Familial atrial fibrillation

Anaphylaxis due to hypersensitivity to Anisakis simplex

Anaphylactic reactions are among the most frequent causes for requests for emergency medical care. It is possible that no clear precipitating factor can be found delaying the onset of adequate treatment and increasing the risk of new episodes of anaphylaxis in the future. Hypersensitivity to Anisakis simplex, an intestinal parasite found in fish, is an unusual cause of anaphylaxis but it should always be borne in mind in countries where a great deal of fish is consumed, especially if it is eaten raw or undercooked. 3 cases of anaphylaxis due to hypersensitivity to A. simplex are described.

Molecular cloning of paramyosin, a new allergen of Anisakis simplex

BACKGROUND

Anisakis simplex is a fish parasite that, when accidentally ingested by humans, may cause allergic reactions in sensitized individuals. The main objectives of our study were to: (1) construct a cDNA expression library of A. simplex; (2) identify clones producing specific IgE binding protein antigens, and (3) produce and purify the protein/s codified by the isolated clones produced in Escherichia coli.

METHODS

An expression cDNA library from the third stage larvae (L3) of A. simplex was constructed. This library was first screened with a rabbit anti A. simplex hyperimmune serum. The positive clones, identified using the rabbit serum, were rescreened with a pool of human sera containing high titers of IgE antibodies against A. simplex.

RESULTS

Two positive clones were isolated carrying the genes which codify for paramyosin. The paramyosin protein was produced in E. coli and purified. The partial sequence of a second paramyosin gene was also identified. The frequency of specific IgE binding to the recombinant and native forms of paramyosin using the sera of 26 A. simplex-sensitive individuals was 23 and 88%, respectively. Both paramyosins were able to inhibit 11% of the specific IgE binding to a total extract.

CONCLUSIONS

We describe the primary structure of a paramyosin of A. simplex. It can be considered as an allergen based on its IgE binding capacity. We suggest that the recombinant protein does not maintain the complete allergenic properties of the native paramyosin, considering its lower IgE binding capacity of the recombinant protein. However, both proteins have the same specific IgE inhibition capacity. The recombinant protein can be produced in large quantities in E. coli. We propose the term Ani s 2 for this allergen.

Purification and cloning of an apoptosis-inducing protein derived from fish infected with Anisakis simplex, a causative nematode of human anisakiasis

While investigating the effect of marine products on cell growth, we found that visceral extracts of Chub mackerel, an ocean fish, had a powerful and dose-dependent apoptosis-inducing effect on a variety of mammalian tumor cells. This activity was strikingly dependent on infection of the C. mackerel with the larval nematode, Anisakis simplex. After purification of the protein responsible for the apoptosis-inducing activity, we cloned the corresponding gene and found it to be a flavoprotein. This protein, termed apoptosis-inducing protein (AIP), was also found to possess an endoplasmic reticulum retention signal (C-terminal KDEL sequence) and H2O2-producing activity, indicating that we had isolated a novel reticuloplasimin with potent apoptosis-inducing activity. AIP was induced in fish only after infection with larval nematode and was localized to capsules that formed around larvae to prevent their migration to host tissues. Our results suggest that AIP may function to impede nematode infection.