Computational analysis of specific IgE epitopes responsible for allergy to fish

Authors: MOHSEN, MOHAMADI - University Medical Center Utrecht; FALAK, REZA - University Medical Center Utrecht; EMAMEH, REZA - University Medical Center Utrecht; Maleki, Soheila; KARDAR, GHOLAM ALI - University Medical Center Utrecht

Submitted to: Critical Reviews in Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/6/2018
Publication Date: 8/1/2018
Citation: Mohsen, M., Falak, R., Emameh, R.Z., Maleki, S.J., Kardar, G. 2018. Computational analysis of specific IgE epitopes responsible for allergy to fish. Critical Reviews in Immunology. 14(2):130-136.

Interpretive Summary: Fish is one of the most common causes of IgE-mediated food allergic reactions and is responsible for approximately 0.4% of food allergic reactions in US population. A high percentage of fish-mediated anaphylaxis is reported by emergency departments in various countries. Up to now several allergens have been identified and characterized form different fish species, parvalbumin was identified as a major allergen. Parvalbumin is a glycoprotein that belongs to calcium binding family of EF-hand superfamily of proteins. Parvalbumin has a highly conserved amino acid sequence and shows high percentage of identity among different fish species, making this protein the most common cause of cross reactivity in fish allergy. Although most fish allergic patients are sensitive to various species of fish, it was shown that some patients are only sensitive to certain species of it. Sensitization to a single fish (monosensitivity) was demonstrated for salmonid fish including salmo salar and trout and it was demonstrated that those patients were sensitized only to the beta-1 isoform of parvalbumin. In addition to parvalbumin, several other proteins including gelatin, aldolase and enolase were identified as minor allergens of fish. The growth of knowledge about the molecular and allergic properties of fish allergens can improve accurate diagnosis of fish allergy and its management in the future.

Technical Abstract: Fish is one of the most common causes of IgE-mediated adverse reactions to food. Several allergens have been identified and characterized from different fish species, parvalbumin, as a highly conserved protein, is the most common causative agent of fish-borne allergies. Although most fish-allergic patients are sensitive to various species, some patients only show hypersensitivity to certain species such as salmonids. In this study, we computationally identified and mapped mono-sensitivity-causing epitopes of salmonid fish and their cross-reactive epitopes using in silico methods. Amino acid sequences of parvalbumins were retrieved from NCBI, and following alignment, the phylogenic tree was drawn and potential epitopes were determined and theirphysicochemical properties analyzed. We found that fish-allergic patients are mostly sensitized to beta-1 isoform of parvalbumin and its epitope C region (65-109) in salmonids is probably the causative agent of monosensitivity, while in beta-2 isoforms it may justify cross-reactivity of parvalbumins. Surely, any progresses in biochemical, immunological, and molecular mechanism of allergic reactions to fish allergens can improve accurate diagnosis of fish allergy and its' prevention and treatment in the future.