Ani s 11-Like Protein Is a Pepsin- and Heat-Resistant Major Allergen of Anisakis spp. and a Valuable Tool for Anisakis Allergy Component-Resolved Diagnosis.

Background: Anisakis simplex is a fish parasite responsible for gastrointestinal and allergic symptoms in humans. The Ani s 11-like protein has been proposed as an Anisakis allergen because its primary structure is similar to that of Ani s 11. The aims of this work were to analyse the frequency of detection of the Ani s 11-like protein and assess its diagnostic value.

Methods: rAni s 11-like protein, rAni s 5 and rAni s 4 were expressed in Escherichia coli and rAni s 1 was produced in Pichia pastoris. Recombinant allergen detection patterns in 37 Anisakis-sensitised patients were determined. The stability to pepsin digestion and heat treatment of rAni s 11-like protein was also analysed by IgE immunoblotting.

Results: Ani s 11-like protein is a major allergen detected by 78% of Anisakis-allergic patients, and 13.5% of patients detect only the rAni s 11-like allergen. This allergen is heat stable because it retains its capability of binding IgE after boiling for 30 min and it is resistant to pepsin digestion for 120 min.

Conclusions: These data indicate that the Ani s 11-like protein is a pepsin- and heat-resistant major allergen (Ani s 11.0201) of Anisakis spp. and a valuable tool for Anisakis allergy component-resolved diagnosis.