Tropomyosin

In several molluscs, an important structural protein of the musculature, which plays an important role as an allergenic substance, has been characterised: tropomyosin is involved in muscle contraction together with troponin. Allergenic tropomyosin is found in crustaceans, house dust mites, cockroaches and other insects. Tropomyosins characterized in molluscs and various crustaceans show similarities in their allergen structures. Allergenic fish tropomyosins do not play a big role and have so far only been found in one single fish species (Mozambique cichlid). The following allergens have been identified as tropomyosins:

• Cra g1: Oysters
• Hal m1: Abalone
• Death p1: squid.

There is a cross-reactivity of the tropomyosins with each other. In case of allergy to molluscs, all mollusc species should be avoided. Furthermore, cross-reactions to the similar tropomyosins of crustaceans may occur ( mite crustacean mollusc syndrome).

1. Leung et al (1998) Molecular identification of the lobster muscle protein tropomyosin as a seafood allergen. Mol Mar Biol Biotechnol 7: 12-20
2. Nakano et al (2008) Reactivity of shrimp allergy-related IgE antibodies to krill tropomyosin. Int Arch Allergy Immunol 175-181
3. Zhang et al (2006): Cross-reactivity among shrimp, crab and scallops in a patient with a seafood allergy. J Dermatol 33: 174-177