Muscle Transcriptome Provides Insights into the Allergen Profile of Habitat-specific Mature Hilsa shad (Tenualosa ilisha)

Background: Hilsa shad (Tenualosa ilisha) is a popular anadromous fish in Bangladesh known to cause allergies. Despite recognized allergenicity, there is a paucity of research at the molecular level on hilsa allergen. Methods: Muscle transcriptomes of hilsa from freshwater, brackish, and deep sea habitats were sequenced using Illumina NovaSeq 6000 and assembled. BLASTx analysis of the Allergen Online database identified potential allergens. The molecular docking study investigated parvalbumin's interaction with human IgE. Results: An analysis of hilsa muscle transcriptomes revealed 28 known fish allergens, including parvalbumin, tropomyosin, including parvalbumin, tropomyosin, filamin C, creatine kinase-2, aldolase A, triosephosphate isomerase B, and Glyceraldehyde-3-phosphate Dehydrogenase (G3PD). Creatine kinase showed significantly higher abundance (p < 0.05) and habitat variation (freshwater vs. brackish water). In silico analysis suggested upregulation of Sal s 2 enolase and Equ c 6 lysozyme in freshwater and brackish water compared to the deep sea. Docking studies identified a potential B-cell epitope in parvalbumin that interacts with human IgE. Conclusion: This study has unveiled 28 potential allergens in hilsa, including habitat-specific variations. The parvalbumin-IgE interaction has been suggested as a mechanism for allergies. The findings have illuminated fish allergy in Bangladesh and paved the way for further investigation.