstriction in exposed nurses. Alpha-amylase is a major allergenic component within PPE.

Cloning of a gene encoding raw-starch-digesting amylase from a Cytophaga sp. and its expression in Escherichia coli

A raw-starch-digesting amylase (RSDA) gene from a Cytophaga sp. was cloned and sequenced. The predicted protein product contained 519 amino acids and had high amino acid identity to alpha-amylases from three Bacillus species. Only one of the Bacillus alpha-amylases has raw-starch-digesting capability, however. The RSDA, expressed in Escherichia coli, had properties similar to those of the enzyme purified from the Cytophaga sp.

Allergen and dust exposure as determinants of work-related symptoms and sensitization in a cohort of flour-exposed workers; a case-control analysis

OBJECTIVES

To estimate the incidence of specific IgE sensitization and allergic respiratory symptoms among UK bakery and flour mill workers; and to examine the roles of flour aeroallergen and total dust exposures in determining these outcomes.

METHODS

A cohort of 300 new employees, without previous occupational exposure to flour, were followed prospectively for a median (range) of 40 (1-91) months. Cases-defined as those developing work-related symptoms or a positive skin prick test to flour or alpha-amylase during follow up--were compared with controls, matched for duration of employment. Exposures to flour aeroallergen and total inhalable dust were estimated using a questionnaire and personal sampling techniques.

RESULTS

Incidence rates for work-related eye/nose and chest symptoms were 11.8 and 4.1 cases per 100 person years (py), respectively. Fewer employees developed positive skin prick tests to flour (2.2 cases per 100 py) or alpha-amylase (2.5 cases per 100 py). Positive skin tests to occupational allergens were more common among those with new work-related symptoms. There were clear relationships between the risks of developing work-related symptoms or a positive skin prick test and three categories of estimated exposure to total dust or flour aeroallergen. Atopic employees were more likely to develop a positive skin prick test-but not work-related symptoms. These findings were unaffected by age, sex or cigarette smoking.

CONCLUSIONS

In this population, many work-related symptoms which develop after first employment in modern UK bakeries or flour mills were not accompanied by evidence of IgE sensitization to flour or alpha-amylase. Although average dust exposures were within current occupational standards, the risks of development of upper and lower respiratory symptoms and of specific sensitization were clearly related to total dust and/or flour aeroallergen exposure. The incidence of work-related chest symptoms in the presence of a positive skin test to flour or alpha-amylase in this setting was approximately 1 case per 100 py.

Evidence that the glucoamylases and alpha-amylase secreted by Aspergillus niger are proteolytically processed products of a precursor enzyme

A 125-kDa starch hydrolysing enzyme of Aspergillus niger characterised by its ability to dextrinise and saccharify starch [Suresh et al. (1999) Appl. Microbiol. Biotechnol. 51, 673-675] was also found to possess activity towards raw starch. Segregation of these activities in the 71-kDa glucoamylase and a 53-kDa alpha-amylase-like enzyme supported by antibody cross-reactivity studies and the isolation of mutants based on assay screens for the secretion of particular enzyme forms revealed the 125-kDa starch hydrolysing enzyme as their precursor. N-terminal sequence analysis further revealed that the 71-kDa glucoamylase was the N-terminal product of the precursor enzyme. Immunological cross reactivity of the 53-kDa amylase with antibodies raised against the precursor enzyme but not with the 71- and 61-kDa glucoamylase antibodies suggested that this enzyme activity is represented by the C-terminal fragment of the precursor. The N-terminal sequence of the 53-kDa protein showed similarity to the reported Taka amylase of Aspergillus oryzae. Antibody cross-reactivity to a 10-kDa non-enzymic peptide and a 61-kDa glucoamylase described these proteins as products of the 71-kDa glucoamylase. Identification of only the precursor starch hydrolysing enzyme in the protein extracts of fungal protoplasts suggested proteolytic processing in the cellular periplasmic space as the cause for the secretion of multiple forms of amylases by A. niger.

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.

