Castor Bean Allergens Research Articles

Identification of Critical Amino Acids in the IgE Epitopes of Ric c 1 and Ric c 3 and the Application of Glutamic Acid as an IgE Blocker

BackgroundThe allergenicity of Ricinus communis L. (castor bean, Euphorbiaceae) is associated with components of its seeds and pollen. Castor bean allergy has been described not only in laboratory workers, but also in personnel working in oil processing mills, fertilizer retail, the upholstery industry and other industrial fields. In the present study, we describe the critical amino acids in the IgE-binding epitopes in Ric c 1 and Ric c 3, two major allergens of R. communis. In addition, we also investigate the cross-reactivity between castor bean and some air and food allergen extracts commonly used in allergy diagnosis.Methodology/Principal FindingsThe IgE reactivity of human sera from atopic patients was screened by immune-dot blot against castor bean allergens. Allergenic activity was evaluated in vitro using a rat mast cell activation assay and by ELISA. Cross-reactivity was observed between castor bean allergens and extracts from shrimp, fish, gluten, wheat, soybean, peanut, corn, house dust, tobacco and airborne fungal allergens. We observed that treatment of rat and human sera (from atopic patients) with glutamic acid reduced the IgE-epitope interaction.Conclusions/SignificanceThe identification of glutamic acid residues with critical roles in IgE-binding to Ric c 3 and Ric c 1 support the potential use of free amino acids in allergy treatment.

Mapping IgE-binding epitopes of Ric c 1 and Ric c 3, allergens from Ricinus communis, by mast cell degranulation assay

Ric c 1 and Ric c 3 are the major castor bean allergens. In order to identify continuous IgE-epitopes in Ric c 1 and Ric c 3, pools of sera from rats immunized with a pool of 2S albumin from these seeds, Ric c 1 and Ric c 3 overlapping synthetic peptides, were used to screen for IgE-binding epitopes. The allergenic properties were monitored by mast cell degranulation assays, histamine quantification and human-IgE binding. Large and small chains isolated from these proteins present allergenic properties. Four continuous epitopes were identified in Ric c 3 and two in Ric c 1. This knowledge may allow the induction of protective antibody responses to antagonize the IgE recognition.

The Effectiveness of Control Measures to Reduce Exposure to Henna and Castor Bean Allergens in a Cosmetics Factory

The Effectiveness of Control Measures to Reduce Exposure to Henna and Castor Bean Allergens in a Cosmetics Factory

Factors related to the development of sensitization to green coffee and castor bean allergens among coffee workers.

Occupational allergic respiratory symptoms in coffee workers have been frequently reported, but the ultimate cause of sensitization is still debated, castor bean being considered besides green coffee beans. Atopy and cigarette smoking have been suggested as promoting factors of sensitization for several occupational allergens. This study was carried out to assess the prevalence of allergic respiratory symptoms and of sensitization to both green coffee beans and castor bean in the whole workforce of a coffee manufacturing plant. Furthermore we wanted to ascertain both the presence of castor bean antigens in the settled dust of the green coffee beans warehouse and the possible crossreactivity between the two beans. Meanwhile, the effect of smoking and atopy was considered. Two-hundred and eleven workers were examined. A questionnaire on oculorhinitis and asthma was administered and skin-prick tests for green coffee beans, castor bean and 15 common inhalant allergens were carried out. Isoelectric focusing, isoelectric focusing immunoblot and radioallergosorbent assay (RAST) inhibition were performed on samples of settled environmental dust from the green coffee area, as well as on castor bean and green coffee beans. Ten per cent of the workers complained of oculorhinitis alone and 16% of asthma (nearly always associated with oculorhinitis). The overall prevalence of skin-sensitization was: 15% for green coffee beans, 22% for castor bean, 22% for common allergens. Evidence of sensitization to occupational allergens was more common in smokers, with a more than twofold increase in relative risk. The strong association between skin positivity to common and occupational allergens suggests that atopy acts as an enhancing host factor towards occupational sensitization. The analysis of the dust confirmed the presence of castor bean antigens. Our findings indicate that castor bean is the major cause of occupational sensitization among coffee workers, whereas smoking and atopy act as enhancing factors.

