IgE Epitope Mapping of Cross-Reactive Tropomyosin between Shrimp and Edible Cricket ( Gryllus bimaculatus )

Tropomyosin is a pan-allergen in crustaceans known to cross-react with homologous proteins from edible insects. However, epitope-level cross-reactivity in edible insects remains poorly defined. This study aimed to identify IgE-binding epitopes of tropomyosin and to evaluate their cross-reactivity between shrimp and the edible two-spotted cricket. Here, sera from shrimp-allergic patients were screened for IgE-binding to proteins from Pacific white shrimp (Penaeus vannamei) and two-spotted cricket (Gryllus bimaculatus). Candidate tropomyosin epitopes from the two-spotted cricket were predicted. The cross-reactivity of tropomyosin was assessed using an inhibition dot blot assay, inhibition ELISA, and LAD2 cell degranulation assay. Approximately 40% of shrimp-allergic patients showed IgE reactivity to crude proteins from shrimp and the two-spotted cricket. Four identified peptide epitopes induced β-hexosaminidase release from LAD2 cells. These findings provide insights into the molecular basis of tropomyosin cross-reactivity essential for the development of biomarker-based tools for allergen risk assessment in the food industry.