Short communicationElucidation of IgE-binding epitopes of Ani s 1: The major Anisakis simplex allergen

Ani s 1, the major allergen of Anisakis simplex, is expected to be a useful antigen in allergen-specific immunotherapy of Anisakis allergy. To avoid side-effects such as anaphylactic shock in immunotherapy, it is desirable to use not native allergens but hypoallergenic mutants devoid of IgE-binding epitopes. This study was hence aimed to elucidate IgE-binding epitopes of Ani s 1 toward the development of hypoallergenic Ani s 1 mutants. Mapping experiments using 32 peptides (P1-32) revealed that major IgE-binding epitopes are included in P24 (region 116-130) and P28 (region 136-150). Furthermore, Ala-scanning and truncation experiments established that eight (underlined in the sequence 116-ELFAREYEGVCKSGK-130) and nine amino acid residues (underlined in the sequence 136-RGSGWMMTILGKSCD-150) are crucial for the IgE-binding of P24 and P28, respectively. The determined crucial residues of P24 and P28 were assumed to be involved in electrostatic and hydrophobic interactions with IgE, respectively.

Graphical abstract. Ani s 1 has two IgE-binding regions (116-130 and 136-150), in which some residues are critical for IgE-binding through electrostatic or hydrophobic interaction.Download high-res image (142KB)Download full-size imageResearch highlights▶ Ani s 1 has two IgE-binding regions (116-130 and 136-150). ▶ Eight residues in 116-130 are critical for the electrostatic binding with IgE. ▶ Nine residues in 136-150 are critical for the hydrophobic binding with IgE.