Cross-reactive epitopes and their role in food allergy

Cross-reactivity and conserved epitope analysis of tropomyosin from Lateolabrax japonicus and shellfish species

The phenomenon of cross-reactivity within TM between fish and shellfish has received scant attention. In the study, TM of Lateolabrax japonicus, Scylla paramamosain and Mactra quadrangularis were considered as research objects. The results indicated L. japonicus TM exhibited weak binding for both rabbit anti-S. paramamosain/M. quadrangularis TM antibody. However, a significant IgE-binding capacity was observed for three TM in 11 of 18 fish-sensitised patients. Additionally, three TM also could activated basophils in 6 fish-sensitised patients. Subsequently, seven IgE epitopes of L. japonicus TM were confirmed. Two conserved epitopes (LERTEERA, LKTVQNN) and four critical amino acids (E, A, L, and R) were found across L. japonicus and shellfish TM, suggesting these could be responsible for cross-reactivity. These findings were expected to reduce the allergenicity of fish by destroying IgE epitopes through food processing or deleting IgE epitopes using molecular biotechnology, which have important implications for food safety and allergy management.

Non-allergenic mixed T cell epitope peptides for preventing Scy p 9 allergic reactions

Filamin c is an allergen with strong IgE-binding activity of Scylla paramamosain (named Scy p 9). In this study, the T cell epitopes of Scy p 9 were identified using the CD4+T lymphocyte proliferation assay in the mononuclear cells of the spleen allergic mice. Nine of the thirteen T cell epitope peptides that have been found have the ability to trigger the production of the Th1 cytokine (IFN-γ) and TGF-β. Meanwhile, the findings of the inhibitory Dot blot and basophil activation test of crab allergy patients showed that the mixed nine T cell epitope peptides lacked IgE-binding activity and was unable to stimulate the expression of CD63 and CD203c on the surface of basophils. Non-allergenic mixed T cell epitope peptides (NAMTEP) demonstrate the potential for preventing Scy p 9 allergies. According to the evaluation of the preventive effect of Scy p 9 allergy mouse model, mice challenged with oral administration of Scy p 9 after early injection of NAMTEP did not show any allergic symptoms. NAMTEP inhibited IgE generation and Th2 immune response, preventing Scy p 9 allergy reactions in mice. These results would provide a theoretical foundation for the specific prevention of allergens in crustacean aquatic products.

Screening and Interaction Analysis of Shark-Derived Nanobodies against Crayfish Major Allergen Pro c 2

Pro c 2 (arginine kinase) is a major allergen in crayfish (Procambarus clarkii). Shark-derived variable domains of new antigen receptors (VNARs) have advantages in developing allergen detection and immunotherapy. This study constructed a VNAR domain library from Chiloscyllium plagiosum immunized with Pro c 2. Three VNARs (VNAR-11, VNAR-20, and VNAR-29) against Pro c 2 obtained by screening the library were expressed in the HEK293F cells, fusing with the immunoglobulin (Ig) G1 Fc fragment (VNAR-Fc-11, VNAR-Fc-29, and VNAR-Fc-20). The VNAR-Fc fusions bound to Pro c 2 with an affinity KD ranging from 0.2131 ∼ 465.3 μM, with the ability to inhibit patients' IgE binding to Pro c 2. VNAR-20 and VNAR-29 displayed more stable binding with Pro c 2 during molecular dynamics simulation. The binding sites of the VNARs are distributed in the conserved IgE epitopes of arginine kinase. These achievements indicate the application potential of VNARs in allergen detection and allergy therapeutics.

Food allergy endotypes revisited

In the last century, food allergy has become recognized as an increasingly prevalent and heterogeneous condition. Advances in biomedical technology have revealed complex genetic, environmental, immune, and metabolic pathways underlying the pathogenesis of food-allergic disorders. These findings permit classification of distinct food allergy endotypes with unique pathophysiologic features. In this review, we suggest that these endotypes of food-allergic disorders should be defined on the basis of (1) whether or not the allergic antibody IgE plays an essential role in disease pathogenesis, (2) the molecular features of the allergen (protein vs carbohydrate), and (3) the molecular markers associated with prognosis, severity, or clinical presentation. Beyond these broad categories, additional subtypes with unique mechanistic characteristics are discussed.

Deciphering the Cross-Reactivity of Tropomyosin across Three Molluscan Species: Insights into the Role of Conserved T-Cell and B-Cell Epitopes

Haliotis discus hannai tropomyosin (HTM), Alectryonella plicatula tropomyosin (ATM), and Mimachlamys nobilis tropomyosin (MTM) were reported as significant seafood allergens capable of eliciting severe allergic reactions. However, studies of cross-reactivity and epitope mapping among them are notably limited. This study discovered their cross-reactivity property through inhibition of IgG/IgE binding capacity and promotion of specific CD4+T-cell proliferation. For T-cell epitopes, 3, 4, and 3 epitopes were identified from the splenocytes of mice immunized with HTM, ATM, and MTM, respectively. In terms of B-cell epitopes, a combination of bioinformatics techniques and serological assays identified 4, 3, and 4 epitopes for HTM, ATM, and MTM, respectively. Sequence logo analysis revealed 2 conserved T-cell epitopes and 5 conserved B-cell epitopes, which may be critical for the observed cross-reactivity property. In conclusion, these findings provide crucial molecular evidence that could enhance the prevention of allergic reactions to aquatic mollusks.

