The longtail tuna (Thunnus tonggol) is widely consumed in Asia. Parvalbumin, the main major allergen of fish, has been well identified in multiple fish species, yet little is known about the allergenic proteins in T. tonggol. Thus, the aim of this study was to characterize the major allergens of T. tonggol using a proteomics approach.
Crab meat is a valuable source of proteins and functional lipids and it is widely consumed worldwide. However, the prevalence of crab allergy has increased over the past few years. In order to understand crab allergy better, it is necessary to identify crab allergens. The aim of the present study was to compare the IgE-binding proteins of raw and cooked extracts of mud crab (Scylla serrata). Raw and cooked extracts of the mud crab were prepared. Protein profiles and IgE reactivity patterns were identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) followed by immunoblotting using sera from 21 skin prick test (SPT) positive patients. In SDS-PAGE, 20 protein bands (12 to 250 kDa) were observed in the raw extract while the cooked extract demonstrated fewer bands. Protein bands between 40 to 250 kDa were sensitive to heat denaturation and no longer observed in the cooked extract. In immunoblotting experiments, raw and cooked extracts demonstrated 11 and 4 IgE-binding proteins, respectively, with molecular weights of between 23 and 250 kDa. A heat-resistant 36 kDa protein, corresponding to crab tropomyosin was identified as the major allergen of both extracts. In addition, a 41 kDa heat-sensitive protein believed to be arginine kinase was shown to be a major allergen of the raw extract. Other minor allergens were also observed at various molecular weights.
BACKGROUND: Prawns and shrimp are a frequent cause of seafood allergy mediated by IgE antibodies. Penaeus monodon and Penaeus latisulcatus, commonly known as black tiger prawn and king prawn, respectively, are among the most frequently consumed prawns in Malaysia. The aim of this study was to identify the IgE-binding proteins of these 2 prawn species.
METHODS: Raw and boiled prawn extracts were prepared and then resolved by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). IgE-immunoblotting was then performed using sera from patients with positive skin prick tests to the raw prawn extracts.
RESULTS: SDS-PAGE analysis of the raw extracts of both prawn species revealed 23 protein bands; the boiled extracts yielded fewer protein bands. The bands in the range of 40 to 100 kDa were sensitive to heat and therefore were not found in the boiled extracts. Immunoblot of raw extracts of black tiger prawns and king prawns yielded 14 and 11 IgE-binding proteins, respectively, with molecular weights of between 15 and 200 kDa. Proteins at 36, 42, and 49 kDa were detected as the major allergens in both species of prawns. A protein of 75 kDa was also identified as a major allergen in black tiger prawns. Other potential allergens were also observed at various molecular masses.
CONCLUSION: Proteins of 36, 42, and 49 kDa were identified as the major allergens of both species of prawns. The 36 and 42 kDa proteins are hypothesised to be tropomyosin and arginine kinase, respectively. A high molecular weight protein of 75 kDa was found to be an additional major allergen in black tiger prawns.
KEYWORDS: Penaeus; allergens; allergy and clinical immunology; hypersensitivity; immunoblotting; tropomyosin
The aim of this study was to identify the major allergens of wildflower honey in local patients with atopic disease. SDS-PAGE revealed ten protein bands of 25 to 110 kDa, with a heavy cluster in region of 40-75 kDa. Immunoblotting demonstrated seven IgE-binding bands of 39 to 110 kDa. The 60 kDa protein had the highest frequency of IgE-binding (100%) followed by 54 kDa protein (95%), thus identified as the major allergens of wildflowerhoney. Our findings indicate that the allergen extract used for diagnosis of honey allergy contains both the 54 kDa and 60 kDa proteins.