Antibody to glucosyltransferase induced by synthetic peptides associated with catalytic regions of alpha-amylases

We examined the immunogenicity and induction of inhibitory activity of 19-mer synthetic peptides which contained putative catalytic regions that were associated with the beta5 (EAW) and beta7 (HDS) strand elements of the suggested (beta,alpha)8 catalytic barrel domain of Streptococcus mutans glucosyltransferase (GTF). Both peptides readily induced serum immunoglobulin G (IgG) and salivary IgA antipeptide activity which was reactive both with the inciting peptide and with intact S. mutans GTF. Antisera to each peptide construct also inhibited the ability of S. mutans GTF to synthesize glucan. These observations support the existence of catalytic subdomains containing glutamate and tryptophan (EAW) or aspartate and histidine (HDS) residues, each of which have been suggested to be involved with the catalytic activity of GTF. Furthermore, the epitopes defined in these sequences have significant immunogenicity and can induce immune responses which interfere with GTF-mediated glucan synthesis.

Alpha-amylase functions as a salivary gland-specific self T cell epitope in patients with Sjögren's syndrome

Analyses of T cell receptors (TCR) on T cells infiltrating labial salivary glands of patients with Sjögren's syndrome (SS) indicate that the cells expand by antigen stimulation in context of major histocompatibility complex (MHC). To elucidate the autoantigens recognized by T cells infiltrating in labial salivary glands from patients with SS, proteins derived from human salivary gland cDNA libraries were screened by West-Western method using TCR-CDR3 probe, which is antigen recognition region of TCR on T cells. 13 cDNA clones were detected as proteins binding to TCR-CDR3 region. One was a human alpha-amylase salivary precursor (AA54-407), suggesting that alpha-amylase might be a salivary gland-specific autoantigen. To examine whether alpha-amylase acts as an antigen in labial salivary glands, PBL from 11 patients with SS were incubated with 9 different synthetic amino acids of alpha-amylase or salivary alpha-amylase. SSCP analysis on TCR clearly showed that alpha-amylase reactive T cells were observed in labial salivary glands from 3 of 11 patients with SS (27%). These findings support the possibility that alpha-amylase functions as a salivary gland-specific T cell epitope and induces autoimmunity in SS.

Exposure-response relations of alpha-amylase sensitisation in British bakeries and flour mills

OBJECTIVES

To describe the levels of exposure to fungal alpha-amylase in British bakeries and flour mills, and to describe the relation between exposure to alpha-amylase and sensitisation to fungal alpha-amylase.

METHODS

495 personal flour dust samples were taken in seven British bakeries and flour mills and analysed for alpha-amylase with an immunoassay. Workers at the sites were asked to fill out questionnaires on work related symptoms, smoking history, and work history, and they were skin prick tested with common allergens and fungal alpha-amylase to assess sensitisation.

RESULTS

Exposure to high concentrations of alpha-amylase occur in a few areas of British bakeries and flour mills, and there can be considerable differences in exposures to alpha-amylase between sites and between exposure groups, and even within similar exposure groups from different sites. Exposure to the highest concentrations of alpha-amylase was found in the dispensing and mixing areas of the bakeries (geometric mean (GM) 39.7 ng/m3). Exposure to alpha-amylase showed only a moderate correlation with concentrations of dust (r = 0.42) and flour aeroallergen (r = 0.46). The results also showed a relation between exposure to alpha-amylase and sensitisation to fungal alpha-amylase (prevalence ratio (PR) for medium exposure 3.9, 95% confidence interval (95% CI) 0.8 to 20.2, PR for high exposure 9.9, 95% CI 2.8 to 34.6) compared with the low exposure category). Atopic subjects had an increased risk of sensitisation, but this was not significant.

CONCLUSION

This study suggests that exposure to alpha-amylase is a considerable health risk in British bakeries and flour mills. A small proportion of workers are exposed to alpha-amylase at concentrations that result in high rates of sensitisation. A reduction in exposure to alpha-amylase is likely to reduce this risk.

[Sjögren's syndrome]

Sjögren's syndrome(SS) is a chronic inflammatory disease characterized by keratoconjunctivitis sicca and xerostomia. According to the epidemiological survey done by the Japan Ministry of Health and Welfare(MHW) in 1994, about 17,000 SS patients visit hospitals and the prevalence rate is approximately 0.06% for females. SS is diagnosed mainly by the criteria of MHW in 1977, and the revised ones will be published in the near future. Several candidates for the corresponding antigens for SS autoimmunity have discovered, such as alpha-fodrin and 203-211 amino acid residues of Ro/SSA-52 kDa. The sicca complex is treated with fluid replacement, but corticosteroids or immunosuppressive drugs are sometimes indicated in the treatment of extraglandular involvement. Several new drugs are now under investigation.

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.