Immune Reactivity to Raw and Processed Foods and Their Possible Contributions to Autoimmunity

It is now known that diet or food is one of the environmental factors that can induce or contribute to autoimmunity. In a healthy person with a normal functioning immune system, food substances encounter no resistance and are allowed passage through the immune barriers without triggering immune reactivity. However, clinicians are becoming increasingly aware that modern food-processing methods can increase or decrease the immune reactivity of foods, including allergic reactions. Immune reactions to undigested food antigens could result in the production of IgE antibodies, which are involved in immediate immune reactivity, and in IgG and IgA antibodies, which are involved in delayed immune reactivity. Currently, measurements of these antibodies are generally only performed against antigens derived from raw foods. However, testing for food reactivity based only on raw food consumption is inaccurate because people eat both raw and cooked foods. Even home-cooked foods undergo different kinds of preparation or processing. Food processing can change the structure of raw food materials into secondary, tertiary, and quaternary structures that can have different reactive properties. This can affect the body's normal oral tolerance of food, causing the immune system to mistakenly identify food as a harmful foreign substance and react to it immunologically, leading to food immune reactivity. This abnormal reaction to food molecules can lead to the production of antibodies against not just target food antigens but also the body's own tissues, which can have significant implications in autoimmunity induction due to cross-reactivity and the other mechanisms discussed here. We hope that this present review will stimulate further research on the role of modified food antigens in the induction of autoimmunity based on some or all of the key points discussed in this review.

Allergenicity of Alternative Proteins: Reduction Mechanisms and Processing Strategies

The increasing popularity of alternative proteins has raised concerns about allergenic potential, especially for plant-, insect-, fungal-, and algae-based proteins. Allergies arise when the immune system misidentifies proteins as harmful, triggering IgE-mediated reactions that range from mild to severe. Main factors influencing allergenicity include protein structure, cross-reactivity, processing methods, and gut microbiota. Disruptions in gut health or microbiota balance heighten risks. Common allergens in legumes, cereals, nuts, oilseeds, single-cell proteins, and insect-based proteins are particularly challenging, as they often remain stable and resistant to heat and digestion despite various processing techniques. Processing methods, such as roasting, enzymatic hydrolysis, and fermentation, show promise in reducing allergenicity by altering protein structures and breaking down epitopes that trigger immune responses. Future research should focus on optimizing these methods to ensure that they effectively reduce allergenic risks while maintaining the nutritional quality and safety of alternative protein products.

Patterns and Prevalence of Food Allergen Cross-Reactivity: A Cross-Sectional Study of Food-Allergic Adults in the Makkah Region, Saudi Arabia

BACKGROUND AND OBJECTIVES

Food allergies are a growing public health concern, with cross-reactivity complicating diagnosis and management. Cross-reactivity occurs when immune responses to one allergen trigger reactions to similar proteins in other allergens. There is a lack of regional data on the prevalence and patterns of food allergen cross-reactivity in Saudi Arabia, particularly in the Makkah region. This study investigates the prevalence and patterns of food allergen cross-reactivity among adults in Makkah, considering gender- and age-related differences.

METHODS

A cross-sectional survey was conducted between July and October 2021 among 93 adults aged 18 years or older residing in the Makkah region who self-reported doctor-diagnosed food allergies. Participants were recruited through an online questionnaire distributed via social media. The survey, validated by expert reviewers and pretested for clarity, collected demographic information, allergen types, and cross-reactivity data. Descriptive statistics, chi-square tests, and a cross-reactivity matrix were used to assess allergen co-sensitization patterns and demographic associations.

RESULTS

The study identified high rates of nut, egg, and fruit allergies, with significant cross-reactivity, particularly among participants allergic to nuts. Females reported higher allergy prevalence of cross-reactivity (65.6%) compared to males (34.4%), aligning with global trends. Middle-aged females exhibited the highest rates of allergen cross-reactivity. The most frequent cross-reactivity was observed in participants with nut (100%), egg (90.7%), and fruit (89.2%) allergies. Specifically, 90.9% of individuals allergic to nuts experienced cross-reactivity with more than two other allergens. The cross-reactivity matrix revealed both expected (e.g., between tree nuts and peanuts) and unexpected patterns (e.g., between fruits and seafood), suggesting the possible influence of panallergens, co-sensitization, or regional dietary factors.

CONCLUSIONS

This study highlights a high prevalence of food allergen cross-reactivity among adults in the Makkah region, with significant gender- and age-related trends. The findings underscore the need for clinician awareness of atypical and panallergen-driven cross-reactivity to support tailored patient counseling and management strategies. Region-specific screening protocols and culturally informed public health campaigns are recommended to address local dietary practices and improve allergy awareness. Future longitudinal and interventional studies incorporating objective diagnostic tools are essential to validate these findings and assess the effectiveness of targeted interventions. These insights can inform clinical guidelines and national health policies to improve diagnosis, treatment, and patient education in Saudi Arabia.

