Cloning, Expression, and the Effects of Processing on Sarcoplasmic-Calcium-Binding Protein: An Important Allergen in Mud Crab

Four amino acids play an important role in the allergenicity of hemocyanin allergen

To identify the key amino acids (AAs) affecting the allergenicity of hemocyanin (HC) allergens from Chinese mitten crabs, in this study, two epitopes, P1-SHFTGSKSNPEQR and P2-LSPGANTITR were employed and four potential key AAs (P1: F3 and N9 and P2: N6 and R10) were predicted. Mast cell and mouse models revealed that four mutants induced lower levels of Immunoglobulin E (IgE) and Th2 type cytokines (15.47-49.89 %), proving that F3, N9, N6, and R10 were the key AAs of two epitopes. Mutants reduce allergic responses via the Th2 pathway. However, the roles of every key AA affecting allergenicity were different (P1-F3 > N9 and P2-N6 > R10). In addition, lower transport and higher efflux were observed in the mutants during transport absorption by Caco-2 cells. The allergenicity of HC was stronger when the transport absorption efficiency of epitopes and mutants was higher and their efflux was lower. Our study provides a novel method for revealing the allergenic molecular mechanisms of food allergens.

Animal-derived food allergen: A review on the available crystal structure and new insights into structural epitope

Immunoglobulin E (IgE)-mediated food allergy is a rapidly growing public health problem. The interaction between allergens and IgE is at the core of the allergic response. One of the best ways to understand this interaction is through structural characterization. This review focuses on animal-derived food allergens, overviews allergen structures determined by X-ray crystallography, presents an update on IgE conformational epitopes, and explores the structural features of these epitopes. The structural determinants of allergenicity and cross-reactivity are also discussed. Animal-derived food allergens are classified into limited protein families according to structural features, with the calcium-binding protein and actin-binding protein families dominating. Progress in epitope characterization has provided useful information on the structural properties of the IgE recognition region. The data reveals that epitopes are located in relatively protruding areas with negative surface electrostatic potential. Ligand binding and disulfide bonds are two intrinsic characteristics that influence protein structure and impact allergenicity. Shared structures, local motifs, and shared epitopes are factors that lead to cross-reactivity. The structural properties of epitope regions and structural determinants of allergenicity and cross-reactivity may provide directions for the prevention, diagnosis, and treatment of food allergies. Experimentally determined structure, especially that of antigen-antibody complexes, remains limited, and the identification of epitopes continues to be a bottleneck in the study of animal-derived food allergens. A combination of traditional immunological techniques and emerging bioinformatics technology will revolutionize how protein interactions are characterized.

A comprehensive review on glycation and its potential application to reduce food allergenicity

Food allergens are a major concern for individuals who are susceptible to food allergies and may experience various health issues due to allergens in their food. Most allergenic foods are subjected to heat treatment before being consumed. However, thermal processing and prolonged storage can cause glycation reactions to occur in food. The glycation reaction is a common processing method requiring no special chemicals or equipment. It may affect the allergenicity of proteins by altering the structure of the epitope, revealing hidden epitopes, concealing linear epitopes, or creating new ones. Changes in food allergenicity following glycation processing depend on several factors, including the allergen's characteristics, processing parameters, and matrix, and are therefore hard to predict. This review examines how glycation reactions affect the allergenicity of different allergen groups in allergenic foods.

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.

Crystal Structure Analysis of Sarcoplasmic-Calcium-Binding Protein: An Allergen in Scylla paramamosain

The structure of allergenic proteins provides important information about the binding of allergens to antibodies. In this study, the crystal structure of Scy p 4 with a resolution of 1.60 Å was obtained by X-ray diffraction. Epitope mapping of Scy p 4 revealed that linear epitopes are located on the surface of Scy p 4. Also, conformational epitopes are mostly located in the structural conservative region. Further structural comparison, surface electrostatic potential, and hydrogen bond force analysis showed that mutation of Asp₇₀ and Asp_18/20/70 would lead to calcium-binding capacity being lost and destruction of allergenicity. Furthermore, a comparative analysis of structure showed that sarcoplasmic-calcium-binding protein (SCP) had high sequence, secondary, and spatial structural identity in crustaceans, which may be an important factor leading to cross-reactivity among crustaceans. The structure of Scy p 4 provides a template for epitope evaluation and localization of SCPs, which will help to reveal cross-reactivity among species.