Utilization of antipeptide antibodies as affinity ligands in immunoaffinity purification

Anti-peptide antibodies against the C-terminal regions of chimeric alpha-amylase, recombinant CD2 and insulin B-chain were obtained by using peptides corresponding to the C-terminal regions as immunogens. These anti-peptide antibodies adsorbed the native proteins, as well as the antigen peptides. The proteins were purified to high purity using the anti-peptide antibodies as affinity ligands. These ligands could discriminate the target proteins having different C-terminal regions. The adsorbed proteins were specifically eluted by the eluents containing the antigen peptides.

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.

Potent enzyme inhibitors derived from dromedary heavy-chain antibodies

Evidence is provided that dromedary heavy-chain antibodies, in vivo-matured in the absence of light chains, are a unique source of inhibitory antibodies. After immunization of a dromedary with bovine erythrocyte carbonic anhydrase and porcine pancreatic alpha-amylase, it was demonstrated that a considerable amount of heavy-chain antibodies, acting as true competitive inhibitors, circulate in the bloodstream. In contrast, the conventional antibodies apparently do not interact with the enzyme's active site. Next we illustrated that peripheral blood lymphocytes are suitable for one-step cloning of the variable domain fragments in a phage-display vector. By bio-panning, several antigen-specific single-domain fragments are readily isolated for both enzymes. In addition we show that among those isolated fragments active site binders are well represented. When produced as recombinant protein in Escherichia coli, these active site binders appear to be potent enzyme inhibitors when tested in chromogenic assays. The low complexity of the antigen-binding site of these single-domain antibodies composed of only three loops could be valuable for designing smaller synthetic inhibitors.

Determinants of wheat antigen and fungal alpha-amylase exposure in bakeries

The study's objectives were to measure flour antigen exposure in bakeries and define the determinants of exposure. Ninety-six bakery workers, employed in seven different bakeries, participated in the study. Two side-by-side full-shift inhalable dust samples were obtained from each study participant on a single occasion. The flour antigen exposure was measured as wheat antigen and fungal alpha-amylase content of the water-soluble fraction of inhalable dust, assayed via enzyme-linked immunosorbent assays. During the entire sampling period bakers were observed and information on 14 different tasks was recorded at 15-minute intervals. Other production characteristics were also recorded for each sampling day and used in statistical modeling to identify significant predictors of exposure. The mean alpha-amylase antigen exposure was 22.0 ng/m3 (ranging from below the limit of detection of 0.1 ng/m3 to 307.1 ng/m3) and the mean wheat antigen exposure was 109 micrograms/m3 (ranging from below the limit of detection of 1 microgram/m3 to 1018 micrograms/m3). Regression models that explained 74% of variability in wheat antigen and alpha-amylase antigen exposures were constructed. The models indicated that tasks such as weighing, pouring, and operating dough-brakers increased flour antigen exposure, while packing and decorating resulted in lower exposures. Croissant, puff-pastry, and bread/bun production lines were associated with increased exposure, while cake production and substitution of dusting with the use of divider oil were associated with decreased exposure. Exposure levels can be reduced by the automation of forming tasks, alteration of tasks requiring pouring of flour, and changes to the types of products manufactured.

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.

Purification of alpha-amylase by specific elution from anti-peptide antibodies

Chimeric alpha-amylase, produced by recombinant yeast cells, was purified by immunoaffinity chromatography by use of an anti-peptide antibody and an eluent containing an antigen peptide. Chimeric alpha-amylase was adsorbed by the antibody against the peptide corresponding to the C-terminal region of target alpha-amylase, and specifically eluted by the eluent containing the antigen peptide used for immunization. A low concentration of the peptide could competitively elute adsorbed alpha-amylase, and the rate-limiting step of the elution was mass transfer of desorbed alpha-amylase. With this specific method, target proteins can be effectively eluted, and highly purified under mild conditions, from the antibody ligand showing a high-affinity for the adsorption step

Clinical responses to ingested fungal alpha-amylase and hemicellulase in persons sensitized to Aspergillus fumigatus?

alpha-Amylase and hemicellulase, derived from culture of Aspergillus species, are commonly added to flour as improvers during baking. Two cases of women occupationally sensitized to alpha-amylase who developed allergic symptoms after eating baked bread have been reported. With a randomized, controlled study design, we have investigated whether similar responses occur in those sensitized to Aspergillus species. Seventeen subjects with positive skin prick tests to Aspergillus fumigatus were studied. Symptomatic and physiologic responses after ingestion of bread baked with alpha-amylase and hemicellulase were compared, in a crossover fashion, with those after ingestion of bread baked without enzymes. No increase in respiratory or other symptoms, lung function, or nonspecific bronchial hyperreactivity was reported after ingestion of the enzyme-containing bread. We conclude that important clinical reactions to alpha-amylase and hemicellulase in baked bread do not frequently occur in those sensitized to Aspergillus species.