Basophil Activation Test for the Improved Diagnosis of Peanut and Tree Nut Allergy

PURPOSE OF REVIEW

As an ex-vivo test of allergic effector cell activation, basophil activation testing (BAT) to allergen enables quantification of the in-vivo IgE-mediated allergic response. BAT thus holds promise in the diagnosis and monitoring of peanut and tree nut allergies. Recent systematic analyses and expert recommendations support a role for BAT in the diagnosis of peanut and tree nut allergy.

RECENT FINDINGS

Diagnostic cut-offs for BAT in peanut and tree nut allergy have been identified. Consistently, BAT can discriminate with high sensitivity and specificity between allergy and tolerance when measured against oral food challenges. Furthermore, the utilization of BAT has can increase the sensitivity and specificity of peanut allergy and tree nut allergy diagnosis, both alone and in conjunction with specific IgE testing and skin prick testing. BAT is a promising tool in the diagnosis of peanut and tree nut allergy.

Corydalis yanhusuo extract and its pharmacological substances alleviate food allergy by inhibiting mast cells activation via PLC/PKC/STAT3 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Food allergies have increasingly become a disease that affects global health and need for corresponding therapeutic drugs urgently. As a traditional Chinses medicine with a wide range of pharmacological effects, however, there was no clear research confirming therapeutic effect and pharmacological substances of Corydalis yanhusuo (YHS) on food allergies. Mast cells (MCs) are the main effector cells which mediate allergic and pseudo-allergic reactions.

MATERIALS AND METHODS

In this study, we investigated the effect of YHS extract on treating food allergy and its underlying mechanism. The inhibitory effect of YHS on MCs activation in vitro was evaluated by Ca2+ influx, degranulation, and cytokine release detection. The in vivo effect was investigated using the passive cutaneous anaphylaxis (PCA), active systemic allergy as well as OVA-induced food allergy mice. Western blot was performed to reveal the signaling pathway.

RESULTS

YHS extract showed an inhibitory effect on MCs activation and food allergy both in vitro and in vivo. PLC/PKC/STAT3 signaling pathway was suppressed by YHS extract in the disease. HPLC analysis revealed YHS extract contains corydaline and tetrahydropalmatine, and both compounds inhibited MCs activation induced by C48/80 in vitro.

CONCLUSION

YHS extract inhibited the MCs activation and food allergy via PLC/PKC/STAT3 pathway.

The gut microbiome and cross-reactivity of food allergens: current understanding, insights, and future directions

This mini-review examines the emerging role of the gut microbiome in influencing food allergen cross-reactivity. It specifically focuses on how microbial diversity, antigens, and metabolites impact IgE-mediated allergic responses. Cross-reactivity occurs when structurally similar food and microbial antigens trigger hypersensitivities, affecting millions of people worldwide. Recent research underscores the significance of microbial diversity in early life for developing immune tolerance. Beneficial strains, such as Lactobacillus and Bifidobacterium, play a crucial role in supporting the functions of T regulatory cells (Tregs) and immunoglobulin A (IgA). Additionally, we discuss microbial metabolites, particularly short-chain fatty acids (SCFAs), which enhance immune tolerance by promoting Treg differentiation and maintaining gut barrier integrity, thereby reducing allergen entry. However, it is important to note that SCFAs can provoke inflammatory responses under certain conditions, highlighting the necessity for targeted research on their dual effects. Dysbiosis-related intestinal permeability, often referred to as "leaky gut," can further worsen cross-reactivity. Microbial antigens like lipopolysaccharides (LPS) are known to influence Th2-dominant responses.

Murine model of cross-IgE sensitization and cross-anaphylactic reactions among multiple group food allergens

Rationale

Approximately 32 million people in the United States suffer from food allergies. Some food groups, such as legumes - peanuts, tree nuts, fish, and shellfish, have a high risk of cross-reactivity. However, the murine model of multiple food group cross-reactivity is limited.

Objective

We sought to develop a murine model that can be used to investigate novel therapeutics for the treatment of multiple food allergies.

Methods

C3H/HeJ mice were sensitized intraperitoneally (i.p.) once a week for three weeks with a mixture of 500µg of protein from peanut, cashew, walnut, shrimp, cod, and 2 mg Alum. The control group consisted of naïve mice. IgE levels against the sensitized allergens and their cross-reactive allergens were measured by ELISA at baseline and 3 weeks after sensitization. In weeks 4 and 5, the mice were given intragastric challenges with 200mg/mouse of each food: peanut, chickpea, lentil, cashew, almond, pistachio, hazelnut, brazil nut, walnut, pecan, shrimp, lobster, cod, salmon, and mackerel. After each challenge, anaphylactic symptoms, rectal temperatures, and plasma histamine were measured.

