Myosin light chain is a novel shrimp allergen, Lit v 3.
BACKGROUND
Shellfish allergy is a prevalent, long-lasting disorder usually persisting throughout life. Few options are available for treatment, and avoidance is the only therapy recommended.


OBJECTIVE
We sought to identify relevant crustacean allergens for use as diagnostic and safe immunotherapeutic agents for subjects with shellfish allergy.


METHODS
Thirty-eight patients were selected with immediate allergic reactions to shrimp and increased shrimp-specific serum IgE levels. One-dimensional and 2-dimensional electrophoresis of shrimp extracts were followed by IgE immunoblotting. Protein identification was done with matrix-assisted laser desorption/ionization-mass spectrometry and Edman sequencing. A cDNA library was generated from white pacific shrimp (Litopenaeus vannamei) and screened with primers designed on the basis of internal sequences obtained from 2-dimensional tryptic digests. Full-length cDNA clones were isolated from the library and sequenced. Recombinant protein was expressed and tested with sera from patients with shrimp allergy.


RESULTS
Immunoblotting demonstrated IgE binding to a 20-kDa shrimp protein by 21 (55%) of 38 sera. Tryptic digestion of the protein followed by matrix-assisted laser desorption/ionization-mass spectrometric analysis and Edman sequencing identified it as a myosin light chain (MLC). Screening of the shrimp cDNA library resulted in isolation of a novel protein cDNA. Open reading frame translation provided the amino acid sequence of a new allergenic shrimp protein with high similarity to Bla g 8 (cockroach MLC). Recombinant protein was recognized by 17 patients, confirming the allergenicity of shrimp MLC.


CONCLUSIONS
We have identified and cloned a new major shrimp allergen, Lit v 3.0101, an MLC protein.
Ayuso
Rosalía
R
Division of Allergy and Immunology and the Jaffe Food Allergy Research Institute, Mount Sinai School of Medicine, New York, NY. Electronic address: rosalia.ayuso@mssm.edu.
Grishina
Galina
G
Division of Allergy and Immunology and the Jaffe Food Allergy Research Institute, Mount Sinai School of Medicine, New York, NY.
Bardina
Ludmilla
L
Division of Allergy and Immunology and the Jaffe Food Allergy Research Institute, Mount Sinai School of Medicine, New York, NY.
Carrillo
Teresa
T
Section of Allergy and Respiratory Diseases, Hospital Universitario Dr. Negrín, Las Palmas de Gran Canaria, Spain.
Blanco
Carlos
C
Section of Allergy, Hospital Universitario de la Princesa, Madrid, Spain.
Ibáñez
María Dolores
MD
Pediatric Allergy, Hospital del Niño Jesús, Madrid, Spain.
Sampson
Hugh A
HA
Division of Allergy and Immunology and the Jaffe Food Allergy Research Institute, Mount Sinai School of Medicine, New York, NY.
Beyer
Kirsten
K
Department of Pediatric Pneumology and Immunology, University Children's Hospital Charité, Berlin, Germany.