Isolation of a heat-resistant allergen from the fish parasite Anisakis simplex

Abstract

The thermal stability of allergenic peptides from the fish parasite Anisakis simplex has not been fully elucidated. This is of special relevance for physicians who should clearly indicate if sensitized patients should avoid ingestion of raw fish only or whether well-cooked fish should also be avoided, if allergenic peptides derived from the parasite remain immunologically detectable. An allergen was purified after heating a crude parasite extract for 30 min. The allergen was further purified by an ethanol fractionation procedure followed by a reversed-phase HPLC. The N-terminal amino acid sequence was obtained. This allergen was detected by 27% of sensitized subjects. The N-terminal amino acid sequence of the 9 kDa allergen showed no similarities to other known proteins. A minor low molecular weight allergen from A. simplex is highly resistant to heating and it could therefore have significant clinical relevance.

Anisakis pegreffii-Induced Airway Hyperresponsiveness Is Mediated by Gamma Interferon in the Absence of Interleukin-4 Receptor Alpha Responsiveness

“…Both live and heat-killed Anisakis larvae induced specific IgE in wild-type mice. This outcome suggests the presence of heat-stable somatic allergens and confirms evidence that cooking of contaminated fish may not be sufficient to prevent allergic reactions to Anisakis (10,35). Furthermore, our additional finding that intranasal sensitization/challenge with an Anisakis extract induced allergic airway inflammation and AHR in the absence of a detectable antibody response may have consequences for the diagnosis of Anisakis allergies, which currently relies on the detection of specific IgE antibodies (29).…”

Anisakis simplex: from Obscure Infectious Worm to Inducer of Immune Hypersensitivity

“…It was noted in the original work that led to the wide recognition of A. simplex allergy that cooking and freezing cannot be relied upon to destroy allergenicity and protect against hypersensitivity reactions to parasite material contaminating ingested fish (24,(27)(28)(29)100). Recently, thermostable allergens have been detected in A. simplex extracts (reviewed in the previous section), and this recalls the controversy about the safety of human consumption of these parasites in cooked fish (48,188). In an experimental situation, it has been found that crude Ascaris materials remain allergenically active even after autoclaving, which would raise the temperature of a sample to well beyond that routinely encountered in cooking (54,144).…”

A quantitative sandwich ELISA for the detection of Anisakis simplex protein in seafood

“…Ani s 1 is a secretory protein of 21 kDa and the only major allergen described with no described function or homology to date [37,38]. Two allergens, Ani s 4 (9 kDa) and Ani s 6 (7 kDa) [13], are both protease inhibitors [14,39]. Ani s 5 (15 kDa) [13], Ani s 8 (15 kDa) [40], and Ani s 9 (15 kDa) [41] are all proteins in the SXP/RAL-2 family, whose function is still unclear.…”

“…In some cases, both may apply when the larvae has penetrated the tissue, is killed by the host, and subsequently degenerates inside the host [11]. Several of the identified A. simplex allergens seem to retain their allergenic potential even after freezing and/or heating [12][13][14] and appear to be pepsin resistant [15]. In a study on the progression of allergens in the food chain, it was suggested that Anisakis-allergic consumers were affected by the intake of meat from chicken that had been fed with a high proportion of Anisakis-containing fishmeal [16].…”