Sensitization to green coffee bean (GCB) and castor bean (CB) allergens among dock workers.

Dock workers (n = 218) occupationally exposed to green coffee beans (GCB) were studied, using a specific questionnaire for allergic symptoms and skin tests for common and occupational allergens. Thirty-one workers (14.3%) complained of allergic symptoms of the eye, nose and bronchial system at the workplace. The prick tests, using both commercial allergens and specific extracts prepared from the most common types of coffee and their corresponding sacks, confirmed a sensitization in 21 workers (9.6%). A positive skin reaction to castor beans (CB) was found in nearly all these cases; in ten workers there was also a positive reaction to GCB allergens and in 14 cases prick tests were positive to extracts of sacks. There was a good concordance between prick tests and specific IgE for CB (95.0%) and also, but to a lesser extent, for GCB. The authors concluded that there is a significant risk of sensitization to CB and GCB allergens in dock workers occupied in handling green coffee bean, despite the fact that the exposure is not continuous. CB emerged as a common contaminant of GCB from various countries. For effective prevention, a modification of the methods of transport is required to avoid CB contamination to other products. Eliminating environmental dust during shipping operations is the most important preventive measure and it can be achieved by the use of containers, as some exporting countries are already doing.

Castor bean allergy among workers in the felt industry.

We describe occupational allergy to castor bean in workers in a felt manufacturing plant. Twenty-six (37%) of the workers complained they were affected by the felt and were examined by us. Of these, 12 were considered to have occupational allergy. These 12 subjects had raised specific IgE levels to both felt and castor bean extracts. In addition, three subjects without occupational allergy had raised specific IgE. The presence of castor bean allergens in the felt was suggested by the correlation between the RAST scores to the felt and castor bean and confirmed by RAST inhibition experiments. The RAST results correlated well with the results of skin prick tests to felt and castor bean extracts. In addition it was found that atopy did not predispose the workers to castor bean allergy.

Castor bean allergy in the upholstery department of a furniture factory.

In this study, undertaken to identify the cause of allergy in several upholstery workers in a furniture factory, the workers were handling several different materials, including glue, silicone spray, upholstery fabrics, and felt. Radio-allergo-sorbent test (RAST) assays showed that sera from sensitised workers contained specific IgE towards the felt; however, further investigations using RAST showed that the allergen was not the felt itself but a contaminant of the felt. The felt was manufactured from sacks, some of which had been used to store castor beans. The sera with raised IgE to the felt also had raised IgE to the castor bean extract. By means of RAST inhibition we confirmed that castor bean allergens in the felt were solely responsible for the raised IgE in the sera. The in-vitro RAST results were found to correlate well with the in-vivo pick tests and clinical symptoms.

Analysis of green coffee bean and castor bean allergens using RAST inhibition.

Coffee workers with occupational allergic symptoms and positive skin tests to green coffee bean and factor dust antigens have elevated serum IgE antibodies (by radioallergosorbent test--RAST) to green coffee and castor bean allergens. These antibodies were used in a RAST inhibition assay to analyse coffee and castor allergens. Bean allergens were extracted by homogenization in PBS, centrifugation and concentration of supernates by ultrafiltration. Green coffee bean allergens, fractionated by gel filtration and Pevikon block electrophoresis, were shown to be very heterogeneous with a molecular weight range of 50 000 to 500 000 daltons. Castor allergens were more homogeneous with a molecular weight of 14 000 daltons and were partially purified by Pevikon block electrophoresis, gel filtration and isoelectrofocusing. Chemical analysis showed that protein was the major component in both allergen extracts. However, proteolytic enzymes could only partially destroy allergenic activity. Such isolation and characterization of these allergens should result in better methods of diagnosis and treatment of coffee workers with occupational allergic disease.

Castor bean allergens: evidence for distinct heat-labile and stable entities.

