Antigenicity of Anisakis simplex s.s. L3 in parasitized fish after heating conditions used in the canning processing.

BACKGROUND: Some technological and food processing treatments applied to parasitized fish kill the Anisakis larvae and prevent infection and sensitization of consumers. However, residual allergenic activity of parasite allergens has been shown. The aim here was to study the effect of different heat treatments used in the fish canning processing industry on the antigen recognition of Anisakis L3. Bigeye tuna (Thunnus obesus) and yellowfin tuna (Thunnus albacares) were experimentally infected with live L3 Anisakis. After 48 h at 5 ± 1 °C, brine was added to the muscle, which was then canned raw (live larvae) or heated (90 °C, 30 min) (dead larvae) and treated at 113 °C for 60 min or at 115 °C for 90 min. Anisakis antigens and Ani s 4 were detected with anti-crude extract and anti-Ani s 4 antisera respectively. RESULTS: Ani s 4 decreased in all lots, but the muscle retained part of the allergenicity irrespective of the canning method, as observed by immunohistochemistry. Dot blot analysis showed a high loss of Ani s 4 recognition after canning, but residual antigenicity was present. CONCLUSION: The results indicate that heat treatment for sterilization under the conditions studied produces a decrease in Ani s 4 and suggest a potential exposure risk for Anisakis-sensitized patients.

IgE sensitization to Thaumetopoea pityocampa : diagnostic utility of a setae extract, clinical picture and associated risk factors.

BACKGROUND: Setae from Thaumetopoea pityocampa larvae (the pine processionary moth or PPM) can induce hypersensitivity reactions, but their clinical role in IgE-mediated responses is still subject to discussion. The aim of this study was to evaluate a setae extract for in vivo and in vitro diagnosis in nonhospitalized patients with reactions to PPM. METHODS: Forty-eight adult patients presenting with PPM cutaneous reactions were studied by skin prick test (SPT) and specific IgE using setae and whole larval (WL) extracts. Biological standardized extracts were used for skin tests. RESULTS: A total of 47.9% patients had a positive SPT for PPM (70% to both extracts, 17% only to the WL extract and 13% only to the setae extract). IgE immunoblotting detected several reactive bands in 91% of the SPT-positive cases. In multivariate analysis, male sex, immediate latency (<1 h) and duration of skin symptoms (<24 h) were independent predictors of a positive SPT. CONCLUSIONS: IgE sensitization to PPM was found in 48% of the study patients, which was associated with immediate reactions and evanescent cutaneous lesions. Most of these patients reacted to both WL and setae extracts, but some reacted to only one of them. According to our data, skin and in vitro tests to PPM should be performed using both extracts.

Setae from the pine processionary moth (Thaumetopoea pityocampa) contain several relevant allergens.

BACKGROUND: Pine processionary larvae produce urticating hairs (setae) that serve for protection against predators. Setae induce cutaneous reactions in animals and humans. The presence of toxic or allergic mechanisms is a matter of debate. OBJECTIVES: To detect the presence of allergens in setae and to characterize them. MATERIALS AND METHODS: Setae extracts were characterized by gel staining and immunoblot, with sera from patients with immediate reactions and positive prick test reactions, as well as a rabbit antiserum raised against setae. Setae proteins were fractionated by high-performance liquid chromatography. The most relevant allergen was analysed by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS), and its sequence was deduced from an expressed sequence tag bank. Results. Setae contained at least seven different allergens. The most intense detection corresponded to a protein of MW ~ 14,000 that was similar to thaumetopoein, a previously described protein with mast cell-degranulating properties. MALDI-MS-based de novo sequencing provided a partial amino acid sequence different from that of the previously described allergen Tha p 1, and it was named Tha p 2. This allergen was detected in 61% of patients, and it is therefore a new major caterpillar allergen. CONCLUSIONS: Penetration of the setae from the pine processionary caterpillar delivers their allergenic content in addition to causing mechanical or toxic injury.

Quantification of Anisakis simplex allergens in fresh, long-term frozen, and cooked fish muscle.

Fish-borne parasitic zoonoses such as Anisakiasis were once limited to people living in countries where raw or undercooked fish is traditionally consumed. Nowadays, several factors, such as the growing international markets, the improved transportation systems, the population movements, and the expansion of ethnic ways of cooking in developed countries, have increased the population exposed to these parasites. Improved diagnosis technology and a better knowledge of the symptoms by clinicians have increased the Anisakiasis cases worldwide. Dietary recommendations to Anisakis-sensitized patients include the consumption of frozen or well-cooked fish, but these probably do not defend sensitized patients from allergen exposure. The aim of our work was to develop a sensitive and specific method to detect and quantify Anisakis simplex allergens in fish muscle and its derivatives. Protein extraction was made in saline buffer followed by preparation under acid conditions. A. simplex antigens were detected by IgG immunoblot and quantified by dot blot. The allergenic properties of the extracts were assessed by IgE immunoblotting and basophil activation test. We were able to detect less than 1 ppm of A. simplex antigens, among them the allergen Ani s 4, in fish muscle with no cross-reactions and with a recovery rate of 82.5%. A. simplex antigens were detected in hakes and anchovies but not in sardines, red mullets, or shellfish. We detected A. simplex allergens in cooked hakes and also in hake stock. We proved that A. simplex allergens are preserved in long-term frozen storage (-20 degrees C +/- 2 degrees C for 11 months) of parasitized hakes. Basophil activation tests have proven the capability of the A. simplex-positive fish extracts to induce allergic symptoms.