Electron microscopic investigation of the diffusion of Bacillus licheniformis alpha-amylase into corn starch granules

A method for the direct electron microscopic observation of amylases in interaction with starch granules is presented. The technique involves immuno-gold labeling of the enzymes and cross-sectioning of hydrated starch granules. This approach allows the analysis of the internal degradation of starch with a concomitant visualization of enzymes at the sites of hydrolysis. The visualization of enzymes at the surface, inside the channel and inside the core of the degraded granules shows that the alpha-amylase molecules first proceed from the surface toward the center (centripetal hydrolysis). Then the core is completely degraded from within by erosion of its periphery (centrifugal hydrolysis). In the first case (centripetal hydrolysis), the enzymes act by progressing along the polysaccharide chains. By contrast, the centrifugal hydrolysis leads to even erosion, indicative of a more diffusive motion of the enzymes.

Physicochemical and serological characterization of rice alpha-amylase isoforms and identification of their corresponding genes

We have identified, purified, and characterized 10 alpha-amylase isoforms from suspension-cultured rice (Oryza sativa L.) cells having different isoelectric point values. They had distinguishable optimum temperatures for enzymatic activity and molecular sizes. The results of immunoblotting indicated that polyclonal anti-A + B antibodies bound well to isoforms A, B, Y, and Z but weakly or not at all to E, F, G, H, I, and J. However, the anti-A + B antibodies inhibited the enzyme activities of only isoforms A and B. Polyclonal anti-H antibodies strongly bound to isoforms F, G, H, I, and J, whereas polyclonal anti-E antibodies preferentially recognized isoform E. A monoclonal antibody against isoform H (H-G49) inhibited the activities of isoforms E, G, H, I, and J, whereas it did not inhibit those of isoforms A, B, Y, and Z. Judging from their physicochemical and serological properties, we classified the rice alpha-amylase isoforms into two major classes, class I (A, B, Y, and Z) and class II (E, F, G, H, I, and J), and into four subgroups, group 1 (A and B), group 2 (Y and Z), group 3 (E), and group 4 (F, G, H, I, and J). Partial amino acid sequences for isoforms A, E, G, and H were also determined. In addition, the recombinant alpha-amylases expressed by plasmid pEno/103 containing the rice alpha-amylase gene RAmy1A in yeast were identified as both isoforms A and B. These analyses indicated that isoforms A and B were encoded by the gene RAmy1A, isoforms G and H were encoded by the gene RAmy3D, and isoform E was encoded by RAmy3E. The results strongly suggest that some isoforms within subgroups are formed by posttranslational modifications.

[Some patterns in formation of antibody-antigen-antibody complexes on a solid phase: experimental study and mathematical modeling]

Equilibrium and kinetic constants were determined for interactions between alpha-amylase from Bacillus subtilis and polyclonal antibodies (with immobilization of either reagent). The effects of desorption of immobilized molecules and intermolecular complexes on the immunochemical reaction were studied. Models of sandwich enzyme immunoassay, whereby complexes of immobilized antibody-determined antigen-labeled antibody were formed, were developed from these results. The results obtained from the model and experiments were compared. The desorption was shown to cause the hook-effect, that is, a decrease in the label binding at high concentrations of the antigen.

[Immunoenzyme assay of staphylococcal toxin using polyamide micropore membranes]

The optimum conditions for extraction of catalytic active conjugates of alpha-amylase and antibodies for staphylococcal toxin (ST) have been created. The optimum correlation of antibodies and enzyme for the effective use of the extracted conjugate during enzyme immunoassay for ST has been established. The covalent immobilization of antibodies on the micropore polyamide membranes has been carried out. Apart from this, the extracted conjugated were purified by TSK-gel HN-55 chromatography. The optimum concentration of the conjugates has been defined.