Crustacean shellfish allergens: influence of food processing and their detection strategies

Despite the increasing popularity of crustacean shellfish among consumers due to their rich nutrients, they can induce a serious allergic response, sometimes even life-threatening. In the past decades, a variety of crustacean allergens have been identified to facilitate the diagnosis and management of crustacean allergies. Although food processing techniques can ease the risk of crustacean shellfish allergy, no available processing methods to tackle crustacean allergies thoroughly. Strict dietary avoidance of crustacean shellfish and its component is the best option for the protection of sensitized individuals, which should rely on the compliance of food labeling and, as such, on their verification by sensitive, reliable, and accurate detection techniques. In this present review, the physiochemical properties, structure aspects, and immunological characteristics of the major crustacean allergens have been described and discussed. Subsequently, the current research progresses on how various processing techniques cause the alterations and modifications in crustacean allergens to produce hypoallergenic crustacean food products were summarized and discussed. Particularly, various analytical methodologies employed in crustacean shellfish allergen detection, and the effect of food processing and matrix on these techniques, are also herein emphasized for the appropriate selection of analytical detection tools to safeguard consumers safety.

Identification of the Immunoglobulin E Epitope of Arginine Kinase, an Important Allergen from Crassostrea angulata

Arginine kinase (AK) was identified as an allergen in Crassostrea angulata. However, little information is available about its epitopes. In this study, AK from C. angulata was registered to the World Health Organization/International Union of Immunological Societies allergen nomenclature committee to be named as Cra a 2. The immunoglobulin G/immunoglobulin E-binding capacity of Cra a 2 was significantly reduced after chemical denaturation treatment. Further, eight linear mimotopes and five conformational mimotopes of Cra a 2 were obtained using phage panning. In addition to six linear epitopes that have been identified, two linear epitopes were verified by a synthetic peptide, of which L-Cra a 2-2 was conserved in shellfish. Four conformational epitopes were verified by site-directed mutation, among which mutation of C-Cra a 2-1 affected the structure and reduced the immunoreactivity of Cra a 2 most significantly. Overall, the identified epitopes may lay a foundation for the development of hypoallergenic oyster products through food processing.

Characterization, Epitope Identification, and Cross-reactivity Analysis of Tropomyosin: An Important Allergen of Crassostrea angulata

Oyster is a common shellfish product in China, which is associated with food allergy. However, there is still lack of research on allergens in oysters. In this study, tropomyosin (TM), an important allergen of Crassostrea angulata, was purified and identified by mass spectrometry. Subsequently, TM was cloned and expressed, with a sequence of size 852 bp, encoding 284 amino acid residues. The results of circular dichroism, digestion assay, inhibition enzyme-linked immunosorbent assay, and basophil activation test showed that recombinant TM had similar physicochemical properties and immunological properties to native TM. Furthermore, two conformational mimotopes were obtained and 10 IgE linear epitopes were verified. Meanwhile, different degrees of cross-reactivity were observed between C. angulata TM and the other 8 shellfish TMs using antibodies and serological analysis, which may relate to the 3 conserved epitope regions. These findings are expected to provide a theoretical basis for the molecular diagnosis of oyster allergy and cross-reactivity among shellfish.

Major shrimp allergen peptidomics signatures and potential biomarkers of heat processing

It is important to develop tools that can be used to understand the effects of processing on allergenic foods in order to achieve personalized food labeling. To evaluate the effect of heating on the allergy-relevant structural properties of tropomyosin (TM), arginine kinase (AK), myosin light chain (MLC) and sarcoplasmic calcium-binding protein (SCP) shrimp allergens, trypsin digests of raw, fried and baked shrimp extracts were analyzed by peptidomics and epitope correlations. Processing altered the number of peptides released from the distinct allergens, and each treatment generated a specific epitope-matched peptide allergen fingerprint. Among the four allergens, TM led to a number of released peptides and epitope changes being detected, and AK provided the epitope-matched ³³¹MGLTEFQAVK³⁴⁰ sequence as a common differentiating peptide for heat processing. These results provide new views on the structural effects of processing on major shrimp allergens and peptide candidates as processing biomarkers.

