Isolation and characterization of a major allergen from the fish parasite Anisakis simplex.
BACKGROUND
Ingestion of raw or undercooked fish can lead to infection of human subjects by the fish parasite Anisakis simplex, a disease known as anisakiasis or anisakidosis. Patients sensitized to this fish parasite show high levels of total and specific IgE. Cross-reactions seem to explain the fact that specific IgE antibodies are also found in a high number of normal subjects, as reported in other parasitoses.


OBJECTIVE
We sought to purify and characterize a major IgE-binding protein from the parasite.


METHODS
A protein was purified from the crude parasite extract by means of ethanol precipitation and reversed-phase HPLC. Its clinical relevance was tested on 20 parasite-positive sera by using IgE and IgG4 immunoblotting. A monospecific human serum was used to study its localization in the parasite body.


RESULTS
A 24-kd protein was purified, to which only 45% of the sera had specific IgG4, but 85% of sera had specific IgE. The protein was present only in the excretory gland, as shown by immunohistochemistry. N-terminal amino acid sequence (17 residues) showed no homology to previously described proteins.


CONCLUSIONS
A simplex contains a potent allergen in the excretory gland. This major parasite allergen, named Ani s 1, could have important clinical relevance, as shown by the high number of positive sera in the specific IgE immunoblotting.
Moneo
I
I
Centro de Investigación Clinica, Instituto de Salud Carlos III, and Hospital Ramón y Cajal, Madrid.
Caballero
M L
ML
Gómez
F
F
Ortega
E
E
Alonso
M J
MJ
D000485:Allergens / Q000737:chemistry / Q000302:isolation & purification*; D000818:Animals; D017129:Anisakiasis / Q000276:immunology*; D017163:Anisakis / Q000737:chemistry* / Q000276:immunology; D002352:Carrier Proteins / Q000378:metabolism; D003429:Cross Reactions; D005393:Fish Diseases / Q000276:immunology*; D006801:Humans; D007073:Immunoglobulin E / Q000378:metabolism
D000485:Allergens; D002352:Carrier Proteins; D007073:Immunoglobulin E