Results

There was a significant elevation of IgE against sensitized antigens (peanut cashew, walnut, shrimp, and cod) as well as cross-reactive allergens used for oral food challenge from legumes including peanut, chickpea, and lentil, as well as tree nuts such as cashew, almond, pistachio, hazelnut, brazil nut, walnut, and pecan. Furthermore, there was a significant increase in crustaceans such as shrimp, lobster and fish like cod, salmon, and mackerel (p<0.01). Consistently, significantly increased anaphylactic symptom scores (p<0.05), decreased rectal temperature (p<0.001), and increased plasma histamine (p<0.05) compared to the naïve mice occurred following each challenge with sensitized foods and unsensitized, but cross-reactive foods.

Conclusion

We generated a comprehensive murine model of IgE-mediated multiple food groups of cross-reactive anaphylaxes. This will provide an essential tool for developing novel therapies for cross-reactivity multiple food allergies.

Multiple Allergen Simultaneous Test for Food Allergens Cannot Screen Wheat-Dependent, Exercise-Induced Anaphylaxis and α-Gal Syndrome

Screening tests for specific immunoglobulin E (sIgE) to food allergens, such as the multiple allergen simultaneous test (MAST), are widely used in patients with suspected food allergies in South Korea. We evaluated whether MAST could effectively screen wheat-dependent exercise-induced anaphylaxis (WDEIA) and α-gal syndrome (AGS). We retrospectively reviewed patients with WDEIA and AGS diagnosed with unequivocal history and positive sIgE results for omega-5 gliadin and α-gal using ImmunoCAP, respectively. The clinical manifestations and results of MAST and ImmunoCAP (sIgE to wheat for WDEIA and beef/pork for AGS) were reviewed. In the MAST and ImmunoCAP results, class 0 (<0.35 units in each test) was considered negative. Medical records of 45 patients with WDEIA and 39 patients with AGS were reviewed. For WDEIA, 37 (82.2%) of patients had a history of anaphylaxis. Among those positive for omega-5 gliadin sIgE, 39 (87.7%) and 25 (55.6%) tested positive for gluten- and wheat-sIgE using ImmunoCAP, respectively. MAST performed on 15 patients yielded positive results for wheat-sIgE in 5 (33.3%). For AGS, 23 (59.0%) of patients had a history of anaphylaxis. Among those positive for α-gal sIgE, 32 (85.7%) and 37 (96.4%) tested positive for pork- and beef-sIgE using ImmunoCAP, respectively, whereas MAST could not detect sIgE for pork and beef (0%, 0/17). MAST for sIgE to food allergens cannot screen WDEIA and AGS. The tests for sIgE to a specific component of food allergen, such as omega-5 gliadin for WDEIA and α-gal for AGS, should be used to screen WDEIA and AGS.

Immunoglobulin E (IgE)-mediated food allergy

Food allergy is defined as an adverse immunologic response to a food. Immunoglobulin E (IgE)-mediated reactions to foods are associated with a broad range of signs and symptoms that may involve any of the following body systems: the skin, gastrointestinal tract, respiratory tract, and cardiovascular system. IgE-mediated food allergy is a leading cause of anaphylaxis. Therefore, timely and appropriate diagnosis and treatment are imperative. A diagnosis of food allergy entails a careful history and diagnostic tests, which may include skin prick tests, serum-specific IgE, and oral food challenge. The goal of food allergy care is to empower patients and caregivers to manage the risk of food-allergic reactions, reduce food allergy-related anxiety, and achieve a sense of control over their condition. This can be achieved in different ways for different patients and across different life stages. This article provides an overview of the epidemiology, pathophysiology, diagnosis, and management of IgE-mediated food allergy.

A Crystal Structure of Pro c 2 Provides Insights into Cross-Reactivity of Aquatic Allergens from the Phosphagen Kinase Family

Arginine kinase (AK) from the phosphagen kinase family is a cross-reactive shellfish allergen. Structurally related cross-reactive allergens are involved in the pathogenesis of allergic symptoms. This study aimed to unravel the cross-reactivity of AK from a structural perspective. The crystal structure of Procambarus clarkii AK (Pro c 2) was resolved at 1.57 Å resolution, which showed a well-conserved structure not only to shellfish AKs but also to fish creatine kinase (CK), another allergen from the phosphagen kinase family. In Western blot, the CK corresponding protein in fish muscles was found to be reactive with AK-specific immunoglobulin (Ig) G. Recombinant Pro c 2 (rPro c 2) and CKs from Lateolabrax japonicus (rCK-L) and Ctenopharyngodon idell (rCK-C) were then produced, and the IgE reactivity of rCK-L and rCK-C, as well as their IgG/IgE cross-reactivity with rPro c 2, was confirmed by immunological assays. This study demonstrated the cross-reactivity among aquatic allergens from the phosphagen kinase family due to their structural similarity.

