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Isolation and Chemical Characterization of Lipid A from Gram-negative Bacteria
Published on: September 17, 2013
Isolation and characterization of a major allergen from the fish parasite Anisakis simplex
I Moneo1, M L Caballero, F Gómez
1Centro de Investigación Clinica, Instituto de Salud Carlos III, and Hospital Ramón y Cajal, Madrid.
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.
Conclusion:
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.
