Scientists Map the Five Proteins Behind Pacific Abalone Allergy

For millions of people who develop itching, swelling, or even life-threatening anaphylaxis after eating shellfish, the Pacific abalone, Haliotis discus hannai, has long been a molecular black box. This high-value sea snail, farmed intensively along the coasts of China and East Asia, is a staple of the seafood trade, yet the specific proteins that trigger its allergic reactions were poorly characterized. A new study published in npj Science of Food has now delivered the first comprehensive allergen landscape of the species, combining genome assembly, transcriptomics, quantitative proteomics, and serological testing to pinpoint five immunodominant allergens that dominate the human immune response to this mollusk.

The research team, led by scientists at Fujian Medical University, Xiamen Ocean Vocational College, Jimei University, and The Chinese University of Hong Kong, faced a fundamental challenge: without a well-annotated genome and proteome, it is nearly impossible to know which of the thousands of proteins in abalone flesh are actually present, abundant, and capable of binding IgE antibodies from allergic patients. To solve this, the researchers built a high-quality genome-transcriptome assembly that predicted 53,245 protein-coding genes, then used proteomic sequencing to confirm 3,916 reliably expressed proteins in the edible tissue. This integrated multi-omics approach ensured that the allergen search was grounded in proteins that are genuinely produced by the animal, not merely predicted from DNA sequence alone.

Cross-referencing this expressed protein repertoire with authoritative allergen databases, including the WHO/IUIS Allergen Nomenclature database, AllergenOnline, and UniProt, the team identified 37 high-abundance allergens in the Pacific abalone. Sequence homology analysis revealed that many of these proteins share close evolutionary relatives across mollusks and crustaceans, a finding that helps explain why patients allergic to shrimp or crab often react to abalone as well. The shared allergen families, such as tropomyosin and arginine kinase, are conserved across distantly related shellfish groups, creating a molecular bridge between molluscan and crustacean allergy that clinicians have long suspected but rarely been able to trace at this level of detail.

To determine which of these 37 candidate allergens actually dominate the human immune response, the researchers turned to serological profiling. They collected 90 serum samples from abalone-allergic patients and performed dot-blot and Western-blot assays to detect IgE reactivity. The results were striking: the sera resolved six IgE-reactive bands, corresponding to one polymer and five distinct allergens. These five proteins were paramyosin, arginine kinase, tropomyosin, triosephosphate isomerase, and fructose-bisphosphate aldolase. Each of the five exhibited high seropositivity across the patient cohort, confirming their immunodominance in abalone allergy and narrowing the field from dozens of candidates to a handful of molecular culprits.

Paramyosin, one of the five identified allergens, is a large structural protein found in invertebrate muscle, where it sits alongside myosin in the thick filaments that power contraction. Its abundance in abalone flesh makes it a prime target for IgE antibodies, and its role as a major allergen has been documented in other mollusks, including oysters and mussels. Arginine kinase, by contrast, is an energy-transfer enzyme that regenerates ATP in invertebrate muscle, playing a role analogous to creatine kinase in vertebrates. It is a well-known allergen in shrimp and crab, and its detection in abalone reinforces the cross-reactivity pattern between mollusks and crustaceans.

Tropomyosin, perhaps the most notorious shellfish allergen, is a thin-filament regulatory protein that is recognized as a major allergen in virtually every crustacean and many mollusks studied to date. Its presence as an immunodominant allergen in Pacific abalone was expected, but the study confirmed its high seropositivity in this species for the first time. Triosephosphate isomerase and fructose-bisphosphate aldolase, both glycolytic enzymes, are less commonly cited as major allergens, but their identification here suggests that metabolic enzymes in general may deserve more attention in shellfish allergy research than they have traditionally received.

Beyond simply naming the allergens, the team probed their structural properties to understand how they interact with the immune system. Denaturant treatments suggested that paramyosin and tropomyosin are likely primarily linear allergens, meaning their IgE-binding sites are exposed along the protein chain and remain accessible even when the protein is unfolded. Arginine kinase, in contrast, appears to be predominantly conformational, with its IgE epitopes dependent on the intact three-dimensional fold of the protein. This distinction accounted for the higher detection rate of arginine kinase in dot-blot assays, which preserve native structure, compared with Western-blot, which denatures proteins before separation.

Structural modeling and B-cell epitope predictions added further molecular detail. Paramyosin and tropomyosin possess simple alpha-helix-dominated structures harboring mainly linear epitopes, consistent with their classification as primarily linear allergens. Arginine kinase, triosephosphate isomerase, and fructose-bisphosphate aldolase exhibit more complex three-dimensional folds with additional conformational epitopes, meaning their IgE-binding sites depend on the precise spatial arrangement of amino acids rather than a simple linear sequence. This structural dichotomy has practical implications for food processing, since linear allergens tend to survive cooking and digestion more readily, while conformational allergens may be partially inactivated by heat treatment that disrupts their folded state.

The identification of these five immunodominant allergens provides a molecular basis for precise diagnostics in abalone allergy. Rather than testing patients against a crude extract of abalone flesh, which contains thousands of proteins and can produce ambiguous results, clinicians could in principle develop component-resolved diagnostic tests targeting paramyosin, arginine kinase, tropomyosin, triosephosphate isomerase, and fructose-bisphosphate aldolase individually. Such tests would allow allergists to determine which specific proteins a patient reacts to, refining risk assessment for cross-reactivity with other shellfish and guiding decisions about dietary avoidance.

The study also highlights the power of integrated multi-omics strategies for allergen discovery in understudied food species. By combining genome-guided proteogenomics with quantitative proteomics and serological validation, the researchers moved from a predicted gene catalog of 53,245 proteins to a validated set of five immunodominant allergens in a single workflow. As global seafood consumption rises and mollusk farming expands, this framework offers a template for systematically mapping allergens in other high-abundance food proteins, potentially transforming how food safety regulators and allergists approach the growing burden of shellfish allergy worldwide.

Subject of Research: Immunology

Article Title: Integrated multi-omics and serological profiling identifies five immunodominant allergens from the high-abundance protein repertoire of Haliotis discus hannai

Article References: Zhi, S., Han, X.-Y., Chen, T.-B., Que, J.-H., Xiao, Q., Yang, S.-Y., Xie, Y.-N., Tsui, S. K.-W., Liu, G.-M., & Rao, S.-T. (2026). Integrated multi-omics and serological profiling identifies five immunodominant allergens from the high-abundance protein repertoire of Haliotis discus hannai. npj Science of Food. https://doi.org/10.1038/s41538-026-01181-z

Image Credits: AI Generated

DOI: 10.1038/s41538-026-01181-z

Keywords: abalone, food allergy, allergens, IgE, tropomyosin, paramyosin, arginine kinase, multi-omics, proteomics, shellfish cross-reactivity, Integrated, serological