Purification of recombinant alpha-amylase by immunoaffinity chromatography with anti-peptide antibody

Adsorption characteristics of an anti-peptide antibody, obtained by immunization of eight amino acids in the C-terminal region of chimeric alpha-amylase of rice alpha-amylase isozymes, were studied by use of the chimeric enzyme and the peptide used for immunization. This anti-peptide antibody adsorbed the enzyme, as well as the peptide antigen, with sufficient affinity for immunoaffinity purification and was used for purification of the enzyme secreted from yeast cells. Chimeric alpha-amylase was purified by immunoaffinity chromatography to high purity in one step from the fermentation broth. One-third of the secreted enzyme was not adsorbed by the column of anti-peptide antibody because of processing in the C-terminal region.

Characterization of a new cell-bound alpha-amylase in Bacillus subtilis 168 Marburg that is only immunologically related to the exocellular alpha-amylase

Immunoblot analysis of Bacillus subtilis cell extracts with polyclonal antibodies, raised against purified exocellular alpha-amylase, revealed one protein species of 82,000 Da. This protein was found even in cells in which the amyE gene, encoding exocellular alpha-amylase, was disrupted. Isolated from the membrane fraction, the 82,000-M(r) protein displayed an alpha-amylase activity in vitro.

Skin-prick tests for hypersensitivity to alpha-amylase preparations

Twenty-five asthmatic subjects with suspected alpha-amylase hypersensitivity were studied by skin-prick tests, a capture ELISA, immunoblotting and bronchial provocation tests. At the same time, different amylases were analysed by SDS-PAGE and immunoblotting using a polyclonal rabbit antiserum. Eight patients showed a positive bronchial response to amylase. Seven of them had positive skin-prick tests, with this method being the most sensitive approach for diagnosis. However, in four cases, skin tests were also positive although the patients had a negative provocation test, thus demonstrating that skin tests are not specific. ELISA and blotting showed similar results in terms of sensitivity and specificity. The enzymes used by the workers included several antigens besides alpha-amylase. The rabbit antiserum to alpha-amylase detected a protein in a wheat flour extract. In one case, the IgE antibodies were specific only for a contaminant of lower molecular weight than amylase. These facts suggest that proteins from the culture medium could be responsible for some cases of amylase hypersensitivity, making the diagnosis difficult. The presence of amylase in another enzymatic extract, a protease produced by Aspergillus oryzae, was proved by means of skin tests and immunoblotting, thus demonstrating the allergenic properties of this enzymatic preparation.

[Complement-binding antibodies to alpha-amylase in the diagnosis of chronic pancreatitis]

Results are reported of measurement of blood levels of compliment-fixing antibodies to alphaamilase in 20 patients with chronic pancreatitis, 20 patients with different affections of the alimentary canal and no involvement of pancreas, and 20 essentially healthy subjects. Measuring antibodies to alphaamilase we obtain a new diagnostic aid identifying chronic pancreatitis, that of high sensitivity (95%), specificity and prognostic value.

Pre-employment screening among trainee bakers

OBJECTIVES

To assess the prevalence of atopy in a vocational school so as to evaluate the feasibility of pre-employment screening.

METHODS

The prevalence of atopy by family diathesis, prick tests, immunoglobulin E (IgE) concentrations, and personal history of allergic respiratory diseases was investigated in 144 trainee bakers and 81 students on a graphic artists course (mean age 15.4 years). Skin sensitisation to wheat, rye, and barley flours, to alpha amylase, and to storage mites was also evaluated.

RESULTS

Personal allergic symptoms were reported by 13.2% of the bakers and 14.7% of the graphic artists and there was a significant association between symptoms and atopy by prick tests (odds ratio (OR) 17.2; 95% confidence interval (95% CI) 5.27-56.4) and by family history (OR 3.11; 95% CI 1.02-9.53). When bakers were grouped according to the presence of allergic symptoms and results of immunological tests, 6.9% had asthma, 6.3% had rhinoconjunctivitis, and a high percentage (28.5%) were without symptoms but scored positive on prick tests or family symptoms. Skin sensitisation to storage mites had similar prevalences (16%) in the two groups of trainees and occurred nearly always in atopic people. Positive skin tests to wheat flour (3.5%), rye (0.7%), and alpha amylase (0.7%) were specific to bakers.

CONCLUSIONS

Pre-employment screening is a useful source of medical information and allows for counseling. The presence of asthma, or of another allergic disease in a severe form, is suggested as a criterion for excluding students of a vocational school from training as bakers. Student bakers without allergic symptoms but atopic by other criteria should be informed about their risks of developing occupational asthma, and periodic check ups must be recommended. Screening studies in vocational school provide a better understanding of specificity of skin sensitisation to occupational allergens.

