TheAnisakis simplexAni s 7 major allergen as an indicator of trueAnisakisinfections

Abstract

SummaryAni s 7 is currently the most important excretory/secretory (ES) Anisakis simplex allergen, as it is the only one recognized by 100% of infected patients. The allergenicity of this molecule is due mainly to the presence of a novel CX17-25CX9-22CX8CX6 tandem repeat motif not seen in any previously reported protein. In this study we used this allergen as a model to investigate how ES allergens are recognized during Anisakis infections, and the usefulness of a recombinant fragment of Ani s 7 allergen (t-Ani s 7) as a marker of true Anisakis infections. The possible antigenic relationship between native Ani s 7 (nAni s 7) from Anisakis and Pseudoterranova decipens antigens was also investigated. Our results demonstrate that nAni s 7 is secreted and recognized by the immune system of rats only when the larvae are alive (i.e. during the acute phase of infection), and that this molecule is not present in, or is antigenically different from, Pseudoterranova allergens. The t-Ani s 7 polypeptide is a useful target for differentiating immunoglobulin E antibodies induced by true Anisakis infections from those induced by other antigens that may crossreact with Anisakis allergens, including P. decipiens. The results also support the hypothesis that the Ani s 7 major allergen does not participate in maintaining the antigenic stimulus during chronic infections.

Cross-sectional study of serum reactivity to Anisakis simplex in healthy adults in Niterói, Brazil

“…Excretory/secretory antigens are secreted by the parasite to help penetrate the gut mucosa and are probably the antigens involved in stimulation of the host immune system during active infection (Valls et al 2005). In an experimental study, Anadón et al demonstrated that anti-Ani s 7 IgE antibodies induced by live Anisakis larvae peaked on day 30 postinfection, decreasing over the course of two months (Anadon et al 2009), and that their presence could constitute a possible recent infection (Anadon et al 2010). In the present study, 7.46% (5/67) of volunteers were seroreactive to excretory/secretory antigens.…”

Diagnosing Human Anisakiasis: Recombinant Ani s 1 and Ani s 7 Allergens versus the UniCAP 100 Fluorescence Enzyme Immunoassay

“…Interestingly, the major Anisakis allergen recognized by MAb UA3 (Ani s 7) was recently characterized (31), and an internal portion of its sequence (t-Ani s 7) was cloned and expressed in Escherichia coli. Previous results obtained with this allergen as a target in indirect ELISA showed it to be highly specific (3), with a similar sensitivity to that obtained with UA3-capture ELISA (31). However, the t-Ani s 7 ELISA has not yet been tested under field conditions.…”

<b><i>Anisakis</i></b> Allergy Component-Resolved Diagnosis: Clinical and Immunologic Differences between Patients from Italy and Spain

“…The panel of allergens studied here was calibrated on the Spanish population, which might explain why Italian patients frequently showed IgE to ‘other' allergens. It has to be kept in mind that our panel lacked Ani s 7, a major allergen and a marker of Anisakis infection [19]. …”