Castor beans contain one of the most potent allergens known to man. Previous studies suggested that these allergens are heat-stable; but our current data suggest that both heat-stable and labile allergens are present in castor bean extracts. The heat-labile allergen is of large molecular weight and is immunochemically distinct from the smaller molecular weight heat-stable allergen. Both allergens have different isoelectric points. These antigens may be clinically relevant since coffee workers sensitized to castor have IgE antibodies to both allergens.

Detection of castor allergens in castor wax.

The presence of castor bean allergens in castor wax products was determined by in vivo and in vitro analysis of castor wax extracts. Allergens were detected in one extract of castor wax by the PCA reaction in mice, the RAST inhibition reaction, and skin prick test in castor bean sensitive individuals. However, these allergens in the wax were of much lower potency than those in the bean, and were not detectable in a deodorant product utilizing castor wax.

Bronchoprovocation studies in coffee worker's asthma

Occupational asthma in affected workers is generally defined as asthma resulting from an inhalant exposure to a specific etiologic agent used in industry. The offending agent may occur in 1 of 2 forms, either as a particulate or as a gas. Procedures for human bronchoprovocation (BP) studies have been developed for both forms, and 1 will use the example of coffee worker’s asthma to illustrate such testing with a particulate occupational antigen. Following my article, Drs. Butcher and Gerblich et al. will use the example of toluene diisocyanate (TDI)-induced asthma to illustrate the application of bronchoprovocation techniques where an offending gas or vapor is involved. It should be emphasized at this point that the technique of bronchoprovocation, when performed with appropriate controls, is at present the single best way to prove a direct “cause and effect” relationship between a suspect antigen and occupational asthma. The study of any form of occupational asthma requires a stepwise approach. The first step is to identify those industrial agents most likely to be important in the production of disease. Studies reported in the literature and an epidemiologic analysis of affected workers provide the basis for making this determination. Using coffee worker’s asthma as an example, work dating back to the 19.50s suggests a reaginmediated reaction to inhaled green coffee and contaminating castor bean allergens. ‘--3 In a recent evaluation of a local New Orleans coffee processing plant, all symptomatic subjects worked in areas of the plant concerned with the processing of the raw green beans. In contrast, there was a striking lack of allergic symptoms in workers who processed only roasted beans. Processing of beans begins with the manual transfer of beans from their sacks into a dump bin (Fig. 1). After jets of air in the coffee cleaner remove most of the stems, sack remnants, and other large debris, the beans are transferred to hold bins where the chaff is removed. The beans are then roasted, cooled, and then transferred to another hold bin from which they may be processed further by decaffeination, extrac

Evidence That the Castor Bean Allergens Are the Albumin Storage Proteins in the Protein Bodies of Castor Bean

The well characterized castor bean (Ricinus communis L.) allergens were identified as the low molecular weight albumin storage proteins in the matrix of the protein bodies in the endosperm. The methods of identification involved molecular weight estimation, amino acid composition, stability at 100 degrees C, solubility in various solvents, gel electrophoresis, and immunological techniques. The finding explains the wide distribution of allergens in various seeds.

Extraction and analysis of coffee bean allergens.

Workers in the coffee industry can develop occupational allergic disease upon exposure to dust associated with coffee manufacturing. Since controversy exists as to the source or chemical nature of these allergens, the mouse model of reaginic antibody production was used to assess the potential sources of allergens in samples obtained from a local coffee manufacturing plant. Mice were immunized with extracts of coffee dust and beans and the resulting reaginic antibody response determined by the passive cutaneous anaphylaxis reaction. Cross-reacting allergens were detected in samples of coffee dust, cleaner can debris and green coffee beans, but not in chaff or roasted coffee beans. None of the allergens detected in coffee samples cross-reacted with extract of castor beans, although these extracts contained the potent castor bean allergen. Green coffee bean allergens partially purified by gel filtration were heterogeneous with respect to molecular size, although quite similar in their reactivity with reaginic antiserum. These results suggest that the green coffee bean is the major source of allergen in coffee manufacturing plants. This allergen is heterogeneous with respect to size and heat lability, and is immunochemically different from the castor bean allergen.

The IgG subclasses of antibodies to castor bean allergen in patients with allergic asthma: detection of a high incidence of antibodies of the IgG4 subclass.

