Greater epitope recognition of shrimp allergens by children than by adults suggests that shrimp sensitization decreases with age.
BACKGROUND
Shellfish allergy is a long-lasting disorder typically affecting adults. Despite its high prevalence, there is limited information about allergenic shrimp proteins and the epitopes implicated in such allergic reactions.


OBJECTIVE
We sought to identify the IgE-binding epitopes of the 4 shrimp allergens and to characterize epitope recognition profiles of children and adults with shrimp allergy.


METHODS
Fifty-three subjects, 34 children and 19 adults, were selected with immediate allergic reactions to shrimp, increased shrimp-specific serum IgE levels, and positive immunoblot binding to shrimp. Study subjects and 7 nonatopic control subjects were tested by means of peptide microarray for IgE binding with synthetic overlapping peptides spanning the sequences of Litopenaeus vannamei shrimp tropomyosin, arginine kinase (AK), myosin light chain (MLC), and sarcoplasmic calcium-binding protein (SCP). The Wilcoxon test was used to determine significant differences in z scores between patients and control subjects.


RESULTS
The median shrimp IgE level was 4-fold higher in children than in adults (47 vs 12.5 kU(A)/L). The frequency of allergen recognition was higher in children (tropomyosin, 81% [94% for children and 61% for adults]; MLC, 57% [70% for children and 31% for adults]; AK, 51% [67% for children and 21% for adults]; and SCP, 45% [59% for children and 21% for adults]), whereas control subjects showed negligible binding. Seven IgE-binding regions were identified in tropomyosin by means of peptide microarray, confirming previously identified shrimp epitopes. In addition, 3 new epitopes were identified in tropomyosin (epitopes 1, 3, and 5b-c), 5 epitopes were identified in MLC, 3 epitopes were identified in SCP, and 7 epitopes were identified in AK. Interestingly, frequency of individual epitope recognition, as well as intensity of IgE binding, was significantly greater in children than in adults for all 4 proteins.


CONCLUSIONS
Children with shrimp allergy have greater shrimp-specific IgE antibody levels and show more intense binding to shrimp peptides and greater epitope diversity than adults.
Ayuso
Rosalía
R
Division of Allergy and Immunology and the Jaffe Food Allergy Research Institute, Mount Sinai School of Medicine, New York, NY 10029, USA. rosalia.ayuso@mssm.edu
Sánchez-Garcia
Silvia
S
Lin
Jing
J
Fu
Zhiyan
Z
Ibáñez
María Dolores
MD
Carrillo
Teresa
T
Blanco
Carlos
C
Goldis
Marina
M
Bardina
Ludmila
L
Sastre
Joaquín
J
Sampson
Hugh A
HA
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000485:Allergens / Q000737:chemistry / Q000276:immunology; D000818:Animals; D001122:Arginine Kinase / Q000276:immunology / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D018985:Epitopes, B-Lymphocyte / Q000276:immunology / Q000378:metabolism*; D005512:Food Hypersensitivity / Q000276:immunology*; D006801:Humans; D007114:Immunization; D008875:Middle Aged; D018994:Myosin Light Chains / Q000276:immunology / Q000378:metabolism; D033561:Penaeidae / Q000276:immunology*; D010446:Peptide Fragments / Q000737:chemistry / Q000276:immunology; D012758:Shellfish
D000485:Allergens; D018985:Epitopes, B-Lymphocyte; D018994:Myosin Light Chains; D010446:Peptide Fragments; D001122:Arginine Kinase