Two allergens from Scylla paramamosain share common epitopes showed different allergenic potential in Balb/c mice

Filamin C (FLN c) and triosephosphate isomerase (TIM) are novel allergens of crab (Scylla paramamosain) which are sharing common epitopes. This work aimed to assess their contributions to the induction and elicitation of allergenic responses. Balb/c mice were sensitized by intraperitoneal injections and challenged by intragastric gavage with purified proteins. Upon oral challenge, FLN c triggered more severe anaphylactic symptoms, higher levels of specific antibodies and histamine in serum than TIM, while TIM was a more active promotor of early specific antibody production and stimulated stronger Th2-biased responses. Combined with the results of in vitro assays, the data demonstrated that though with common epitopes, the two allergens showed a different allergenicity, TIM favored Th2 polarization in sensitization stage, while FLN c had a better ability to stimulate B cells and is highly immunogenic in oral challenge stage. The findings can help with the better understanding of allergenicity of crab allergens.

Maillard Reaction Induced Changes in Allergenicity of Food

Food allergy is increasing in prevalence, posing aheavier social and financial burden. At present, there is still no widely accepted treatment for it. Methods to reduce or eliminate the allergenicity of trigger foods are urgently needed. Technological processing contributes to producing some hypoallergenic foods. Among the processing methods, the Maillard reaction (MR) is popular because neither special chemical materials nor sophisticated equipment is needed. MR may affect the allergenicity of proteins by disrupting the conformational epitope, disclosing the hidden epitope, masking the linear epitope, and/or forming a new epitope. Changes in the allergenicity of foods after processing are affected by various factors, such as the characteristics of the allergen, the processing parameters, and the processing matrix, and they are therefore variable and difficult to predict. This paper reviews the effects of MR on the allergenicity of each allergen group from common allergenic foods.

Analysis of Immunoreactivity of α/α2-Tropomyosin from Haliotis discus hannai, Based on IgE Epitopes and Structural Characteristics

Tropomyosin (TM) was reported to be a supercoil allergen of shellfish. However, little information is available about its link between structure and allergenicity. In this study, the subunit of TM (α-TM) and supercoil of TM (α₂-TM) were identified from Haliotis discus hannai. α₂-TM showed higher immunoreactivity than α-TM. Meanwhile, seven linear epitopes in α-TM and α₂-TM were verified, and two conformational epitopes in α₂-TM were predicted. The physicochemical properties and chemical bond assays confirmed the existence of the disulfide bond in α₂-TM. According to spectroscopy and hydrophobicity analysis, α-TM showed higher α-helix features and blueshift of the fluorescence intensity peak compared with those of α₂-TM. The structure analysis revealed the possibility of conformational epitopes in α₂-TM, which could explain the immunoreactivity differences between α-TM and α₂-TM further. These results improved the understanding of Haliotis discus hannai TM, which lay the foundation for the food processing of abalone.

Linear Epitopes Play an Important Role in the Immunoglobulin G (IgG)/Immunoglobulin E (IgE)-Binding Capacity of Scy p 4

Sarcoplasmic calcium-binding protein is a stable allergen in Scylla paramamosain and named Scy p 4. To explore the importance of linear epitopes in the immunoglobulin G (IgG)/immunoglobulin E (IgE)-binding capacity of Scy p 4, chemical denaturants were used to destroy the structure. Scy p 4 was reduced with dithiothreitol and subsequently alkylated with iodoacetamide (IAA). Furthermore, the structural analysis indicated that IAA-Scy p 4 was an unstructured protein. The inhibition enzyme-linked immunosorbent assay showed that IAA-Scy p 4 could inhibit the binding of Scy p 4 to sensitize serum, with inhibition rates reached 55%. Moreover, the linear mimotopes of Scy p 4 were predicted in silico. Three linear epitopes were verified by serological tests and named L-Scy p 4-1 (AA_76-91), L-Scy p 4-2 (AA_111-125), and L-Scy p 4-3 (AA_137-146). Overall, these data provide an understanding of the relationship between the structure and allergenicity about Scy p 4, and the identified linear epitopes can be used for diagnosis and food processing of shellfish allergy.