Fish has been recognized as a source of potent allergens both in food and occupational allergy. Lutjanus argentimaculatus (red snapper) and Lutjanus johnii (golden snapper) locally known as merah and jenahak, respectively, are among the most commonly consumed fish in Malaysia. The objective of this study is to identify the IgE-binding proteins and major allergens of these species of fishes. Extracts of both fish species were prepared and fractionated by sodium dodecyl polyacrylamide gel electrophoresis (SDS-PAGE). IgE binding patterns were then demonstrated by immunoblotting using sera from patients allergic to the fishes. The raw extracts of both fish produced 26 protein bands. Both species of fishes had similar protein profiles. In cooked extracts, several protein bands in the range of about 40 to 90 kD which were present in the uncooked extracts appeared to be denatured and formed high molecular weight complexes. The immunoblotting of golden snapper and red snapper revealed 16 and 15 various IgE-binding bands, in the range of 151 to 12-11 kD, respectively. A 51 kD protein was identified as a major allergen for both fishes. A 46 kD protein was also demonstrated as a major allergen in golden snapper and a 42 kD protein was also seen as a major allergen in red snapper. A heat-resistant protein of ~12 kD which is equivalent in size with fish parvalbumin was demonstrated only as minor allergen for both fishes.
Allergy to different classes of mollusks, including squid, which are members of the class Cephalopods has been reported. Tropomyosin, a major muscle protein, is the only well-recognized allergen in squid. The aim of this study was to characterize IgE-binding proteins of local Loligo edulis (white squid) consumed in Malaysia. Protein profiles and IgE-binding proteins were detected by sodium dodecyl sulfate-polyacrylamide gel-electrophoresis (SDS-PAGE) and immunoblotting using sera from 23 patients with positive skin prick test to raw squid extract. SDS-PAGE of the raw extract exhibited 21 protein bands (10-170 kDa) but those ranging from 19 to 29 kDa and 41 to 94 kDa were not found in the cooked extract. Immunoblotting of raw extract demonstrated 16 IgE-binding bands, ranging from 13 to 170 kDa. A heat-resistant 36 kDa protein, corresponding to squid tropomyosin, was identified as the major allergen of both extracts. In addition, a 50 kDa heat-sensitive protein was shown to be a major allergen of the raw extract. Our findings indicate that the allergen extract used for diagnosis of squid allergy should contain both the 36 kDa and 50 kDa proteins.
Crab allergy is reported as a serious form of food allergy in many countries. This study was aimed to identify the major allergens of the local mud crab, Scylla tranquebarica (S. tranquebarica), and subsequently, determine the effect of vinegar treatments on the crab allergens. Crab muscles were treated with synthetic and natural vinegar. Crab proteins were then extracted from the untreated and vinegar-treated crabs. All extracts were then fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and analyzed by immunoblotting; using sera from crab-allergic patients. The crab proteins were then further fractionated by two-dimensional electrophoresis (2-DE)and analyzed by mass spectrometry (MS). The untreated crab had 38 protein bands, while that was only a few bands between 18 to 73 kDa for the vinegar-treated crabs. Immunoblotting of untreated crab revealed 20 IgE-binding bands, whereas the vinegar-treated crabs could only retain a few IgE-binding bands. Five major allergens were identified with molecular weightsof38, 42, 49, 63, and 73 kDa in the untreated crab. In contrast, the vinegar-treated crabs had only a few major allergens with molecular weights of 38, 42, and 73 kDa. MS identified the 43 and 49 kDa as arginine kinase, while the 38, 63, and 73 kDa were identified as tropomyosin, actin, and hemocyanin, respectively. Inconclusion, we found three common major allergens for S. tranquebarica including tropomyosin, arginine kinase, and actin, and one novel allergen known as hemocyanin. All the major allergens could retain minimal allergenic capability in vinegar-treated crabs, suggesting that vinegar treatments might be useful to reduce crab allergenicity. These data would assist the clinicians in the management of crab-allergic patients worldwide.