Antigenic epitopes and cross-reactivity analysis of tropomyosin from Oratosquilla oratorio

Tropomyosin (TM) has been determined as the major allergen in Oratosquilla oratoria. However, little information is available about its antigenic epitopes and cross-reactivity. In this study, recombinant TM was obtained through genetic engineering and its IgG-/IgE-binding activity was similar to native TM. Subsequently, four T-cell epitopes were identified by using bioinformatics technology combined with CD4+ T-cell proliferation assay, and seven B-cell epitopes were identified by bioinformatics technology combined with serological assay. Moreover, dot blot analysis showed that TM had cross-reactivity among O. oratoria and other shellfish by using IgE polycolonal antibody from sera of shrimp-sensitive individuals or O. oratoria TM-immunized mice. Interestingly, three T-cell epitopes (AA4-24, AA194-212, and AA221-243) and four B-cell epitopes (AA85-100, AA121-138, AA209-233, and AA242-259) of TM in O. oratoria were conserved between O. oratoria and other shellfish, which may be the main reason for the cross-reactivity between them. In summary, these findings could serve for the diagnosis and prevention of shrimp allergy.

Development of an indirect competitive ELISA based on the common epitope of fish parvalbumin for its detection

A common epitope (AGSFDHKKFFKACGLSGKST) of parvalbumin from 16 fish species was excavated using bioinformatics tools combined with the characterization of fish parvalbumin binding profile of anti-single epitope antibody in this study. A competitive enzyme-linked immunosorbent assay (ELISA) based on the common epitope was established with a limit of detection of 10.15 ng/mL and a limit of quantification of 49.29 ng/mL. The developed ELISA exhibited a narrow range (71% to 107%) of related cross-reactivity of 15 fish parvalbumin. Besides, the recovery, the coefficient of variations for the intra-assay and the inter-assay were 84.3% to 108.2%, 7.4% to 13.9% and 8.5% to 15.6%. Our findings provide a novel idea for the development of a broad detection method for fish allergens and a practical tool for the detection of parvalbumin of economic fish species in food samples.

A review and outlook on expression of animal proteins in plants

This review delves into the multifaceted technologies, benefits and considerations surrounding the expression of animal proteins in plants, emphasizing its potential role in advancing global nutrition, enhancing sustainability, while being mindful of the safety considerations. As the world's population continues to grow and is projected to reach 9 billion people by 2050, there is a growing need for alternative protein sources that can meet nutritional demands while minimizing environmental impact. Plant expression of animal proteins is a cutting-edge biotechnology approach that allows crops to produce proteins traditionally derived from animals, offering a sustainable and resource-efficient manner of producing these proteins that diversifies protein production and increases food security. In the United States, it will be important for there to be clear guidance in order for these technologies to reach consumers. As consumer demand for sustainable and alternative food sources rise, biotechnologies can offer economic opportunities, making this emerging technology a key player in the market landscape.

The Allergen Profile of Two Edible Insect Species-Acheta domesticus and Hermetia illucens

SCOPE

Edible insect proteins are increasingly introduced as an alternative sustainable food source to address the world's need to feed the growing population. Tropomyosin is the main insect allergen; however, additional potential allergens are not well characterized and the impact of extraction procedures on immunological reactivity is unknown.

METHODS AND RESULTS

Proteins from different commercial food products derived from cricket (Acheta domesticus) and black soldier fly (BSF) (Hermetia illucens) are extracted using five different extraction buffers. The proteins are analyzed by SDS-PAGE and immunoblotting using allergen-specific antibodies and crustacean allergic patient sera. IgE binding bands are analyzed by mass spectrometry as well as the complete allergen profile of all 30 extracts. Urea-based buffers are most efficient in extracting insect allergens. Shrimp-specific antibody cross-reactivity to tropomyosin from cricket and BSF indicates high sequence and structural similarity between shrimp and insects. Additional unique allergens are identified in both species, including hemocyanin, vitellogenin, HSP20, apolipophorin-III, and chitin-binding protein.

CONCLUSIONS

Identifying potential allergenic proteins and their isoforms in cricket and BSF requires specific extraction approaches using urea-based methods. While tropomyosin is the most abundant and immunoreactive allergen, seven unique allergens are identified, highlighting the need for insect species-specific allergen detection in food products.

Profiles of apple allergen components and its diagnostic value in Northern China

Background

Limited is known on the profiles of apple allergy in China.

Objective

To explore the clinical significance of apple allergen components in northern China.

Methods

This study recruited 40 participants and categorized into apple tolerance (n = 19) and allergy (n = 21) group. The latter was categorized into oral allergy symptoms (OAS, n = 14) and generalized symptoms (GS, n = 7). All participants underwent ImmunoCAP screening to assess sIgE levels of birch, apple, and their components.

