Differential responses to natural and recombinant allergens in a murine model of fish allergy

Seafood allergy: Allergen, epitope mapping and immunotherapy strategy

Seafoods are fashionable delicacies with high nutritional values and culinary properties, while seafood belongs to worldwide common food allergens. In recent years, many seafood allergens have been identified, while the diversity of various seafood species give a great challenge in identifying and characterizing seafood allergens, mapping IgE-binding epitopes and allergen immunotherapy development, which are critical for allergy diagnostics and immunotherapy treatments. This paper reviewed the recent progress on seafood (fish, crustacean, and mollusk) allergens, IgE-binding epitopes and allergen immunotherapy for seafood allergy. In recent years, many newly identified seafood allergens were reported, this work concluded the current situation of seafood allergen identification and designation by the World Health Organization (WHO)/International Union of Immunological Societies (IUIS) Allergen Nomenclature Sub-Committee. Moreover, this review represented the recent advances in identifying the IgE-binding epitopes of seafood allergens, which were helpful to the diagnosis, prevention and treatment for seafood allergy. Furthermore, the allergen immunotherapy could alleviate seafood allergy and provide promising approaches for seafood allergy treatment. This review represents the recent advances and future outlook on seafood allergen identification, IgE-binding epitope mapping and allergen immunotherapy strategies for seafood allergy prevention and treatment.

Cross-reactive monoclonal antibodies against fish parvalbumins as a tool for studying antigenic similarity of different parvalbumins and analysis of fish extracts

Fish parvalbumins are heat-stable calcium-binding proteins that are highly cross-reactive in causing allergy symptoms in fish-sensitized patients. The reactivities of parvalbumin-specific monoclonal or polyclonal antibodies with parvalbumins of different fish species allowed their application for development of various immunoassays for allergen identification in fish samples. In this study, monoclonal antibodies (MAbs) were generated against two parvalbumins - natural Atlantic cod parvalbumin and recombinant common carp β-parvalbumin expressed in E. coli. Large collections of recombinant parvalbumins and natural allergen extracts of different fish species and other animals were used to identify the specificities of these MAbs using ELISA, Western blot, and dot blot. MAbs demonstrated different patterns of cross-reactivities with recombinant parvalbumins. Their binding affinities were affected by the addition and removal of Ca²⁺ ions. Moreover, all MAbs showed a broad reactivity with the target antigens in natural fish, chicken, and pork extracts. The ability of two MAbs (clones 7B2 and 3F6) to identify and isolate native parvalbumins from allergen extracts was confirmed by Western blot. Epitope mapping using recombinant fragments of Atlantic cod parvalbumin (Gad m 1) and common carp parvalbumin (Cyp c 1) revealed that 4 out of 5 MAbs recognize parvalbumin regions that contain calcium binding sites. In conclusion, the generated broadly reactive well-characterized MAbs against fish β-parvalbumins could be applied for investigation of parvalbumins of fish and other animals and their detection in allergen extracts.

Development of a sensitive sandwich-ELISA assay for reliable detection of fish residues in foods

A new sandwich-type Enzyme-Linked Immunosorbent Assay (ELISA) method was developed based on goat IgG as capturing antibody and rabbit IgG as detecting antibody targeting soluble antigenic fish proteins in foods as detection targets. The assay has provided a relatively lower limit of quantitation (LoQ) for fish proteins with LoQ 0.5 ng/ml and appears highly sensitive. The analysis of 24 different substances, both raw and boiled, revealed no cross-reactivity above the cut-off point of the limit of quantitation. Recoveries of the SB spiked food matrixes were in the range of 83-131%. Assay precision testing proved that repeatability (<5%) and reproducibility (<11%) had an acceptable level of variation. The sandwich ELISA was capable of detecting all tested commercially important fish. As a potential analytical tool, the newly developed immunoenzymatic method is suitable for detecting undeclared fish residues in real food samples available in the market, thereby will help to reduce the incidents of fish allergies.

Expanding the allergen repertoire of salmon and catfish

BACKGROUND

Diagnostic tests for fish allergy are hampered by the large number of under-investigated fish species. Four salmon allergens are well-characterized and registered with the WHO/IUIS while no catfish allergens have been described so far. In 2008, freshwater-cultured catfish production surpassed that of salmon, the globally most-cultured marine species. We aimed to identify, quantify, and compare all IgE-binding proteins in salmon and catfish.

