Epitope Mapping of the Main Four Shrimp Allergens and Comparison of IgE Recognition Between Children and Adults

Abstract

RATIONALE: Shellfish allergy is a long-lasting disorder typically persisting throughout life. We aimed to characterize the IgE-binding profiles of four shrimp allergens recognized by children and adults.METHODS: Sera from 34 children (P) and 19 adults (A), with immediate allergic reactions and elevated serum IgE to shrimp were tested by microarray analysis for IgE binding to overlapping synthetic peptides spanning the sequences of the shrimp allergens tropomyosin, myosin light chain (MLC), sarcoplasmic calcium-binding protein (SCP) and arginine kinase (AK).RESULTS: Median shrimp-specific IgE was 4 fold higher in children (47 versus 12.5 kUA/L). Frequency of allergen recognition was: tropomyosin 81% (94%P, 61%A), MLC 57% (70%P, 31%A), AK 51% (67%P, 21%A) and SCP 45% (59%P, 21%A).Identified epitopes in tropomyosin are: Epitope 1 (amino acids 1-39), Epitope 2 (40-63), Epitope 3 (61-81), Epitope 4 (82-105), Epitope 5a (115-153), 5b (142-165), 5c (156-186), Epitope 6 (190-210), Epitope 7 (246-284). In MLC: Epitope 1 (13-30), Epitope 2 (22-48), Epitope 3 (46-66), Epitope 4a (58-90), Epitope 4b (79-99), and Epitope 5 (118-141). In SCP: Epitope 1 (10-33), Epitope 2 (49-72) and Epitope 3 (130-147). And, in AK: Epitope 1 (1-18), Epitope 2a (61-87), 2b (79-96), Epitope 3 (121-141), Epitope 4 (160-192), Epitope 5 (232-249), Epitope 6 (319-342).CONCLUSIONS: Shrimp-allergic children have higher IgE levels, show more intense recognition of shrimp allergens and epitope diversity than adults, who almost only recognize tropomyosin. Our work is the first to show that sensitization to shrimp proteins is greater in children and that appears to decrease in adulthood. RATIONALE: Shellfish allergy is a long-lasting disorder typically persisting throughout life. We aimed to characterize the IgE-binding profiles of four shrimp allergens recognized by children and adults. METHODS: Sera from 34 children (P) and 19 adults (A), with immediate allergic reactions and elevated serum IgE to shrimp were tested by microarray analysis for IgE binding to overlapping synthetic peptides spanning the sequences of the shrimp allergens tropomyosin, myosin light chain (MLC), sarcoplasmic calcium-binding protein (SCP) and arginine kinase (AK). RESULTS: Median shrimp-specific IgE was 4 fold higher in children (47 versus 12.5 kUA/L). Frequency of allergen recognition was: tropomyosin 81% (94%P, 61%A), MLC 57% (70%P, 31%A), AK 51% (67%P, 21%A) and SCP 45% (59%P, 21%A). Identified epitopes in tropomyosin are: Epitope 1 (amino acids 1-39), Epitope 2 (40-63), Epitope 3 (61-81), Epitope 4 (82-105), Epitope 5a (115-153), 5b (142-165), 5c (156-186), Epitope 6 (190-210), Epitope 7 (246-284). In MLC: Epitope 1 (13-30), Epitope 2 (22-48), Epitope 3 (46-66), Epitope 4a (58-90), Epitope 4b (79-99), and Epitope 5 (118-141). In SCP: Epitope 1 (10-33), Epitope 2 (49-72) and Epitope 3 (130-147). And, in AK: Epitope 1 (1-18), Epitope 2a (61-87), 2b (79-96), Epitope 3 (121-141), Epitope 4 (160-192), Epitope 5 (232-249), Epitope 6 (319-342). CONCLUSIONS: Shrimp-allergic children have higher IgE levels, show more intense recognition of shrimp allergens and epitope diversity than adults, who almost only recognize tropomyosin. Our work is the first to show that sensitization to shrimp proteins is greater in children and that appears to decrease in adulthood.