[Respiratory allergies among symptomatic bakers and pastry cooks: initial results of a prevalence study]

A survey was carried out on respiratory symptoms and skin prick response to common allergens, storage mite and occupational allergens. Among 178 symptomatics bakers and pastry workers from small businesses in western France, only 65 people underwent skin prick and specific-IgE. 12 (18%) workers were skin positive to at least one common or occupational allergens. The more often skin positive were D. Ptero. mite 36 (57%); Alpha amylase 23 (35%); wheat flour 17 (26%); saccharomyces cerevisiae 16 (25%); Ephestia 15 (24%). The sensitivity of skin test was better than specific IgE for D. Ptero. Mite 36 (57%); and Alpha amylase 23 (35%). The sensitivity of specific IgE was better than skin test for wheat flour 26 (45%) and rye flour 23 (40%). Occurrence of skin positive to occupational allergen among symptomatics with rhinitis and asthma is much more frequent in workers with skin positive to common allergens (40/36) than in workers with skin negative (8/20). Atopy must be regarded as an important predisposing factor for skin sensitisation to occupational allergens. We conclude in the necessity of a standardised allergologic exploration to be done in symptomatics bakers.

Allergic reaction after eating alpha-amylase (Asp o 2)-containing bread. A case report

A 29-year-old female bakery shop assistant was occupationally sensitized to flour allergens and Aspergillus alpha-amylase (Asp o 2). The latter represents a strongly allergenic component of routinely used baking additives. The patient had repeatedly responded to the consumption of white bread with rhinitis, conjunctivitis, and, occasionally, wheal and flare reactions. She underwent allergologic investigations including oral challenge tests with commercially available bread loaves. Elevated specific IgE antibodies against bread extracts, Asp o 2, and flour allergens were detectable in her serum. The provocation test with bread resulted in a running nose together with a strong increase in nasal resistance. All symptoms subsided about 3 h after the challenge. None of the above symptoms could be observed when bread free of Aspergillus alpha-amylase was administered. This outcome provides evidence of a clinically relevant persistent allergenicity to Asp o 2 in bread.

Purification of secreted alpha-amylases by immunoaffinity chromatography with cross-reactive antibody

Two isozymes of rice alpha-amylases expressed and secreted by recombinant yeast were purified by immunoaffinity chromatography by using cross-reactive antibody. Antibodies raised against partially purified barley alpha-amylase adsorbed rice alpha-amylases in fermentation broth by a cross-reaction. By use of these antibodies as ligands, rice alpha-amylases were concentrated and purified to a high degree in one-step immunoaffinity chromatography. Because of the differences in the contaminating impurities between the barley alpha-amylase (antigen) from barley malt and rice alpha-amylases (target protein) secreted from yeast, the high purity of eluted alpha-amylases was attained without the use of highly purified antigen for immunization. Utilization of cross-reactive antibodies in immunoaffinity chromatography is useful for the purification of recombinant proteins in the absence of a sufficient amount and high enough purity of the target proteins to be purified.

Characterization of skin prick testing responses for detecting sensitization to detergent enzymes at extreme dilutions: inability of the RAST to detect lightly sensitized individuals

We observed that a group of detergent enzyme workers with known exposure to the subtilisin enzyme, Alcalase (Novo Industries, Bagsvaerde, Denmark), exhibited percutaneous sensitivity to Savinase (Novo Industries), a microbial protease, to which there was no previous occupational exposure. This was attributed to either cross-reactivity between these enzymes or to foreign enzyme contaminants contained in the Savinase antigen. The aims of this study were to determine the range of concentrations eliciting percutaneous responses to Alcalase and to another enzyme, Rapidase (an alpha-amylase) (Gist Brocades, Belgie, Netherlands); to compare the sensitivity of RAST and skin prick testing; and to characterize the relationship between wheal size and antigen concentration. Prick testing was conducted over six log10 antigen dilutions of Alcalase and Rapidase in 30 workers with previous exposure and skin reactivity to enzymes (group 1) and compared to nonexposed control groups, which included 60 atopic subjects (group 2) and 30 nonatopic subjects (group 3). The RAST was performed with Alcalase and Rapidase antigens. The percutaneous threshold concentrations in group 1 subjects varied widely from 10(3) to 10(-3) micrograms of protein per milliliter. Of 19 group 1 workers with skin test reactivity to Alcalase, 84% had positive RAST results; 83% of 24 workers who were reactive to Rapidase had positive RAST results. It was concluded that skin prick testing is preferred over in vitro methods for longitudinal monitoring of human sensitization to workplace allergens. In addition, the data predicted that based on a known Alcalase level of 0.07% in Savinase, 26% of Alcalase-sensitized subjects could react to Savinase. An excellent correlation (r > 0.97) was found between log concentration of antigen and wheal size parameters, with the log diameter and log area performing equally as well (r > 0.98). Analysis of variance revealed that more than 60% of intragroup variation represented human variability in wheal parameters at each concentration tested, whereas at least 95% of intergroup variation was due to regression. The excellent correlations of both wheal diameter and area with antigen concentrations were attributed to the very small changes observed between test concentrations.