Results

The sensitization rates were 90% for Bet v 1, 85% for Mal d 1, 35% for Bet v 2, and 20% for Mal d 3. The overall positive rate for apple allergens was 97.5%, with half demonstrating mono-sensitization to Mal d 1. Birch, Bet v 1 and Mal d 1 sIgE levels had consistent areas under the curve (AUC 0.747, p = 0.037; AUC 0.799, p = 0.012; AUC 0.902, p < 0.001 respectively) in diagnosing apple allergy. The optimal cut-off values were determined to be 22.85 kUA/L (63.6% sensitivity, 85.7% specificity), 6.84 kUA/L (81.8% sensitivity, 71.4% specificity) and 1.61 kUA/L (93.8% sensitivity, 75.0% specificity), respectively. No allergens or components demonstrated diagnostic value in distinguishing between OAS and GS. Mal d 3 sensitization was correlated with mugwort allergy and higher risk of peach, nuts or legumes generalized allergy.

Conclusion

Mal d 1 was major allergen and the best for diagnosing apple allergy. Mal d 3 does not necessarily indicate severe allergic reaction to apples in northern China but may indicate mugwort sensitization and an increased risk of peach, nuts or legumes allergy.

Allergenicity and Linear Epitope Analysis of Scy p 8, an Allergen from Mud Crab

Scy p 8 (triosephosphate isomerase) as a crab allergen in inducing distinct T-helper (Th) cell differentiation and a linear epitope associated with allergenicity remain elusive. In this study, mice sensitized with Scy p 8 exhibited significantly upregulated levels of IgE, IgG1, and IL-4 release, inducing a Th2 immune response. Moreover, the release of IFN-γ (Th1) and the levels of Treg cells were downregulated, while IL-17A (Th17) was upregulated, indicating that Scy p 8 disrupted the Th1/Th2 balance and Th17/Treg balance in mice. Furthermore, bioinformatics prediction and serum samples from crab-allergic patients and mice enabled the discovery of 8 linear epitopes of Scy p 8. Meanwhile, the analysis of peptide similarity and tertiary superposition revealed that 8 epitopes of Scy p 8 exhibited conservation across various species, potentially resulting in cross-reactivity. These findings possess the potential to enhance the comprehension of crab allergens, thereby establishing a foundation for investigating cross-reactivity.

Differential effects of heating modes on the immunogenic potential of soy-derived peptides released after in vitro infant digestion

During production of soy-based infant formula, soy protein undergoes heating processes. This study investigated the differential impact of heating modes on the immunogenic potential of peptides in soy protein digests. Wet or dry heating was applied, followed by in vitro gastrointestinal infant digestion. The released peptides were analyzed by LC-MS/MS. Bioinformatics tools were utilized to predict and identify potential linear B-cell and T-cell epitopes, as well as to explore cross-reactivity with other legumes. Subsequently, the peptide intensities of the same potential epitope across different experimental conditions were compared. As a result, we confirmed the previously observed enhancing effect of wet heating on infant digestion and inhibitory effect of dry heating. A total of 8,546 peptides were detected in the digests, and 6,684 peptides were with a score over 80. Among them, 29 potential T-cell epitopes and 27 potential B-cell epitopes were predicted. Cross-reactivity between soy and other legumes, including peanut, pea, chickpea, lentil, kidney bean, and lupine, was also detected. Overall, heating and digestion time could modulate the potential to trigger peptide-induced immune responses.

Worldwide Heterogeneity of Food Allergy: Focus on Peach Allergy in Southern Italy

Food allergy (FA) has shown an increasing prevalence in the last decades, becoming a major public health problem. However, data on the prevalence of FA across the world are heterogeneous because they are influenced by several factors. Among IgE-mediated FA, an important role is played by FA related to plant-derived food which can result from the sensitization to a single protein (specific FA) or to homologous proteins present in different foods (cross-reactive FA) including non-specific lipid transfer proteins (nsLTPs), profilins, and pathogenesis-related class 10 (PR-10). In addition, the clinical presentation of FA is widely heterogeneous ranging from mild symptoms to severe reactions up to anaphylaxis, most frequently associated with nsLTP-related FA (LTP syndrome). Considering the potential life-threatening nature of nsLTP-related FA, the patient's geographical setting should always be taken into account; thereby, it is highly recommended to build a personalized approach for managing FA across the world in the precision medicine era. For this reason, in this review, we aim to provide an overview of the prevalence of nsLTP-mediated allergies in the Mediterranean area and to point out the potential reasons for the different geographical significance of LTP-driven allergies with a particular focus on the allergenic properties of food allergens and their cross reactivity.

Utilizing the Banana S-Adenosyl-L-Homocysteine Hydrolase Allergen to Identify Cross-Reactive IgE in Ryegrass-, Latex-, and Kiwifruit-Allergic Individuals