Hyaluronic acid (HA), a major component of extracellular matrix has been widely applied in pharmaceutical and cosmetic industries due to its reported pharmacological properties. Various types of HA drug delivery system including nanoparticles, cryogel-based formulations, microneedle patches, and nano-emulsions were developed. There are studies reporting that several HA-based transdermal delivery systems exhibit excellent biocompatibility, enhanced permeability and efficient localized release of anti-psoriasis drugs and have shown to inhibit psoriasis-associated skin inflammation. Similarly HA is found in abundant at epidermis of atopic dermatitis (AD) suggesting its role in atopic AD pathology. Anti-allergenic effect of atopic eczema can be achieved through the inhibition of CD44 and protein kinase C alpha (PKCα) interaction by HA. Herein, we aim to evaluate the current innovation on HA drug delivery system and the other potential applications of HA in inflammatory skin diseases, focusing on atopic dermatitis and psoriasis. HA is typically integrated into different delivery systems including nanoparticles, liposomes, ethosomes and microneedle patches in supporting drug penetration through the stratum corneum layer of the skin. For instance, ethosomes and microneedle delivery system such as curcumin-loaded HA-modified ethosomes were developed to enhance skin retention and delivery of curcumin to CD44-expressing psoriatic cells whereas methotrexate-loaded HA-based microneedle was shown to enhance skin penetration of methotrexate to alleviate psoriasis-like skin inflammation. HA-based nanoparticles and pluronic F-127 based dual responsive (pH/temperature) hydrogels had been described to enhance drug permeation through and into the intact skin for AD treatment.
House dust mites have lived in human contact from time immemorial. Human dander or dead skin constitutes the major organic component of the house dust ecosystem. Because the mites feed on dander, dust mites and human association will continue to co-exist as part of our environment. Efficient house-keeping practice is the best form of control to reduce infestation. However, special precautions are important when individuals are susceptible or sensitive to dust mites. House dust mites are responsible for causing asthma, rhinitis and contact dermatitis. The respiratory allergies are caused by the inhalation of dead or live mites, their faecal matter or other byproducts. Immune factors are of paramount importance in the development of dust related or mite induced respiratory diseases. House dust mites were found in some 1,000 samples of dust taken from approximately 330 dwellings in Peninsular Malaysia and Singapore. Mattresses, carpets, corners of a bedroom, and floor beneath the bed are favourable dust mite habitats. The incriminating species based on studies here and elsewhere, as well as many other species of dust mites of unknown etiological importance are widely distributed in Malaysian homes. Density of dust mites in Malaysia and Singapore is greater than in temperate countries. Prevention and control measures with reference to subjects sensitive to dust mite allergies, including chemical control described in studies conducted in Europe and America are discussed. However, a cost free and most practical way to remove mites, their faecal matter and other products is to resort to sunning the bedding and carpets to kill the living mites, and then beaten and brushed to remove the dust and other components.
Allergy to house dust mites (HDM) is an important cause of asthma and rhinitis in Malaysia. This study was carried out to evaluate the dust mite fauna in the Klang Valley. Dust samples were collected from 20 houses from March 1994 to February 1995. Thirty-three dust samples from mattresses were examined monthly for the occurrence of HDM. A total of 22 species in 9 families of HDM was identified. The most common and densely populated species was Blomia tropicalis with an average density of 8,934 mites/g of dust. Dermatophagoides pteronyssinus was the next in abundance, followed by Malayoglyphus intermedius. All houses surveyed were found to be infested with HDM and every house had at least 6 species of HDM. B. tropicalis and D. pteronyssinus were found in all mattresses. HDM in the Klang Valley were found to be highly prevalent and present in high densities. In this study, counts of D. pteronyssinus was found to exceed the proposed exposure threshold of 500 mites/g dust, for triggering acute asthma. Although counts of B. tropicalis exceeded D. pteronyssinus, no conclusion could be made because there is currently no exposure threshold for triggering acute asthma, for this species. Monthly distribution of B. tropicalis and D. pteronyssinus showed 2 peaks and 4 peaks, respectively. The major peak for D. pteronysinus was in January 1995 whereas for B. tropicalis, the major peak was more variable and occurred between November 1994 to January 1995. Both the species showed minor peak in April 1994.
