Molecular characterization and comparison of four Anisakis allergens between Anisakis simplex sensu stricto and Anisakis pegreffii from Japan

- Epitopes and motif are conserved in both A. simplex s.s. and A. pegreffii in Ani s 1, 2 and 9.
- Two Anisakis sibling species revealed amino acid variable sites in Ani s 1, 2 and 12 allergens.
- Both intra- and inter-species variations were present in the same amino acid positions.
- No amino acid variations were detected in clearly distinguishing A. simplex s.s. from A. pegreffii.
- Similarities on allergen's amino acid sequences indicate possible similar health risks to humans.

It remains unclear whether allergens are the same among the sibling species of Anisakis simplex sensu lato. This study was carried out to compare the amino acid sequences of three major (Ani s 1, 2 and 12) and one minor (Ani s 9) Anisakis allergens between A. simplex s.s. and Anisakis pegreffii. We found 2 (out of 163), 1 (out of 869), and 29 (out of 266) amino acid variable sites for Ani s 1, 2, and 12, respectively. However, as both intra- and inter-species variations were present at the same amino acid positions, no amino acid variations clearly distinguished the two sibling species. IgE-binding epitopes (Ani s 1) and a binding motif of human leukocyte antigen (Ani s 2 and 9) demonstrated by previous studies were conserved. The similarities of the amino acid sequences of the allergens indicate possible similar allergy-associated health risks in humans infected with or accidentally ingesting either Anisakis species.

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