Identification and characterization of Crassostrea angulata arginine kinase, a novel allergen that causes cross-reactivity among shellfish

Oyster is a common food that causes allergy. However, little information is available about its allergens and cross-reactivity. In this study, arginine kinase (AK) was identified as a novel allergen in Crassostrea angulata. The primary sequence of AK was cloned which encoded 350 amino acids, and recombinant AK (rAK) was obtained. The immunodot results, secondary structure and digestive stability showed that native AK and rAK had similar IgG/IgE-binding activity and physicochemical properties. Serological analysis of 14 oyster-sensitive individuals demonstrated that AK exhibited cross-reactivity among oysters, shrimps, and crabs. Furthermore, nine epitopes in oyster AK were verified using inhibition dot blots and inhibition enzyme linked immunosorbent assay, six of which were similar to the epitopes of shrimp/crab AK. The most conserved epitopes were P5 (121-133) and P6 (133-146), which may be responsible for the cross-reactivity caused by AK. These findings will provide a deeper understanding of oyster allergens and cross-reactivity among shellfish.

IgE epitope analysis of sarcoplasmic-calcium-binding protein, a heat-resistant allergen in Crassostrea angulata

Sarcoplasmic-calcium-binding protein (SCP) has been investigated as a novel allergen in Crassostrea angulata. Nevertheless, knowledge of its effector-cell-based allergic relevance and epitopes is limited. In this study, the heat-resistant allergen SCP was able to induce significant upregulation of CD63 and CD203c (p < 0.05), which showed obvious allergenicity in a basophil activation test. Furthermore, immunoinformatic tools, a one-bead-one-compound peptide library, and phage display technology were combined to analyze the allergenic epitopes of SCP. Five linear epitopes named L-SCP-1 (AA22-33), L-SCP-2 (AA64-75), L-SCP-3 (AA80-90), L-SCP-4 (AA107-116), and L-SCP-5 (AA144-159) were verified using serological tests. Additionally, two conformational epitopes (C-SCP-1 and C-SCP-2) were determined, and C-SCP-1 was located at one of the calcium-binding sites (AA106-117). Moreover, SCP showed weaker typical α-helical features and higher hydrophobicity after Ca2+ depletion, which reduced its IgE-binding capacity. Overall, these epitope data could enhance our understanding of oyster allergens, which could be used to develop hypoallergenic shellfish products.

Site-Directed Mutations of Calcium-Binding Sites Contribute to Reducing the Immunoreactivity of the EF-Hand Sarcoplasmic Calcium-Binding Protein in Scylla paramamosain

In order to reduce the immunoreactivity of sarcoplasmic calcium-binding protein (SCP), site-directed mutations were used to replace key amino acids in the conformational epitopes and calcium-binding sites. The mutant SCPs (mSCPs) were expressed in Escherichia coli, and their immunoreactivities were analyzed using iELISA and basophil activation assays. Furthermore, the structural changes of mSCPs were determined from the circular dichroism spectra. The iELISA results showed that mSCPs could effectively inhibit the binding of wild-type SCP (wtSCP) to sensitive serum, with inhibition rates that reached 90%. Moreover, mSCPs could downregulate the expression levels of CD63 and CD203c on the basophil surface. Compared with wtSCP, the peak values were significantly changed, and the calcium binding ability was impaired, which explained the decline in immunoreactivities of the mSCPs. All of the data confirmed that this approach was effective in reducing the immunoreactivity of SCP and could be applied to other shellfish allergens.

Effects of thermal processing on the allergenicity, structure, and critical epitope amino acids of crab tropomyosin

Food processing can change the structure and immunoreactivity of purified allergens, but the effect of food processing on the immunoreactivity of the processed and purified allergen is still poorly understood.

