Identification and allergenic characterisation of a new isoform of the A. simplex allergen Ani s 4

Anisakis simplex hypersensitivity is a growing disease in developed countries. A positive diagnosis usually leads to the dietary recommendation of avoiding fish and seafood consumption. The protein Ani s 4 is a clinically relevant allergen due to its heat and pepsin resistant properties and its importance in the anaphylaxis process. The attempt of cloning Ani s 4 has led to the identification and characterisation of a new isoform that differs only in one amino acid with the previously published. This isoform was produced as an His tagged recombinant protein and its allergenic properties were tested by IgE immunoblot and by a flow cytometry basophil activation test. The results were compared to the allergenic properties of the isoform previously described. Both isoforms of Ani s 4 showed different capacities to bind IgE from sensitised patients and different potencies in the basophil activation test.