Food allergies mediated by specific IgE (sIgE) have a significant socioeconomic impact on society. Evaluating the IgE cross-reactivity between allergens from different allergen sources can enable the better management of these potentially life-threatening adverse reactions to food proteins and enhance food safety. A novel banana fruit allergen, S-adenosyl-L-homocysteine hydrolase (SAHH), has been recently identified and its recombinant homolog was heterologously overproduced in E. coli. In this study, we performed a search in the NCBI (National Center for Biotechnology Information) for SAHH homologs in ryegrass, latex, and kiwifruit, all of which are commonly associated with pollen-latex-fruit syndrome. In addition, Western immunoblot analysis was utilized to identify the cross-reactive IgE to banana SAHH in the sera of patients with a latex allergy, kiwifruit allergy, and ryegrass allergy. ClustalOmega analysis showed more than 92% amino acid sequence identity among the banana SAHH homologs in ryegrass, latex, and kiwifruit. In addition to five B-cell epitopes, in silico analysis predicted eleven T-cell epitopes in banana SAHH, seventeen in kiwifruit SAHH, twelve in ryegrass SAHH, and eight in latex SAHH, which were related to the seven-allele HLA reference set (HLA-DRB1*03:01, HLA-DRB1*07:01, HLA-DRB1*15:01, HLA-DRB3*01:01, HLA-DRB3*02:02, HLA-DRB4*01:01, HLA-DRB5*01:01). Four T-cell epitopes were identical in banana and kiwifruit SAHH (positions 328, 278, 142, 341), as well as banana and ryegrass SAHH (positions 278, 142, 96, and 341). All four SAHHs shared two T-cell epitopes (positions 278 and 341). In line with the high amino acid sequence identity and B-cell epitope homology among the analyzed proteins, the cross-reactive IgE to banana SAHH was detected in three of three latex-allergic patients, five of six ryegrass-allergic patients, and two of three kiwifruit-allergic patients. Although banana SAHH has only been studied in a small group of allergic individuals, it is a novel cross-reactive food allergen that should be considered when testing for pollen-latex-fruit syndrome.

Decoding food reactions: a detailed exploration of food allergies vs. intolerances and sensitivities

The food matrix is a complex system encompassing all constituent elements in food production. It influences the digestibility of these elements through direct interactions and affects the digestive environment. Furthermore, the gastrointestinal system possesses precise mechanisms that efficiently process dietary components into essential nutrients, effectively preventing the onset of abnormal immune responses or dysfunctional host reactions in most instances. However, the incidence of adverse food reactions is constantly increasing, and evidence indicates that this process is environmental. Adverse reactions can be categorized as toxic or nontoxic. Toxic reactions are dose-dependent and can result from natural compounds, processing-induced substances, or contaminants. Nontoxic reactions like food intolerance and hypersensitivity depend on individual susceptibility and evoke specific pathological and physiological responses. This review aims to elucidate the mechanisms underlying the occurrence of immune- (food allergies and sensitivities) and non-immune-mediated (food intolerance) reactions, emphasizing the fundamental distinctions between these two categories. Enhanced comprehension and distinction of these mechanisms will significantly contribute to advancing preventive and therapeutic approaches and establishing guidelines for food labeling concerning immune-mediated reactions.

Structure-based epitope prediction and assessment of cross-reactivity of Myrmecia pilosula venom-specific IgE and recombinant Sol g proteins (Solenopsis geminata)

The global distribution of tropical fire ants (Solenopsis geminata) raises concerns about anaphylaxis and serious medical issues in numerous countries. This investigation focused on the cross-reactivity of allergen-specific IgE antibodies between S. geminata and Myrmecia pilosula (Jack Jumper ant) venom proteins due to the potential emergence of cross-reactive allergies in the future. Antibody epitope analysis unveiled one predominant conformational epitope on Sol g 1.1 (PI score of 0.989), followed by Sol g 2.2, Sol g 4.1, and Sol g 3.1. Additionally, Pilosulin 1 showed high allergenic potential (PI score of 0.94), with Pilosulin 5a (PI score of 0.797) leading in B-cell epitopes. The sequence analysis indicated that Sol g 2.2 and Sol g 4.1 pose a high risk of cross-reactivity with Pilosulins 4.1a and 5a. Furthermore, the cross-reactivity of recombinant Sol g proteins with M. pilosula-specific IgE antibodies from 41 patients revealed high cross-reactivity for r-Sol g 3.1 (58.53%) and r-Sol g 4.1 (43.90%), followed by r-Sol g 2.2 (26.82%), and r-Sol g 1.1 (9.75%). Therefore, this study demonstrates cross-reactivity (85.36%) between S. geminata and M. pilosula, highlighting the allergenic risk. Understanding these reactions is vital for the prevention of severe allergic reactions, especially in individuals with pre-existing Jumper Jack ant allergy, informing future management strategies.

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.

Differences in the Course, Diagnosis, and Treatment of Food Allergies Depending on Age-Comparison of Children and Adults

Food allergy (FA) has become a common global public health issue, with a growing prevalence in the modern world and a significant impact on the lives of patients, their families, and caregivers. It affects every area of life and is associated with elevated costs. Food allergy is an adverse immune reaction that occurs in response to a given food. The symptoms vary from mild to severe and can lead to anaphylaxis. This is why it is important to focus on the factors influencing the occurrence of food allergies, specific diagnostic methods, effective therapies, and especially prevention. Recently, many guidelines have emphasized the impact of introducing specific foods into a child's diet at an early age in order to prevent food allergies. Childhood allergies vary with age. In infants, the most common allergy is to cow's milk. Later in life, peanut allergy is more frequently diagnosed. Numerous common childhood allergies can be outgrown by adulthood. Adults can also develop new IgE-mediated FA. The gold standard for diagnosis is the oral provocation test. Skin prick tests, specific IgE measurements, and component-resolved diagnostic techniques are helpful in the diagnosis. Multiple different approaches are being tried as possible treatments, such as immunotherapy or monoclonal antibodies. This article focuses on the prevention and quality of life of allergic patients. This article aims to systematize the latest knowledge and highlight the differences between food allergies in pediatric and adult populations.