Identification and Cross-reactivity Analysis of Sarcoplasmic-Calcium-Binding Protein: A Novel Allergen in Crassostrea angulata

Oysters are an important shellfish group known to cause food allergy; however, knowledge of their sensitization components and cross-reactivity is limited. This study aimed to identify a novel allergen in Crassostrea angulata and investigate its cross-reactivity. To this end, a 20 kDa protein was purified from oyster and confirmed to be a sarcoplasmic-calcium-binding protein (SCP) by LC-MS/MS. A 537 bp open reading frame was obtained from oyster SCP total RNA, which encoded 179 amino acids, and was expressed in Escherichia coli. According to the circular dichroism results, digestion assay, and inhibition ELISA, the recombinant SCP (rSCP) exhibited similar physicochemical properties and IgG-binding activity to native SCP. rSCP displayed stronger IgE-binding activity by immunological method. Moreover, a different intensity of cross-reactivity and sequence homology were demonstrated between shellfish species. Collectively, these findings provide novel insight into shellfish allergens, which can be used to aid in the in vitro diagnosis of oyster-sensitized patients.

Cloning, expression and comparison of the properties of Scy p 9, a Scylla paramamosain allergen

This study investigated the properties of Scy p 9 in mud crab (Scylla paramamosain). The gene sequence of filamin C obtained from crabs, which was denoted as Scy p 9, contains a 2544 bp open reading frame and encodes 848 amino acid residues. Recombinant Scy p 9 (rScy p 9) is expressed in Escherichia coli, which exhibits tertiary structure changes, and the IgE binding activity of rScy p 9 is higher than that of native Scy p 9 (nScy p 9). Moreover, this study explored the possibility of the presence and cross-reactivity of filamin C in 8 shellfish. IgE-specific binding to nScy p 9 and rScy p 9 in patients allergic to shellfish revealed that rScy p 9 was more sensitive than nScy p 9. The gene sequence of filamin C fills in the blank in shellfish. This study contributes to the understanding of the properties of Scy p 9, and the results indicate that rScy p 9 can be used as a candidate for component-resolved diagnosis in shellfish.

Cloning, Expression, and Epitope Identification of Myosin Light Chain 1: An Allergen in Mud Crab

Mud crab (Scylla paramamosain) is a commonly consumed seafood as a result of its high nutritional value; however, it is associated with food allergy. The current understanding of crab allergens remains insufficient. In the present study, an 18 kDa protein was purified from crab muscle and confirmed to be myosin light chain 1 (MLC1) by matrix-assisted laser desorption/ionization-tandem time-of-flight mass spectrometry. Total RNA was isolated and amplified to obtain a MLC1 open reading frame of 462 bp, encoding 154 amino acids. A structural analysis revealed that recombinant MLC1 (rMLC1) expressed in Escherichia coli contained α-helix and random coil. Moreover, rMLC1 displayed strong immunoactivity by dot blot and a basophil activation test. Furthermore, seven allergenic epitopes of MLC1 were predicted, and five critical epitope regions were identified by an inhibition enzyme-linked immunosorbent assay and human mast cell degranulation assay. This comprehensive research of an allergen helps to conduct component-resolved diagnoses and immunotherapies related to crab allergies.

Reducing Allergenicity to Arginine Kinase from Mud Crab Using Site-Directed Mutagenesis and Peptide Aptamers

The mud crab ( Scylla paramamosain) is widely consumed but can cause a severe food allergic reaction. To reduce allergenicity to arginine kinase (AK), site-directed mutagenesis was used to destroy disulfide bonds or mutate critical amino acids of conformational epitopes. Three hypoallergenic mutant AKs (mAK1, mAK2, and mAK3) were generated, with the immunoreactivity decreasing by 54.2, 40.1, and 71.4%, respectively. In comparison to recombinant AK (rAK), the structure of mAKs was clearly changed. Additionally, antisense peptides were designed on the basis of linear epitopes and pepsin-cutting sites of AK. Five peptide aptamers were screened by molecular docking and then analyzed by the immunoglobulin E inhibition enzyme-linked immunosorbent assay and human Laboratory of Allergic Diseases 2 mast cell degranulation assay. The peptide aptamers could significantly inhibit allergenicity of rAK and mAKs, and the inhibitory effect of peptide aptamer 3 was slightly better than the others. These results provide synergistic methods to reduce allergenicity to AK, which could be applied to other shellfish allergens.

Effects of thermal processing on digestion stability and immunoreactivity of the Litopenaeus vannamei matrix

Many types of shellfish, including shrimp, are sometimes cooked before ingestion.