[Are amylases in bakery products and flour potential food allergens?]

The enzyme alpha-amylase from the mould Aspergillus oryzae (Asp o II) routinely used for the production of bread, cakes and pastries has in recent years been identified as an inhalative allergen for occupational diseases (bakers' asthma). It is doubtful whether this amylase in the final product, i.e. after the baking procedure, can still be regarded as an allergen. To clarify this question, detailed case histories on 138 subjects were recorded (98 allergics, 20 patients suffering form chronic intestinal diseases, 20 healthy controls). The clinical examinations included prick skin test and IgE antibody determination using one of the customary enzyme preparations. EAST showed a few of these 138 bread consumers to be weakly sensitized to the enzyme. One of the subjects displayed a significant reaction to alpha-amylase heated to 200 degrees C. As expected, eleven bakers sensitized to alpha-amylase by inhaling it in the workplace (positive prick test, positive case history) predominantly exhibited specific IgE antibodies to the native enzyme. Apart from one weakly positive finding, heated alpha-amylase yielded negative results in this collective. Baking conditions vary widely, especially with regard to single components, temperature and duration. Thus, further investigations as to residual allergenicity or the feasible occurrence of new antigenic determinants during the production of bread, cake and pastries are required. 27% of bakers examined and 9% of atopics showed antibodies to a flour inherent enzyme, a beta-amylase. On the whole, the selected conditions hinted at a weakly sensitizing potential inherent in baking flour and in added amylase.

alpha-Amylase hypersensitivity in non-exposed millers

Occupational hypersensitivity to alpha-amylase among bakers and workers in the pharmaceutical industry has been described. We present the results of skin tests and in vitro methods used to assess alpha-amylase sensitivity in 259 millers. There was no occupational contact with the enzyme in this population. Positive skin tests to this allergen were obtained in 16 subjects (6.18 per cent), specific IgE values were found in seven subjects (2.7 per cent), specific IgG was detected on 45 workers (17.37 per cent) and high values for IgG (> 2.5 absorbance units) were found in 12 subjects (4.63 per cent). Furthermore, specific IgE and IgG could be determined in several sera by immunoblotting. All these facts suggested that millers were sensitized to Aspergillus oryzae alpha-amylase, although the allergen was not used by these workers. A cross-reaction cannot be excluded; however, it is the authors' opinion that wheat or wheat flour is a natural substrate for fungi and that the moulds that grow on cereals or cereal-derived by-products need to secrete amylases to support their own development. Hence the workers may be indirectly sensitized to amylases.

Presence of pancreatic alpha-amylase, trypsinogen, and lipase immunoreactivity in normal human pancreatic ducts

Presence of pancreatic alpha-amylase, trypsinogen, and lipase in normal pancreatic ducts was evaluated immunohistochemically in 10 surgically resected normal pancreatic specimens, using monoclonal antibodies against human pancreatic alpha-amylase, trypsinogen, and lipase. Immunoreactivity to all enzymes occurred patchily in some epithelial cells not only of the common bile duct and its periductal glands but also of the main and interlobular pancreatic ducts and periductal glands in the main pancreatic duct, as well as in pancreatic acinar cells. Ductal staining was fine-granular, and generally present in the supranuclear cytoplasm. Immunoreactivity was abolished by preabsorption. Centroacinar cells and intercalated and intralobular pancreatic ducts did not stain for any enzyme. These findings suggest that some epithelial cells of the large-sized pancreatic duct and its periductal glands express pancreatic alpha-amylase-, trypsinogen-, and lipase-like peptides, as do some epithelial cells of common bile duct and its periductal glands.