METHODS

Seventy-seven pediatric patients with clinically confirmed fish allergy underwent skin prick tests to salmon and catfish. The allergen repertoire of raw and heated protein extracts was evaluated by immunoblotting using five allergen-specific antibodies and patients' serum followed by mass spectrometric analyses.

RESULTS

Raw and heated extracts from catfish displayed a higher frequency of IgE-binding compared to those from salmon (77% vs 70% and 64% vs 53%, respectively). The major fish allergen parvalbumin demonstrated the highest IgE-binding capacity (10%-49%), followed by triosephosphate isomerase (TPI; 19%-34%) in raw and tropomyosin (6%-32%) in heated extracts. Six previously unidentified fish allergens, including TPI, were registered with the WHO/IUIS. Creatine kinase from salmon and catfish was detected by IgE from 14% and 10% of patients, respectively. Catfish L-lactate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, pyruvate kinase, and glucose-6-phosphate isomerase showed IgE-binding for 6%-13% of patients. In salmon, these proteins could not be separated successfully.

CONCLUSIONS

We detail the allergen repertoire of two highly farmed fish species. IgE-binding to fish tropomyosins and TPIs was demonstrated for the first time in a large patient cohort. Tropomyosins, in addition to parvalbumins, should be considered for urgently needed improved fish allergy diagnostics.

IgE-Mediated Fish Allergy in Children

Fish allergy constitutes a severe problem worldwide. Its prevalence has been calculated as high as 7% in paediatric populations, and in many cases, it persists into adulthood with life-threatening signs and symptoms. The following review focuses on the epidemiology of Immunoglobulin E (IgE)-mediated fish allergy, its pathogenesis, clinical manifestations, and a thorough approach to diagnosis and management in the paediatric population. The traditional approach for managing fish allergy is avoidance and rescue medication for accidental exposures. Food avoidance poses many obstacles and is not easily maintained. In the specific case of fish, food is also not the only source of allergens; aerosolisation of fish proteins when cooking is a common source of highly allergenic parvalbumin, and elimination diets cannot prevent these contacts. Novel management approaches based on immunomodulation are a promising strategy for the future of these patients.

Assessment of the effects of a work-related allergy to seafood on the reduction of earning capacity in the context of BK No. 5101

Fish, crustaceans, and mollusks are among the most potent allergenic foods of animal origin and are thus important triggers of work-related immediate-food allergies. In Germany, work-related seafood allergies are of great importance in the fishing and processing industries as well as in the areas of food preparation, food control, and food sales. There is no causal therapy of seafood allergy, only the strict and lifelong avoidance of allergens remains. The following recommendations serve to assess the impact of a seafood allergy with regard to the work opportunities ended by it for the assessment of the reduction of earning capacity (MdE (German for Minderung der Erwerbsfähigkeit)) in the context of the occupational disease number 5101 of the Annex to the German regulation for occupational diseases. As a special feature of work-related seafood allergy with regard to insurance law aspects, it must be taken into account that there is a potential risk of systemic reaction with subsequent multi-organ involvement. For the estimation of MdE in the general labor market, the impact of a seafood allergy can therefore be assessed, depending on its clinical severity, as generally “mild” to “severe” in justified individual cases.

IgE and IgG4 epitopes revealed on the major fish allergen Lat c 1

BACKGROUND

The IgE- and IgG₄-binding patterns of the major fish allergen parvalbumins are not clearly understood. IgE antibody-binding to parvalbumin from Asian seabass, Lat c 1.01, is implicated in up to 90 % of allergic reactions, although the region of IgE or IgG4 epitopes are unknown. In the present study, we characterized the specific IgE- and IgG₄-binding regions of Lat c 1.01 using serum from pediatric and adult patients with clinically-confirmed fish allergy.

METHODS

A comparative investigation of patient IgE- and IgG₄-binding to recombinant Lat c 1.01 was performed by immunoblotting and indirect ELISA using serum from 15 children and eight adults with clinically confirmed IgE-mediated reactions to fish. The IgE- and IgG₄-binding regions of Lat c 1.01 were determined by inhibition ELISA using seven overlapping peptides spanning the entire 102 amino acid sequence. Elucidated IgE-binding regions were modelled and compared to known antibody-binding regions of parvalbumins from five other fish species.

