Comparison of allergenicity and allergens between fish white and dark muscles.
BACKGROUND
Fish is one of the most frequent causes of immunoglobulin E (IgE)-mediated food allergy. Although the fish dark muscle is often ingested with the white muscle, no information about its allergenicity and allergens is available.


METHODS
Heated extracts were prepared from both white and dark muscles of five species of fish and examined for reactivity with IgE in fish-allergic patients by enzyme-linked immunosorbent assay (ELISA) and for allergens by immunoblotting. Cloning of cDNAs encoding parvalbumins was performed by rapid amplification cDNA ends. Parvalbumin contents in both white and dark muscles were determined by ELISA using antiserum against mackerel parvalbumin.


RESULTS
Patient sera were less reactive to the heated extract from the dark muscle than to that from the white muscle. A prominent IgE-reactive protein of 12 kDa, which was detected in both white and dark muscles, was identified as parvalbumin. Molecular cloning experiments revealed that the same parvalbumin molecule is contained in both white and dark muscles of either horse mackerel or Pacific mackerel. Parvalbumin contents were four to eight times lower in the dark muscle than in the white muscle.


CONCLUSIONS
The fish dark muscle is less allergenic than the white muscle, because the same allergen molecule (parvalbumin) is contained at much lower levels in the dark muscle than in the white muscle. Thus, the dark muscle is less implicated in fish allergy than the white muscle.
Kobayashi
A
A
Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Minato-ku, Tokyo, Japan.
Tanaka
H
H
Hamada
Y
Y
Ishizaki
S
S
Nagashima
Y
Y
Shiomi
K
K
D000485:Allergens / Q000009:adverse effects* / Q000276:immunology; D000818:Animals; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay; D005399:Fishes; D005512:Food Hypersensitivity / Q000175:diagnosis* / Q000276:immunology; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000175:diagnosis*; D015151:Immunoblotting; D007159:Immunologic Tests / Q000379:methods; D018482:Muscle, Skeletal / Q000276:immunology*; D010320:Parvalbumins / Q000032:analysis / Q000276:immunology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012307:Risk Factors; D012680:Sensitivity and Specificity
D000485:Allergens; D018076:DNA, Complementary; D010320:Parvalbumins