Precision engineering for localization, validation, and modification of allergenic epitopes

The allergen-IgE interaction is essential for the genesis of allergic responses, yet investigation of the molecular basis of these interactions is in its infancy. Precision engineering has unveiled the molecular features of allergen-antibody interactions at the atomic level. High-resolution technologies, including x-ray crystallography, nuclear magnetic resonance spectroscopy, and cryo-electron microscopy, determine allergen-antibody structures. X-ray crystallography of an allergen-antibody complex localizes in detail amino acid residues and interactions that define the epitope-paratope interface. Multiple structures involving murine IgG mAbs have recently been resolved. The number of amino acids forming the epitope broadly correlates with the epitope area. The production of human IgE mAbs from B cells of allergic subjects is an exciting recent development that has for the first time enabled an actual IgE epitope to be defined. The biologic activity of defined IgE epitopes can be validated in vivo in animal models or by measuring mediator release from engineered basophilic cell lines. Finally, gene-editing approaches using the Clustered Regularly Interspaced Short Palindromic Repeats technology to either remove allergen genes or make targeted epitope engineering at the source are on the horizon. This review presents an overview of the identification and validation of allergenic epitopes by precision engineering.

Sensitization profiles to house dust mite Dermatophagoides pteronyssinus molecular allergens in the Lithuanian population: Understanding allergic sensitization patterns

BACKGROUND

House dust mite (HDM) allergy is a prevalent global health concern, with varying sensitization profiles observed across populations. We aimed to provide a comprehensive assessment of molecular allergen sensitization patterns in the Lithuanian population, with a focus on Dermatophagoides pteronyssinus (Der p), and investigate patterns of concomitant reactivity among different allergens to enhance the accuracy of HDM allergy diagnostics.

METHODS

A comprehensive analysis of 1520 patient test results in Lithuania from 2020 to 2022 was performed. Sensitization patterns to major (Der p 1, Der p 2, and Der p 23) and minor (Der p 5, Der p 7, and Der p 21) Der p allergen components were described using molecular-based diagnostics. Additionally, we investigated sensitization to allergen components from other allergen sources, including tropomyosins (Der p 10, Per a 7, Pen m 1, Ani s 3, Blo t 10) and arginine kinases (Pen m 2, Bla g 9, Der p 20).

RESULTS

This study reveals a high prevalence of HDM sensitization in Lithuania - 481 individuals (45.38% of the sensitized group) exhibited sensitization to at least one Der p allergen component. Importantly, within the sensitized group, 37.21% of patients were sensitized to Der p 5, Der p 7, or Der p 21 in addition to major allergenic components. Distinct sensitization patterns were observed across different age groups, indicating the influence of age-related factors. Furthermore, we confirmed cross-reactivity between Der p 5 and Blo t 5 as well as between Der p 21 and Blo t 21, emphasizing the clinical relevance of these associations. We also highlighted the complexity of sensitization patterns among tropomyosins and arginine kinases.

CONCLUSION

This study provides valuable insights into HDM allergy sensitization profiles in Lithuania, emphasizing the importance of considering major and minor HDM allergen components for accurate diagnosis and management of HDM-related allergic diseases. Differences between populations and age-related factors impact sensitization patterns. Understanding concomitant reactivity among allergens, such as Der p 5 and Blo t 5, Der p 21 and Blo t 21, tropomyosins, and arginine kinases, is crucial for improving diagnostic strategies and developing targeted interventions for allergic individuals.

Peanut Allergy and Component-Resolved Diagnostics Possibilities-What Are the Benefits?

Peanut allergy is a widespread and potentially life-threatening condition that affects both children and adults, with a growing incidence worldwide. It is estimated to affect around 1-2% of the population in several developed countries. Component-resolved diagnostics is a modern approach to allergy diagnosis that focuses on identifying specific allergenic proteins to provide precise diagnoses and personalized treatment plans. It is a technique that enables the analysis of specific IgE antibodies against tightly defined molecules (components) that constitute the allergen. Component-resolved diagnostics is particularly valuable in peanut allergy diagnosis, helping to determine allergen components associated with severe reactions. It also aids in predicting the course of the allergy and enables the development of personalized immunotherapy plans; however, the full application of it for these purposes still requires more precise studies. In this paper, we present the current knowledge about peanut allergy and component-resolved diagnostics possibilities. We discuss the possibilities of using molecular diagnostics in the diagnosis of peanut allergy. We focus on examining and predicting the development of peanut allergy, including the risk of anaphylaxis, and describe the latest data related to desensitization to peanuts.