RESULTS

Ninety five percent (22/23) patients demonstrated IgE-binding to rLat c 1.01, while fewer patients (10/15 children and 7/8 adults) demonstrated robust IgG₄ binding when determined by immunoblots. IgE-binding for both cohorts was significantly higher compared to IgG₄-binding by ELISA. All patients in this study presented individual IgE and IgG₄ epitope-recognition profiles. In addition to these patient-specific antibody binding sites, general IgE epitopes were also identified at the C- and N-terminal regions of this major fish allergen.

CONCLUSIONS AND CLINICAL RELEVANCE

Our findings demonstrate two specific IgE epitopes on parvalbumin from Asian seabass, while IgG₄ binding is much lower and patient specific. This study highlights the importance of advancement in epitope analysis regardless of the age group for diagnostics and immunotherapies for fish allergy.

A review on food processing and preparation methods for altering fish allergenicity

People eat many varieties of food to satiate their hunger. Among them, a few numbers of food cause overreaction of the body's immune system, and fish holds a permanent position on that list. Processing methods, including one treatment or a combination, can have different effects on the allergenic potential of food proteins. An important point to note, however, is that not all of these methods can eliminate the potential for protein allergy. Thus, it is essential to understand the risk involved with the consumption of processed fish and its derivatives. Fish could be prepared in various ways before come to the dining plate. It has shown some of these methods can effectively manipulate the allergenicity owing to the alterations occurred in the protein conformation. This article provides an overview of the impact of fish processing methods (thermal and non-thermal) on the allergenic potential of fish along with possible causative structural modification provokes allergen stability. The article begins with current trends related to fish consumption, proceeds with the prevalence and underlying mechanism of fish allergy. Properties of clinically relevant fish proteins, projected IgE epitopes of PV, cross-reactivity of fish allergens are also addressed in this context to understand and compare the behavioral patterns of PV profiles of different species on processing methods.

Tertiary lymphoid structure related B-cell IgE isotype switching and secondary lymphoid organ linked IgE production in mouse allergy model

Background

Numerous data obtained by different research laboratories indicate that specific IgE production is triggered independently of specific IgG or IgA ones and so it is not linked to fully matured germinal centers formation in the secondary lymphoid organs. The aim of this study was to clarify whether specific IgE production is triggered by low antigen doses administrated in tertiary tissues enriched by lymphoid structures.

Methods

Ovalbumin (OVA) in different doses (100 ng to 10 μg) was administrated three times a week for 4–5 weeks intraperitoneally (i.p.) or subcutaneously (s.c.) to female BALB/c mice in the wither region which is enriched in fat-associated lymphoid clusters or in the foot pad region not containing them.

Results

OVA-specific IgE was predominantly induced by low but not high antigen doses and only after immunization into the withers. IgE isotype switching was triggered exclusively in the withers adipose tissue but not in the regional lymph nodes while mature IgE expressing cells were observed both in the withers and lymph nodes. Anti-proliferative genotoxic stress inducing drugs shifted the balance from IgG1 towards IgE production.

Conclusions

Tertiary lymphoid structures possess unique environment where B-cell antibody isotype switching to IgE predominantly occurs. This phenomenon is partially explained by hampered proliferation of B-cells in these structures.

Serum IgE cross-reactivity between fish and chicken meats in dogs

BACKGROUND

In humans, a cross-reactive clinical allergy has been reported between three chicken and fish meat proteins: beta-enolase, aldolase A and parvalbumin.

OBJECTIVE

To evaluate if IgE cross-reactivity between chicken and fish also existed in the dog.

ANIMALS

Sera from dogs with suspected allergic skin disease and with IgE against chicken and fish.

METHODS AND MATERIALS

Sera were analysed by ELISA and immunoblotting with chicken, white fish (haddock and cod) and salmon extracts. Reciprocal inhibition ELISAs and inhibition immunoblots were then performed. Protein sequencing of bands identified on multiple extracts was determined by mass spectrometry.

RESULTS

Out of 53 archived canine sera tested by ELISA against chicken, white fish or salmon, 15 (28%), 12 (23%) and 26 (49%), respectively, had elevated IgE against one, two or all three of these extracts. Seven of the triple-reactive sera were subjected to reciprocal inhibition ELISAs. A >50% inhibition was found between chicken-fish, chicken-salmon and fish-salmon in seven, four and five of seven dogs, respectively. Immunoblotting identified multiple IgE-binding proteins of identical molecular weights in the three extracts; these were partially to fully cross-reactive by inhibition immunoblotting. Mass spectrometry identified nine cross-reactive proteins as: pyruvate kinase, creatine kinase, alpha-actin, glyceraldehyde-3-phosphate dehydrogenase, beta-enolase, aldolase, malate dehydrogenase, lactate dehydrogenase and triose-phosphate isomerase 1. All of these have been reported previously as fish, shellfish and/or chicken allergens for humans.