Sera from patients with allergic asthma to castor bean dust were tested for specific antibodies in the red cell linked antigen-antiglobulin reaction (RCLAAR) using antiglobulin sera specific for IgE and the four subclasses of IgG. Approximately one-third of the patients with specific IgG antibodies had an antibody response that was predominantly in the IgG4 subclass. Two patients who were thought not to be sensitive to castor bean allergen, despite long exposure to the dust, did not have detectable IgE antibodies, but had high titres of IgG antibodies that were predominantly IgG4. Specific IgG4 antibodies to castor bean allergen were heat stable, did not appear to passively sensitize monkey skin in the PCA reaction and did not passively sensitize human basophils for the rosette reaction with castor bean-coated red cells.

Castor Bean Components, The Chemistry of Allergens. Inactivation of the Castor Bean Allergens and Ricin by Heating with Aqueous Calcium Hydroxide

Castor Bean Components, The Chemistry of Allergens. Inactivation of the Castor Bean Allergens and Ricin by Heating with Aqueous Calcium Hydroxide

Response of nonallergic persons to injected castor bean allergen, CB-1A

The immunologic responses of development of blocking antibodies, reagins, skin sensitivity and/or clinical symptoms of hypersensitivity of 161 nonallergic men to 1.0 mg. subcutaneous injections of the castor bean allergen, CB-1A, have been studied. These data were obtained in previously described studies in which the men served as recipients for passive transfer tests. One hundred and thirty-two recipients (82 per cent), who had one series of tests consisting of from one to 5 consecutive weekly injections of 1.0 mg. of CB-1A, had no apparent response. Four (2.5 per cent) had slight clinical response in the first series, two of which followed the first and two the third injection of CB-1A. Eight recipients (5 per cent) had two series of injections of CB-1A with intervals of 10 to 95 weeks between series with no response. Fifteen recipients (9.3 per cent) had responses attributed to CB-1A in the second or third series of weekly injections of CB-1A. Twelve of these developed blocking antibodies as shown by loss of their ability to give passive transfer reactions but developed no clinically evident hypersensitivity. Two complained of soreness at the site of the injection. One of this group (J. B.) had hives and generalized itching after the fourth injection of CB-1A. Two of the injections of J. B. were given in one series and two in a second series, 89 weeks after the first. J. B. developed skin sensitivity to CB-1A and reagins in his blood serum. Of the 23 who had two or more series of tests, 15, or 65 per cent, developed blocking antibodies or some clinical response. None who developed blocking antibodies had clinical symptoms and those who developed clinical symptoms did not develop blocking antibodies. None of the clinical reactions were respiratory as is the case with naturally occurring castor bean allergy, a difference which may be due to different routes of entry of the allergen to shock tissues; one, naturally by inhalation of dust and the other by injection.

Identification of castor bean allergen in green coffee

Castor bean allergen was identified in 3 samples of green coffee dust from different coffee roasting plants. Castor bean allergen was also found in 1 sample of cleaned, green coffee beans from a commercial source. No castor bean allergen was detected in samples of parchment coffee or cleaned, green coffee beans which were produced at a Guatemalan experiment station and were known to have had no contact with castor bean. Available evidence indicates that hazards resulting from contamination of green coffee with a castor bean derivative are significant only to those who are exposed to green coffee.

Castor bean: An industrial hazard as a contaminant of green coffee dust and used burlap bags

1. 1. Nine cases of sensitivity to the castor bean allergen are reported. The source of contact was dust from burlap bags used (1) in shipping green coffee, or (2) in shipping metal castings. These bags had been contaminated by contact with castor bean or castor pomace. 2. 2. Dericinized castor bean extract should be included in the allergist's routine list of testing materials. 3. 3. Only dericinized castor bean extract should be used for skin testing, and then only by the scratch (dermal) method. Never should even weak dilutions of any type of castor bean extract be used for direct intracutaneous testing. 4. 4. The coffee bean contains a dominant allergenic fraction that is stable on autoclaving for 20 minutes at 15 pounds' pressure, but is inactivated by the commercial roasting process.