The prevalence of house dust mite (HDM) allergy, especially in Asian countries with rapid urbanization, has been increasing. House dust mites thrive in places with relatively high humidity. With the combination of climate change, naturally high humidity, and urbanization, tropical countries like Malaysia are becoming a hotspot for HDM allergy fast. With a previously reported sensitization rate of between 60 and 80%, it is a worrying trend for Malaysia. However, due to incomplete and out-of-date data, as seen by the limited study coverage in the past, these numbers do not paint a complete picture of the true HDM allergy scene in Malaysia. This review briefly discusses the HDM fauna, the HDM sensitization rate, the common diagnosis and therapeutic tools for HDM allergy in Malaysia, and makes suggestions for possible improvements in the future. This review also highlights the need of more comprehensive population-based prevalence studies to be done in Malaysia, encompassing the three main HDMs-Dermatophagoides pteronyssinus, Dermatophagoides farinae, and Blomia tropicalis-as the lack of up-to-date studies failed to give a clearer picture on the current scenario of HDM allergy in Malaysia. Future studies will be beneficial to the nation in preparing a better blueprint for the management and treatment of HDM allergy.
BACKGROUND:
Sensitization to natural rubber latex has been linked to proteins from medical latex gloves. Various assays to estimate the amount of residual allergenic proteins extractable from latex gloves to assess their potential exposure hazard have inherent weaknesses.
OBJECTIVE:
This investigation was aimed at developing 2-site immunoenzymetric assays and identifying appropriate protein markers to assess the allergenic potential of latex gloves.
METHODS:
The presence of 6 latex allergens--Hev b 1, 2, 3, 5, 6, and 13--was measured in a cross-section of commercial latex medical gloves by using monoclonal and polyclonal antibody-based 2-site immunoenzymetric assays. The overall allergenic potential of these gloves was assessed by IgE-inhibition assay. Stepwise multiple regression analyses were performed to identify marker allergens that best explained the variation in latex glove allergenicity.
RESULTS:
All 6 latex allergens were detected in at least some of the glove samples. Hev b 5 and Hev b 13 were identified as the marker allergens that combined best to explain the variation in the glove allergenicity. The significant multiple correlation (R=0.855) between these 2 markers and glove allergenic potency forms the basis of an assay to gauge latex glove allergenicity.
CONCLUSION:
The overall allergenic potential of latex gloves can be estimated by using Hev b 5 and Hev b 13 as indicator allergens. The correlation between glove allergenicity and the level of these allergens was maintained for low-protein gloves (<200 microg/g). This estimation of glove allergenicity was superior to that obtained by using total protein readings.