CONCLUSIONS AND CLINICAL IMPORTANCE

Whether any of these newly identified IgE cross-reactive chicken-fish allergens is the cause of clinical allergy needs to be determined in dogs reacting to at least two of these common food sources.

Seafood allergy: A comprehensive review of fish and shellfish allergens

Seafood refers to several distinct groups of edible aquatic animals including fish, crustacean, and mollusc. The two invertebrate groups of crustacean and mollusc are, for culinary reasons, often combined as shellfish but belong to two very different phyla. The evolutionary and taxonomic diversity of the various consumed seafood species poses a challenge in the identification and characterisation of the major and minor allergens critical for reliable diagnostics and therapeutic treatments. Many allergenic proteins are very different between these groups; however, some pan-allergens, including parvalbumin, tropomyosin and arginine kinase, seem to induce immunological and clinical cross-reactivity. This extensive review details the advances in the bio-molecular characterisation of 20 allergenic proteins within the three distinct seafood groups; fish, crustacean and molluscs. Furthermore, the structural and biochemical properties of the major allergens are described to highlight the immunological and subsequent clinical cross-reactivities. A comprehensive list of purified and recombinant allergens is provided, and the applications of component-resolved diagnostics and current therapeutic developments are discussed.

Effects of daily food processing on allergenicity

Daily food processing has the potential to alter the allergenicity of foods due to modification of the physico-chemical properties of proteins. The degree of such modifications depends on factors such as processing conditions, type of food considered, allergenic content, etc. The impact of daily food processing like boiling, roasting, frying or baking on food allergenicity have been extensively studied. The influence of other thermal treatments such as microwave heating or pressure cooking on allergenicity has also been analyzed. Non-thermal treatment such as peeling impacts on the allergenic content of certain foods such as fruits. In this review, we give an updated overview of the effects of daily processing treatments on the allergenicity of a wide variety of foods. The different variables that contribute to the modification of food allergenicity due to processing are also reviewed and discussed.

[Seafood allergy in cooks: a case series and review of the literature]

BACKGROUND

Seafood is a very potent allergen. Epidemiological studies of seafood allergy in the highly exposed cooking profession are lacking. The objective of this first case series was to demonstrate the high relevance and consequences of seafood allergy in cooks. PATIENTS UND METHODS: Retrospective analysis of all the case files sent in which the presence of an occupational disease according to no. 5101 of the appendix of the German ordinance on industrial disease was to be clarified.

RESULTS

Thirty cooks (men 70 %) with an occupational seafood allergy were assessed between January 2008 and April 2014. Seafood allergy was observed in youngish workers(median age 24.7 yrs.) with an early manifestation of the disease (after 1.7 yrs. of occupation in median). In all except one (96.7 %) onset was localized on the hands.Most commonly documented were immediate sensitizations to cod, salmon, trout,and herring. Emergency treatment due to an anaphylactic shock at the workplace became necessary in 5 cases (16.7 %). In 27 cases (90 %) discontinuation of occupation was needed and was carried out after 6.3 yrs. of occupation in median.

CONCLUSIONS

Seafood allergy in cooks is mostly characterized by a quick progressive course of disease, already at the start of the cooking career. The prognosis for continuance in occupation is poor and an occupational disease is to be considered at a nearly stage. An emergency kit with an epinephrine auto-injector should be provided for life by the responsible accident insurer.

Identification of novel allergen in edible insect, Gryllus bimaculatus and its cross-reactivity with Macrobrachium spp. allergens

Edible insects have recently been promoted as a source of protein and have a high nutrition value. Identification of allergens and cross-reactivity between Macrobrachium spp. and the field cricket (Gryllus bimaculatus) is necessary for food safety control and to assist in the diagnosis and therapy of allergy symptoms. Denaturing polyacrylamide gel electrophoresis (SDS-PAGE) was used to separate proteins. Allergens were determined and identified by IgE-immunoblotting with pooled sera from prawn-allergic patients (n=16) and LC-MS/MS. Arginine kinase (AK) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) were determined as the important allergens in muscle of Macrobrachium rosenbergii whereas, hemocyanin (HC) was identified as an allergen in Macrobrachium spp. The allergens in Macrobrachium lanchesteri were identified as AK and HC. In addition, hexamerin1B (HEX1B) was identified as a novel and specific allergen in G. bimaculatus. The important allergen in G. bimaculatus and Macrobrachium spp. is AK and was found to cross-react between both species.

