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

<i>Haliotis discus hannai</i> tropomyosin (HTM), <i>Alectryonella plicatula</i> tropomyosin (ATM), and <i>Mimachlamys nobilis</i> 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.