[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.