Development of a hypoallergenic recombinant parvalbumin for first-in-man subcutaneous immunotherapy of fish allergy

BACKGROUND

The FAST (food allergy-specific immunotherapy) project aims at developing safe and effective subcutaneous immunotherapy for fish allergy, using recombinant hypoallergenic carp parvalbumin, Cyp c 1.

OBJECTIVES

Preclinical characterization and good manufacturing practice (GMP) production of mutant Cyp (mCyp) c 1.

METHODS

Escherichia coli-produced mCyp c 1 was purified using standard chromatographic techniques. Physicochemical properties were investigated by gel electrophoresis, size exclusion chromatography, circular dichroism spectroscopy, reverse-phase high-performance liquid chromatography and mass spectrometry. Allergenicity was assessed by ImmunoCAP inhibition and basophil histamine release assay, immunogenicity by immunization of laboratory animals and stimulation of patients' peripheral blood mononuclear cells (PBMCs). Reference molecules were purified wild-type Cyp c 1 (natural and/or recombinant). GMP-compliant alum-adsorbed mCyp c 1 was tested for acute toxicity in mice and rabbits and for repeated-dose toxicity in mice. Accelerated and real-time protocols were used to evaluate stability of mCyp c 1 as drug substance and drug product.

RESULTS

Purified mCyp c 1 behaves as a folded and stable molecule. Using sera of 26 double-blind placebo-controlled food-challenge-proven fish-allergic patients, reduction in allergenic activity ranged from 10- to 5,000-fold (1,000-fold on average), but with retained immunogenicity (immunization in mice/rabbits) and potency to stimulate human PBMCs. Toxicity studies revealed no toxic effects and real-time stability studies on the Al(OH)3-adsorbed drug product demonstrated at least 20 months of stability.

CONCLUSION

The GMP drug product developed for treatment of fish allergy has the characteristics targeted for in FAST: i.e. hypoallergenicity with retained immunogenicity. These results have warranted first-in-man immunotherapy studies to evaluate the safety of this innovative vaccine.

Fish-allergic patients may be able to eat fish

Reported fish allergy prevalence varies widely, with an estimated prevalence of 0.2% in the general population. Sensitization to fish can occur by ingestion, skin contact or inhalation. The manifestations can be IgE or non-IgE mediated. Several fish allergens have been identified, with parvalbumins being the major allergen in various species. Allergenicity varies among fish species and is affected by processing or preparation methods. Adverse reactions after eating fish are often claimed to be 'allergy' but could be a reaction to hidden food allergen, fish parasite, fish toxins or histamine in spoiled fish. Identifying such causes would allow free consumption of fish. Correct diagnosis of fish allergy, including the specific species, might provide the patient with safe alternatives. Patients have been generally advised for strict universal avoidance of fish. However, testing with various fish species or preparations might identify one or more forms that can be tolerated.

Fish allergy: in review

Globally, the rising consumption of fish and its derivatives, due to its nutritional value and divergence of international cuisines, has led to an increase in reports of adverse reactions to fish. Reactions to fish are not only mediated by the immune system causing allergies, but are often caused by various toxins and parasites including ciguatera and Anisakis. Allergic reactions to fish can be serious and life threatening and children usually do not outgrow this type of food allergy. The route of exposure is not only restricted to ingestion but include manual handling and inhalation of cooking vapors in the domestic and occupational environment. Prevalence rates of self-reported fish allergy range from 0.2 to 2.29 % in the general population, but can reach up to 8 % among fish processing workers. Fish allergy seems to vary with geographical eating habits, type of fish processing, and fish species exposure. The major fish allergen characterized is parvalbumin in addition to several less well-known allergens. This contemporary review discusses interesting and new findings in the area of fish allergy including demographics, novel allergens identified, immunological mechanisms of sensitization, and innovative approaches in diagnosing and managing this life-long disease.