While there is a large variation of prevalence of asthma symptoms worldwide, what we do know is that it is on the rise in developing countries. However, there are few studies on allergens, moulds and mycotoxin exposure in schools in tropical countries. The aims were to measure selected fungal DNA, furry pet allergens and mycotoxins in dust samples from schools in Malaysia and to study associations with pupils' respiratory health effects. Eight secondary schools and 32 classrooms in Johor Bahru, Malaysia were randomly selected. A questionnaire with standardized questions was used for health assessment in 15 randomly selected pupils from each class. The school buildings were inspected and both indoor and outdoor climate were measured. Dust samples were collected by cotton swabs and Petri dishes for fungal DNA, mycotoxins and allergens analysis. The participation rate was 96% (462/480 invited pupils), with a mean age of 14 yr (range 14-16). The pupils mostly reported daytime breathlessness (41%), parental asthma or allergy (22%), pollen or pet allergy (21%) and doctor-diagnosed asthma (13%) but rarely reported night-time breathlessness (7%), asthma in the last 12 months (3%), medication for asthma (4%) or smoking (5%). The inspection showed that no school had any mechanical ventilation system, but all classrooms had openable windows that were kept open during lectures. The mean building age was 16 yr (range 3-40) and the mean indoor and outdoor CO(2) levels were 492 ppm and 408 ppm, respectively. The mean values of indoor and outdoor temperature and relative humidity were the same, 29°C and 70% respectively. In cotton swab dust samples, the Geometric Mean (GM) value for total fungal DNA and Aspergillus/Penicillium (Asp/Pen) DNA in swab samples (Cell Equivalents (CE)/m(2)) was 5.7*10(8) and 0.5*10(8), respectively. The arithmetic mean (CE/m(2)) for Aspergillus versicolor DNA was 8780, Stachybotrys chartarum DNA was 26 and Streptomyces DNA was 893. The arithmetic means (pg/m(2)) for the mycotoxins sterigmatocystin and verrucarol were 2547 and 17, respectively. In Petri dish dust samples, the GM value for total fungal DNA and Asp/Pen DNA (CE/m(2) per day) was 9.2*10(6) and 1.6*10(6), respectively. The arithmetic mean (CE/m(2) per day) for A. versicolor DNA was 1478, S. chartarum DNA was 105 and Streptomyces DNA was 1271, respectively. The GM value for cat (Fel d1) allergen was 5.9 ng/m(2) per day. There were positive associations between A. versicolor DNA, wheeze and daytime breathlessness and between Streptomyces DNA and doctor-diagnosed asthma. However, the associations were inverse between S. chartarum DNA and daytime breathlessness and between verrucarol and daytime breathlessness. In conclusion, fungal DNA and cat allergen contamination were common in schools from Malaysia and there was a high prevalence of respiratory symptoms among pupils. Moreover, there were associations between levels of some fungal DNA and reported respiratory health in the pupils.
Food allergen labelling is mandatory and regulated whilst precautionary allergen labelling (PAL) remains voluntary in most countries. It is the aim of this study to identify the food allergens declared in food products sold in a developing country and to what extent food allergens and PAL are emphasised in the products. A total of 505 food and beverages (snacks, baked goods, confectionary, baby food, condiments & jams, beverages, powder & paste, instant food, chilled & frozen food and canned food) were evaluated in Malaysia. Soybean represents the largest group of food allergen declared in labels, followed by wheat and milk products. Thirteen variations of contains statement were found with "Contains [allergen(s)]" being the most common (55.02%). There were 22 different types of "may contain" statements with 'May contain traces of [allergen(s)]' being the most common advice labelling used (55.41%). Different font type or emphasis such as brackets (51.57%) and bold font (33.86%) were used to inform consumers about presence of allergens. The national regulations on food allergen labelling are then critically contrasted with other Asian countries and the EU Regulation No. 1169/2011, which represents one of the most stringent food regulations in the world. Improving current allergen labelling limitations and practices would be of great benefit to consumers to prevent risk of food hypersensitivity.
A species of house dust mite, Suidasia pontifica, was recently shown to produce allergens affecting man. The species may be as important as other allergen producing mite in sensitization and causing allergic symptoms in Malaysians. Surveys conducted demonstrated that 80% of the houses surveyed were positive for this mite with densities ranged from 2 to 50 mites per gram of dust. Colonies of the species has been successfully established and materials from those colonies have been used to produce extracts for studies on sensitization to the mites. A total of 85 suspected allergic rhinitis patients were tested and 74.1% demonstrated positive reactions. Extract of this mite should be considered for routine diagnostic testing and possible immunotherapy.
