Immunological characteristics of monoclonal antibodies against shellfish major allergen tropomyosin

Two types of murine monoclonal antibodies (MAbs) against American lobster (Homarus americanus) were generated and characterized. Three purified MAbs were characterized to be specific to the shellfish major allergen tropomyosin. MAbs 5G5E1 and 1A3A7 were reactive to tropomyosin from crustacean species only, whereas MAb 2A7H6 was reactive to both crustacean and mollusk tropomyosins. None of the antibodies reacted to vertebrate tropomyosins. Competitive ELISA indicated that the antigenic epitopes recognized by the two types of MAbs were different from each other. In addition, competitive immunoblot results showed that the binding of shellfish-allergic patient IgEs to lobster tropomyosin was inhibited by the MAb 2A7H6 only. This finding suggests that the antigenic epitope for the 2A7H6 antibody might be similar or close to the allergenic epitope shared by crustaceans and mollusks. Consequently, the MAbs recognizing the different common antigenic epiotopes obtained in the present study would not only facilitate the allergen characterization of shellfish, but may also be useful for the development of specific and sensitive immunoassays for allergen quantification or epitope mapping.