Immunological cross-reactivity between four distant parvalbumins-Impact on allergen detection and diagnostics

Fish are the largest and most diverse group of vertebrates. Fish are also a part of the eight food groups that cause the majority of IgE mediated food reactions. Detection tools for fish allergens are however limited due to the great diversity of fish species, despite fish allergy and its major allergen parvalbumin being well documented. The most commonly studied fish are frequently consumed in North America and Europe. However, much less is known about fish allergens in the Australasian region although fish is widely consumed in this region. A comprehensive phylogenetic analysis was performed of known parvalbumin amino acid sequences to determine possible candidate antigens for new cross-reactive antibodies to be used to detect most fish parvalbumins. Polyclonal rabbit antibodies were raised against parvalbumins from frequently consumed barramundi (Lates calcarifer), basa (Pangasius bocourti), pilchard (Sardinops sagax) and Atlantic salmon (Salmo salar). These were evaluated for cross-reactivity against a panel of 45 fish extracts (raw, heated and canned fish). Anti-barramundi parvalbumin proved to be the most cross-reactive antibody, detecting 87.5% of the 40 species analyzed, followed by anti-pilchard and anti-basa antibody. In contrast the anti-salmon antibody was very specific and only reacted to salmonidae and a few other fish. All analyzed fish species, except mahi mahi, swordfish, yellowfin tuna and all 5 canned fish had parvalbumin detected in raw extracts. However antibody reactivity to many fish was heat liable or susceptible to denaturation, demonstrating that some parvalbumins have most likely conformational epitopes, which lose antibody reactivity after heat treatment. We have demonstrated the generation of highly cross-reactive anti-parvalbumin antibodies that could be used for the detection of allergenic fish parvalbumin in contaminated food products. This cross-reactivity study thus shows processing of fish, especially canning, can have on impact on antibody recognition by ELISA, possibly similar to IgE-binding in vivo.

Auto-induction for high yield expression of recombinant novel isoallergen tropomyosin from King prawn (Melicertus latisulcatus) for improved diagnostics and immunotherapeutics

Food allergies are increasing worldwide, demonstrating a considerable public health concern. Shellfish allergy is one of the major food groups causing allergic sensitization among adults and children, affecting up to 2% of the general world population. Tropomyosin (TM) is the major allergen in shellfish and frequently used in the diagnosis of allergic sensitization and the detection of cross-contaminated food. To improve and establish better and more sensitive diagnostics for allergies and immunotherapeutics, large quantities of pure allergens are required. To establish a reproducible method for the generation of pure recombinant tropomyosin we utilized in this study different Escherichia coli strains (NM522, TOP10 and BL21(DE3)RIPL). In addition, isopropyl-β-D-thiogalactoside (IPTG) induction was compared with a novel auto-induction system to allow the generation of larger quantities of recombinant allergen. We demonstrated that the B-strain of E. coli is better for the expression of TM compared to the K-strain. Moreover, a higher yield could be achieved when using the auto-induction system, with up to 62 mg/l. High yield expressed recombinant TM from King prawn (KP) was compared to recombinant TM from Black tiger prawn (Pen m 1). We demonstrated that recombinant TM from KP and known isoallergen Pen m 1 have very similar molecular and immunological characteristics. Overall, we demonstrate that auto-induction can be used to express larger quantities of recombinant allergens for the development of diagnostic, to quantify allergens as well as immunotherapeutics employing isoallergens.

Identification of a novel allergen from muscle and various organs in banana shrimp (Fenneropenaeus merguiensis)

BACKGROUND

The increasing consumption of shellfish can cause an increase in allergic symptoms. Shrimp allergy can be species specific, but specific allergies in different organs have not been studied. Identification of allergens in muscle and others organs of banana shrimp is necessary for improved diagnostics of allergies for shrimp and food safety control.

OBJECTIVE

To identify the IgE-binding proteins in various organs of Fenneropenaeus merguiensis by immunoblotting and tandem mass spectrometry.

METHODS

Proteomic methods were used to investigate the allergenic proteins from banana shrimp. Proteins from muscle and various organs were separated by denaturing polyacrylamide gel electrophoresis. Allergens were analyzed by immunoblotting with pooled sera from shrimp allergic patients (n = 21) and tandem mass spectrometry.

RESULTS

The important allergens in banana shrimp are arginine kinase, sarcoplasmic calcium-binding protein, myosin heavy chain, hemocyanin, enolase, and glyceraldehyde-3-phosphate dehydrogenase, which can be demonstrated by immunoblotting in muscle and shell. Moreover, vitellogenin, ovarian peritrophin 1 precursor, β-actin, and 14-3-3 protein were suggested as allergens in the ovary at different stages of ovarian development.

