Identification and characterization of allergens in two species of tuna fish

Background: In countries where fish consumption is high, allergenic reactio ns to fish are common among patients diagnosed with food hypersensitivity. For tuna fish, allergenic proteins are not known. In addition, it is not kn own how the tuna fish extracts should be processed to obtain optimal in vit ro diagnostic performance and to preserve labile antigens. Objective: The aim of this study was to characterize IgE-binding components of Yellowfin and Albacore tuna fish. Methods: Various tuna fish extract preparations were fractionated by sodium dodecylsulfate-polyacrylamide gel electrophoresis and transferred to nitro cellulose and analyzed by using tuna positive patients with different Weste rn blot profiles. The functional activity of the extracts was evaluated by basophil histamine release. Results: Immunoblot analysis showed the majority of patients responding to Yellowfin tuna extract. Inhibition studies using immunoblot analysis and hi stamine release testing showed a specific protein with a molecular weight o f similar to 46 kD that is present in Yellowfin tuna, but absent in Albacor e. Only defatted, lyophilized tuna fish extracts were able to induce histam ine release from sensitized basophils although IgE-binding components were detected in fresh raw, fresh cooked, and canned tuna fish preparations. Conclusion: These studies indicate that patient sera may contain different tuna fish species IgE specific antibodies directed against unique species s pecific allergens present in Yellowfin and Albacore tuna fish. Possibly, ex tracts should contain specific allergenic components from both Albacore and Yellowfin to cover the epitope heterogeneity observed in sera from patient s developing IgE antibodies against tuna fish.