Bifidobacterium lactis Ameliorates the Risk of Food Allergy in Chinese Children by Affecting Relative Percentage of Treg and Th17 Cells

We aimed to explore the therapeutic effect of Bifidobacterium lactis on food allergy by investigating the percentage of Treg and Th17 cells in Chinese children and related molecular mechanisms. A total of 256 children with food allergy were evenly assigned into two groups: BG, the children received 10 ml B. lactis (1 × 10⁶/ml) daily, and CG, the children received the solution without B. lactis daily for three months. Allergic symptoms, serum IgE, and food antigen-specific IgE were measured. A mouse allergy model was established by using shrimp tropomyosin and treated with B. lactis. Relative mRNA levels of Treg- and Th17-associated cytokines were measured by using quantitative PCR. The percentage of Treg and Th17 cells in spleen were measured by using flow cytometry. After 3-month therapy, the allergic symptoms of the BG were remarkably reduced when compared with the CG (P < 0.05). Serum levels of IgE and food antigen-specific IgE were decreased too (P < 0.05). Similar results were also found in a mouse allergy model. After B. lactis treatment, the relative mRNA level of FoxP3 was significantly enhanced in the B. lactis therapy group when compared to positive controls. In addition, relative mRNA levels of FoxP3 and TGF-β associated with Treg cells were increased, whereas relative mRNA levels of IL-17A and IL-23 associated with Th17 were reduced. B. lactis treatment significantly increased the ratio of Treg and Th17 cells in a mouse allergy model (P < 0.05). B. lactis effectively alleviates allergic symptoms by increasing the ratio of Treg and Th17 cells.

Diagnosis of fish and shellfish allergies

Seafood allergy is a hypersensitive disorder with increasing prevalence worldwide. Effective and accurate diagnostic workup for seafood allergy is essential for clinicians and patients. Parvalbumin and tropomyosin are the most common fish and shellfish allergens, respectively. The diagnosis of seafood allergies is complicated by cross-reactivity among fish allergens and between shellfish allergens and other arthropods. Current clinical diagnosis of seafood allergy is a complex algorithm that includes clinical assessment, skin prick test, specific IgE measurement, and oral food challenges. Emerging diagnostic strategies, such as component-resolved diagnosis (CRD), which uses single allergenic components for assessment of epitope specific IgE, can provide critical information in predicting individualized sensitization patterns and risk of severe allergic reactions. Further understanding of the molecular identities and characteristics of seafood allergens can advance the development of CRD and lead to more precise diagnosis and improved clinical management of seafood allergies.

A comprehensive analysis of the allergenicity and IgE epitopes of myosinogen allergens in Scylla paramamosain

BACKGROUND

Scylla paramamosain is one of the most common and serious food allergens in Asia. Therefore, research on its prevalence, accurate diagnosis, and IgE-binding pattern of the allergens is crucial.

OBJECTIVE

To identify the IgE epitopes of the myosinogen allergens in S. paramamosain using phage peptide library.

METHODS

The prevalence of allergy to crabs (AC) and of sensitization was analysed using a questionnaire and a serological assay. BAT was performed by flow cytometry, and its diagnostic performance was evaluated in relation to allergens purified from crab myosinogen. IgE-binding epitopes were identified by phage display using the IgE from patients with AC. Sequence- and structure-based bioinformatics analyses were performed to identify allergenic epitopes.

RESULTS

Crab was the most common cause of food allergies in this study. Subjects with AC (n = 30) with clear clinical symptoms were identified by immunoblotting and BAT. All of the myosinogen allergens triggered basophil activation; surface expression of CD63 and CD203c was higher in patients allergic to AK and FLN c than in patients allergic to SCP and TIM. In addition to six conformational epitopes of SCP, six linear epitopes and eight conformational epitopes of AK were identified. Five linear epitopes and three conformational epitopes of TIM, nine linear and ten conformational epitopes of FLN c were also identified, and the sequence VH(I/T) L was appeared in epitopes of both TIM and FLN c. The number of epitopes showed consistency with the value of BAT.

CONCLUSIONS AND CLINICAL RELEVANCE

BAT can be used for accurate diagnosis of AC. Identification of particular allergenic motifs could be a valuable tool for prevention, diagnosis, and treatment of food allergies.

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.