CONCLUSION

Ten allergens were identified as allergens in various organs, and they are suggested as novel allergens in banana shrimp. The major allergen in muscle and shell from this shrimp is arginine kinase, whereas the major allergen in the ovary is vitellogenin.

Sex-response differences of immunological and histopathological biomarkers in gill of Prochilodus argenteus from a polluted river in southeast Brazil

The fish gill is in direct and standing contact with the immediate external environment and, therefore, is highly vulnerable to aquatic pollutants. In this study, Prochilodus argenteus were caught at two different points in São Francisco river. The first point is located near Três Marias dam, while the second is placed downstream the Abaeté river. Chemical approaches showed the presence of metals contamination in the first point. Thus, the main goal of this study was to investigate the possible toxic effects of these contaminants and the likely use of biomarkers on fish gills. Biometric data of length and weight of fish were obtained in order to calculate the condition factor as an organismal biomarker. The histological changes in gills and alterations in mucous and rodlet cells occurrence were detected microscopically and evaluated with quantitative analyses. Myeloperoxidase (MPO) and Eosinophil Peroxidase (EPO) were also assessed in fish gill. The analysis of the water and sediment samples revealed the presence of metals at the two points. As and Cd were detected at higher concentrations at point 1. The presence of lamellar cell hyperplasia, lamellar fusion, lamellar edema and inflammatory foci varied according to the point. Additionally, mucous and rodlet cells and MPO and EPO activities showed variability according to the environmental conditions. Furthermore, with exception of lamellar hyperplasia and eosinophil peroxidase activity, all others parameters showed sex-variation responses. At the first point, male fish showed a chronical inflammation in gills due to the lowest activity of MPO and EPO, as well as low occurrence of inflammatory foci and glycoprotein secretion by mucous cells, while female fish presented an opposite pattern of response to the same environmental conditions. Therefore, we suggest the use of such biomarkers in future monitoring of aquatic systems, taking into account the sex-variation responses.

Immunogenic activity of the fish tapeworm Pterobothrium heteracanthum (Trypanorhyncha: Pterobothriidae) in BALB/c mice

The aim of this study was to verify the immunogenicity of Pterobothrium heteracanthum (Cestoda: Trypanorhyncha) crude protein extract (PH-CPE) in BALB/c mice. The parasites were obtained from Micropogonias furnieri (Osteichthyes: Sciaenidae). Groups of six mice were each immunized with 10, 50 or 100 μg of PH-CPE, on days 0 and 35. Both specific IgG and IgE responses were developed after immunization. The immunoblot assay revealed that specific IgG recognizes PH-CPE proteins with two molecular weight ranges, 60-75 and 30-40 kDa, and that IgE recognizes larger proteins over 120 kDa. This appears to be the first report on the immunogenicity of metacestodes within the Pterobothriidae and that PH-CPE is a potential inducer of a specific IgE response.

Airborne seafood allergens as a cause of occupational allergy and asthma

Occupational allergy and asthma is a serious adverse health outcome affecting seafood-processing workers. Allergic reactions are directed to two major seafood groups: fish and shellfish, with the latter group comprising crustaceans and molluscs. Several allergenic proteins have been identified in these different groups, but few have been characterised on a molecular level. Parvalbumin appears to be the major fish allergen, while tropomyosin the major crustacean allergen. Other IgE-binding proteins have also been identified in molluscs and other seafood-associated agents (e.g. Anisakis sp), although their molecular nature has not been characterised. Aerosolised allergens can be identified and quantified using immunological and chemical approaches, detecting levels as low as 10 ng/m(3). This contemporary review discusses interesting and recent findings in the area of occupational seafood allergy including high-risk occupations, environmental risk factors for airborne exposures, major and minor allergens implicated and innovative approaches in diagnosing and managing occupational allergy and asthma associated with seafood processing.

