Comparison of pediatric and adult IgE antibody binding to fish proteins.
BACKGROUND
Allergic reactions to fish are a common cause of food allergy.


OBJECTIVE
We compared the binding of pediatric and adult fish-allergic patient IgE antibodies to fish proteins.


METHODS
Clinical histories of fish allergy were confirmed by prick skin tests, RAST and if possible, with blinded oral food challenges. The patients included five children with severe allergic reactions to catfish (4/5), cod (1/5), and tuna (1/5) and five adults with severe allergic reactions to catfish (5/5), cod (2/5), snapper (3/5), and tuna (2/5). Extracted proteins from catfish, cod, snapper, and tuna were separated with SDS-PAGE. IgE immunoblots and immunoblot inhibition studies were performed using serum sample from these patients.


RESULTS
Multiple fish proteins ranging from 12 to 45 kD from the four fish extracts were identified by SDS-PAGE. A major protein (12.5 kD) was present in all fish extracts except for raw tuna. Immunoblots using individual pediatric and adult serum samples revealed that the major IgE binding was to the 12.5-kD protein from catfish, cod, and snapper. The immunoblot with tuna using serum from a pediatric patient with isolated tuna anaphylaxis revealed an IgE binding protein band at 40 kD. Preincubation of serum samples from two separate fish-allergic patients with 1 mg of cod fish extract completely inhibited IgE binding to the 12.5-kD fish protein in subsequent immunoblots.


CONCLUSIONS
Pediatric and adult fish-allergic patients have similar in vitro IgE binding to a 12.5-kD protein from fish extracts. This protein is immunochemically similar to Gad c I, the major allergen in cod.
James
J M
JM
University of Arkansas for Medical Sciences, Arkansas Children's Hospital Research Institute, Little Rock 72202, USA.
Helm
R M
RM
Burks
A W
AW
Lehrer
S B
SB
D000328:Adult; D000818:Animals; D001666:Binding Sites, Antibody; D002397:Catfishes; D002648:Child; D002675:Child, Preschool; D005260:Female; D005399:Fishes; D005512:Food Hypersensitivity / Q000097:blood / Q000209:etiology; D006801:Humans; D015151:Immunoblotting; D007073:Immunoglobulin E / Q000097:blood* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D011506:Proteins / Q000276:immunology / Q000378:metabolism*; D011852:Radioallergosorbent Test; D012882:Skin Tests; D014020:Tissue Extracts / Q000009:adverse effects; D014413:Tuna
D011506:Proteins; D014020:Tissue Extracts; D007073:Immunoglobulin E