Allergenicity and allergens of amphipods found in nori (dried laver).

Gammaridean and caprellid amphipods, crustaceans of the order Amphipoda, inhabit laver culture platforms and, hence, are occasionally found in nori (dried laver) sheets. Amphipods mixed in nori may cause allergic reactions in sensitized patients, as is the case with other crustaceans, such as shrimp and crab, members of the order Decapoda. In this study, dried samples of amphipods (unidentified) found in nori and fresh samples of gammaridean amphipod (Gammarus sp., not accurately identified) and caprellid amphipod (Caprella equilibra) were examined for allergenicity and allergens using two species of decapods (black tiger prawn and spiny lobster) as references. When analyzed by ELISA, sera from crustacean-allergic patients reacted to extracts from amphipod samples, although less potently than to the extracts from decapods. In IgE-immunoblotting, a 37-kDa protein was found to be the major allergen in amphipods. Based on the molecular mass and the cross-reactivity with decapod tropomyosin evidenced by inhibition ELISA and inhibition immunoblotting, the 37-kDa protein was identified as amphipod tropomyosin.