Comprehensive proteomics approach in characterizing and quantifying allergenic proteins from northern shrimp: toward better occupational asthma prevention

Occupational asthma is a major chronic health dilemma among workers involved in the seafood industry. Several proteins notoriously known to cause asthma have been reported in different seafood. This work involves the application of an allergenomics strategy to study the most potent allergens of northern shrimp. The proteins were extracted from shrimp tissue and profiled by gel electrophoresis. Allergenic proteins were identified based on their reactivity to patient sera and were structurally identified using tandem mass spectrometry. Northern shrimp tropomyosin, arginine kinase, and sarcoplasmic calcium-binding protein were found to be the most significant allergens. Multiple proteolytic enzymes enabled 100% coverage of the sequence of shrimp tropomyosin by tandem mass specrometry. Only partial sequence coverage was obtained, however, for the shrimp allergen arginine kinase. Signature peptides, for both tropomyosin and arginine kinase, were assigned and synthesized for use in developing the multiple reaction monitoring tandem mass spectrometric method. Subsequently, air samples were collected from a shrimp processing plant and two aerosolized proteins quantified using tandem mass specrometry. Allergens were detected in all areas of the plant, reaching levels as high as 375 and 480 ng/m(3) for tropomyosine and arginine kinase, respectively. Tropomyosine is much more abundant than arginine kinase in shrimp tissues, so the high levels of arginine kinase suggest it is more easily aerosolized. The present study shows that mass spectrometric analysis is a sensitive and accurate tool in identifying and quantifying aerosolized allergens.

Occupational allergies in seafood-processing workers

Global increased demand for seafood and its products has been associated with a concomitant rise in fishing, aquaculture, and processing activities. This increased harvesting of seafood is associated with more frequent reporting of allergic health problems among seafood processors. This review outlines the high-risk working populations, work processes, as well as host and environmental exposure risk factors for occupational respiratory and skin allergies. It also provides insights into the major and minor allergens as well as the pathophysiological mechanisms implicated. Diagnostic and preventive approaches are outlined in managing work-related allergy associated with seafood processing.

Fish and shellfish allergy in children: review of a persistent food allergy

The increased consumption of fish and shellfish has resulted in more frequent reports of adverse reactions to seafood, emphasizing the need for more specific diagnosis and treatment of this condition and exploring reasons for the persistence of this allergy. This review discusses interesting and new findings in the area of fish and shellfish allergy. New allergens and important potential cross-reacting allergens have been identified within the fish family and between shellfish, arachnids, and insects. The diagnostic approach may require prick to-prick tests using crude extracts of both raw and cooked forms of seafood for screening seafood sensitization before a food challenge or where food challenge is not feasible. Allergen-specific immunotherapy can be important; mutated less allergenic seafood proteins have been developed for this purpose. The persistence of allergy because of seafood proteins' resistance after rigorous treatment like cooking and extreme pH is well documented. Additionally, IgE antibodies from individuals with persistent allergy may be directed against different epitopes than those in patients with transient allergy. For a topic as important as this one, new areas of technological developments will likely have a significant impact, to provide more accurate methods of diagnosing useful information to patients about the likely course of their seafood allergy over the course of their childhood and beyond.

Heat-induced structural changes affect OVA-antigen processing and reduce allergic response in mouse model of food allergy

Background and Aims

The egg protein ovalbumin (OVA) belongs to six most frequent food allergens. We investigated how thermal processing influences its ability to induce allergic symptoms and immune responses in mouse model of food allergy.

Methodology/Principal Findings

Effect of increased temperature (70°C and 95°C) on OVA secondary structure was characterized by circular dichroism and by the kinetics of pepsin digestion with subsequent HPLC. BALB/c mice were sensitized intraperitoneally and challenged with repeated gavages of OVA or OVA heated to 70°C (h-OVA). Levels of allergen-specific serum antibodies were determined by ELISA (IgA and IgGs) or by β-hexosaminidase release test (IgE). Specific activities of digestive enzymes were determined in brush border membrane vesicles of jejunal enterocytes. Cytokine production and changes in regulatory T cells in mesenteric lymph nodes and spleen were assessed by ELISA and FACS. Heating of OVA to 70°C caused mild irreversible changes in secondary structure compared to boiling to 95°C (b-OVA), but both OVA treatments led to markedly different digestion kinetics and Tregs induction ability in vitro, compared to native OVA. Heating of OVA significantly decreased clinical symptoms (allergic diarrhea) and immune allergic response on the level of IgE, IL-4, IL-5, IL-13. Furthermore, h-OVA induced lower activities of serum mast cell protease-1 and enterocyte brush border membrane alkaline phosphatase as compared to native OVA. On the other hand h-OVA stimulated higher IgG2a in sera and IFN-γ secretion by splenocytes.

Conclusions

Minor irreversible changes in OVA secondary structure caused by thermal processing changes both its digestion and antigenic epitopes formation, which leads to activation of different T cell subpopulations, induces shift towards Th1 response and ultimately reduces its allergenicity.