Background: Almost one third of the world population suffers from allergic conditions. Respiratory symptoms are common in Malaysian children but there are few studies on fractional exhaled nitric oxide (FeNO), inclusive of field clinical test for asthma among children in Malaysia. The aim was to provide insight on factors related to level of FeNO among students in Terengganu, Malaysia.Methods: In total, 487 randomly selected students from eight secondary schools participated (13-14 years old). A Standardized questionnaire was used to obtained information on doctors' diagnosed asthma, current asthma and respiratory symptoms. FeNO measurement and skin prick test (SPT to common allergen) were conducted.Results: The geometric mean FeNO was 16.7 ppb. Totally, 38.4% of students had elevated FeNO level (>20 ppb) and 40.3% had had positive SPT to house dust mites allergens (HDM), Dermatophagoides pteronyssinus (Der p 1), Dermatophagoides farinae (Der f 1) or Felis domisticus (cat). Male gender, height, parental history of allergy, self-reported allergy, and atopy were associated with FeNO. In particular, a combination of sensitization to HDM or cat and elevated FeNO were associated with doctor-diagnosed asthma and self-reported allergy to food, pollen and cat.Conclusion: Asthma, respiratory symptoms and sensitization to HDM and cat are common among students and presence of elevated FeNO levels indicate ongoing airway inflammation.
Current diagnostic tools for peanut allergy using crude peanut extract showed low predictive value and reduced specificity for detection of peanut allergen-specific immunoglobulin E (IgE). The Ara h 2.02, an isoform of the major peanut allergen Ara h 2, contains three IgE epitope recognition sequence of 'DPYSPS' and may be a better reagent for component resolve diagnosis. This research aimed to generate a codon-optimised Ara h 2.02 gene for heterologous expression in Escherichia coli and allergenicity study of this recombinant protein. The codon-optimised gene was generated by PCR using overlapping primers and cloned into the pET-28a (+) expression vector. Moderate expression of a 22.5 kDa 6xhistidine-tagged recombinant Ara h 2.02 protein (6xHis-rAra h 2.02) in BL21 (DE3) host cells was observed upon induction with 1 mM isopropyl β-D-1-thiogalactopyranoside (IPTG). The insoluble recombinant protein was purified under denaturing condition using nickel-nitrilotriacetic acid (Ni-NTA) affinity chromatography and refolded by dialysis in decreasing urea concentration, amounting to a yield of 74 mg/l of expression culture. Matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) and immunoblot analysis confirmed the production of the recombinant 6xHis-rAra h 2.02. The refolded recombinant 6xHis-rAra h 2.02, with or without adjuvant, was able to elicit comparable level of allergen-specific IgE and IgG1 in sensitised Balb/c mice. In addition, the specific IgE antibodies raised against the recombinant protein were able to recognise the native Ara h 2 protein, demonstrating its allergenicity and potential as a reagent for diagnosis and therapeutic study.
There is increasing consumption of exotic food in Malaysia. Animals such as insects, worms and wild life animals also form part of the staple food of the local population. This practice may lead to more incidence of food allergy and anaphylaxis. We report a non-indigenous man who developed food anaphylaxis after consuming fried sago worms and consequently Takotsubo cardiomyopathy. We postulate that certain food allergy and anaphylaxis could be another causative trigger for Takotsubo cardiomyopathy.
The MAST CLA system was evaluated against skin prick test (SPT) for diagnosis of allergies to house dust mites (Dermatophagoides pteronyssinus, Dermatophagoides farinae) and cats. Forty three asthmatic children were examined by SPT and MAST CLA. Chi-square analysis indicated significant association between SPT and MAST CLA results for the house dust mites but not for cats. The sensitivities of MAST CLA for house dust mites and cats were 100 and 25% respectively; specificities were all less than 50%. The efficiency of MAST CLA for detection of allergy to the house dust mites was 88% and 44% for cats. A significant linear correlation was found between SPT wheal size and MAST CLA grade for D. farinae but not for D. pteronyssinus and cats. It is concluded that the MAST CLA allergy system can be used to supplement SPT for diagnosis of allergies to house dust mites but not to cats.